drivers/usb/gadget/function/f_fs.c

   1 /*
   2  * f_fs.c -- user mode file system API for USB composite function controllers
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  * Author: Michal Nazarewicz <mina86@mina86.com>
   6  *
   7  * Based on inode.c (GadgetFS) which was:
   8  * Copyright (C) 2003-2004 David Brownell
   9  * Copyright (C) 2003 Agilent Technologies
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17
  18 /* #define DEBUG */
  19 /* #define VERBOSE_DEBUG */
  20
  21 #include <linux/blkdev.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/export.h>
  24 #include <linux/hid.h>
  25 #include <linux/module.h>
  26 #include <linux/uio.h>
  27 #include <asm/unaligned.h>
  28
  29 #include <linux/usb/composite.h>
  30 #include <linux/usb/functionfs.h>
  31
  32 #include <linux/aio.h>
  33 #include <linux/mmu_context.h>
  34 #include <linux/poll.h>
  35 #include <linux/eventfd.h>
  36
  37 #include "u_fs.h"
  38 #include "u_f.h"
  39 #include "u_os_desc.h"
  40 #include "configfs.h"
  41
  42 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  43
  44 /* Reference counter handling */
  45 static void ffs_data_get(struct ffs_data *ffs);
  46 static void ffs_data_put(struct ffs_data *ffs);
  47 /* Creates new ffs_data object. */
  48 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
  49
  50 /* Opened counter handling. */
  51 static void ffs_data_opened(struct ffs_data *ffs);
  52 static void ffs_data_closed(struct ffs_data *ffs);
  53
  54 /* Called with ffs->mutex held; take over ownership of data. */
  55 static int __must_check
  56 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  57 static int __must_check
  58 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  59
  60
  61 /* The function structure ***************************************************/
  62
  63 struct ffs_ep;
  64
  65 struct ffs_function {
  66         struct usb_configuration        *conf;
  67         struct usb_gadget               *gadget;
  68         struct ffs_data                 *ffs;
  69
  70         struct ffs_ep                   *eps;
  71         u8                              eps_revmap[16];
  72         short                           *interfaces_nums;
  73
  74         struct usb_function             function;
  75 };
  76
  77
  78 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  79 {
  80         return container_of(f, struct ffs_function, function);
  81 }
  82
  83
  84 static inline enum ffs_setup_state
  85 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  86 {
  87         return (enum ffs_setup_state)
  88                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  89 }
  90
  91
  92 static void ffs_func_eps_disable(struct ffs_function *func);
  93 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  94
  95 static int ffs_func_bind(struct usb_configuration *,
  96                          struct usb_function *);
  97 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
  98 static void ffs_func_disable(struct usb_function *);
  99 static int ffs_func_setup(struct usb_function *,
 100                           const struct usb_ctrlrequest *);
 101 static void ffs_func_suspend(struct usb_function *);
 102 static void ffs_func_resume(struct usb_function *);
 103
 104
 105 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 106 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 107
 108
 109 /* The endpoints structures *************************************************/
 110
 111 struct ffs_ep {
 112         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 113         struct usb_request              *req;   /* P: epfile->mutex */
 114
 115         /* [0]: full speed, [1]: high speed, [2]: super speed */
 116         struct usb_endpoint_descriptor  *descs[3];
 117
 118         u8                              num;
 119
 120         int                             status; /* P: epfile->mutex */
 121 };
 122
 123 struct ffs_epfile {
 124         /* Protects ep->ep and ep->req. */
 125         struct mutex                    mutex;
 126         wait_queue_head_t               wait;
 127
 128         struct ffs_data                 *ffs;
 129         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 130
 131         struct dentry                   *dentry;
 132
 133         char                            name[5];
 134
 135         unsigned char                   in;     /* P: ffs->eps_lock */
 136         unsigned char                   isoc;   /* P: ffs->eps_lock */
 137
 138         unsigned char                   _pad;
 139 };
 140
 141 /*  ffs_io_data structure ***************************************************/
 142
 143 struct ffs_io_data {
 144         bool aio;
 145         bool read;
 146
 147         struct kiocb *kiocb;
 148         struct iov_iter data;
 149         const void *to_free;
 150         char *buf;
 151
 152         struct mm_struct *mm;
 153         struct work_struct work;
 154
 155         struct usb_ep *ep;
 156         struct usb_request *req;
 157
 158         struct ffs_data *ffs;
 159 };
 160
 161 struct ffs_desc_helper {
 162         struct ffs_data *ffs;
 163         unsigned interfaces_count;
 164         unsigned eps_count;
 165 };
 166
 167 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 168 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 169
 170 static struct dentry *
 171 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 172                    const struct file_operations *fops);
 173
 174 /* Devices management *******************************************************/
 175
 176 DEFINE_MUTEX(ffs_lock);
 177 EXPORT_SYMBOL_GPL(ffs_lock);
 178
 179 static struct ffs_dev *_ffs_find_dev(const char *name);
 180 static struct ffs_dev *_ffs_alloc_dev(void);
 181 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
 182 static void _ffs_free_dev(struct ffs_dev *dev);
 183 static void *ffs_acquire_dev(const char *dev_name);
 184 static void ffs_release_dev(struct ffs_data *ffs_data);
 185 static int ffs_ready(struct ffs_data *ffs);
 186 static void ffs_closed(struct ffs_data *ffs);
 187
 188 /* Misc helper functions ****************************************************/
 189
 190 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 191         __attribute__((warn_unused_result, nonnull));
 192 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 193         __attribute__((warn_unused_result, nonnull));
 194
 195
 196 /* Control file aka ep0 *****************************************************/
 197
 198 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 199 {
 200         struct ffs_data *ffs = req->context;
 201
 202         complete_all(&ffs->ep0req_completion);
 203 }
 204
 205 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 206 {
 207         struct usb_request *req = ffs->ep0req;
 208         int ret;
 209
 210         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 211
 212         spin_unlock_irq(&ffs->ev.waitq.lock);
 213
 214         req->buf      = data;
 215         req->length   = len;
 216
 217         /*
 218          * UDC layer requires to provide a buffer even for ZLP, but should
 219          * not use it at all. Let's provide some poisoned pointer to catch
 220          * possible bug in the driver.
 221          */
 222         if (req->buf == NULL)
 223                 req->buf = (void *)0xDEADBABE;
 224
 225         reinit_completion(&ffs->ep0req_completion);
 226
 227         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 228         if (unlikely(ret < 0))
 229                 return ret;
 230
 231         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 232         if (unlikely(ret)) {
 233                 usb_ep_dequeue(ffs->gadget->ep0, req);
 234                 return -EINTR;
 235         }
 236
 237         ffs->setup_state = FFS_NO_SETUP;
 238         return req->status ? req->status : req->actual;
 239 }
 240
 241 static int __ffs_ep0_stall(struct ffs_data *ffs)
 242 {
 243         if (ffs->ev.can_stall) {
 244                 pr_vdebug("ep0 stall\n");
 245                 usb_ep_set_halt(ffs->gadget->ep0);
 246                 ffs->setup_state = FFS_NO_SETUP;
 247                 return -EL2HLT;
 248         } else {
 249                 pr_debug("bogus ep0 stall!\n");
 250                 return -ESRCH;
 251         }
 252 }
 253
 254 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 255                              size_t len, loff_t *ptr)
 256 {
 257         struct ffs_data *ffs = file->private_data;
 258         ssize_t ret;
 259         char *data;
 260
 261         ENTER();
 262
 263         /* Fast check if setup was canceled */
 264         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 265                 return -EIDRM;
 266
 267         /* Acquire mutex */
 268         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 269         if (unlikely(ret < 0))
 270                 return ret;
 271
 272         /* Check state */
 273         switch (ffs->state) {
 274         case FFS_READ_DESCRIPTORS:
 275         case FFS_READ_STRINGS:
 276                 /* Copy data */
 277                 if (unlikely(len < 16)) {
 278                         ret = -EINVAL;
 279                         break;
 280                 }
 281
 282                 data = ffs_prepare_buffer(buf, len);
 283                 if (IS_ERR(data)) {
 284                         ret = PTR_ERR(data);
 285                         break;
 286                 }
 287
 288                 /* Handle data */
 289                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 290                         pr_info("read descriptors\n");
 291                         ret = __ffs_data_got_descs(ffs, data, len);
 292                         if (unlikely(ret < 0))
 293                                 break;
 294
 295                         ffs->state = FFS_READ_STRINGS;
 296                         ret = len;
 297                 } else {
 298                         pr_info("read strings\n");
 299                         ret = __ffs_data_got_strings(ffs, data, len);
 300                         if (unlikely(ret < 0))
 301                                 break;
 302
 303                         ret = ffs_epfiles_create(ffs);
 304                         if (unlikely(ret)) {
 305                                 ffs->state = FFS_CLOSING;
 306                                 break;
 307                         }
 308
 309                         ffs->state = FFS_ACTIVE;
 310                         mutex_unlock(&ffs->mutex);
 311
 312                         ret = ffs_ready(ffs);
 313                         if (unlikely(ret < 0)) {
 314                                 ffs->state = FFS_CLOSING;
 315                                 return ret;
 316                         }
 317
 318                         return len;
 319                 }
 320                 break;
 321
 322         case FFS_ACTIVE:
 323                 data = NULL;
 324                 /*
 325                  * We're called from user space, we can use _irq
 326                  * rather then _irqsave
 327                  */
 328                 spin_lock_irq(&ffs->ev.waitq.lock);
 329                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 330                 case FFS_SETUP_CANCELLED:
 331                         ret = -EIDRM;
 332                         goto done_spin;
 333
 334                 case FFS_NO_SETUP:
 335                         ret = -ESRCH;
 336                         goto done_spin;
 337
 338                 case FFS_SETUP_PENDING:
 339                         break;
 340                 }
 341
 342                 /* FFS_SETUP_PENDING */
 343                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 344                         spin_unlock_irq(&ffs->ev.waitq.lock);
 345                         ret = __ffs_ep0_stall(ffs);
 346                         break;
 347                 }
 348
 349                 /* FFS_SETUP_PENDING and not stall */
 350                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 351
 352                 spin_unlock_irq(&ffs->ev.waitq.lock);
 353
 354                 data = ffs_prepare_buffer(buf, len);
 355                 if (IS_ERR(data)) {
 356                         ret = PTR_ERR(data);
 357                         break;
 358                 }
 359
 360                 spin_lock_irq(&ffs->ev.waitq.lock);
 361
 362                 /*
 363                  * We are guaranteed to be still in FFS_ACTIVE state
 364                  * but the state of setup could have changed from
 365                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 366                  * to check for that.  If that happened we copied data
 367                  * from user space in vain but it's unlikely.
 368                  *
 369                  * For sure we are not in FFS_NO_SETUP since this is
 370                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 371                  * transition can be performed and it's protected by
 372                  * mutex.
 373                  */
 374                 if (ffs_setup_state_clear_cancelled(ffs) ==
 375                     FFS_SETUP_CANCELLED) {
 376                         ret = -EIDRM;
 377 done_spin:
 378                         spin_unlock_irq(&ffs->ev.waitq.lock);
 379                 } else {
 380                         /* unlocks spinlock */
 381                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 382                 }
 383                 kfree(data);
 384                 break;
 385
 386         default:
 387                 ret = -EBADFD;
 388                 break;
 389         }
 390
 391         mutex_unlock(&ffs->mutex);
 392         return ret;
 393 }
 394
 395 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 396 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 397                                      size_t n)
 398 {
 399         /*
 400          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 401          * size of ffs->ev.types array (which is four) so that's how much space
 402          * we reserve.
