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