Merge tag 'pinctrl-v4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw...
[sfrench/cifs-2.6.git] / 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/sched/signal.h>
27 #include <linux/uio.h>
28 #include <asm/unaligned.h>
29
30 #include <linux/usb/composite.h>
31 #include <linux/usb/functionfs.h>
32
33 #include <linux/aio.h>
34 #include <linux/mmu_context.h>
35 #include <linux/poll.h>
36 #include <linux/eventfd.h>
37
38 #include "u_fs.h"
39 #include "u_f.h"
40 #include "u_os_desc.h"
41 #include "configfs.h"
42
43 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
44
45 /* Reference counter handling */
46 static void ffs_data_get(struct ffs_data *ffs);
47 static void ffs_data_put(struct ffs_data *ffs);
48 /* Creates new ffs_data object. */
49 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
50
51 /* Opened counter handling. */
52 static void ffs_data_opened(struct ffs_data *ffs);
53 static void ffs_data_closed(struct ffs_data *ffs);
54
55 /* Called with ffs->mutex held; take over ownership of data. */
56 static int __must_check
57 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
58 static int __must_check
59 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
60
61
62 /* The function structure ***************************************************/
63
64 struct ffs_ep;
65
66 struct ffs_function {
67         struct usb_configuration        *conf;
68         struct usb_gadget               *gadget;
69         struct ffs_data                 *ffs;
70
71         struct ffs_ep                   *eps;
72         u8                              eps_revmap[16];
73         short                           *interfaces_nums;
74
75         struct usb_function             function;
76 };
77
78
79 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
80 {
81         return container_of(f, struct ffs_function, function);
82 }
83
84
85 static inline enum ffs_setup_state
86 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
87 {
88         return (enum ffs_setup_state)
89                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
90 }
91
92
93 static void ffs_func_eps_disable(struct ffs_function *func);
94 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
95
96 static int ffs_func_bind(struct usb_configuration *,
97                          struct usb_function *);
98 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
99 static void ffs_func_disable(struct usb_function *);
100 static int ffs_func_setup(struct usb_function *,
101                           const struct usb_ctrlrequest *);
102 static bool ffs_func_req_match(struct usb_function *,
103                                const struct usb_ctrlrequest *,
104                                bool config0);
105 static void ffs_func_suspend(struct usb_function *);
106 static void ffs_func_resume(struct usb_function *);
107
108
109 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
110 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
111
112
113 /* The endpoints structures *************************************************/
114
115 struct ffs_ep {
116         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
117         struct usb_request              *req;   /* P: epfile->mutex */
118
119         /* [0]: full speed, [1]: high speed, [2]: super speed */
120         struct usb_endpoint_descriptor  *descs[3];
121
122         u8                              num;
123
124         int                             status; /* P: epfile->mutex */
125 };
126
127 struct ffs_epfile {
128         /* Protects ep->ep and ep->req. */
129         struct mutex                    mutex;
130         wait_queue_head_t               wait;
131
132         struct ffs_data                 *ffs;
133         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
134
135         struct dentry                   *dentry;
136
137         /*
138          * Buffer for holding data from partial reads which may happen since
139          * we’re rounding user read requests to a multiple of a max packet size.
140          *
141          * The pointer is initialised with NULL value and may be set by
142          * __ffs_epfile_read_data function to point to a temporary buffer.
143          *
144          * In normal operation, calls to __ffs_epfile_read_buffered will consume
145          * data from said buffer and eventually free it.  Importantly, while the
146          * function is using the buffer, it sets the pointer to NULL.  This is
147          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
148          * can never run concurrently (they are synchronised by epfile->mutex)
149          * so the latter will not assign a new value to the pointer.
150          *
151          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
152          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
153          * value is crux of the synchronisation between ffs_func_eps_disable and
154          * __ffs_epfile_read_data.
155          *
156          * Once __ffs_epfile_read_data is about to finish it will try to set the
157          * pointer back to its old value (as described above), but seeing as the
158          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
159          * the buffer.
160          *
161          * == State transitions ==
162          *
163          * • ptr == NULL:  (initial state)
164          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
165          *   ◦ __ffs_epfile_read_buffered:    nop
166          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
167          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
168          * • ptr == DROP:
169          *   ◦ __ffs_epfile_read_buffer_free: nop
170          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
171          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
172          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
173          * • ptr == buf:
174          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
175          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
176          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
177          *                                    is always called first
178          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
179          * • ptr == NULL and reading:
180          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
181          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
182          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
183          *   ◦ reading finishes and …
184          *     … all data read:               free buf, go to ptr == NULL
185          *     … otherwise:                   go to ptr == buf and reading
186          * • ptr == DROP and reading:
187          *   ◦ __ffs_epfile_read_buffer_free: nop
188          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
189          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
190          *   ◦ reading finishes:              free buf, go to ptr == DROP
191          */
192         struct ffs_buffer               *read_buffer;
193 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
194
195         char                            name[5];
196
197         unsigned char                   in;     /* P: ffs->eps_lock */
198         unsigned char                   isoc;   /* P: ffs->eps_lock */
199
200         unsigned char                   _pad;
201 };
202
203 struct ffs_buffer {
204         size_t length;
205         char *data;
206         char storage[];
207 };
208
209 /*  ffs_io_data structure ***************************************************/
210
211 struct ffs_io_data {
212         bool aio;
213         bool read;
214
215         struct kiocb *kiocb;
216         struct iov_iter data;
217         const void *to_free;
218         char *buf;
219
220         struct mm_struct *mm;
221         struct work_struct work;
222
223         struct usb_ep *ep;
224         struct usb_request *req;
225
226         struct ffs_data *ffs;
227 };
228
229 struct ffs_desc_helper {
230         struct ffs_data *ffs;
231         unsigned interfaces_count;
232         unsigned eps_count;
233 };
234
235 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
236 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
237
238 static struct dentry *
239 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
240                    const struct file_operations *fops);
241
242 /* Devices management *******************************************************/
243
244 DEFINE_MUTEX(ffs_lock);
245 EXPORT_SYMBOL_GPL(ffs_lock);
246
247 static struct ffs_dev *_ffs_find_dev(const char *name);
248 static struct ffs_dev *_ffs_alloc_dev(void);
249 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
250 static void _ffs_free_dev(struct ffs_dev *dev);
251 static void *ffs_acquire_dev(const char *dev_name);
252 static void ffs_release_dev(struct ffs_data *ffs_data);
253 static int ffs_ready(struct ffs_data *ffs);
254 static void ffs_closed(struct ffs_data *ffs);
255
256 /* Misc helper functions ****************************************************/
257
258 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
259         __attribute__((warn_unused_result, nonnull));
260 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
261         __attribute__((warn_unused_result, nonnull));
262
263
264 /* Control file aka ep0 *****************************************************/
265
266 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
267 {
268         struct ffs_data *ffs = req->context;
269
270         complete(&ffs->ep0req_completion);
271 }
272
273 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
274 {
275         struct usb_request *req = ffs->ep0req;
276         int ret;
277
278         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
279
280         spin_unlock_irq(&ffs->ev.waitq.lock);
281
282         req->buf      = data;
283         req->length   = len;
284
285         /*
286          * UDC layer requires to provide a buffer even for ZLP, but should
287          * not use it at all. Let's provide some poisoned pointer to catch
288          * possible bug in the driver.