 403          */
 404         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 405         const size_t size = n * sizeof *events;
 406         unsigned i = 0;
 407
 408         memset(events, 0, size);
 409
 410         do {
 411                 events[i].type = ffs->ev.types[i];
 412                 if (events[i].type == FUNCTIONFS_SETUP) {
 413                         events[i].u.setup = ffs->ev.setup;
 414                         ffs->setup_state = FFS_SETUP_PENDING;
 415                 }
 416         } while (++i < n);
 417
 418         ffs->ev.count -= n;
 419         if (ffs->ev.count)
 420                 memmove(ffs->ev.types, ffs->ev.types + n,
 421                         ffs->ev.count * sizeof *ffs->ev.types);
 422
 423         spin_unlock_irq(&ffs->ev.waitq.lock);
 424         mutex_unlock(&ffs->mutex);
 425
 426         return unlikely(__copy_to_user(buf, events, size)) ? -EFAULT : size;
 427 }
 428
 429 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 430                             size_t len, loff_t *ptr)
 431 {
 432         struct ffs_data *ffs = file->private_data;
 433         char *data = NULL;
 434         size_t n;
 435         int ret;
 436
 437         ENTER();
 438
 439         /* Fast check if setup was canceled */
 440         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 441                 return -EIDRM;
 442
 443         /* Acquire mutex */
 444         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 445         if (unlikely(ret < 0))
 446                 return ret;
 447
 448         /* Check state */
 449         if (ffs->state != FFS_ACTIVE) {
 450                 ret = -EBADFD;
 451                 goto done_mutex;
 452         }
 453
 454         /*
 455          * We're called from user space, we can use _irq rather then
 456          * _irqsave
 457          */
 458         spin_lock_irq(&ffs->ev.waitq.lock);
 459
 460         switch (ffs_setup_state_clear_cancelled(ffs)) {
 461         case FFS_SETUP_CANCELLED:
 462                 ret = -EIDRM;
 463                 break;
 464
 465         case FFS_NO_SETUP:
 466                 n = len / sizeof(struct usb_functionfs_event);
 467                 if (unlikely(!n)) {
 468                         ret = -EINVAL;
 469                         break;
 470                 }
 471
 472                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 473                         ret = -EAGAIN;
 474                         break;
 475                 }
 476
 477                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 478                                                         ffs->ev.count)) {
 479                         ret = -EINTR;
 480                         break;
 481                 }
 482
 483                 return __ffs_ep0_read_events(ffs, buf,
 484                                              min(n, (size_t)ffs->ev.count));
 485
 486         case FFS_SETUP_PENDING:
 487                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 488                         spin_unlock_irq(&ffs->ev.waitq.lock);
 489                         ret = __ffs_ep0_stall(ffs);
 490                         goto done_mutex;
 491                 }
 492
 493                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 494
 495                 spin_unlock_irq(&ffs->ev.waitq.lock);
 496
 497                 if (likely(len)) {
 498                         data = kmalloc(len, GFP_KERNEL);
 499                         if (unlikely(!data)) {
 500                                 ret = -ENOMEM;
 501                                 goto done_mutex;
 502                         }
 503                 }
 504
 505                 spin_lock_irq(&ffs->ev.waitq.lock);
 506
 507                 /* See ffs_ep0_write() */
 508                 if (ffs_setup_state_clear_cancelled(ffs) ==
 509                     FFS_SETUP_CANCELLED) {
 510                         ret = -EIDRM;
 511                         break;
 512                 }
 513
 514                 /* unlocks spinlock */
 515                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 516                 if (likely(ret > 0) && unlikely(__copy_to_user(buf, data, len)))
 517                         ret = -EFAULT;
 518                 goto done_mutex;
 519
 520         default:
 521                 ret = -EBADFD;
 522                 break;
 523         }
 524
 525         spin_unlock_irq(&ffs->ev.waitq.lock);
 526 done_mutex:
 527         mutex_unlock(&ffs->mutex);
 528         kfree(data);
 529         return ret;
 530 }
 531
 532 static int ffs_ep0_open(struct inode *inode, struct file *file)
 533 {
 534         struct ffs_data *ffs = inode->i_private;
 535
 536         ENTER();
 537
 538         if (unlikely(ffs->state == FFS_CLOSING))
 539                 return -EBUSY;
 540
 541         file->private_data = ffs;
 542         ffs_data_opened(ffs);
 543
 544         return 0;
 545 }
 546
 547 static int ffs_ep0_release(struct inode *inode, struct file *file)
 548 {
 549         struct ffs_data *ffs = file->private_data;
 550
 551         ENTER();
 552
 553         ffs_data_closed(ffs);
 554
 555         return 0;
 556 }
 557
 558 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 559 {
 560         struct ffs_data *ffs = file->private_data;
 561         struct usb_gadget *gadget = ffs->gadget;
 562         long ret;
 563
 564         ENTER();
 565
 566         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 567                 struct ffs_function *func = ffs->func;
 568                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 569         } else if (gadget && gadget->ops->ioctl) {
 570                 ret = gadget->ops->ioctl(gadget, code, value);
 571         } else {
 572                 ret = -ENOTTY;
 573         }
 574
 575         return ret;
 576 }
 577
 578 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 579 {
 580         struct ffs_data *ffs = file->private_data;
 581         unsigned int mask = POLLWRNORM;
 582         int ret;
 583
 584         poll_wait(file, &ffs->ev.waitq, wait);
 585
 586         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 587         if (unlikely(ret < 0))
 588                 return mask;
 589
 590         switch (ffs->state) {
 591         case FFS_READ_DESCRIPTORS:
 592         case FFS_READ_STRINGS:
 593                 mask |= POLLOUT;
 594                 break;
 595
 596         case FFS_ACTIVE:
 597                 switch (ffs->setup_state) {
 598                 case FFS_NO_SETUP:
 599                         if (ffs->ev.count)
 600                                 mask |= POLLIN;
 601                         break;
 602
 603                 case FFS_SETUP_PENDING:
 604                 case FFS_SETUP_CANCELLED:
 605                         mask |= (POLLIN | POLLOUT);
 606                         break;
 607                 }
 608         case FFS_CLOSING:
 609                 break;
 610         case FFS_DEACTIVATED:
 611                 break;
 612         }
 613
 614         mutex_unlock(&ffs->mutex);
 615
 616         return mask;
 617 }
 618
 619 static const struct file_operations ffs_ep0_operations = {
 620         .llseek =       no_llseek,
 621
 622         .open =         ffs_ep0_open,
 623         .write =        ffs_ep0_write,
 624         .read =         ffs_ep0_read,
 625         .release =      ffs_ep0_release,
 626         .unlocked_ioctl =       ffs_ep0_ioctl,
 627         .poll =         ffs_ep0_poll,
 628 };
 629
 630
 631 /* "Normal" endpoints operations ********************************************/
 632
 633 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 634 {
 635         ENTER();
 636         if (likely(req->context)) {
 637                 struct ffs_ep *ep = _ep->driver_data;
 638                 ep->status = req->status ? req->status : req->actual;
 639                 complete(req->context);
 640         }
 641 }
 642
 643 static void ffs_user_copy_worker(struct work_struct *work)
 644 {
 645         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 646                                                    work);
 647         int ret = io_data->req->status ? io_data->req->status :
 648                                          io_data->req->actual;
 649
 650         if (io_data->read && ret > 0) {
 651                 use_mm(io_data->mm);
 652                 ret = copy_to_iter(io_data->buf, ret, &io_data->data);
 653                 if (iov_iter_count(&io_data->data))
 654                         ret = -EFAULT;
 655                 unuse_mm(io_data->mm);
 656         }
 657
 658         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 659
 660         if (io_data->ffs->ffs_eventfd &&
 661             !(io_data->kiocb->ki_flags & IOCB_EVENTFD))
 662                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 663
 664         usb_ep_free_request(io_data->ep, io_data->req);
 665
 666         io_data->kiocb->private = NULL;
 667         if (io_data->read)
 668                 kfree(io_data->to_free);
 669         kfree(io_data->buf);
 670         kfree(io_data);
 671 }
 672
 673 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 674                                          struct usb_request *req)
 675 {
 676         struct ffs_io_data *io_data = req->context;
 677
 678         ENTER();
 679
 680         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 681         schedule_work(&io_data->work);
 682 }
 683
 684 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 685 {
 686         struct ffs_epfile *epfile = file->private_data;
 687         struct ffs_ep *ep;
 688         char *data = NULL;
 689         ssize_t ret, data_len = -EINVAL;
 690         int halt;
 691
 692         /* Are we still active? */
 693         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 694                 ret = -ENODEV;
 695                 goto error;
 696         }
 697
 698         /* Wait for endpoint to be enabled */
 699         ep = epfile->ep;
 700         if (!ep) {
 701                 if (file->f_flags & O_NONBLOCK) {
 702                         ret = -EAGAIN;
 703                         goto error;
 704                 }
 705
 706                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 707                 if (ret) {
 708                         ret = -EINTR;
 709                         goto error;
 710                 }
 711         }
 712
 713         /* Do we halt? */
 714         halt = (!io_data->read == !epfile->in);
 715         if (halt && epfile->isoc) {
 716                 ret = -EINVAL;
 717                 goto error;
 718         }
 719
 720         /* Allocate & copy */
 721         if (!halt) {
 722                 /*
 723                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 724                  * before the waiting completes, so do not assign to 'gadget' earlier
 725                  */
 726                 struct usb_gadget *gadget = epfile->ffs->gadget;
 727                 size_t copied;
 728
 729                 spin_lock_irq(&epfile->ffs->eps_lock);
 730                 /* In the meantime, endpoint got disabled or changed. */
 731                 if (epfile->ep != ep) {
 732                         spin_unlock_irq(&epfile->ffs->eps_lock);
 733                         return -ESHUTDOWN;
 734                 }
 735                 data_len = iov_iter_count(&io_data->data);
 736                 /*
 737                  * Controller may require buffer size to be aligned to
 738                  * maxpacketsize of an out endpoint.
 739                  */
 740                 if (io_data->read)
 741                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 742                 spin_unlock_irq(&epfile->ffs->eps_lock);
 743
 744                 data = kmalloc(data_len, GFP_KERNEL);
 745                 if (unlikely(!data))
 746                         return -ENOMEM;
 747                 if (!io_data->read) {
 748                         copied = copy_from_iter(data, data_len, &io_data->data);
 749                         if (copied != data_len) {
 750                                 ret = -EFAULT;
 751                                 goto error;
 752                         }
 753                 }
 754         }
 755
 756         /* We will be using request */
 757         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 758         if (unlikely(ret))
 759                 goto error;
 760
 761         spin_lock_irq(&epfile->ffs->eps_lock);
 762
 763         if (epfile->ep != ep) {
 764                 /* In the meantime, endpoint got disabled or changed. */
 765                 ret = -ESHUTDOWN;
 766                 spin_unlock_irq(&epfile->ffs->eps_lock);
 767         } else if (halt) {
 768                 /* Halt */
 769                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 770                         usb_ep_set_halt(ep->ep);
 771                 spin_unlock_irq(&epfile->ffs->eps_lock);
 772                 ret = -EBADMSG;
 773         } else {
 774                 /* Fire the request */
 775                 struct usb_request *req;
 776
 777                 /*
 778                  * Sanity Check: even though data_len can't be used
 779                  * uninitialized at the time I write this comment, some
 780                  * compilers complain about this situation.
 781                  * In order to keep the code clean from warnings, data_len is
 782                  * being initialized to -EINVAL during its declaration, which
 783                  * means we can't rely on compiler anymore to warn no future
 784                  * changes won't result in data_len being used uninitialized.
 785                  * For such reason, we're adding this redundant sanity check
 786                  * here.
 787                  */
 788                 if (unlikely(data_len == -EINVAL)) {
 789                         WARN(1, "%s: data_len == -EINVAL\n", __func__);
 790                         ret = -EINVAL;
 791                         goto error_lock;
 792                 }
 793
 794                 if (io_data->aio) {
 795                         req = usb_ep_alloc_request(ep->ep, GFP_KERNEL);
 796                         if (unlikely(!req))
 797                                 goto error_lock;
 798
 799                         req->buf      = data;
 800                         req->length   = data_len;
 801
 802                         io_data->buf = data;
 803                         io_data->ep = ep->ep;
 804                         io_data->req = req;
 805                         io_data->ffs = epfile->ffs;
 806
 807                         req->context  = io_data;
 808                         req->complete = ffs_epfile_async_io_complete;
 809
 810                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 811                         if (unlikely(ret)) {
 812                                 usb_ep_free_request(ep->ep, req);
 813                                 goto error_lock;
 814                         }
 815                         ret = -EIOCBQUEUED;
 816
 817                         spin_unlock_irq(&epfile->ffs->eps_lock);
 818                 } else {
 819                         DECLARE_COMPLETION_ONSTACK(done);
 820
 821                         req = ep->req;
 822                         req->buf      = data;
 823                         req->length   = data_len;
 824
 825                         req->context  = &done;
 826                         req->complete = ffs_epfile_io_complete;
 827
 828                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 829
 830                         spin_unlock_irq(&epfile->ffs->eps_lock);
 831
 832                         if (unlikely(ret < 0)) {
 833                                 /* nop */
 834                         } else if (unlikely(
 835                                    wait_for_completion_interruptible(&done))) {
 836                                 ret = -EINTR;
 837                                 usb_ep_dequeue(ep->ep, req);
 838                         } else {
 839                                 /*
 840                                  * XXX We may end up silently droping data
 841                                  * here.  Since data_len (i.e. req->length) may
 842                                  * be bigger than len (after being rounded up
 843                                  * to maxpacketsize), we may end up with more
 844                                  * data then user space has space for.
 845                                  */
 846                                 ret = ep->status;
 847                                 if (io_data->read && ret > 0) {
 848                                         ret = copy_to_iter(data, ret, &io_data->data);
 849                                         if (!ret)
 850                                                 ret = -EFAULT;
 851                                 }
 852                         }
 853                         kfree(data);
 854                 }
 855         }
 856
 857         mutex_unlock(&epfile->mutex);
 858         return ret;
 859
 860 error_lock:
 861         spin_unlock_irq(&epfile->ffs->eps_lock);
 862         mutex_unlock(&epfile->mutex);
 863 error:
 864         kfree(data);
 865         return ret;
 866 }
 867
 868 static int
 869 ffs_epfile_open(struct inode *inode, struct file *file)
 870 {
 871         struct ffs_epfile *epfile = inode->i_private;
 872
 873         ENTER();
 874
 875         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 876                 return -ENODEV;
 877
 878         file->private_data = epfile;
 879         ffs_data_opened(epfile->ffs);
 880
 881         return 0;
 882 }
 883
 884 static int ffs_aio_cancel(struct kiocb *kiocb)
 885 {
 886         struct ffs_io_data *io_data = kiocb->private;
 887         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
 888         int value;
 889
 890         ENTER();
 891
 892         spin_lock_irq(&epfile->ffs->eps_lock);
 893
 894         if (likely(io_data && io_data->ep && io_data->req))
 895                 value = usb_ep_dequeue(io_data->ep, io_data->req);
 896         else
 897                 value = -EINVAL;
 898
 899         spin_unlock_irq(&epfile->ffs->eps_lock);
 900
 901         return value;
 902 }
 903
 904 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
 905 {
 906         struct ffs_io_data io_data, *p = &io_data;
 907         ssize_t res;
 908
 909         ENTER();
 910
 911         if (!is_sync_kiocb(kiocb)) {
 912                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
 913                 if (unlikely(!p))
 914                         return -ENOMEM;
 915                 p->aio = true;
 916         } else {
 917                 p->aio = false;
 918         }
 919
 920         p->read = false;
 921         p->kiocb = kiocb;
 922         p->data = *from;
 923         p->mm = current->mm;
 924
 925         kiocb->private = p;
 926
 927         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 928
 929         res = ffs_epfile_io(kiocb->ki_filp, p);
 930         if (res == -EIOCBQUEUED)
 931                 return res;
 932         if (p->aio)
 933                 kfree(p);
 934         else
 935                 *from = p->data;
 936         return res;
 937 }
 938
 939 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
 940 {
 941         struct ffs_io_data io_data, *p = &io_data;
 942         ssize_t res;
 943
 944         ENTER();
 945
 946         if (!is_sync_kiocb(kiocb)) {
 947                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
 948                 if (unlikely(!p))
 949                         return -ENOMEM;
 950                 p->aio = true;
 951         } else {
 952                 p->aio = false;
 953         }
 954
 955         p->read = true;
 956         p->kiocb = kiocb;
 957         if (p->aio) {
 958                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
 959                 if (!p->to_free) {
 960                         kfree(p);
 961                         return -ENOMEM;
 962                 }
 963         } else {
 964                 p->data = *to;
 965                 p->to_free = NULL;
 966         }
 967         p->mm = current->mm;
 968
 969         kiocb->private = p;
 970
 971         kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 972
 973         res = ffs_epfile_io(kiocb->ki_filp, p);
 974         if (res == -EIOCBQUEUED)
 975                 return res;
 976
 977         if (p->aio) {
 978                 kfree(p->to_free);
 979                 kfree(p);
 980         } else {
 981                 *to = p->data;
 982         }
 983         return res;
 984 }
 985
 986 static int
 987 ffs_epfile_release(struct inode *inode, struct file *file)
 988 {
 989         struct ffs_epfile *epfile = inode->i_private;
 990
 991         ENTER();
 992
 993         ffs_data_closed(epfile->ffs);
 994
 995         return 0;
 996 }
 997
 998 static long ffs_epfile_ioctl(struct file *file, unsigned code,
 999                              unsigned long value)
1000 {
1001         struct ffs_epfile *epfile = file->private_data;
1002         int ret;
1003
1004         ENTER();
1005
1006         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1007                 return -ENODEV;
1008
1009         spin_lock_irq(&epfile->ffs->eps_lock);
1010         if (likely(epfile->ep)) {
1011                 switch (code) {
1012                 case FUNCTIONFS_FIFO_STATUS:
1013                         ret = usb_ep_fifo_status(epfile->ep->ep);
1014                         break;
1015                 case FUNCTIONFS_FIFO_FLUSH:
1016                         usb_ep_fifo_flush(epfile->ep->ep);
1017                         ret = 0;
1018                         break;
1019                 case FUNCTIONFS_CLEAR_HALT:
1020                         ret = usb_ep_clear_halt(epfile->ep->ep);
1021                         break;
1022                 case FUNCTIONFS_ENDPOINT_REVMAP:
1023                         ret = epfile->ep->num;
1024                         break;
1025                 case FUNCTIONFS_ENDPOINT_DESC:
1026                 {
1027                         int desc_idx;
1028                         struct usb_endpoint_descriptor *desc;
1029
1030                         switch (epfile->ffs->gadget->speed) {
1031                         case USB_SPEED_SUPER:
1032                                 desc_idx = 2;
1033                                 break;
1034                         case USB_SPEED_HIGH:
1035                                 desc_idx = 1;
1036                                 break;
1037                         default:
1038                                 desc_idx = 0;
1039                         }
1040                         desc = epfile->ep->descs[desc_idx];
1041
1042                         spin_unlock_irq(&epfile->ffs->eps_lock);
1043                         ret = copy_to_user((void *)value, desc, sizeof(*desc));
1044                         if (ret)
1045                                 ret = -EFAULT;
1046                         return ret;
1047                 }
1048                 default:
1049                         ret = -ENOTTY;
1050                 }
1051         } else {
1052                 ret = -ENODEV;
1053         }
1054         spin_unlock_irq(&epfile->ffs->eps_lock);
1055
1056         return ret;
1057 }
1058
1059 static const struct file_operations ffs_epfile_operations = {
1060         .llseek =       no_llseek,
1061
1062         .open =         ffs_epfile_open,
1063         .write_iter =   ffs_epfile_write_iter,
1064         .read_iter =    ffs_epfile_read_iter,
1065         .release =      ffs_epfile_release,
1066         .unlocked_ioctl =       ffs_epfile_ioctl,
1067 };
1068
1069
1070 /* File system and super block operations ***********************************/
1071
1072 /*
1073  * Mounting the file system creates a controller file, used first for
1074  * function configuration then later for event monitoring.
1075  */
1076
1077 static struct inode *__must_check
1078 ffs_sb_make_inode(struct super_block *sb, void *data,
1079                   const struct file_operations *fops,
1080                   const struct inode_operations *iops,
1081                   struct ffs_file_perms *perms)
1082 {
1083         struct inode *inode;
1084
1085         ENTER();
1086
1087         inode = new_inode(sb);
1088
1089         if (likely(inode)) {
1090                 struct timespec current_time = CURRENT_TIME;
1091
1092                 inode->i_ino     = get_next_ino();
1093                 inode->i_mode    = perms->mode;
1094                 inode->i_uid     = perms->uid;
1095                 inode->i_gid     = perms->gid;
1096                 inode->i_atime   = current_time;
1097                 inode->i_mtime   = current_time;
1098                 inode->i_ctime   = current_time;
1099                 inode->i_private = data;
1100                 if (fops)
1101                         inode->i_fop = fops;
1102                 if (iops)
1103                         inode->i_op  = iops;
1104         }
1105
1106         return inode;
1107 }
1108
1109 /* Create "regular" file */
1110 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1111                                         const char *name, void *data,
1112                                         const struct file_operations *fops)
1113 {
1114         struct ffs_data *ffs = sb->s_fs_info;
1115         struct dentry   *dentry;
1116         struct inode    *inode;
1117
1118         ENTER();
1119
1120         dentry = d_alloc_name(sb->s_root, name);
1121         if (unlikely(!dentry))
1122                 return NULL;
1123
1124         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1125         if (unlikely(!inode)) {
1126                 dput(dentry);
1127                 return NULL;
1128         }
1129
1130         d_add(dentry, inode);
1131         return dentry;
1132 }
1133
1134 /* Super block */
1135 static const struct super_operations ffs_sb_operations = {
1136         .statfs =       simple_statfs,
1137         .drop_inode =   generic_delete_inode,
1138 };
1139
1140 struct ffs_sb_fill_data {
1141         struct ffs_file_perms perms;
1142         umode_t root_mode;
1143         const char *dev_name;
1144         bool no_disconnect;
1145         struct ffs_data *ffs_data;
1146 };
1147
1148 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1149 {
1150         struct ffs_sb_fill_data *data = _data;
1151         struct inode    *inode;
1152         struct ffs_data *ffs = data->ffs_data;
1153
1154         ENTER();
1155
1156         ffs->sb              = sb;
1157         data->ffs_data       = NULL;
1158         sb->s_fs_info        = ffs;
1159         sb->s_blocksize      = PAGE_CACHE_SIZE;
1160         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1161         sb->s_magic          = FUNCTIONFS_MAGIC;
1162         sb->s_op             = &ffs_sb_operations;
1163         sb->s_time_gran      = 1;
1164
1165         /* Root inode */
1166         data->perms.mode = data->root_mode;
1167         inode = ffs_sb_make_inode(sb, NULL,
1168                                   &simple_dir_operations,
1169                                   &simple_dir_inode_operations,
1170                                   &data->perms);
1171         sb->s_root = d_make_root(inode);
1172         if (unlikely(!sb->s_root))
1173                 return -ENOMEM;
1174
1175         /* EP0 file */
1176         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1177                                          &ffs_ep0_operations)))
1178                 return -ENOMEM;
1179
1180         return 0;
1181 }
1182
1183 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1184 {
1185         ENTER();
1186
1187         if (!opts || !*opts)
1188                 return 0;
1189
1190         for (;;) {
1191                 unsigned long value;
1192                 char *eq, *comma;
1193
1194                 /* Option limit */
1195                 comma = strchr(opts, ',');
1196                 if (comma)
1197                         *comma = 0;
1198
1199                 /* Value limit */
1200                 eq = strchr(opts, '=');
1201                 if (unlikely(!eq)) {
1202                         pr_err("'=' missing in %s\n", opts);
1203                         return -EINVAL;
1204                 }
1205                 *eq = 0;
1206
1207                 /* Parse value */
1208                 if (kstrtoul(eq + 1, 0, &value)) {
1209                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1210                         return -EINVAL;
1211                 }
1212
1213                 /* Interpret option */
1214                 switch (eq - opts) {
1215                 case 13:
1216                         if (!memcmp(opts, "no_disconnect", 13))
1217                                 data->no_disconnect = !!value;
1218                         else
1219                                 goto invalid;
1220                         break;
1221                 case 5:
1222                         if (!memcmp(opts, "rmode", 5))
1223                                 data->root_mode  = (value & 0555) | S_IFDIR;
1224                         else if (!memcmp(opts, "fmode", 5))
1225                                 data->perms.mode = (value & 0666) | S_IFREG;
1226                         else
1227                                 goto invalid;
1228                         break;
1229
1230                 case 4:
1231                         if (!memcmp(opts, "mode", 4)) {
1232                                 data->root_mode  = (value & 0555) | S_IFDIR;
1233                                 data->perms.mode = (value & 0666) | S_IFREG;
1234                         } else {
1235                                 goto invalid;
1236                         }
1237                         break;
1238
1239                 case 3:
1240                         if (!memcmp(opts, "uid", 3)) {
1241                                 data->perms.uid = make_kuid(current_user_ns(), value);
1242                                 if (!uid_valid(data->perms.uid)) {
1243                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1244                                         return -EINVAL;
1245                                 }
1246                         } else if (!memcmp(opts, "gid", 3)) {
1247                                 data->perms.gid = make_kgid(current_user_ns(), value);
1248                                 if (!gid_valid(data->perms.gid)) {
1249                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1250                                         return -EINVAL;
1251                                 }
1252                         } else {
1253                                 goto invalid;
1254                         }
1255                         break;