289          */
290         if (req->buf == NULL)
291                 req->buf = (void *)0xDEADBABE;
292
293         reinit_completion(&ffs->ep0req_completion);
294
295         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
296         if (unlikely(ret < 0))
297                 return ret;
298
299         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
300         if (unlikely(ret)) {
301                 usb_ep_dequeue(ffs->gadget->ep0, req);
302                 return -EINTR;
303         }
304
305         ffs->setup_state = FFS_NO_SETUP;
306         return req->status ? req->status : req->actual;
307 }
308
309 static int __ffs_ep0_stall(struct ffs_data *ffs)
310 {
311         if (ffs->ev.can_stall) {
312                 pr_vdebug("ep0 stall\n");
313                 usb_ep_set_halt(ffs->gadget->ep0);
314                 ffs->setup_state = FFS_NO_SETUP;
315                 return -EL2HLT;
316         } else {
317                 pr_debug("bogus ep0 stall!\n");
318                 return -ESRCH;
319         }
320 }
321
322 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
323                              size_t len, loff_t *ptr)
324 {
325         struct ffs_data *ffs = file->private_data;
326         ssize_t ret;
327         char *data;
328
329         ENTER();
330
331         /* Fast check if setup was canceled */
332         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
333                 return -EIDRM;
334
335         /* Acquire mutex */
336         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
337         if (unlikely(ret < 0))
338                 return ret;
339
340         /* Check state */
341         switch (ffs->state) {
342         case FFS_READ_DESCRIPTORS:
343         case FFS_READ_STRINGS:
344                 /* Copy data */
345                 if (unlikely(len < 16)) {
346                         ret = -EINVAL;
347                         break;
348                 }
349
350                 data = ffs_prepare_buffer(buf, len);
351                 if (IS_ERR(data)) {
352                         ret = PTR_ERR(data);
353                         break;
354                 }
355
356                 /* Handle data */
357                 if (ffs->state == FFS_READ_DESCRIPTORS) {
358                         pr_info("read descriptors\n");
359                         ret = __ffs_data_got_descs(ffs, data, len);
360                         if (unlikely(ret < 0))
361                                 break;
362
363                         ffs->state = FFS_READ_STRINGS;
364                         ret = len;
365                 } else {
366                         pr_info("read strings\n");
367                         ret = __ffs_data_got_strings(ffs, data, len);
368                         if (unlikely(ret < 0))
369                                 break;
370
371                         ret = ffs_epfiles_create(ffs);
372                         if (unlikely(ret)) {
373                                 ffs->state = FFS_CLOSING;
374                                 break;
375                         }
376
377                         ffs->state = FFS_ACTIVE;
378                         mutex_unlock(&ffs->mutex);
379
380                         ret = ffs_ready(ffs);
381                         if (unlikely(ret < 0)) {
382                                 ffs->state = FFS_CLOSING;
383                                 return ret;
384                         }
385
386                         return len;
387                 }
388                 break;
389
390         case FFS_ACTIVE:
391                 data = NULL;
392                 /*
393                  * We're called from user space, we can use _irq
394                  * rather then _irqsave
395                  */
396                 spin_lock_irq(&ffs->ev.waitq.lock);
397                 switch (ffs_setup_state_clear_cancelled(ffs)) {
398                 case FFS_SETUP_CANCELLED:
399                         ret = -EIDRM;
400                         goto done_spin;
401
402                 case FFS_NO_SETUP:
403                         ret = -ESRCH;
404                         goto done_spin;
405
406                 case FFS_SETUP_PENDING:
407                         break;
408                 }
409
410                 /* FFS_SETUP_PENDING */
411                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
412                         spin_unlock_irq(&ffs->ev.waitq.lock);
413                         ret = __ffs_ep0_stall(ffs);
414                         break;
415                 }
416
417                 /* FFS_SETUP_PENDING and not stall */
418                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
419
420                 spin_unlock_irq(&ffs->ev.waitq.lock);
421
422                 data = ffs_prepare_buffer(buf, len);
423                 if (IS_ERR(data)) {
424                         ret = PTR_ERR(data);
425                         break;
426                 }
427
428                 spin_lock_irq(&ffs->ev.waitq.lock);
429
430                 /*
431                  * We are guaranteed to be still in FFS_ACTIVE state
432                  * but the state of setup could have changed from
433                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
434                  * to check for that.  If that happened we copied data
435                  * from user space in vain but it's unlikely.
436                  *
437                  * For sure we are not in FFS_NO_SETUP since this is
438                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
439                  * transition can be performed and it's protected by
440                  * mutex.
441                  */
442                 if (ffs_setup_state_clear_cancelled(ffs) ==
443                     FFS_SETUP_CANCELLED) {
444                         ret = -EIDRM;
445 done_spin:
446                         spin_unlock_irq(&ffs->ev.waitq.lock);
447                 } else {
448                         /* unlocks spinlock */
449                         ret = __ffs_ep0_queue_wait(ffs, data, len);
450                 }
451                 kfree(data);
452                 break;
453
454         default:
455                 ret = -EBADFD;
456                 break;
457         }
458
459         mutex_unlock(&ffs->mutex);
460         return ret;
461 }
462
463 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
464 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
465                                      size_t n)
466 {
467         /*
468          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
469          * size of ffs->ev.types array (which is four) so that's how much space
470          * we reserve.
471          */
472         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
473         const size_t size = n * sizeof *events;
474         unsigned i = 0;
475
476         memset(events, 0, size);
477
478         do {
479                 events[i].type = ffs->ev.types[i];
480                 if (events[i].type == FUNCTIONFS_SETUP) {
481                         events[i].u.setup = ffs->ev.setup;
482                         ffs->setup_state = FFS_SETUP_PENDING;
483                 }
484         } while (++i < n);
485
486         ffs->ev.count -= n;
487         if (ffs->ev.count)
488                 memmove(ffs->ev.types, ffs->ev.types + n,
489                         ffs->ev.count * sizeof *ffs->ev.types);
490
491         spin_unlock_irq(&ffs->ev.waitq.lock);
492         mutex_unlock(&ffs->mutex);
493
494         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
495 }
496
497 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
498                             size_t len, loff_t *ptr)
499 {
500         struct ffs_data *ffs = file->private_data;
501         char *data = NULL;
502         size_t n;
503         int ret;
504
505         ENTER();
506
507         /* Fast check if setup was canceled */
508         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
509                 return -EIDRM;
510
511         /* Acquire mutex */
512         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
513         if (unlikely(ret < 0))
514                 return ret;
515
516         /* Check state */
517         if (ffs->state != FFS_ACTIVE) {
518                 ret = -EBADFD;
519                 goto done_mutex;
520         }
521
522         /*
523          * We're called from user space, we can use _irq rather then
524          * _irqsave
525          */
526         spin_lock_irq(&ffs->ev.waitq.lock);
527
528         switch (ffs_setup_state_clear_cancelled(ffs)) {
529         case FFS_SETUP_CANCELLED:
530                 ret = -EIDRM;
531                 break;
532
533         case FFS_NO_SETUP:
534                 n = len / sizeof(struct usb_functionfs_event);
535                 if (unlikely(!n)) {
536                         ret = -EINVAL;
537                         break;
538                 }
539
540                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
541                         ret = -EAGAIN;
542                         break;
543                 }
544
545                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
546                                                         ffs->ev.count)) {
547                         ret = -EINTR;
548                         break;
549                 }
550
551                 return __ffs_ep0_read_events(ffs, buf,
552                                              min(n, (size_t)ffs->ev.count));
553
554         case FFS_SETUP_PENDING:
555                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
556                         spin_unlock_irq(&ffs->ev.waitq.lock);
557                         ret = __ffs_ep0_stall(ffs);
558                         goto done_mutex;
559                 }
560
561                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
562
563                 spin_unlock_irq(&ffs->ev.waitq.lock);
564
565                 if (likely(len)) {
566                         data = kmalloc(len, GFP_KERNEL);
567                         if (unlikely(!data)) {
568                                 ret = -ENOMEM;
569                                 goto done_mutex;
570                         }
571                 }
572
573                 spin_lock_irq(&ffs->ev.waitq.lock);
574
575                 /* See ffs_ep0_write() */
576                 if (ffs_setup_state_clear_cancelled(ffs) ==
577                     FFS_SETUP_CANCELLED) {
578                         ret = -EIDRM;
579                         break;
580                 }
581
582                 /* unlocks spinlock */
583                 ret = __ffs_ep0_queue_wait(ffs, data, len);
584                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
585                         ret = -EFAULT;
586                 goto done_mutex;
587
588         default:
589                 ret = -EBADFD;
590                 break;
591         }
592
593         spin_unlock_irq(&ffs->ev.waitq.lock);
594 done_mutex:
595         mutex_unlock(&ffs->mutex);
596         kfree(data);