1256
1257                 default:
1258 invalid:
1259                         pr_err("%s: invalid option\n", opts);
1260                         return -EINVAL;
1261                 }
1262
1263                 /* Next iteration */
1264                 if (!comma)
1265                         break;
1266                 opts = comma + 1;
1267         }
1268
1269         return 0;
1270 }
1271
1272 /* "mount -t functionfs dev_name /dev/function" ends up here */
1273
1274 static struct dentry *
1275 ffs_fs_mount(struct file_system_type *t, int flags,
1276               const char *dev_name, void *opts)
1277 {
1278         struct ffs_sb_fill_data data = {
1279                 .perms = {
1280                         .mode = S_IFREG | 0600,
1281                         .uid = GLOBAL_ROOT_UID,
1282                         .gid = GLOBAL_ROOT_GID,
1283                 },
1284                 .root_mode = S_IFDIR | 0500,
1285                 .no_disconnect = false,
1286         };
1287         struct dentry *rv;
1288         int ret;
1289         void *ffs_dev;
1290         struct ffs_data *ffs;
1291
1292         ENTER();
1293
1294         ret = ffs_fs_parse_opts(&data, opts);
1295         if (unlikely(ret < 0))
1296                 return ERR_PTR(ret);
1297
1298         ffs = ffs_data_new();
1299         if (unlikely(!ffs))
1300                 return ERR_PTR(-ENOMEM);
1301         ffs->file_perms = data.perms;
1302         ffs->no_disconnect = data.no_disconnect;
1303
1304         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1305         if (unlikely(!ffs->dev_name)) {
1306                 ffs_data_put(ffs);
1307                 return ERR_PTR(-ENOMEM);
1308         }
1309
1310         ffs_dev = ffs_acquire_dev(dev_name);
1311         if (IS_ERR(ffs_dev)) {
1312                 ffs_data_put(ffs);
1313                 return ERR_CAST(ffs_dev);
1314         }
1315         ffs->private_data = ffs_dev;
1316         data.ffs_data = ffs;
1317
1318         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1319         if (IS_ERR(rv) && data.ffs_data) {
1320                 ffs_release_dev(data.ffs_data);
1321                 ffs_data_put(data.ffs_data);
1322         }
1323         return rv;
1324 }
1325
1326 static void
1327 ffs_fs_kill_sb(struct super_block *sb)
1328 {
1329         ENTER();
1330
1331         kill_litter_super(sb);
1332         if (sb->s_fs_info) {
1333                 ffs_release_dev(sb->s_fs_info);
1334                 ffs_data_closed(sb->s_fs_info);
1335                 ffs_data_put(sb->s_fs_info);
1336         }
1337 }
1338
1339 static struct file_system_type ffs_fs_type = {
1340         .owner          = THIS_MODULE,
1341         .name           = "functionfs",
1342         .mount          = ffs_fs_mount,
1343         .kill_sb        = ffs_fs_kill_sb,
1344 };
1345 MODULE_ALIAS_FS("functionfs");
1346
1347
1348 /* Driver's main init/cleanup functions *************************************/
1349
1350 static int functionfs_init(void)
1351 {
1352         int ret;
1353
1354         ENTER();
1355
1356         ret = register_filesystem(&ffs_fs_type);
1357         if (likely(!ret))
1358                 pr_info("file system registered\n");
1359         else
1360                 pr_err("failed registering file system (%d)\n", ret);
1361
1362         return ret;
1363 }
1364
1365 static void functionfs_cleanup(void)
1366 {
1367         ENTER();
1368
1369         pr_info("unloading\n");
1370         unregister_filesystem(&ffs_fs_type);
1371 }
1372
1373
1374 /* ffs_data and ffs_function construction and destruction code **************/
1375
1376 static void ffs_data_clear(struct ffs_data *ffs);
1377 static void ffs_data_reset(struct ffs_data *ffs);
1378
1379 static void ffs_data_get(struct ffs_data *ffs)
1380 {
1381         ENTER();
1382
1383         atomic_inc(&ffs->ref);
1384 }
1385
1386 static void ffs_data_opened(struct ffs_data *ffs)
1387 {
1388         ENTER();
1389
1390         atomic_inc(&ffs->ref);
1391         if (atomic_add_return(1, &ffs->opened) == 1 &&
1392                         ffs->state == FFS_DEACTIVATED) {
1393                 ffs->state = FFS_CLOSING;
1394                 ffs_data_reset(ffs);
1395         }
1396 }
1397
1398 static void ffs_data_put(struct ffs_data *ffs)
1399 {
1400         ENTER();
1401
1402         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1403                 pr_info("%s(): freeing\n", __func__);
1404                 ffs_data_clear(ffs);
1405                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1406                        waitqueue_active(&ffs->ep0req_completion.wait));
1407                 kfree(ffs->dev_name);
1408                 kfree(ffs);
1409         }
1410 }
1411
1412 static void ffs_data_closed(struct ffs_data *ffs)
1413 {
1414         ENTER();
1415
1416         if (atomic_dec_and_test(&ffs->opened)) {
1417                 if (ffs->no_disconnect) {
1418                         ffs->state = FFS_DEACTIVATED;
1419                         if (ffs->epfiles) {
1420                                 ffs_epfiles_destroy(ffs->epfiles,
1421                                                    ffs->eps_count);
1422                                 ffs->epfiles = NULL;
1423                         }
1424                         if (ffs->setup_state == FFS_SETUP_PENDING)
1425                                 __ffs_ep0_stall(ffs);
1426                 } else {
1427                         ffs->state = FFS_CLOSING;
1428                         ffs_data_reset(ffs);
1429                 }
1430         }
1431         if (atomic_read(&ffs->opened) < 0) {
1432                 ffs->state = FFS_CLOSING;
1433                 ffs_data_reset(ffs);
1434         }
1435
1436         ffs_data_put(ffs);
1437 }
1438
1439 static struct ffs_data *ffs_data_new(void)
1440 {
1441         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1442         if (unlikely(!ffs))
1443                 return NULL;
1444
1445         ENTER();
1446
1447         atomic_set(&ffs->ref, 1);
1448         atomic_set(&ffs->opened, 0);
1449         ffs->state = FFS_READ_DESCRIPTORS;
1450         mutex_init(&ffs->mutex);
1451         spin_lock_init(&ffs->eps_lock);
1452         init_waitqueue_head(&ffs->ev.waitq);
1453         init_completion(&ffs->ep0req_completion);
1454
1455         /* XXX REVISIT need to update it in some places, or do we? */
1456         ffs->ev.can_stall = 1;
1457
1458         return ffs;
1459 }
1460
1461 static void ffs_data_clear(struct ffs_data *ffs)
1462 {
1463         ENTER();
1464
1465         ffs_closed(ffs);
1466
1467         BUG_ON(ffs->gadget);
1468
1469         if (ffs->epfiles)
1470                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1471
1472         if (ffs->ffs_eventfd)
1473                 eventfd_ctx_put(ffs->ffs_eventfd);
1474
1475         kfree(ffs->raw_descs_data);
1476         kfree(ffs->raw_strings);
1477         kfree(ffs->stringtabs);
1478 }
1479
1480 static void ffs_data_reset(struct ffs_data *ffs)
1481 {
1482         ENTER();
1483
1484         ffs_data_clear(ffs);
1485
1486         ffs->epfiles = NULL;
1487         ffs->raw_descs_data = NULL;
1488         ffs->raw_descs = NULL;
1489         ffs->raw_strings = NULL;
1490         ffs->stringtabs = NULL;
1491
1492         ffs->raw_descs_length = 0;
1493         ffs->fs_descs_count = 0;
1494         ffs->hs_descs_count = 0;
1495         ffs->ss_descs_count = 0;
1496
1497         ffs->strings_count = 0;
1498         ffs->interfaces_count = 0;
1499         ffs->eps_count = 0;
1500
1501         ffs->ev.count = 0;
1502
1503         ffs->state = FFS_READ_DESCRIPTORS;
1504         ffs->setup_state = FFS_NO_SETUP;
1505         ffs->flags = 0;
1506 }
1507
1508
1509 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1510 {
1511         struct usb_gadget_strings **lang;
1512         int first_id;
1513
1514         ENTER();
1515
1516         if (WARN_ON(ffs->state != FFS_ACTIVE
1517                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1518                 return -EBADFD;
1519
1520         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1521         if (unlikely(first_id < 0))
1522                 return first_id;
1523
1524         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1525         if (unlikely(!ffs->ep0req))
1526                 return -ENOMEM;
1527         ffs->ep0req->complete = ffs_ep0_complete;
1528         ffs->ep0req->context = ffs;
1529
1530         lang = ffs->stringtabs;
1531         if (lang) {
1532                 for (; *lang; ++lang) {
1533                         struct usb_string *str = (*lang)->strings;
1534                         int id = first_id;
1535                         for (; str->s; ++id, ++str)
1536                                 str->id = id;
1537                 }
1538         }
1539
1540         ffs->gadget = cdev->gadget;
1541         ffs_data_get(ffs);
1542         return 0;
1543 }
1544
1545 static void functionfs_unbind(struct ffs_data *ffs)
1546 {
1547         ENTER();
1548
1549         if (!WARN_ON(!ffs->gadget)) {
1550                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1551                 ffs->ep0req = NULL;
1552                 ffs->gadget = NULL;
1553                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1554                 ffs_data_put(ffs);
1555         }
1556 }
1557
1558 static int ffs_epfiles_create(struct ffs_data *ffs)
1559 {
1560         struct ffs_epfile *epfile, *epfiles;
1561         unsigned i, count;
1562
1563         ENTER();
1564
1565         count = ffs->eps_count;
1566         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1567         if (!epfiles)
1568                 return -ENOMEM;
1569
1570         epfile = epfiles;
1571         for (i = 1; i <= count; ++i, ++epfile) {
1572                 epfile->ffs = ffs;
1573                 mutex_init(&epfile->mutex);
1574                 init_waitqueue_head(&epfile->wait);
1575                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1576                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1577                 else
1578                         sprintf(epfile->name, "ep%u", i);
1579                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1580                                                  epfile,
1581                                                  &ffs_epfile_operations);
1582                 if (unlikely(!epfile->dentry)) {
1583                         ffs_epfiles_destroy(epfiles, i - 1);
1584                         return -ENOMEM;
1585                 }
1586         }
1587
1588         ffs->epfiles = epfiles;
1589         return 0;
1590 }
1591
1592 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1593 {
1594         struct ffs_epfile *epfile = epfiles;
1595
1596         ENTER();
1597
1598         for (; count; --count, ++epfile) {
1599                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1600                        waitqueue_active(&epfile->wait));
1601                 if (epfile->dentry) {
1602                         d_delete(epfile->dentry);
1603                         dput(epfile->dentry);
1604                         epfile->dentry = NULL;
1605                 }
1606         }
1607
1608         kfree(epfiles);
1609 }
1610
1611 static void ffs_func_eps_disable(struct ffs_function *func)
1612 {
1613         struct ffs_ep *ep         = func->eps;
1614         struct ffs_epfile *epfile = func->ffs->epfiles;
1615         unsigned count            = func->ffs->eps_count;
1616         unsigned long flags;
1617
1618         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1619         do {
1620                 /* pending requests get nuked */
1621                 if (likely(ep->ep))
1622                         usb_ep_disable(ep->ep);
1623                 ++ep;
1624
1625                 if (epfile) {
1626                         epfile->ep = NULL;
1627                         ++epfile;
1628                 }
1629         } while (--count);
1630         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1631 }
1632
1633 static int ffs_func_eps_enable(struct ffs_function *func)
1634 {
1635         struct ffs_data *ffs      = func->ffs;
1636         struct ffs_ep *ep         = func->eps;
1637         struct ffs_epfile *epfile = ffs->epfiles;
1638         unsigned count            = ffs->eps_count;
1639         unsigned long flags;
1640         int ret = 0;
1641
1642         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1643         do {
1644                 struct usb_endpoint_descriptor *ds;
1645                 int desc_idx;
1646
1647                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1648                         desc_idx = 2;
1649                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1650                         desc_idx = 1;
1651                 else
1652                         desc_idx = 0;
1653
1654                 /* fall-back to lower speed if desc missing for current speed */
1655                 do {
1656                         ds = ep->descs[desc_idx];
1657                 } while (!ds && --desc_idx >= 0);
1658
1659                 if (!ds) {
1660                         ret = -EINVAL;
1661                         break;
1662                 }
1663
1664                 ep->ep->driver_data = ep;
1665                 ep->ep->desc = ds;
1666                 ret = usb_ep_enable(ep->ep);
1667                 if (likely(!ret)) {
1668                         epfile->ep = ep;
1669                         epfile->in = usb_endpoint_dir_in(ds);
1670                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1671                 } else {
1672                         break;
1673                 }
1674
1675                 wake_up(&epfile->wait);
1676
1677                 ++ep;
1678                 ++epfile;
1679         } while (--count);
1680         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1681
1682         return ret;
1683 }
1684
1685
1686 /* Parsing and building descriptors and strings *****************************/
1687
1688 /*
1689  * This validates if data pointed by data is a valid USB descriptor as
1690  * well as record how many interfaces, endpoints and strings are
1691  * required by given configuration.  Returns address after the
1692  * descriptor or NULL if data is invalid.