597         return ret;
598 }
599
600 static int ffs_ep0_open(struct inode *inode, struct file *file)
601 {
602         struct ffs_data *ffs = inode->i_private;
603
604         ENTER();
605
606         if (unlikely(ffs->state == FFS_CLOSING))
607                 return -EBUSY;
608
609         file->private_data = ffs;
610         ffs_data_opened(ffs);
611
612         return 0;
613 }
614
615 static int ffs_ep0_release(struct inode *inode, struct file *file)
616 {
617         struct ffs_data *ffs = file->private_data;
618
619         ENTER();
620
621         ffs_data_closed(ffs);
622
623         return 0;
624 }
625
626 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
627 {
628         struct ffs_data *ffs = file->private_data;
629         struct usb_gadget *gadget = ffs->gadget;
630         long ret;
631
632         ENTER();
633
634         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
635                 struct ffs_function *func = ffs->func;
636                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
637         } else if (gadget && gadget->ops->ioctl) {
638                 ret = gadget->ops->ioctl(gadget, code, value);
639         } else {
640                 ret = -ENOTTY;
641         }
642
643         return ret;
644 }
645
646 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
647 {
648         struct ffs_data *ffs = file->private_data;
649         unsigned int mask = POLLWRNORM;
650         int ret;
651
652         poll_wait(file, &ffs->ev.waitq, wait);
653
654         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
655         if (unlikely(ret < 0))
656                 return mask;
657
658         switch (ffs->state) {
659         case FFS_READ_DESCRIPTORS:
660         case FFS_READ_STRINGS:
661                 mask |= POLLOUT;
662                 break;
663
664         case FFS_ACTIVE:
665                 switch (ffs->setup_state) {
666                 case FFS_NO_SETUP:
667                         if (ffs->ev.count)
668                                 mask |= POLLIN;
669                         break;
670
671                 case FFS_SETUP_PENDING:
672                 case FFS_SETUP_CANCELLED:
673                         mask |= (POLLIN | POLLOUT);
674                         break;
675                 }
676         case FFS_CLOSING:
677                 break;
678         case FFS_DEACTIVATED:
679                 break;
680         }
681
682         mutex_unlock(&ffs->mutex);
683
684         return mask;
685 }
686
687 static const struct file_operations ffs_ep0_operations = {
688         .llseek =       no_llseek,
689
690         .open =         ffs_ep0_open,
691         .write =        ffs_ep0_write,
692         .read =         ffs_ep0_read,
693         .release =      ffs_ep0_release,
694         .unlocked_ioctl =       ffs_ep0_ioctl,
695         .poll =         ffs_ep0_poll,
696 };
697
698
699 /* "Normal" endpoints operations ********************************************/
700
701 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
702 {
703         ENTER();
704         if (likely(req->context)) {
705                 struct ffs_ep *ep = _ep->driver_data;
706                 ep->status = req->status ? req->status : req->actual;
707                 complete(req->context);
708         }
709 }
710
711 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
712 {
713         ssize_t ret = copy_to_iter(data, data_len, iter);
714         if (likely(ret == data_len))
715                 return ret;
716
717         if (unlikely(iov_iter_count(iter)))
718                 return -EFAULT;
719
720         /*
721          * Dear user space developer!
722          *
723          * TL;DR: To stop getting below error message in your kernel log, change
724          * user space code using functionfs to align read buffers to a max
725          * packet size.
726          *
727          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
728          * packet size.  When unaligned buffer is passed to functionfs, it
729          * internally uses a larger, aligned buffer so that such UDCs are happy.
730          *
731          * Unfortunately, this means that host may send more data than was
732          * requested in read(2) system call.  f_fs doesn’t know what to do with
733          * that excess data so it simply drops it.
734          *
735          * Was the buffer aligned in the first place, no such problem would
736          * happen.
737          *
738          * Data may be dropped only in AIO reads.  Synchronous reads are handled
739          * by splitting a request into multiple parts.  This splitting may still
740          * be a problem though so it’s likely best to align the buffer
741          * regardless of it being AIO or not..
742          *
743          * This only affects OUT endpoints, i.e. reading data with a read(2),
744          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
745          * affected.
746          */
747         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
748                "Align read buffer size to max packet size to avoid the problem.\n",
749                data_len, ret);
750
751         return ret;
752 }
753
754 static void ffs_user_copy_worker(struct work_struct *work)
755 {
756         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
757                                                    work);
758         int ret = io_data->req->status ? io_data->req->status :
759                                          io_data->req->actual;
760         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
761
762         if (io_data->read && ret > 0) {
763                 use_mm(io_data->mm);
764                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
765                 unuse_mm(io_data->mm);
766         }
767
768         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
769
770         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
771                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
772
773         usb_ep_free_request(io_data->ep, io_data->req);
774
775         if (io_data->read)
776                 kfree(io_data->to_free);
777         kfree(io_data->buf);
778         kfree(io_data);
779 }
780
781 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
782                                          struct usb_request *req)
783 {
784         struct ffs_io_data *io_data = req->context;
785
786         ENTER();
787
788         INIT_WORK(&io_data->work, ffs_user_copy_worker);
789         schedule_work(&io_data->work);
790 }
791
792 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
793 {
794         /*
795          * See comment in struct ffs_epfile for full read_buffer pointer
796          * synchronisation story.
797          */
798         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
799         if (buf && buf != READ_BUFFER_DROP)
800                 kfree(buf);
801 }
802
803 /* Assumes epfile->mutex is held. */
804 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
805                                           struct iov_iter *iter)
806 {
807         /*
808          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
809          * the buffer while we are using it.  See comment in struct ffs_epfile
810          * for full read_buffer pointer synchronisation story.
811          */
812         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
813         ssize_t ret;
814         if (!buf || buf == READ_BUFFER_DROP)
815                 return 0;
816
817         ret = copy_to_iter(buf->data, buf->length, iter);
818         if (buf->length == ret) {
819                 kfree(buf);
820                 return ret;
821         }
822
823         if (unlikely(iov_iter_count(iter))) {
824                 ret = -EFAULT;
825         } else {
826                 buf->length -= ret;
827                 buf->data += ret;
828         }
829
830         if (cmpxchg(&epfile->read_buffer, NULL, buf))
831                 kfree(buf);
832
833         return ret;
834 }
835
836 /* Assumes epfile->mutex is held. */
837 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
838                                       void *data, int data_len,
839                                       struct iov_iter *iter)
840 {
841         struct ffs_buffer *buf;
842
843         ssize_t ret = copy_to_iter(data, data_len, iter);
844         if (likely(data_len == ret))
845                 return ret;
846
847         if (unlikely(iov_iter_count(iter)))
848                 return -EFAULT;
849
850         /* See ffs_copy_to_iter for more context. */
851         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
852                 data_len, ret);
853
854         data_len -= ret;
855         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
856         if (!buf)
857                 return -ENOMEM;
858         buf->length = data_len;
859         buf->data = buf->storage;
860         memcpy(buf->storage, data + ret, data_len);
861
862         /*
863          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
864          * ffs_func_eps_disable has been called in the meanwhile).  See comment
865          * in struct ffs_epfile for full read_buffer pointer synchronisation
866          * story.
867          */
868         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
869                 kfree(buf);
870
871         return ret;
872 }
873
874 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
875 {
876         struct ffs_epfile *epfile = file->private_data;
877         struct usb_request *req;
878         struct ffs_ep *ep;
879         char *data = NULL;
880         ssize_t ret, data_len = -EINVAL;
881         int halt;
882
883         /* Are we still active? */
884         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
885                 return -ENODEV;
886
887         /* Wait for endpoint to be enabled */
888         ep = epfile->ep;
889         if (!ep) {
890                 if (file->f_flags & O_NONBLOCK)
891                         return -EAGAIN;
892
893                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
894                 if (ret)
895                         return -EINTR;
896         }
897
898         /* Do we halt? */
899         halt = (!io_data->read == !epfile->in);
900         if (halt && epfile->isoc)
901                 return -EINVAL;
902
903         /* We will be using request and read_buffer */
904         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
905         if (unlikely(ret))
906                 goto error;
907
908         /* Allocate & copy */
909         if (!halt) {
910                 struct usb_gadget *gadget;
911
912                 /*
913                  * Do we have buffered data from previous partial read?  Check
914                  * that for synchronous case only because we do not have
915                  * facility to ‘wake up’ a pending asynchronous read and push
916                  * buffered data to it which we would need to make things behave
917                  * consistently.