1693  */
1694
1695 enum ffs_entity_type {
1696         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1697 };
1698
1699 enum ffs_os_desc_type {
1700         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1701 };
1702
1703 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1704                                    u8 *valuep,
1705                                    struct usb_descriptor_header *desc,
1706                                    void *priv);
1707
1708 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1709                                     struct usb_os_desc_header *h, void *data,
1710                                     unsigned len, void *priv);
1711
1712 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1713                                            ffs_entity_callback entity,
1714                                            void *priv)
1715 {
1716         struct usb_descriptor_header *_ds = (void *)data;
1717         u8 length;
1718         int ret;
1719
1720         ENTER();
1721
1722         /* At least two bytes are required: length and type */
1723         if (len < 2) {
1724                 pr_vdebug("descriptor too short\n");
1725                 return -EINVAL;
1726         }
1727
1728         /* If we have at least as many bytes as the descriptor takes? */
1729         length = _ds->bLength;
1730         if (len < length) {
1731                 pr_vdebug("descriptor longer then available data\n");
1732                 return -EINVAL;
1733         }
1734
1735 #define __entity_check_INTERFACE(val)  1
1736 #define __entity_check_STRING(val)     (val)
1737 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1738 #define __entity(type, val) do {                                        \
1739                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1740                 if (unlikely(!__entity_check_ ##type(val))) {           \
1741                         pr_vdebug("invalid entity's value\n");          \
1742                         return -EINVAL;                                 \
1743                 }                                                       \
1744                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1745                 if (unlikely(ret < 0)) {                                \
1746                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1747                                  (val), ret);                           \
1748                         return ret;                                     \
1749                 }                                                       \
1750         } while (0)
1751
1752         /* Parse descriptor depending on type. */
1753         switch (_ds->bDescriptorType) {
1754         case USB_DT_DEVICE:
1755         case USB_DT_CONFIG:
1756         case USB_DT_STRING:
1757         case USB_DT_DEVICE_QUALIFIER:
1758                 /* function can't have any of those */
1759                 pr_vdebug("descriptor reserved for gadget: %d\n",
1760                       _ds->bDescriptorType);
1761                 return -EINVAL;
1762
1763         case USB_DT_INTERFACE: {
1764                 struct usb_interface_descriptor *ds = (void *)_ds;
1765                 pr_vdebug("interface descriptor\n");
1766                 if (length != sizeof *ds)
1767                         goto inv_length;
1768
1769                 __entity(INTERFACE, ds->bInterfaceNumber);
1770                 if (ds->iInterface)
1771                         __entity(STRING, ds->iInterface);
1772         }
1773                 break;
1774
1775         case USB_DT_ENDPOINT: {
1776                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1777                 pr_vdebug("endpoint descriptor\n");
1778                 if (length != USB_DT_ENDPOINT_SIZE &&
1779                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1780                         goto inv_length;
1781                 __entity(ENDPOINT, ds->bEndpointAddress);
1782         }
1783                 break;
1784
1785         case HID_DT_HID:
1786                 pr_vdebug("hid descriptor\n");
1787                 if (length != sizeof(struct hid_descriptor))
1788                         goto inv_length;
1789                 break;
1790
1791         case USB_DT_OTG:
1792                 if (length != sizeof(struct usb_otg_descriptor))
1793                         goto inv_length;
1794                 break;
1795
1796         case USB_DT_INTERFACE_ASSOCIATION: {
1797                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1798                 pr_vdebug("interface association descriptor\n");
1799                 if (length != sizeof *ds)
1800                         goto inv_length;
1801                 if (ds->iFunction)
1802                         __entity(STRING, ds->iFunction);
1803         }
1804                 break;
1805
1806         case USB_DT_SS_ENDPOINT_COMP:
1807                 pr_vdebug("EP SS companion descriptor\n");
1808                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1809                         goto inv_length;
1810                 break;
1811
1812         case USB_DT_OTHER_SPEED_CONFIG:
1813         case USB_DT_INTERFACE_POWER:
1814         case USB_DT_DEBUG:
1815         case USB_DT_SECURITY:
1816         case USB_DT_CS_RADIO_CONTROL:
1817                 /* TODO */
1818                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1819                 return -EINVAL;
1820
1821         default:
1822                 /* We should never be here */
1823                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1824                 return -EINVAL;
1825
1826 inv_length:
1827                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1828                           _ds->bLength, _ds->bDescriptorType);
1829                 return -EINVAL;
1830         }
1831
1832 #undef __entity
1833 #undef __entity_check_DESCRIPTOR
1834 #undef __entity_check_INTERFACE
1835 #undef __entity_check_STRING
1836 #undef __entity_check_ENDPOINT
1837
1838         return length;
1839 }
1840
1841 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1842                                      ffs_entity_callback entity, void *priv)
1843 {
1844         const unsigned _len = len;
1845         unsigned long num = 0;
1846
1847         ENTER();
1848
1849         for (;;) {
1850                 int ret;
1851
1852                 if (num == count)
1853                         data = NULL;
1854
1855                 /* Record "descriptor" entity */
1856                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1857                 if (unlikely(ret < 0)) {
1858                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1859                                  num, ret);
1860                         return ret;
1861                 }
1862
1863                 if (!data)
1864                         return _len - len;
1865
1866                 ret = ffs_do_single_desc(data, len, entity, priv);
1867                 if (unlikely(ret < 0)) {
1868                         pr_debug("%s returns %d\n", __func__, ret);
1869                         return ret;
1870                 }
1871
1872                 len -= ret;
1873                 data += ret;
1874                 ++num;
1875         }
1876 }
1877
1878 static int __ffs_data_do_entity(enum ffs_entity_type type,
1879                                 u8 *valuep, struct usb_descriptor_header *desc,
1880                                 void *priv)
1881 {
1882         struct ffs_desc_helper *helper = priv;
1883         struct usb_endpoint_descriptor *d;
1884
1885         ENTER();
1886
1887         switch (type) {
1888         case FFS_DESCRIPTOR:
1889                 break;
1890
1891         case FFS_INTERFACE:
1892                 /*
1893                  * Interfaces are indexed from zero so if we
1894                  * encountered interface "n" then there are at least
1895                  * "n+1" interfaces.
1896                  */
1897                 if (*valuep >= helper->interfaces_count)
1898                         helper->interfaces_count = *valuep + 1;
1899                 break;
1900
1901         case FFS_STRING:
1902                 /*
1903                  * Strings are indexed from 1 (0 is magic ;) reserved
1904                  * for languages list or some such)
1905                  */
1906                 if (*valuep > helper->ffs->strings_count)
1907                         helper->ffs->strings_count = *valuep;
1908                 break;
1909
1910         case FFS_ENDPOINT:
1911                 d = (void *)desc;
1912                 helper->eps_count++;
1913                 if (helper->eps_count >= 15)
1914                         return -EINVAL;
1915                 /* Check if descriptors for any speed were already parsed */
1916                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
1917                         helper->ffs->eps_addrmap[helper->eps_count] =
1918                                 d->bEndpointAddress;
1919                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
1920                                 d->bEndpointAddress)
1921                         return -EINVAL;
1922                 break;
1923         }
1924
1925         return 0;
1926 }
1927
1928 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
1929                                    struct usb_os_desc_header *desc)
1930 {
1931         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
1932         u16 w_index = le16_to_cpu(desc->wIndex);
1933
1934         if (bcd_version != 1) {
1935                 pr_vdebug("unsupported os descriptors version: %d",
1936                           bcd_version);
1937                 return -EINVAL;
1938         }
1939         switch (w_index) {
1940         case 0x4:
1941                 *next_type = FFS_OS_DESC_EXT_COMPAT;
1942                 break;
1943         case 0x5:
1944                 *next_type = FFS_OS_DESC_EXT_PROP;
1945                 break;
1946         default:
1947                 pr_vdebug("unsupported os descriptor type: %d", w_index);
1948                 return -EINVAL;
1949         }
1950
1951         return sizeof(*desc);
1952 }
1953
1954 /*
1955  * Process all extended compatibility/extended property descriptors
1956  * of a feature descriptor
1957  */
1958 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
1959                                               enum ffs_os_desc_type type,
1960                                               u16 feature_count,
1961                                               ffs_os_desc_callback entity,
1962                                               void *priv,
1963                                               struct usb_os_desc_header *h)
1964 {
1965         int ret;
1966         const unsigned _len = len;
1967
1968         ENTER();
1969
1970         /* loop over all ext compat/ext prop descriptors */
1971         while (feature_count--) {
1972                 ret = entity(type, h, data, len, priv);
1973                 if (unlikely(ret < 0)) {
1974                         pr_debug("bad OS descriptor, type: %d\n", type);
1975                         return ret;
1976                 }
1977                 data += ret;
1978                 len -= ret;
1979         }
1980         return _len - len;
1981 }
1982
1983 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
1984 static int __must_check ffs_do_os_descs(unsigned count,
1985                                         char *data, unsigned len,
1986                                         ffs_os_desc_callback entity, void *priv)
1987 {
1988         const unsigned _len = len;
1989         unsigned long num = 0;
1990
1991         ENTER();
1992
1993         for (num = 0; num < count; ++num) {
1994                 int ret;
1995                 enum ffs_os_desc_type type;
1996                 u16 feature_count;
1997                 struct usb_os_desc_header *desc = (void *)data;
1998
1999                 if (len < sizeof(*desc))
2000                         return -EINVAL;
2001
2002                 /*
2003                  * Record "descriptor" entity.
2004                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2005                  * Move the data pointer to the beginning of extended
2006                  * compatibilities proper or extended properties proper
2007                  * portions of the data
2008                  */
2009                 if (le32_to_cpu(desc->dwLength) > len)
2010                         return -EINVAL;
2011
2012                 ret = __ffs_do_os_desc_header(&type, desc);
2013                 if (unlikely(ret < 0)) {
2014                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2015                                  num, ret);
2016                         return ret;
2017                 }
2018                 /*
2019                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2020                  */
2021                 feature_count = le16_to_cpu(desc->wCount);
2022                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2023                     (feature_count > 255 || desc->Reserved))
2024                                 return -EINVAL;
2025                 len -= ret;
2026                 data += ret;
2027
2028                 /*
2029                  * Process all function/property descriptors
2030                  * of this Feature Descriptor
2031                  */
2032                 ret = ffs_do_single_os_desc(data, len, type,
2033                                             feature_count, entity, priv, desc);
2034                 if (unlikely(ret < 0)) {
2035                         pr_debug("%s returns %d\n", __func__, ret);
2036                         return ret;
2037                 }
2038
2039                 len -= ret;
2040                 data += ret;
2041         }
2042         return _len - len;
2043 }
2044
2045 /**
2046  * Validate contents of the buffer from userspace related to OS descriptors.
2047  */
2048 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2049                                  struct usb_os_desc_header *h, void *data,
2050                                  unsigned len, void *priv)
2051 {
2052         struct ffs_data *ffs = priv;
2053         u8 length;
2054
2055         ENTER();
2056
2057         switch (type) {
2058         case FFS_OS_DESC_EXT_COMPAT: {
2059                 struct usb_ext_compat_desc *d = data;
2060                 int i;
2061
2062                 if (len < sizeof(*d) ||
2063                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2064                     d->Reserved1)
2065                         return -EINVAL;
2066                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2067                         if (d->Reserved2[i])
2068                                 return -EINVAL;
2069
2070                 length = sizeof(struct usb_ext_compat_desc);
2071         }
2072                 break;
2073         case FFS_OS_DESC_EXT_PROP: {
2074                 struct usb_ext_prop_desc *d = data;
2075                 u32 type, pdl;
2076                 u16 pnl;
2077
2078                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2079                         return -EINVAL;
2080                 length = le32_to_cpu(d->dwSize);
2081                 type = le32_to_cpu(d->dwPropertyDataType);
2082                 if (type < USB_EXT_PROP_UNICODE ||
2083                     type > USB_EXT_PROP_UNICODE_MULTI) {
2084                         pr_vdebug("unsupported os descriptor property type: %d",
2085                                   type);
2086                         return -EINVAL;
2087                 }
2088                 pnl = le16_to_cpu(d->wPropertyNameLength);
2089                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2090                 if (length != 14 + pnl + pdl) {
2091                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2092                                   length, pnl, pdl, type);
2093                         return -EINVAL;
2094                 }
2095                 ++ffs->ms_os_descs_ext_prop_count;
2096                 /* property name reported to the host as "WCHAR"s */
2097                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2098                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2099         }
2100                 break;
2101         default:
2102                 pr_vdebug("unknown descriptor: %d\n", type);
2103                 return -EINVAL;
2104         }
2105         return length;
2106 }
2107
2108 static int __ffs_data_got_descs(struct ffs_data *ffs,
2109                                 char *const _data, size_t len)
2110 {
2111         char *data = _data, *raw_descs;
2112         unsigned os_descs_count = 0, counts[3], flags;
2113         int ret = -EINVAL, i;
2114         struct ffs_desc_helper helper;
2115
2116         ENTER();
2117
2118         if (get_unaligned_le32(data + 4) != len)
2119                 goto error;
2120
2121         switch (get_unaligned_le32(data)) {
2122         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2123                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2124                 data += 8;
2125                 len  -= 8;
2126                 break;
2127         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2128                 flags = get_unaligned_le32(data + 8);
2129                 ffs->user_flags = flags;
2130                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2131                               FUNCTIONFS_HAS_HS_DESC |
2132                               FUNCTIONFS_HAS_SS_DESC |
2133                               FUNCTIONFS_HAS_MS_OS_DESC |
2134                               FUNCTIONFS_VIRTUAL_ADDR |
2135                               FUNCTIONFS_EVENTFD)) {
2136                         ret = -ENOSYS;
2137                         goto error;
2138                 }
2139                 data += 12;
2140                 len  -= 12;
2141                 break;
2142         default:
2143                 goto error;
2144         }
2145
2146         if (flags & FUNCTIONFS_EVENTFD) {
2147                 if (len < 4)
2148                         goto error;
2149                 ffs->ffs_eventfd =
2150                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2151                 if (IS_ERR(ffs->ffs_eventfd)) {
2152                         ret = PTR_ERR(ffs->ffs_eventfd);
2153                         ffs->ffs_eventfd = NULL;
2154                         goto error;
2155                 }
2156                 data += 4;
2157                 len  -= 4;
2158         }
2159
2160         /* Read fs_count, hs_count and ss_count (if present) */
2161         for (i = 0; i < 3; ++i) {
2162                 if (!(flags & (1 << i))) {
2163                         counts[i] = 0;
2164                 } else if (len < 4) {
2165                         goto error;
2166                 } else {
2167                         counts[i] = get_unaligned_le32(data);
2168                         data += 4;
2169                         len  -= 4;
2170                 }
2171         }
2172         if (flags & (1 << i)) {
2173                 os_descs_count = get_unaligned_le32(data);
2174                 data += 4;
2175                 len -= 4;
2176         };
2177
2178         /* Read descriptors */
2179         raw_descs = data;
2180         helper.ffs = ffs;
2181         for (i = 0; i < 3; ++i) {
2182                 if (!counts[i])
2183                         continue;
2184                 helper.interfaces_count = 0;
2185                 helper.eps_count = 0;
2186                 ret = ffs_do_descs(counts[i], data, len,
2187                                    __ffs_data_do_entity, &helper);
2188                 if (ret < 0)
2189                         goto error;
2190                 if (!ffs->eps_count && !ffs->interfaces_count) {
2191                         ffs->eps_count = helper.eps_count;
2192                         ffs->interfaces_count = helper.interfaces_count;
2193                 } else {
2194                         if (ffs->eps_count != helper.eps_count) {
2195                                 ret = -EINVAL;
2196                                 goto error;
2197                         }
2198                         if (ffs->interfaces_count != helper.interfaces_count) {
2199                                 ret = -EINVAL;
2200                                 goto error;
2201                         }
2202                 }
2203                 data += ret;
2204                 len  -= ret;
2205         }
2206         if (os_descs_count) {
2207                 ret = ffs_do_os_descs(os_descs_count, data, len,
2208                                       __ffs_data_do_os_desc, ffs);
2209                 if (ret < 0)
2210                         goto error;
2211                 data += ret;
2212                 len -= ret;
2213         }
2214
2215         if (raw_descs == data || len) {
2216                 ret = -EINVAL;
2217                 goto error;
2218         }
2219
2220         ffs->raw_descs_data     = _data;
2221         ffs->raw_descs          = raw_descs;
2222         ffs->raw_descs_length   = data - raw_descs;
2223         ffs->fs_descs_count     = counts[0];
2224         ffs->hs_descs_count     = counts[1];
2225         ffs->ss_descs_count     = counts[2];
2226         ffs->ms_os_descs_count  = os_descs_count;
2227
2228         return 0;
2229
2230 error:
2231         kfree(_data);
2232         return ret;
2233 }
2234
2235 static int __ffs_data_got_strings(struct ffs_data *ffs,
2236                                   char *const _data, size_t len)
2237 {
2238         u32 str_count, needed_count, lang_count;
2239         struct usb_gadget_strings **stringtabs, *t;
2240         struct usb_string *strings, *s;
2241         const char *data = _data;
2242
2243         ENTER();
2244
2245         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2246                      get_unaligned_le32(data + 4) != len))
2247                 goto error;
2248         str_count  = get_unaligned_le32(data + 8);
2249         lang_count = get_unaligned_le32(data + 12);
2250
2251         /* if one is zero the other must be zero */
2252         if (unlikely(!str_count != !lang_count))
2253                 goto error;
2254
2255         /* Do we have at least as many strings as descriptors need? */
2256         needed_count = ffs->strings_count;
2257         if (unlikely(str_count < needed_count))
2258                 goto error;
2259
2260         /*
2261          * If we don't need any strings just return and free all
2262          * memory.