918                  */
919                 if (!io_data->aio && io_data->read) {
920                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
921                         if (ret)
922                                 goto error_mutex;
923                 }
924
925                 /*
926                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
927                  * before the waiting completes, so do not assign to 'gadget'
928                  * earlier
929                  */
930                 gadget = epfile->ffs->gadget;
931
932                 spin_lock_irq(&epfile->ffs->eps_lock);
933                 /* In the meantime, endpoint got disabled or changed. */
934                 if (epfile->ep != ep) {
935                         ret = -ESHUTDOWN;
936                         goto error_lock;
937                 }
938                 data_len = iov_iter_count(&io_data->data);
939                 /*
940                  * Controller may require buffer size to be aligned to
941                  * maxpacketsize of an out endpoint.
942                  */
943                 if (io_data->read)
944                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
945                 spin_unlock_irq(&epfile->ffs->eps_lock);
946
947                 data = kmalloc(data_len, GFP_KERNEL);
948                 if (unlikely(!data)) {
949                         ret = -ENOMEM;
950                         goto error_mutex;
951                 }
952                 if (!io_data->read &&
953                     !copy_from_iter_full(data, data_len, &io_data->data)) {
954                         ret = -EFAULT;
955                         goto error_mutex;
956                 }
957         }
958
959         spin_lock_irq(&epfile->ffs->eps_lock);
960
961         if (epfile->ep != ep) {
962                 /* In the meantime, endpoint got disabled or changed. */
963                 ret = -ESHUTDOWN;
964         } else if (halt) {
965                 /* Halt */
966                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
967                         usb_ep_set_halt(ep->ep);
968                 ret = -EBADMSG;
969         } else if (unlikely(data_len == -EINVAL)) {
970                 /*
971                  * Sanity Check: even though data_len can't be used
972                  * uninitialized at the time I write this comment, some
973                  * compilers complain about this situation.
974                  * In order to keep the code clean from warnings, data_len is
975                  * being initialized to -EINVAL during its declaration, which
976                  * means we can't rely on compiler anymore to warn no future
977                  * changes won't result in data_len being used uninitialized.
978                  * For such reason, we're adding this redundant sanity check
979                  * here.
980                  */
981                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
982                 ret = -EINVAL;
983         } else if (!io_data->aio) {
984                 DECLARE_COMPLETION_ONSTACK(done);
985                 bool interrupted = false;
986
987                 req = ep->req;
988                 req->buf      = data;
989                 req->length   = data_len;
990
991                 req->context  = &done;
992                 req->complete = ffs_epfile_io_complete;
993
994                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
995                 if (unlikely(ret < 0))
996                         goto error_lock;
997
998                 spin_unlock_irq(&epfile->ffs->eps_lock);
999
1000                 if (unlikely(wait_for_completion_interruptible(&done))) {
1001                         /*
1002                          * To avoid race condition with ffs_epfile_io_complete,
1003                          * dequeue the request first then check
1004                          * status. usb_ep_dequeue API should guarantee no race
1005                          * condition with req->complete callback.
1006                          */
1007                         usb_ep_dequeue(ep->ep, req);
1008                         interrupted = ep->status < 0;
1009                 }
1010
1011                 if (interrupted)
1012                         ret = -EINTR;
1013                 else if (io_data->read && ep->status > 0)
1014                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1015                                                      &io_data->data);
1016                 else
1017                         ret = ep->status;
1018                 goto error_mutex;
1019         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_KERNEL))) {
1020                 ret = -ENOMEM;
1021         } else {
1022                 req->buf      = data;
1023                 req->length   = data_len;
1024
1025                 io_data->buf = data;
1026                 io_data->ep = ep->ep;
1027                 io_data->req = req;
1028                 io_data->ffs = epfile->ffs;
1029
1030                 req->context  = io_data;
1031                 req->complete = ffs_epfile_async_io_complete;
1032
1033                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1034                 if (unlikely(ret)) {
1035                         usb_ep_free_request(ep->ep, req);
1036                         goto error_lock;
1037                 }
1038
1039                 ret = -EIOCBQUEUED;
1040                 /*
1041                  * Do not kfree the buffer in this function.  It will be freed
1042                  * by ffs_user_copy_worker.
1043                  */
1044                 data = NULL;
1045         }
1046
1047 error_lock:
1048         spin_unlock_irq(&epfile->ffs->eps_lock);
1049 error_mutex:
1050         mutex_unlock(&epfile->mutex);
1051 error:
1052         kfree(data);
1053         return ret;
1054 }
1055
1056 static int
1057 ffs_epfile_open(struct inode *inode, struct file *file)
1058 {
1059         struct ffs_epfile *epfile = inode->i_private;
1060
1061         ENTER();
1062
1063         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1064                 return -ENODEV;
1065
1066         file->private_data = epfile;
1067         ffs_data_opened(epfile->ffs);
1068
1069         return 0;
1070 }
1071
1072 static int ffs_aio_cancel(struct kiocb *kiocb)
1073 {
1074         struct ffs_io_data *io_data = kiocb->private;
1075         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1076         int value;
1077
1078         ENTER();
1079
1080         spin_lock_irq(&epfile->ffs->eps_lock);
1081
1082         if (likely(io_data && io_data->ep && io_data->req))
1083                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1084         else
1085                 value = -EINVAL;
1086
1087         spin_unlock_irq(&epfile->ffs->eps_lock);
1088
1089         return value;
1090 }
1091
1092 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1093 {
1094         struct ffs_io_data io_data, *p = &io_data;
1095         ssize_t res;
1096
1097         ENTER();
1098
1099         if (!is_sync_kiocb(kiocb)) {
1100                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1101                 if (unlikely(!p))
1102                         return -ENOMEM;
1103                 p->aio = true;
1104         } else {
1105                 p->aio = false;
1106         }
1107
1108         p->read = false;
1109         p->kiocb = kiocb;
1110         p->data = *from;
1111         p->mm = current->mm;
1112
1113         kiocb->private = p;
1114
1115         if (p->aio)
1116                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1117
1118         res = ffs_epfile_io(kiocb->ki_filp, p);
1119         if (res == -EIOCBQUEUED)
1120                 return res;
1121         if (p->aio)
1122                 kfree(p);
1123         else
1124                 *from = p->data;
1125         return res;
1126 }
1127
1128 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1129 {
1130         struct ffs_io_data io_data, *p = &io_data;
1131         ssize_t res;
1132
1133         ENTER();
1134
1135         if (!is_sync_kiocb(kiocb)) {
1136                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1137                 if (unlikely(!p))
1138                         return -ENOMEM;
1139                 p->aio = true;
1140         } else {
1141                 p->aio = false;
1142         }
1143
1144         p->read = true;
1145         p->kiocb = kiocb;
1146         if (p->aio) {
1147                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1148                 if (!p->to_free) {
1149                         kfree(p);
1150                         return -ENOMEM;
1151                 }
1152         } else {
1153                 p->data = *to;
1154                 p->to_free = NULL;
1155         }
1156         p->mm = current->mm;
1157
1158         kiocb->private = p;
1159
1160         if (p->aio)
1161                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1162
1163         res = ffs_epfile_io(kiocb->ki_filp, p);
1164         if (res == -EIOCBQUEUED)
1165                 return res;
1166
1167         if (p->aio) {
1168                 kfree(p->to_free);
1169                 kfree(p);
1170         } else {
1171                 *to = p->data;
1172         }
1173         return res;
1174 }
1175
1176 static int
1177 ffs_epfile_release(struct inode *inode, struct file *file)
1178 {
1179         struct ffs_epfile *epfile = inode->i_private;
1180
1181         ENTER();
1182
1183         __ffs_epfile_read_buffer_free(epfile);
1184         ffs_data_closed(epfile->ffs);
1185
1186         return 0;
1187 }
1188
1189 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1190                              unsigned long value)
1191 {
1192         struct ffs_epfile *epfile = file->private_data;
1193         int ret;
1194
1195         ENTER();
1196
1197         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1198                 return -ENODEV;
1199
1200         spin_lock_irq(&epfile->ffs->eps_lock);
1201         if (likely(epfile->ep)) {
1202                 switch (code) {
1203                 case FUNCTIONFS_FIFO_STATUS:
1204                         ret = usb_ep_fifo_status(epfile->ep->ep);
1205                         break;
1206                 case FUNCTIONFS_FIFO_FLUSH:
1207                         usb_ep_fifo_flush(epfile->ep->ep);
1208                         ret = 0;
1209                         break;
1210                 case FUNCTIONFS_CLEAR_HALT:
1211                         ret = usb_ep_clear_halt(epfile->ep->ep);
1212                         break;
1213                 case FUNCTIONFS_ENDPOINT_REVMAP:
1214                         ret = epfile->ep->num;
1215                         break;
1216                 case FUNCTIONFS_ENDPOINT_DESC:
1217                 {
1218                         int desc_idx;
1219                         struct usb_endpoint_descriptor *desc;
1220
1221                         switch (epfile->ffs->gadget->speed) {
1222                         case USB_SPEED_SUPER:
1223                                 desc_idx = 2;
1224                                 break;
1225                         case USB_SPEED_HIGH:
1226                                 desc_idx = 1;
1227                                 break;
1228                         default:
1229                                 desc_idx = 0;
1230                         }
1231                         desc = epfile->ep->descs[desc_idx];
1232
1233                         spin_unlock_irq(&epfile->ffs->eps_lock);
1234                         ret = copy_to_user((void *)value, desc, desc->bLength);
1235                         if (ret)
1236                                 ret = -EFAULT;
1237                         return ret;
1238                 }
1239                 default:
1240                         ret = -ENOTTY;
1241                 }
1242         } else {
1243                 ret = -ENODEV;
1244         }
1245         spin_unlock_irq(&epfile->ffs->eps_lock);
1246
1247         return ret;
1248 }
1249
1250 static const struct file_operations ffs_epfile_operations = {
1251         .llseek =       no_llseek,
1252
1253         .open =         ffs_epfile_open,
1254         .write_iter =   ffs_epfile_write_iter,
1255         .read_iter =    ffs_epfile_read_iter,
1256         .release =      ffs_epfile_release,
1257         .unlocked_ioctl =       ffs_epfile_ioctl,
1258 };
1259
1260
1261 /* File system and super block operations ***********************************/
1262
1263 /*
1264  * Mounting the file system creates a controller file, used first for
1265  * function configuration then later for event monitoring.