2263          */
2264         if (!needed_count) {
2265                 kfree(_data);
2266                 return 0;
2267         }
2268
2269         /* Allocate everything in one chunk so there's less maintenance. */
2270         {
2271                 unsigned i = 0;
2272                 vla_group(d);
2273                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2274                         lang_count + 1);
2275                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2276                 vla_item(d, struct usb_string, strings,
2277                         lang_count*(needed_count+1));
2278
2279                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2280
2281                 if (unlikely(!vlabuf)) {
2282                         kfree(_data);
2283                         return -ENOMEM;
2284                 }
2285
2286                 /* Initialize the VLA pointers */
2287                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2288                 t = vla_ptr(vlabuf, d, stringtab);
2289                 i = lang_count;
2290                 do {
2291                         *stringtabs++ = t++;
2292                 } while (--i);
2293                 *stringtabs = NULL;
2294
2295                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2296                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2297                 t = vla_ptr(vlabuf, d, stringtab);
2298                 s = vla_ptr(vlabuf, d, strings);
2299                 strings = s;
2300         }
2301
2302         /* For each language */
2303         data += 16;
2304         len -= 16;
2305
2306         do { /* lang_count > 0 so we can use do-while */
2307                 unsigned needed = needed_count;
2308
2309                 if (unlikely(len < 3))
2310                         goto error_free;
2311                 t->language = get_unaligned_le16(data);
2312                 t->strings  = s;
2313                 ++t;
2314
2315                 data += 2;
2316                 len -= 2;
2317
2318                 /* For each string */
2319                 do { /* str_count > 0 so we can use do-while */
2320                         size_t length = strnlen(data, len);
2321
2322                         if (unlikely(length == len))
2323                                 goto error_free;
2324
2325                         /*
2326                          * User may provide more strings then we need,
2327                          * if that's the case we simply ignore the
2328                          * rest
2329                          */
2330                         if (likely(needed)) {
2331                                 /*
2332                                  * s->id will be set while adding
2333                                  * function to configuration so for
2334                                  * now just leave garbage here.
2335                                  */
2336                                 s->s = data;
2337                                 --needed;
2338                                 ++s;
2339                         }
2340
2341                         data += length + 1;
2342                         len -= length + 1;
2343                 } while (--str_count);
2344
2345                 s->id = 0;   /* terminator */
2346                 s->s = NULL;
2347                 ++s;
2348
2349         } while (--lang_count);
2350
2351         /* Some garbage left? */
2352         if (unlikely(len))
2353                 goto error_free;
2354
2355         /* Done! */
2356         ffs->stringtabs = stringtabs;
2357         ffs->raw_strings = _data;
2358
2359         return 0;
2360
2361 error_free:
2362         kfree(stringtabs);
2363 error:
2364         kfree(_data);
2365         return -EINVAL;
2366 }
2367
2368
2369 /* Events handling and management *******************************************/
2370
2371 static void __ffs_event_add(struct ffs_data *ffs,
2372                             enum usb_functionfs_event_type type)
2373 {
2374         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2375         int neg = 0;
2376
2377         /*
2378          * Abort any unhandled setup
2379          *
2380          * We do not need to worry about some cmpxchg() changing value
2381          * of ffs->setup_state without holding the lock because when
2382          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2383          * the source does nothing.
2384          */
2385         if (ffs->setup_state == FFS_SETUP_PENDING)
2386                 ffs->setup_state = FFS_SETUP_CANCELLED;
2387
2388         /*
2389          * Logic of this function guarantees that there are at most four pending
2390          * evens on ffs->ev.types queue.  This is important because the queue
2391          * has space for four elements only and __ffs_ep0_read_events function
2392          * depends on that limit as well.  If more event types are added, those
2393          * limits have to be revisited or guaranteed to still hold.
2394          */
2395         switch (type) {
2396         case FUNCTIONFS_RESUME:
2397                 rem_type2 = FUNCTIONFS_SUSPEND;
2398                 /* FALL THROUGH */
2399         case FUNCTIONFS_SUSPEND:
2400         case FUNCTIONFS_SETUP:
2401                 rem_type1 = type;
2402                 /* Discard all similar events */
2403                 break;
2404
2405         case FUNCTIONFS_BIND:
2406         case FUNCTIONFS_UNBIND:
2407         case FUNCTIONFS_DISABLE:
2408         case FUNCTIONFS_ENABLE:
2409                 /* Discard everything other then power management. */
2410                 rem_type1 = FUNCTIONFS_SUSPEND;
2411                 rem_type2 = FUNCTIONFS_RESUME;
2412                 neg = 1;
2413                 break;
2414
2415         default:
2416                 WARN(1, "%d: unknown event, this should not happen\n", type);
2417                 return;
2418         }
2419
2420         {
2421                 u8 *ev  = ffs->ev.types, *out = ev;
2422                 unsigned n = ffs->ev.count;
2423                 for (; n; --n, ++ev)
2424                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2425                                 *out++ = *ev;
2426                         else
2427                                 pr_vdebug("purging event %d\n", *ev);
2428                 ffs->ev.count = out - ffs->ev.types;
2429         }
2430
2431         pr_vdebug("adding event %d\n", type);
2432         ffs->ev.types[ffs->ev.count++] = type;
2433         wake_up_locked(&ffs->ev.waitq);
2434         if (ffs->ffs_eventfd)
2435                 eventfd_signal(ffs->ffs_eventfd, 1);
2436 }
2437
2438 static void ffs_event_add(struct ffs_data *ffs,
2439                           enum usb_functionfs_event_type type)
2440 {
2441         unsigned long flags;
2442         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2443         __ffs_event_add(ffs, type);
2444         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2445 }
2446
2447 /* Bind/unbind USB function hooks *******************************************/
2448
2449 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2450 {
2451         int i;
2452
2453         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2454                 if (ffs->eps_addrmap[i] == endpoint_address)
2455                         return i;
2456         return -ENOENT;
2457 }
2458
2459 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2460                                     struct usb_descriptor_header *desc,
2461                                     void *priv)
2462 {
2463         struct usb_endpoint_descriptor *ds = (void *)desc;
2464         struct ffs_function *func = priv;
2465         struct ffs_ep *ffs_ep;
2466         unsigned ep_desc_id;
2467         int idx;
2468         static const char *speed_names[] = { "full", "high", "super" };
2469
2470         if (type != FFS_DESCRIPTOR)
2471                 return 0;
2472
2473         /*
2474          * If ss_descriptors is not NULL, we are reading super speed
2475          * descriptors; if hs_descriptors is not NULL, we are reading high
2476          * speed descriptors; otherwise, we are reading full speed
2477          * descriptors.
2478          */
2479         if (func->function.ss_descriptors) {
2480                 ep_desc_id = 2;
2481                 func->function.ss_descriptors[(long)valuep] = desc;
2482         } else if (func->function.hs_descriptors) {
2483                 ep_desc_id = 1;
2484                 func->function.hs_descriptors[(long)valuep] = desc;
2485         } else {
2486                 ep_desc_id = 0;
2487                 func->function.fs_descriptors[(long)valuep]    = desc;
2488         }
2489
2490         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2491                 return 0;
2492
2493         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2494         if (idx < 0)
2495                 return idx;
2496
2497         ffs_ep = func->eps + idx;
2498
2499         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2500                 pr_err("two %sspeed descriptors for EP %d\n",
2501                           speed_names[ep_desc_id],
2502                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2503                 return -EINVAL;
2504         }
2505         ffs_ep->descs[ep_desc_id] = ds;
2506
2507         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2508         if (ffs_ep->ep) {
2509                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2510                 if (!ds->wMaxPacketSize)
2511                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2512         } else {
2513                 struct usb_request *req;
2514                 struct usb_ep *ep;
2515                 u8 bEndpointAddress;
2516
2517                 /*
2518                  * We back up bEndpointAddress because autoconfig overwrites
2519                  * it with physical endpoint address.
2520                  */
2521                 bEndpointAddress = ds->bEndpointAddress;
2522                 pr_vdebug("autoconfig\n");
2523                 ep = usb_ep_autoconfig(func->gadget, ds);
2524                 if (unlikely(!ep))
2525                         return -ENOTSUPP;
2526                 ep->driver_data = func->eps + idx;
2527
2528                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2529                 if (unlikely(!req))
2530                         return -ENOMEM;
2531
2532                 ffs_ep->ep  = ep;
2533                 ffs_ep->req = req;
2534                 func->eps_revmap[ds->bEndpointAddress &
2535                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2536                 /*
2537                  * If we use virtual address mapping, we restore
2538                  * original bEndpointAddress value.
2539                  */
2540                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2541                         ds->bEndpointAddress = bEndpointAddress;
2542         }
2543         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2544
2545         return 0;
2546 }
2547
2548 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2549                                    struct usb_descriptor_header *desc,
2550                                    void *priv)
2551 {
2552         struct ffs_function *func = priv;
2553         unsigned idx;
2554         u8 newValue;
2555
2556         switch (type) {
2557         default:
2558         case FFS_DESCRIPTOR:
2559                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2560                 return 0;
2561
2562         case FFS_INTERFACE:
2563                 idx = *valuep;
2564                 if (func->interfaces_nums[idx] < 0) {
2565                         int id = usb_interface_id(func->conf, &func->function);
2566                         if (unlikely(id < 0))
2567                                 return id;
2568                         func->interfaces_nums[idx] = id;
2569                 }
2570                 newValue = func->interfaces_nums[idx];
2571                 break;
2572
2573         case FFS_STRING:
2574                 /* String' IDs are allocated when fsf_data is bound to cdev */
2575                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2576                 break;
2577
2578         case FFS_ENDPOINT:
2579                 /*
2580                  * USB_DT_ENDPOINT are handled in
2581                  * __ffs_func_bind_do_descs().