1266  */
1267
1268 static struct inode *__must_check
1269 ffs_sb_make_inode(struct super_block *sb, void *data,
1270                   const struct file_operations *fops,
1271                   const struct inode_operations *iops,
1272                   struct ffs_file_perms *perms)
1273 {
1274         struct inode *inode;
1275
1276         ENTER();
1277
1278         inode = new_inode(sb);
1279
1280         if (likely(inode)) {
1281                 struct timespec ts = current_time(inode);
1282
1283                 inode->i_ino     = get_next_ino();
1284                 inode->i_mode    = perms->mode;
1285                 inode->i_uid     = perms->uid;
1286                 inode->i_gid     = perms->gid;
1287                 inode->i_atime   = ts;
1288                 inode->i_mtime   = ts;
1289                 inode->i_ctime   = ts;
1290                 inode->i_private = data;
1291                 if (fops)
1292                         inode->i_fop = fops;
1293                 if (iops)
1294                         inode->i_op  = iops;
1295         }
1296
1297         return inode;
1298 }
1299
1300 /* Create "regular" file */
1301 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1302                                         const char *name, void *data,
1303                                         const struct file_operations *fops)
1304 {
1305         struct ffs_data *ffs = sb->s_fs_info;
1306         struct dentry   *dentry;
1307         struct inode    *inode;
1308
1309         ENTER();
1310
1311         dentry = d_alloc_name(sb->s_root, name);
1312         if (unlikely(!dentry))
1313                 return NULL;
1314
1315         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1316         if (unlikely(!inode)) {
1317                 dput(dentry);
1318                 return NULL;
1319         }
1320
1321         d_add(dentry, inode);
1322         return dentry;
1323 }
1324
1325 /* Super block */
1326 static const struct super_operations ffs_sb_operations = {
1327         .statfs =       simple_statfs,
1328         .drop_inode =   generic_delete_inode,
1329 };
1330
1331 struct ffs_sb_fill_data {
1332         struct ffs_file_perms perms;
1333         umode_t root_mode;
1334         const char *dev_name;
1335         bool no_disconnect;
1336         struct ffs_data *ffs_data;
1337 };
1338
1339 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1340 {
1341         struct ffs_sb_fill_data *data = _data;
1342         struct inode    *inode;
1343         struct ffs_data *ffs = data->ffs_data;
1344
1345         ENTER();
1346
1347         ffs->sb              = sb;
1348         data->ffs_data       = NULL;
1349         sb->s_fs_info        = ffs;
1350         sb->s_blocksize      = PAGE_SIZE;
1351         sb->s_blocksize_bits = PAGE_SHIFT;
1352         sb->s_magic          = FUNCTIONFS_MAGIC;
1353         sb->s_op             = &ffs_sb_operations;
1354         sb->s_time_gran      = 1;
1355
1356         /* Root inode */
1357         data->perms.mode = data->root_mode;
1358         inode = ffs_sb_make_inode(sb, NULL,
1359                                   &simple_dir_operations,
1360                                   &simple_dir_inode_operations,
1361                                   &data->perms);
1362         sb->s_root = d_make_root(inode);
1363         if (unlikely(!sb->s_root))
1364                 return -ENOMEM;
1365
1366         /* EP0 file */
1367         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1368                                          &ffs_ep0_operations)))
1369                 return -ENOMEM;
1370
1371         return 0;
1372 }
1373
1374 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1375 {
1376         ENTER();
1377
1378         if (!opts || !*opts)
1379                 return 0;
1380
1381         for (;;) {
1382                 unsigned long value;
1383                 char *eq, *comma;
1384
1385                 /* Option limit */
1386                 comma = strchr(opts, ',');
1387                 if (comma)
1388                         *comma = 0;
1389
1390                 /* Value limit */
1391                 eq = strchr(opts, '=');
1392                 if (unlikely(!eq)) {
1393                         pr_err("'=' missing in %s\n", opts);
1394                         return -EINVAL;
1395                 }
1396                 *eq = 0;
1397
1398                 /* Parse value */
1399                 if (kstrtoul(eq + 1, 0, &value)) {
1400                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1401                         return -EINVAL;
1402                 }
1403
1404                 /* Interpret option */
1405                 switch (eq - opts) {
1406                 case 13:
1407                         if (!memcmp(opts, "no_disconnect", 13))
1408                                 data->no_disconnect = !!value;
1409                         else
1410                                 goto invalid;
1411                         break;
1412                 case 5:
1413                         if (!memcmp(opts, "rmode", 5))
1414                                 data->root_mode  = (value & 0555) | S_IFDIR;
1415                         else if (!memcmp(opts, "fmode", 5))
1416                                 data->perms.mode = (value & 0666) | S_IFREG;
1417                         else
1418                                 goto invalid;
1419                         break;
1420
1421                 case 4:
1422                         if (!memcmp(opts, "mode", 4)) {
1423                                 data->root_mode  = (value & 0555) | S_IFDIR;
1424                                 data->perms.mode = (value & 0666) | S_IFREG;
1425                         } else {
1426                                 goto invalid;
1427                         }
1428                         break;
1429
1430                 case 3:
1431                         if (!memcmp(opts, "uid", 3)) {
1432                                 data->perms.uid = make_kuid(current_user_ns(), value);
1433                                 if (!uid_valid(data->perms.uid)) {
1434                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1435                                         return -EINVAL;
1436                                 }
1437                         } else if (!memcmp(opts, "gid", 3)) {
1438                                 data->perms.gid = make_kgid(current_user_ns(), value);
1439                                 if (!gid_valid(data->perms.gid)) {
1440                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1441                                         return -EINVAL;
1442                                 }
1443                         } else {
1444                                 goto invalid;
1445                         }
1446                         break;
1447
1448                 default:
1449 invalid:
1450                         pr_err("%s: invalid option\n", opts);
1451                         return -EINVAL;
1452                 }
1453
1454                 /* Next iteration */
1455                 if (!comma)
1456                         break;
1457                 opts = comma + 1;
1458         }
1459
1460         return 0;
1461 }
1462
1463 /* "mount -t functionfs dev_name /dev/function" ends up here */
1464
1465 static struct dentry *
1466 ffs_fs_mount(struct file_system_type *t, int flags,
1467               const char *dev_name, void *opts)
1468 {
1469         struct ffs_sb_fill_data data = {
1470                 .perms = {
1471                         .mode = S_IFREG | 0600,
1472                         .uid = GLOBAL_ROOT_UID,
1473                         .gid = GLOBAL_ROOT_GID,
1474                 },
1475                 .root_mode = S_IFDIR | 0500,
1476                 .no_disconnect = false,
1477         };
1478         struct dentry *rv;
1479         int ret;
1480         void *ffs_dev;
1481         struct ffs_data *ffs;
1482
1483         ENTER();
1484
1485         ret = ffs_fs_parse_opts(&data, opts);
1486         if (unlikely(ret < 0))
1487                 return ERR_PTR(ret);
1488
1489         ffs = ffs_data_new();
1490         if (unlikely(!ffs))
1491                 return ERR_PTR(-ENOMEM);
1492         ffs->file_perms = data.perms;
1493         ffs->no_disconnect = data.no_disconnect;
1494
1495         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1496         if (unlikely(!ffs->dev_name)) {
1497                 ffs_data_put(ffs);
1498                 return ERR_PTR(-ENOMEM);
1499         }
1500
1501         ffs_dev = ffs_acquire_dev(dev_name);
1502         if (IS_ERR(ffs_dev)) {
1503                 ffs_data_put(ffs);
1504                 return ERR_CAST(ffs_dev);
1505         }
1506         ffs->private_data = ffs_dev;
1507         data.ffs_data = ffs;
1508
1509         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1510         if (IS_ERR(rv) && data.ffs_data) {
1511                 ffs_release_dev(data.ffs_data);
1512                 ffs_data_put(data.ffs_data);
1513         }
1514         return rv;
1515 }
1516
1517 static void