2582                  */
2583                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2584                         return 0;
2585
2586                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2587                 if (unlikely(!func->eps[idx].ep))
2588                         return -EINVAL;
2589
2590                 {
2591                         struct usb_endpoint_descriptor **descs;
2592                         descs = func->eps[idx].descs;
2593                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2594                 }
2595                 break;
2596         }
2597
2598         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2599         *valuep = newValue;
2600         return 0;
2601 }
2602
2603 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2604                                       struct usb_os_desc_header *h, void *data,
2605                                       unsigned len, void *priv)
2606 {
2607         struct ffs_function *func = priv;
2608         u8 length = 0;
2609
2610         switch (type) {
2611         case FFS_OS_DESC_EXT_COMPAT: {
2612                 struct usb_ext_compat_desc *desc = data;
2613                 struct usb_os_desc_table *t;
2614
2615                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2616                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2617                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2618                        ARRAY_SIZE(desc->CompatibleID) +
2619                        ARRAY_SIZE(desc->SubCompatibleID));
2620                 length = sizeof(*desc);
2621         }
2622                 break;
2623         case FFS_OS_DESC_EXT_PROP: {
2624                 struct usb_ext_prop_desc *desc = data;
2625                 struct usb_os_desc_table *t;
2626                 struct usb_os_desc_ext_prop *ext_prop;
2627                 char *ext_prop_name;
2628                 char *ext_prop_data;
2629
2630                 t = &func->function.os_desc_table[h->interface];
2631                 t->if_id = func->interfaces_nums[h->interface];
2632
2633                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2634                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2635
2636                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2637                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2638                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2639                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2640                 length = ext_prop->name_len + ext_prop->data_len + 14;
2641
2642                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2643                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2644                         ext_prop->name_len;
2645
2646                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2647                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2648                         ext_prop->data_len;
2649                 memcpy(ext_prop_data,
2650                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2651                        ext_prop->data_len);
2652                 /* unicode data reported to the host as "WCHAR"s */
2653                 switch (ext_prop->type) {
2654                 case USB_EXT_PROP_UNICODE:
2655                 case USB_EXT_PROP_UNICODE_ENV:
2656                 case USB_EXT_PROP_UNICODE_LINK:
2657                 case USB_EXT_PROP_UNICODE_MULTI:
2658                         ext_prop->data_len *= 2;
2659                         break;
2660                 }
2661                 ext_prop->data = ext_prop_data;
2662
2663                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2664                        ext_prop->name_len);
2665                 /* property name reported to the host as "WCHAR"s */
2666                 ext_prop->name_len *= 2;
2667                 ext_prop->name = ext_prop_name;
2668
2669                 t->os_desc->ext_prop_len +=
2670                         ext_prop->name_len + ext_prop->data_len + 14;
2671                 ++t->os_desc->ext_prop_count;
2672                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2673         }
2674                 break;
2675         default:
2676                 pr_vdebug("unknown descriptor: %d\n", type);
2677         }
2678
2679         return length;
2680 }
2681
2682 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2683                                                 struct usb_configuration *c)
2684 {
2685         struct ffs_function *func = ffs_func_from_usb(f);
2686         struct f_fs_opts *ffs_opts =
2687                 container_of(f->fi, struct f_fs_opts, func_inst);
2688         int ret;
2689
2690         ENTER();
2691
2692         /*
2693          * Legacy gadget triggers binding in functionfs_ready_callback,
2694          * which already uses locking; taking the same lock here would
2695          * cause a deadlock.
2696          *
2697          * Configfs-enabled gadgets however do need ffs_dev_lock.
2698          */
2699         if (!ffs_opts->no_configfs)
2700                 ffs_dev_lock();
2701         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2702         func->ffs = ffs_opts->dev->ffs_data;
2703         if (!ffs_opts->no_configfs)
2704                 ffs_dev_unlock();
2705         if (ret)
2706                 return ERR_PTR(ret);
2707
2708         func->conf = c;
2709         func->gadget = c->cdev->gadget;
2710
2711         /*
2712          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2713          * configurations are bound in sequence with list_for_each_entry,
2714          * in each configuration its functions are bound in sequence
2715          * with list_for_each_entry, so we assume no race condition
2716          * with regard to ffs_opts->bound access
2717          */
2718         if (!ffs_opts->refcnt) {
2719                 ret = functionfs_bind(func->ffs, c->cdev);
2720                 if (ret)
2721                         return ERR_PTR(ret);
2722         }
2723         ffs_opts->refcnt++;
2724         func->function.strings = func->ffs->stringtabs;
2725
2726         return ffs_opts;
2727 }
2728
2729 static int _ffs_func_bind(struct usb_configuration *c,
2730                           struct usb_function *f)
2731 {
2732         struct ffs_function *func = ffs_func_from_usb(f);
2733         struct ffs_data *ffs = func->ffs;
2734
2735         const int full = !!func->ffs->fs_descs_count;
2736         const int high = gadget_is_dualspeed(func->gadget) &&
2737                 func->ffs->hs_descs_count;
2738         const int super = gadget_is_superspeed(func->gadget) &&
2739                 func->ffs->ss_descs_count;
2740
2741         int fs_len, hs_len, ss_len, ret, i;
2742
2743         /* Make it a single chunk, less management later on */
2744         vla_group(d);
2745         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2746         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2747                 full ? ffs->fs_descs_count + 1 : 0);
2748         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2749                 high ? ffs->hs_descs_count + 1 : 0);
2750         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2751                 super ? ffs->ss_descs_count + 1 : 0);
2752         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2753         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2754                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2755         vla_item_with_sz(d, char[16], ext_compat,
2756                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2757         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2758                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2759         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2760                          ffs->ms_os_descs_ext_prop_count);
2761         vla_item_with_sz(d, char, ext_prop_name,
2762                          ffs->ms_os_descs_ext_prop_name_len);
2763         vla_item_with_sz(d, char, ext_prop_data,
2764                          ffs->ms_os_descs_ext_prop_data_len);
2765         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2766         char *vlabuf;
2767
2768         ENTER();
2769
2770         /* Has descriptors only for speeds gadget does not support */
2771         if (unlikely(!(full | high | super)))
2772                 return -ENOTSUPP;
2773
2774         /* Allocate a single chunk, less management later on */
2775         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2776         if (unlikely(!vlabuf))
2777                 return -ENOMEM;
2778
2779         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2780         ffs->ms_os_descs_ext_prop_name_avail =
2781                 vla_ptr(vlabuf, d, ext_prop_name);
2782         ffs->ms_os_descs_ext_prop_data_avail =
2783                 vla_ptr(vlabuf, d, ext_prop_data);
2784
2785         /* Copy descriptors  */
2786         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2787                ffs->raw_descs_length);
2788
2789         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2790         for (ret = ffs->eps_count; ret; --ret) {
2791                 struct ffs_ep *ptr;
2792
2793                 ptr = vla_ptr(vlabuf, d, eps);
2794                 ptr[ret].num = -1;
2795         }
2796
2797         /* Save pointers
2798          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2799         */
2800         func->eps             = vla_ptr(vlabuf, d, eps);
2801         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2802
2803         /*
2804          * Go through all the endpoint descriptors and allocate
2805          * endpoints first, so that later we can rewrite the endpoint
2806          * numbers without worrying that it may be described later on.
2807          */
2808         if (likely(full)) {
2809                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2810                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2811                                       vla_ptr(vlabuf, d, raw_descs),
2812                                       d_raw_descs__sz,
2813                                       __ffs_func_bind_do_descs, func);
2814                 if (unlikely(fs_len < 0)) {
2815                         ret = fs_len;
2816                         goto error;
2817                 }
2818         } else {
2819                 fs_len = 0;
2820         }
2821
2822         if (likely(high)) {
2823                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2824                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2825                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2826                                       d_raw_descs__sz - fs_len,
2827                                       __ffs_func_bind_do_descs, func);
2828                 if (unlikely(hs_len < 0)) {
2829                         ret = hs_len;
2830                         goto error;
2831                 }
2832         } else {
2833                 hs_len = 0;
2834         }
2835
2836         if (likely(super)) {
2837                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2838                 ss_len = ffs_do_descs(ffs->ss_descs_count,
2839                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2840                                 d_raw_descs__sz - fs_len - hs_len,
2841                                 __ffs_func_bind_do_descs, func);
2842                 if (unlikely(ss_len < 0)) {
2843                         ret = ss_len;
2844                         goto error;
2845                 }
2846         } else {
2847                 ss_len = 0;
2848         }
2849
2850         /*
2851          * Now handle interface numbers allocation and interface and
2852          * endpoint numbers rewriting.  We can do that in one go
2853          * now.
2854          */
2855         ret = ffs_do_descs(ffs->fs_descs_count +
2856                            (high ? ffs->hs_descs_count : 0) +
2857                            (super ? ffs->ss_descs_count : 0),
2858                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2859                            __ffs_func_bind_do_nums, func);
2860         if (unlikely(ret < 0))
2861                 goto error;
2862
2863         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
2864         if (c->cdev->use_os_string)
2865                 for (i = 0; i < ffs->interfaces_count; ++i) {
2866                         struct usb_os_desc *desc;
2867
2868                         desc = func->function.os_desc_table[i].os_desc =
2869                                 vla_ptr(vlabuf, d, os_desc) +
2870                                 i * sizeof(struct usb_os_desc);
2871                         desc->ext_compat_id =
2872                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
2873                         INIT_LIST_HEAD(&desc->ext_prop);
2874                 }
2875         ret = ffs_do_os_descs(ffs->ms_os_descs_count,
2876                               vla_ptr(vlabuf, d, raw_descs) +
2877                               fs_len + hs_len + ss_len,
2878                               d_raw_descs__sz - fs_len - hs_len - ss_len,
2879                               __ffs_func_bind_do_os_desc, func);
2880         if (unlikely(ret < 0))
2881                 goto error;
2882         func->function.os_desc_n =
2883                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
2884
2885         /* And we're done */
2886         ffs_event_add(ffs, FUNCTIONFS_BIND);
2887         return 0;
2888
2889 error:
2890         /* XXX Do we need to release all claimed endpoints here? */
2891         return ret;
2892 }
2893
2894 static int ffs_func_bind(struct usb_configuration *c,
2895                          struct usb_function *f)
2896 {
2897         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2898
2899         if (IS_ERR(ffs_opts))
2900                 return PTR_ERR(ffs_opts);
2901
2902         return _ffs_func_bind(c, f);
2903 }
2904
2905
2906 /* Other USB function hooks *************************************************/
2907
2908 static void ffs_reset_work(struct work_struct *work)
2909 {
2910         struct ffs_data *ffs = container_of(work,
2911                 struct ffs_data, reset_work);
2912         ffs_data_reset(ffs);
2913 }
2914
2915 static int ffs_func_set_alt(struct usb_function *f,
2916                             unsigned interface, unsigned alt)
2917 {
2918         struct ffs_function *func = ffs_func_from_usb(f);
2919         struct ffs_data *ffs = func->ffs;
2920         int ret = 0, intf;
2921
2922         if (alt != (unsigned)-1) {
2923                 intf = ffs_func_revmap_intf(func, interface);
2924                 if (unlikely(intf < 0))
2925                         return intf;
2926         }
2927
2928         if (ffs->func)
2929                 ffs_func_eps_disable(ffs->func);
2930
2931         if (ffs->state == FFS_DEACTIVATED) {
2932                 ffs->state = FFS_CLOSING;
2933                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
2934                 schedule_work(&ffs->reset_work);
2935                 return -ENODEV;
2936         }
2937
2938         if (ffs->state != FFS_ACTIVE)
2939                 return -ENODEV;
2940
2941         if (alt == (unsigned)-1) {
2942                 ffs->func = NULL;
2943                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2944                 return 0;
2945         }
2946
2947         ffs->func = func;
2948         ret = ffs_func_eps_enable(func);
2949         if (likely(ret >= 0))
2950                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2951         return ret;
2952 }
2953
2954 static void ffs_func_disable(struct usb_function *f)
2955 {
2956         ffs_func_set_alt(f, 0, (unsigned)-1);
2957 }
2958
2959 static int ffs_func_setup(struct usb_function *f,
2960                           const struct usb_ctrlrequest *creq)
2961 {
2962         struct ffs_function *func = ffs_func_from_usb(f);
2963         struct ffs_data *ffs = func->ffs;
2964         unsigned long flags;
2965         int ret;
2966
2967         ENTER();
2968
2969         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2970         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2971         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2972         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2973         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2974
2975         /*
2976          * Most requests directed to interface go through here
2977          * (notable exceptions are set/get interface) so we need to
2978          * handle them.  All other either handled by composite or
2979          * passed to usb_configuration->setup() (if one is set).  No
2980          * matter, we will handle requests directed to endpoint here
2981          * as well (as it's straightforward) but what to do with any
2982          * other request?