1518 ffs_fs_kill_sb(struct super_block *sb)
1519 {
1520         ENTER();
1521
1522         kill_litter_super(sb);
1523         if (sb->s_fs_info) {
1524                 ffs_release_dev(sb->s_fs_info);
1525                 ffs_data_closed(sb->s_fs_info);
1526                 ffs_data_put(sb->s_fs_info);
1527         }
1528 }
1529
1530 static struct file_system_type ffs_fs_type = {
1531         .owner          = THIS_MODULE,
1532         .name           = "functionfs",
1533         .mount          = ffs_fs_mount,
1534         .kill_sb        = ffs_fs_kill_sb,
1535 };
1536 MODULE_ALIAS_FS("functionfs");
1537
1538
1539 /* Driver's main init/cleanup functions *************************************/
1540
1541 static int functionfs_init(void)
1542 {
1543         int ret;
1544
1545         ENTER();
1546
1547         ret = register_filesystem(&ffs_fs_type);
1548         if (likely(!ret))
1549                 pr_info("file system registered\n");
1550         else
1551                 pr_err("failed registering file system (%d)\n", ret);
1552
1553         return ret;
1554 }
1555
1556 static void functionfs_cleanup(void)
1557 {
1558         ENTER();
1559
1560         pr_info("unloading\n");
1561         unregister_filesystem(&ffs_fs_type);
1562 }
1563
1564
1565 /* ffs_data and ffs_function construction and destruction code **************/
1566
1567 static void ffs_data_clear(struct ffs_data *ffs);
1568 static void ffs_data_reset(struct ffs_data *ffs);
1569
1570 static void ffs_data_get(struct ffs_data *ffs)
1571 {
1572         ENTER();
1573
1574         atomic_inc(&ffs->ref);
1575 }
1576
1577 static void ffs_data_opened(struct ffs_data *ffs)
1578 {
1579         ENTER();
1580
1581         atomic_inc(&ffs->ref);
1582         if (atomic_add_return(1, &ffs->opened) == 1 &&
1583                         ffs->state == FFS_DEACTIVATED) {
1584                 ffs->state = FFS_CLOSING;
1585                 ffs_data_reset(ffs);
1586         }
1587 }
1588
1589 static void ffs_data_put(struct ffs_data *ffs)
1590 {
1591         ENTER();
1592
1593         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1594                 pr_info("%s(): freeing\n", __func__);
1595                 ffs_data_clear(ffs);
1596                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1597                        waitqueue_active(&ffs->ep0req_completion.wait));
1598                 kfree(ffs->dev_name);
1599                 kfree(ffs);
1600         }
1601 }
1602
1603 static void ffs_data_closed(struct ffs_data *ffs)
1604 {
1605         ENTER();
1606
1607         if (atomic_dec_and_test(&ffs->opened)) {
1608                 if (ffs->no_disconnect) {
1609                         ffs->state = FFS_DEACTIVATED;
1610                         if (ffs->epfiles) {
1611                                 ffs_epfiles_destroy(ffs->epfiles,
1612                                                    ffs->eps_count);
1613                                 ffs->epfiles = NULL;
1614                         }
1615                         if (ffs->setup_state == FFS_SETUP_PENDING)
1616                                 __ffs_ep0_stall(ffs);
1617                 } else {
1618                         ffs->state = FFS_CLOSING;
1619                         ffs_data_reset(ffs);
1620                 }
1621         }
1622         if (atomic_read(&ffs->opened) < 0) {
1623                 ffs->state = FFS_CLOSING;
1624                 ffs_data_reset(ffs);
1625         }
1626
1627         ffs_data_put(ffs);
1628 }
1629
1630 static struct ffs_data *ffs_data_new(void)
1631 {
1632         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1633         if (unlikely(!ffs))
1634                 return NULL;
1635
1636         ENTER();
1637
1638         atomic_set(&ffs->ref, 1);
1639         atomic_set(&ffs->opened, 0);
1640         ffs->state = FFS_READ_DESCRIPTORS;
1641         mutex_init(&ffs->mutex);
1642         spin_lock_init(&ffs->eps_lock);
1643         init_waitqueue_head(&ffs->ev.waitq);
1644         init_completion(&ffs->ep0req_completion);
1645
1646         /* XXX REVISIT need to update it in some places, or do we? */
1647         ffs->ev.can_stall = 1;
1648
1649         return ffs;
1650 }
1651
1652 static void ffs_data_clear(struct ffs_data *ffs)
1653 {
1654         ENTER();
1655
1656         ffs_closed(ffs);
1657
1658         BUG_ON(ffs->gadget);
1659
1660         if (ffs->epfiles)
1661                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1662
1663         if (ffs->ffs_eventfd)
1664                 eventfd_ctx_put(ffs->ffs_eventfd);
1665
1666         kfree(ffs->raw_descs_data);
1667         kfree(ffs->raw_strings);
1668         kfree(ffs->stringtabs);
1669 }
1670
1671 static void ffs_data_reset(struct ffs_data *ffs)
1672 {
1673         ENTER();
1674
1675         ffs_data_clear(ffs);
1676
1677         ffs->epfiles = NULL;
1678         ffs->raw_descs_data = NULL;
1679         ffs->raw_descs = NULL;
1680         ffs->raw_strings = NULL;
1681         ffs->stringtabs = NULL;
1682
1683         ffs->raw_descs_length = 0;
1684         ffs->fs_descs_count = 0;
1685         ffs->hs_descs_count = 0;
1686         ffs->ss_descs_count = 0;
1687
1688         ffs->strings_count = 0;
1689         ffs->interfaces_count = 0;
1690         ffs->eps_count = 0;
1691
1692         ffs->ev.count = 0;
1693
1694         ffs->state = FFS_READ_DESCRIPTORS;
1695         ffs->setup_state = FFS_NO_SETUP;
1696         ffs->flags = 0;
1697 }
1698
1699
1700 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1701 {
1702         struct usb_gadget_strings **lang;
1703         int first_id;
1704
1705         ENTER();
1706
1707         if (WARN_ON(ffs->state != FFS_ACTIVE
1708                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1709                 return -EBADFD;
1710
1711         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1712         if (unlikely(first_id < 0))
1713                 return first_id;
1714
1715         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1716         if (unlikely(!ffs->ep0req))
1717                 return -ENOMEM;
1718         ffs->ep0req->complete = ffs_ep0_complete;
1719         ffs->ep0req->context = ffs;
1720
1721         lang = ffs->stringtabs;
1722         if (lang) {
1723                 for (; *lang; ++lang) {
1724                         struct usb_string *str = (*lang)->strings;
1725                         int id = first_id;
1726                         for (; str->s; ++id, ++str)
1727                                 str->id = id;
1728                 }
1729         }
1730
1731         ffs->gadget = cdev->gadget;
1732         ffs_data_get(ffs);
1733         return 0;
1734 }
1735
1736 static void functionfs_unbind(struct ffs_data *ffs)
1737 {
1738         ENTER();
1739
1740         if (!WARN_ON(!ffs->gadget)) {
1741                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1742                 ffs->ep0req = NULL;
1743                 ffs->gadget = NULL;
1744                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1745                 ffs_data_put(ffs);
1746         }
1747 }
1748
1749 static int ffs_epfiles_create(struct ffs_data *ffs)
1750 {
1751         struct ffs_epfile *epfile, *epfiles;
1752         unsigned i, count;
1753
1754         ENTER();
1755
1756         count = ffs->eps_count;
1757         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1758         if (!epfiles)
1759                 return -ENOMEM;
1760
1761         epfile = epfiles;
1762         for (i = 1; i <= count; ++i, ++epfile) {
1763                 epfile->ffs = ffs;
1764                 mutex_init(&epfile->mutex);
1765                 init_waitqueue_head(&epfile->wait);
1766                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1767                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1768                 else
1769                         sprintf(epfile->name, "ep%u", i);
1770                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1771                                                  epfile,
1772                                                  &ffs_epfile_operations);
1773                 if (unlikely(!epfile->dentry)) {
1774                         ffs_epfiles_destroy(epfiles, i - 1);
1775                         return -ENOMEM;
1776                 }
1777         }
1778
1779         ffs->epfiles = epfiles;
1780         return 0;
1781 }
1782
1783 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1784 {
1785         struct ffs_epfile *epfile = epfiles;
1786
1787         ENTER();
1788
1789         for (; count; --count, ++epfile) {
1790                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1791                        waitqueue_active(&epfile->wait));
1792                 if (epfile->dentry) {
1793                         d_delete(epfile->dentry);
1794                         dput(epfile->dentry);
1795                         epfile->dentry = NULL;
1796                 }
1797         }
1798
1799         kfree(epfiles);
1800 }
1801
1802 static void ffs_func_eps_disable(struct ffs_function *func)