2983          */
2984         if (ffs->state != FFS_ACTIVE)
2985                 return -ENODEV;
2986
2987         switch (creq->bRequestType & USB_RECIP_MASK) {
2988         case USB_RECIP_INTERFACE:
2989                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2990                 if (unlikely(ret < 0))
2991                         return ret;
2992                 break;
2993
2994         case USB_RECIP_ENDPOINT:
2995                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
2996                 if (unlikely(ret < 0))
2997                         return ret;
2998                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2999                         ret = func->ffs->eps_addrmap[ret];
3000                 break;
3001
3002         default:
3003                 return -EOPNOTSUPP;
3004         }
3005
3006         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3007         ffs->ev.setup = *creq;
3008         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3009         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3010         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3011
3012         return 0;
3013 }
3014
3015 static void ffs_func_suspend(struct usb_function *f)
3016 {
3017         ENTER();
3018         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3019 }
3020
3021 static void ffs_func_resume(struct usb_function *f)
3022 {
3023         ENTER();
3024         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3025 }
3026
3027
3028 /* Endpoint and interface numbers reverse mapping ***************************/
3029
3030 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3031 {
3032         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3033         return num ? num : -EDOM;
3034 }
3035
3036 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3037 {
3038         short *nums = func->interfaces_nums;
3039         unsigned count = func->ffs->interfaces_count;
3040
3041         for (; count; --count, ++nums) {
3042                 if (*nums >= 0 && *nums == intf)
3043                         return nums - func->interfaces_nums;
3044         }
3045
3046         return -EDOM;
3047 }
3048
3049
3050 /* Devices management *******************************************************/
3051
3052 static LIST_HEAD(ffs_devices);
3053
3054 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3055 {
3056         struct ffs_dev *dev;
3057
3058         list_for_each_entry(dev, &ffs_devices, entry) {
3059                 if (!dev->name || !name)
3060                         continue;
3061                 if (strcmp(dev->name, name) == 0)
3062                         return dev;
3063         }
3064
3065         return NULL;
3066 }
3067
3068 /*
3069  * ffs_lock must be taken by the caller of this function
3070  */
3071 static struct ffs_dev *_ffs_get_single_dev(void)
3072 {
3073         struct ffs_dev *dev;
3074
3075         if (list_is_singular(&ffs_devices)) {
3076                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3077                 if (dev->single)
3078                         return dev;
3079         }
3080
3081         return NULL;
3082 }
3083
3084 /*
3085  * ffs_lock must be taken by the caller of this function
3086  */
3087 static struct ffs_dev *_ffs_find_dev(const char *name)
3088 {
3089         struct ffs_dev *dev;
3090
3091         dev = _ffs_get_single_dev();
3092         if (dev)
3093                 return dev;
3094
3095         return _ffs_do_find_dev(name);
3096 }
3097
3098 /* Configfs support *********************************************************/
3099
3100 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3101 {
3102         return container_of(to_config_group(item), struct f_fs_opts,
3103                             func_inst.group);
3104 }
3105
3106 static void ffs_attr_release(struct config_item *item)
3107 {
3108         struct f_fs_opts *opts = to_ffs_opts(item);
3109
3110         usb_put_function_instance(&opts->func_inst);
3111 }
3112
3113 static struct configfs_item_operations ffs_item_ops = {
3114         .release        = ffs_attr_release,
3115 };
3116
3117 static struct config_item_type ffs_func_type = {
3118         .ct_item_ops    = &ffs_item_ops,
3119         .ct_owner       = THIS_MODULE,
3120 };
3121
3122
3123 /* Function registration interface ******************************************/
3124
3125 static void ffs_free_inst(struct usb_function_instance *f)
3126 {
3127         struct f_fs_opts *opts;
3128
3129         opts = to_f_fs_opts(f);
3130         ffs_dev_lock();
3131         _ffs_free_dev(opts->dev);
3132         ffs_dev_unlock();
3133         kfree(opts);
3134 }
3135
3136 #define MAX_INST_NAME_LEN       40
3137
3138 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3139 {
3140         struct f_fs_opts *opts;
3141         char *ptr;
3142         const char *tmp;
3143         int name_len, ret;
3144
3145         name_len = strlen(name) + 1;
3146         if (name_len > MAX_INST_NAME_LEN)
3147                 return -ENAMETOOLONG;
3148
3149         ptr = kstrndup(name, name_len, GFP_KERNEL);
3150         if (!ptr)
3151                 return -ENOMEM;
3152
3153         opts = to_f_fs_opts(fi);
3154         tmp = NULL;
3155
3156         ffs_dev_lock();
3157
3158         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3159         ret = _ffs_name_dev(opts->dev, ptr);
3160         if (ret) {
3161                 kfree(ptr);
3162                 ffs_dev_unlock();
3163                 return ret;
3164         }
3165         opts->dev->name_allocated = true;
3166
3167         ffs_dev_unlock();
3168
3169         kfree(tmp);
3170
3171         return 0;
3172 }
3173
3174 static struct usb_function_instance *ffs_alloc_inst(void)
3175 {
3176         struct f_fs_opts *opts;
3177         struct ffs_dev *dev;
3178
3179         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3180         if (!opts)
3181                 return ERR_PTR(-ENOMEM);
3182
3183         opts->func_inst.set_inst_name = ffs_set_inst_name;
3184         opts->func_inst.free_func_inst = ffs_free_inst;
3185         ffs_dev_lock();
3186         dev = _ffs_alloc_dev();
3187         ffs_dev_unlock();
3188         if (IS_ERR(dev)) {
3189                 kfree(opts);
3190                 return ERR_CAST(dev);
3191         }
3192         opts->dev = dev;
3193         dev->opts = opts;
3194
3195         config_group_init_type_name(&opts->func_inst.group, "",
3196                                     &ffs_func_type);
3197         return &opts->func_inst;
3198 }
3199
3200 static void ffs_free(struct usb_function *f)
3201 {
3202         kfree(ffs_func_from_usb(f));
3203 }
3204
3205 static void ffs_func_unbind(struct usb_configuration *c,
3206                             struct usb_function *f)
3207 {
3208         struct ffs_function *func = ffs_func_from_usb(f);
3209         struct ffs_data *ffs = func->ffs;
3210         struct f_fs_opts *opts =
3211                 container_of(f->fi, struct f_fs_opts, func_inst);
3212         struct ffs_ep *ep = func->eps;
3213         unsigned count = ffs->eps_count;
3214         unsigned long flags;
3215
3216         ENTER();
3217         if (ffs->func == func) {
3218                 ffs_func_eps_disable(func);
3219                 ffs->func = NULL;
3220         }
3221
3222         if (!--opts->refcnt)
3223                 functionfs_unbind(ffs);
3224
3225         /* cleanup after autoconfig */
3226         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3227         do {
3228                 if (ep->ep && ep->req)
3229                         usb_ep_free_request(ep->ep, ep->req);
3230                 ep->req = NULL;
3231                 ++ep;
3232         } while (--count);
3233         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3234         kfree(func->eps);
3235         func->eps = NULL;
3236         /*
3237          * eps, descriptors and interfaces_nums are allocated in the
3238          * same chunk so only one free is required.
3239          */
3240         func->function.fs_descriptors = NULL;
3241         func->function.hs_descriptors = NULL;
3242         func->function.ss_descriptors = NULL;
3243         func->interfaces_nums = NULL;
3244
3245         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3246 }
3247
3248 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3249 {
3250         struct ffs_function *func;
3251
3252         ENTER();
3253
3254         func = kzalloc(sizeof(*func), GFP_KERNEL);
3255         if (unlikely(!func))
3256                 return ERR_PTR(-ENOMEM);
3257
3258         func->function.name    = "Function FS Gadget";
3259
3260         func->function.bind    = ffs_func_bind;
3261         func->function.unbind  = ffs_func_unbind;
3262         func->function.set_alt = ffs_func_set_alt;
3263         func->function.disable = ffs_func_disable;
3264         func->function.setup   = ffs_func_setup;
3265         func->function.suspend = ffs_func_suspend;
3266         func->function.resume  = ffs_func_resume;
3267         func->function.free_func = ffs_free;
3268
3269         return &func->function;
3270 }
3271
3272 /*
3273  * ffs_lock must be taken by the caller of this function
3274  */
3275 static struct ffs_dev *_ffs_alloc_dev(void)
3276 {
3277         struct ffs_dev *dev;
3278         int ret;
3279
3280         if (_ffs_get_single_dev())
3281                         return ERR_PTR(-EBUSY);
3282
3283         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3284         if (!dev)
3285                 return ERR_PTR(-ENOMEM);
3286
3287         if (list_empty(&ffs_devices)) {
3288                 ret = functionfs_init();
3289                 if (ret) {
3290                         kfree(dev);
3291                         return ERR_PTR(ret);
3292                 }
3293         }
3294
3295         list_add(&dev->entry, &ffs_devices);
3296
3297         return dev;
3298 }
3299
3300 /*
3301  * ffs_lock must be taken by the caller of this function
3302  * The caller is responsible for "name" being available whenever f_fs needs it
3303  */
3304 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3305 {
3306         struct ffs_dev *existing;
3307
3308         existing = _ffs_do_find_dev(name);
3309         if (existing)
3310                 return -EBUSY;
3311
3312         dev->name = name;
3313
3314         return 0;
3315 }
3316
3317 /*
3318  * The caller is responsible for "name" being available whenever f_fs needs it
3319  */
3320 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3321 {
3322         int ret;
3323
3324         ffs_dev_lock();
3325         ret = _ffs_name_dev(dev, name);
3326         ffs_dev_unlock();
3327
3328         return ret;
3329 }
3330 EXPORT_SYMBOL_GPL(ffs_name_dev);
3331
3332 int ffs_single_dev(struct ffs_dev *dev)
3333 {
3334         int ret;
3335
3336         ret = 0;
3337         ffs_dev_lock();
3338
3339         if (!list_is_singular(&ffs_devices))
3340                 ret = -EBUSY;
3341         else
3342                 dev->single = true;
3343
3344         ffs_dev_unlock();
3345         return ret;
3346 }
3347 EXPORT_SYMBOL_GPL(ffs_single_dev);
3348
3349 /*
3350  * ffs_lock must be taken by the caller of this function
3351  */
3352 static void _ffs_free_dev(struct ffs_dev *dev)
3353 {
3354         list_del(&dev->entry);
3355         if (dev->name_allocated)
3356                 kfree(dev->name);
3357         kfree(dev);
3358         if (list_empty(&ffs_devices))
3359                 functionfs_cleanup();
3360 }
3361
3362 static void *ffs_acquire_dev(const char *dev_name)
3363 {
3364         struct ffs_dev *ffs_dev;
3365
3366         ENTER();
3367         ffs_dev_lock();
3368
3369         ffs_dev = _ffs_find_dev(dev_name);
3370         if (!ffs_dev)
3371                 ffs_dev = ERR_PTR(-ENOENT);
3372         else if (ffs_dev->mounted)
3373                 ffs_dev = ERR_PTR(-EBUSY);
3374         else if (ffs_dev->ffs_acquire_dev_callback &&
3375             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3376                 ffs_dev = ERR_PTR(-ENOENT);
3377         else
3378                 ffs_dev->mounted = true;
3379
3380         ffs_dev_unlock();
3381         return ffs_dev;
3382 }
3383
3384 static void ffs_release_dev(struct ffs_data *ffs_data)
3385 {
3386         struct ffs_dev *ffs_dev;
3387
3388         ENTER();
3389         ffs_dev_lock();
3390
3391         ffs_dev = ffs_data->private_data;
3392         if (ffs_dev) {
3393                 ffs_dev->mounted = false;
3394
3395                 if (ffs_dev->ffs_release_dev_callback)
3396                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3397         }
3398
3399         ffs_dev_unlock();
3400 }
3401
3402 static int ffs_ready(struct ffs_data *ffs)
3403 {
3404         struct ffs_dev *ffs_obj;
3405         int ret = 0;
3406
3407         ENTER();
3408         ffs_dev_lock();
3409
3410         ffs_obj = ffs->private_data;
3411         if (!ffs_obj) {
3412                 ret = -EINVAL;
3413                 goto done;
3414         }
3415         if (WARN_ON(ffs_obj->desc_ready)) {
3416                 ret = -EBUSY;
3417                 goto done;
3418         }
3419
3420         ffs_obj->desc_ready = true;
3421         ffs_obj->ffs_data = ffs;
3422
3423         if (ffs_obj->ffs_ready_callback) {
3424                 ret = ffs_obj->ffs_ready_callback(ffs);
3425                 if (ret)
3426                         goto done;
3427         }
3428
3429         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3430 done:
3431         ffs_dev_unlock();
3432         return ret;
3433 }
3434
3435 static void ffs_closed(struct ffs_data *ffs)
3436 {
3437         struct ffs_dev *ffs_obj;
3438
3439         ENTER();
3440         ffs_dev_lock();
3441
3442         ffs_obj = ffs->private_data;
3443         if (!ffs_obj)
3444                 goto done;
3445
3446         ffs_obj->desc_ready = false;
3447
3448         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3449             ffs_obj->ffs_closed_callback)
3450                 ffs_obj->ffs_closed_callback(ffs);
3451
3452         if (!ffs_obj->opts || ffs_obj->opts->no_configfs
3453             || !ffs_obj->opts->func_inst.group.cg_item.ci_parent)
3454                 goto done;
3455
3456         unregister_gadget_item(ffs_obj->opts->
3457                                func_inst.group.cg_item.ci_parent->ci_parent);
3458 done:
3459         ffs_dev_unlock();
3460 }
3461
3462 /* Misc helper functions ****************************************************/
3463
3464 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3465 {
3466         return nonblock
3467                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3468                 : mutex_lock_interruptible(mutex);
3469 }
3470
3471 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3472 {
3473         char *data;
3474
3475         if (unlikely(!len))
3476                 return NULL;
3477
3478         data = kmalloc(len, GFP_KERNEL);
3479         if (unlikely(!data))
3480                 return ERR_PTR(-ENOMEM);
3481
3482         if (unlikely(__copy_from_user(data, buf, len))) {
3483                 kfree(data);
3484                 return ERR_PTR(-EFAULT);
3485         }
3486
3487         pr_vdebug("Buffer from user space:\n");
3488         ffs_dump_mem("", data, len);
3489
3490         return data;
3491 }
3492
3493 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3494 MODULE_LICENSE("GPL");
3495 MODULE_AUTHOR("Michal Nazarewicz");