1803 {
1804         struct ffs_ep *ep         = func->eps;
1805         struct ffs_epfile *epfile = func->ffs->epfiles;
1806         unsigned count            = func->ffs->eps_count;
1807         unsigned long flags;
1808
1809         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1810         while (count--) {
1811                 /* pending requests get nuked */
1812                 if (likely(ep->ep))
1813                         usb_ep_disable(ep->ep);
1814                 ++ep;
1815
1816                 if (epfile) {
1817                         epfile->ep = NULL;
1818                         __ffs_epfile_read_buffer_free(epfile);
1819                         ++epfile;
1820                 }
1821         }
1822         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1823 }
1824
1825 static int ffs_func_eps_enable(struct ffs_function *func)
1826 {
1827         struct ffs_data *ffs      = func->ffs;
1828         struct ffs_ep *ep         = func->eps;
1829         struct ffs_epfile *epfile = ffs->epfiles;
1830         unsigned count            = ffs->eps_count;
1831         unsigned long flags;
1832         int ret = 0;
1833
1834         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1835         while(count--) {
1836                 struct usb_endpoint_descriptor *ds;
1837                 int desc_idx;
1838
1839                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1840                         desc_idx = 2;
1841                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1842                         desc_idx = 1;
1843                 else
1844                         desc_idx = 0;
1845
1846                 /* fall-back to lower speed if desc missing for current speed */
1847                 do {
1848                         ds = ep->descs[desc_idx];
1849                 } while (!ds && --desc_idx >= 0);
1850
1851                 if (!ds) {
1852                         ret = -EINVAL;
1853                         break;
1854                 }
1855
1856                 ep->ep->driver_data = ep;
1857                 ep->ep->desc = ds;
1858                 ret = usb_ep_enable(ep->ep);
1859                 if (likely(!ret)) {
1860                         epfile->ep = ep;
1861                         epfile->in = usb_endpoint_dir_in(ds);
1862                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1863                 } else {
1864                         break;
1865                 }
1866
1867                 wake_up(&epfile->wait);
1868
1869                 ++ep;
1870                 ++epfile;
1871         }
1872         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1873
1874         return ret;
1875 }
1876
1877
1878 /* Parsing and building descriptors and strings *****************************/
1879
1880 /*
1881  * This validates if data pointed by data is a valid USB descriptor as
1882  * well as record how many interfaces, endpoints and strings are
1883  * required by given configuration.  Returns address after the
1884  * descriptor or NULL if data is invalid.
1885  */
1886
1887 enum ffs_entity_type {
1888         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1889 };
1890
1891 enum ffs_os_desc_type {
1892         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1893 };
1894
1895 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1896                                    u8 *valuep,
1897                                    struct usb_descriptor_header *desc,
1898                                    void *priv);
1899
1900 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1901                                     struct usb_os_desc_header *h, void *data,
1902                                     unsigned len, void *priv);
1903
1904 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1905                                            ffs_entity_callback entity,
1906                                            void *priv)
1907 {
1908         struct usb_descriptor_header *_ds = (void *)data;
1909         u8 length;
1910         int ret;
1911
1912         ENTER();
1913
1914         /* At least two bytes are required: length and type */
1915         if (len < 2) {
1916                 pr_vdebug("descriptor too short\n");
1917                 return -EINVAL;
1918         }
1919
1920         /* If we have at least as many bytes as the descriptor takes? */
1921         length = _ds->bLength;
1922         if (len < length) {
1923                 pr_vdebug("descriptor longer then available data\n");
1924                 return -EINVAL;
1925         }
1926
1927 #define __entity_check_INTERFACE(val)  1
1928 #define __entity_check_STRING(val)     (val)
1929 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1930 #define __entity(type, val) do {                                        \
1931                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1932                 if (unlikely(!__entity_check_ ##type(val))) {           \
1933                         pr_vdebug("invalid entity's value\n");          \
1934                         return -EINVAL;                                 \
1935                 }                                                       \
1936                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1937                 if (unlikely(ret < 0)) {                                \
1938                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1939                                  (val), ret);                           \
1940                         return ret;                                     \
1941                 }                                                       \
1942         } while (0)
1943
1944         /* Parse descriptor depending on type. */
1945         switch (_ds->bDescriptorType) {
1946         case USB_DT_DEVICE:
1947         case USB_DT_CONFIG:
1948         case USB_DT_STRING:
1949         case USB_DT_DEVICE_QUALIFIER:
1950                 /* function can't have any of those */
1951                 pr_vdebug("descriptor reserved for gadget: %d\n",
1952                       _ds->bDescriptorType);
1953                 return -EINVAL;
1954
1955         case USB_DT_INTERFACE: {
1956                 struct usb_interface_descriptor *ds = (void *)_ds;
1957                 pr_vdebug("interface descriptor\n");
1958                 if (length != sizeof *ds)
1959                         goto inv_length;
1960
1961                 __entity(INTERFACE, ds->bInterfaceNumber);
1962                 if (ds->iInterface)
1963                         __entity(STRING, ds->iInterface);
1964         }
1965                 break;
1966
1967         case USB_DT_ENDPOINT: {
1968                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1969                 pr_vdebug("endpoint descriptor\n");
1970                 if (length != USB_DT_ENDPOINT_SIZE &&
1971                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1972                         goto inv_length;
1973                 __entity(ENDPOINT, ds->bEndpointAddress);
1974         }
1975                 break;
1976
1977         case HID_DT_HID:
1978                 pr_vdebug("hid descriptor\n");
1979                 if (length != sizeof(struct hid_descriptor))
1980                         goto inv_length;
1981                 break;
1982
1983         case USB_DT_OTG:
1984                 if (length != sizeof(struct usb_otg_descriptor))
1985                         goto inv_length;
1986                 break;
1987
1988         case USB_DT_INTERFACE_ASSOCIATION: {
1989                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1990                 pr_vdebug("interface association descriptor\n");
1991                 if (length != sizeof *ds)
1992                         goto inv_length;
1993                 if (ds->iFunction)
1994                         __entity(STRING, ds->iFunction);
1995         }
1996                 break;
1997
1998         case USB_DT_SS_ENDPOINT_COMP:
1999                 pr_vdebug("EP SS companion descriptor\n");
2000                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2001                         goto inv_length;
2002                 break;
2003
2004         case USB_DT_OTHER_SPEED_CONFIG:
2005         case USB_DT_INTERFACE_POWER:
2006         case USB_DT_DEBUG:
2007         case USB_DT_SECURITY:
2008         case USB_DT_CS_RADIO_CONTROL:
2009                 /* TODO */
2010                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2011                 return -EINVAL;
2012
2013         default:
2014                 /* We should never be here */
2015                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2016                 return -EINVAL;
2017
2018 inv_length:
2019                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2020                           _ds->bLength, _ds->bDescriptorType);
2021                 return -EINVAL;
2022         }
2023
2024 #undef __entity
2025 #undef __entity_check_DESCRIPTOR
2026 #undef __entity_check_INTERFACE
2027 #undef __entity_check_STRING
2028 #undef __entity_check_ENDPOINT
2029
2030         return length;
2031 }
2032
2033 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2034                                      ffs_entity_callback entity, void *priv)
2035 {
2036         const unsigned _len = len;
2037         unsigned long num = 0;
2038
2039         ENTER();
2040
2041         for (;;) {
2042                 int ret;
2043
2044                 if (num == count)
2045                         data = NULL;
2046
2047                 /* Record "descriptor" entity */
2048                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2049                 if (unlikely(ret < 0)) {
2050                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2051                                  num, ret);
2052                         return ret;
2053                 }
2054
2055                 if (!data)
2056                         return _len - len;
2057
2058                 ret = ffs_do_single_desc(data, len, entity, priv);
2059                 if (unlikely(ret < 0)) {
2060                         pr_debug("%s returns %d\n", __func__, ret);
2061                         return ret;
2062                 }
2063
2064                 len -= ret;
2065                 data += ret;
2066                 ++num;
2067         }
2068 }
2069
2070 static int __ffs_data_do_entity(enum ffs_entity_type type,
2071                                 u8 *valuep, struct usb_descriptor_header *desc,
2072                                 void *priv)
2073 {
2074         struct ffs_desc_helper *helper = priv;
2075         struct usb_endpoint_descriptor *d;
2076
2077         ENTER();
2078
2079         switch (type) {
2080         case FFS_DESCRIPTOR:
2081                 break;
2082
2083         case FFS_INTERFACE:
2084                 /*
2085                  * Interfaces are indexed from zero so if we
2086                  * encountered interface "n" then there are at least
2087                  * "n+1" interfaces.
2088                  */
2089                 if (*valuep >= helper->interfaces_count)
2090                         helper->interfaces_count = *valuep + 1;
2091                 break;
2092
2093         case FFS_STRING:
2094                 /*
2095                  * Strings are indexed from 1 (0 is reserved
2096                  * for languages list)
2097                  */
2098                 if (*valuep > helper->ffs->strings_count)
2099                         helper->ffs->strings_count = *valuep;
2100                 break;
2101
2102         case FFS_ENDPOINT:
2103                 d = (void *)desc;
2104                 helper->eps_count++;
2105                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2106                         return -EINVAL;
2107                 /* Check if descriptors for any speed were already parsed */
2108                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2109                         helper->ffs->eps_addrmap[helper->eps_count] =
2110                                 d->bEndpointAddress;
2111                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2112                                 d->bEndpointAddress)
2113                         return -EINVAL;
2114                 break;
2115         }
2116
2117         return 0;
2118 }
2119
2120 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2121                                    struct usb_os_desc_header *desc)
2122 {
2123         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2124         u16 w_index = le16_to_cpu(desc->wIndex);
2125
2126         if (bcd_version != 1) {
2127                 pr_vdebug("unsupported os descriptors version: %d",
2128                           bcd_version);
2129                 return -EINVAL;
2130         }
2131         switch (w_index) {
2132         case 0x4:
2133                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2134                 break;
2135         case 0x5:
2136                 *next_type = FFS_OS_DESC_EXT_PROP;
2137                 break;
2138         default:
2139                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2140                 return -EINVAL;
2141         }
2142
2143         return sizeof(*desc);
2144 }
2145
2146 /*
2147  * Process all extended compatibility/extended property descriptors
2148  * of a feature descriptor
2149  */
2150 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2151                                               enum ffs_os_desc_type type,
2152                                               u16 feature_count,
2153                                               ffs_os_desc_callback entity,
2154                                               void *priv,
2155                                               struct usb_os_desc_header *h)
2156 {
2157         int ret;
2158         const unsigned _len = len;
2159
2160         ENTER();
2161
2162         /* loop over all ext compat/ext prop descriptors */
2163         while (feature_count--) {
2164                 ret = entity(type, h, data, len, priv);
2165                 if (unlikely(ret < 0)) {
2166                         pr_debug("bad OS descriptor, type: %d\n", type);
2167                         return ret;
2168                 }
2169                 data += ret;
2170                 len -= ret;
2171         }
2172         return _len - len;
2173 }
2174
2175 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2176 static int __must_check ffs_do_os_descs(unsigned count,
2177                                         char *data, unsigned len,
2178                                         ffs_os_desc_callback entity, void *priv)
2179 {
2180         const unsigned _len = len;
2181         unsigned long num = 0;
2182
2183         ENTER();
2184
2185         for (num = 0; num < count; ++num) {
2186                 int ret;
2187                 enum ffs_os_desc_type type;
2188                 u16 feature_count;
2189                 struct usb_os_desc_header *desc = (void *)data;
2190
2191                 if (len < sizeof(*desc))
2192                         return -EINVAL;
2193
2194                 /*
2195                  * Record "descriptor" entity.
2196                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2197                  * Move the data pointer to the beginning of extended
2198                  * compatibilities proper or extended properties proper
2199                  * portions of the data
2200                  */
2201                 if (le32_to_cpu(desc->dwLength) > len)
2202                         return -EINVAL;
2203
2204                 ret = __ffs_do_os_desc_header(&type, desc);
2205                 if (unlikely(ret < 0)) {
2206                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2207                                  num, ret);
2208                         return ret;
2209                 }
2210                 /*
2211                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2212                  */
2213                 feature_count = le16_to_cpu(desc->wCount);
2214                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2215                     (feature_count > 255 || desc->Reserved))
2216                                 return -EINVAL;
2217                 len -= ret;
2218                 data += ret;
2219
2220                 /*
2221                  * Process all function/property descriptors
2222                  * of this Feature Descriptor
2223                  */
2224                 ret = ffs_do_single_os_desc(data, len, type,
2225                                             feature_count, entity, priv, desc);
2226                 if (unlikely(ret < 0)) {
2227                         pr_debug("%s returns %d\n", __func__, ret);
2228                         return ret;
2229                 }
2230
2231                 len -= ret;
2232                 data += ret;
2233         }
2234         return _len - len;
2235 }
2236
2237 /**
2238  * Validate contents of the buffer from userspace related to OS descriptors.
2239  */
2240 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2241                                  struct usb_os_desc_header *h, void *data,
2242                                  unsigned len, void *priv)
2243 {
2244         struct ffs_data *ffs = priv;
2245         u8 length;
2246
2247         ENTER();
2248
2249         switch (type) {
2250         case FFS_OS_DESC_EXT_COMPAT: {
2251                 struct usb_ext_compat_desc *d = data;
2252                 int i;
2253
2254                 if (len < sizeof(*d) ||
2255                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2256                     d->Reserved1)
2257                         return -EINVAL;
2258                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2259                         if (d->Reserved2[i])
2260                                 return -EINVAL;
2261
2262                 length = sizeof(struct usb_ext_compat_desc);
2263         }
2264                 break;
2265         case FFS_OS_DESC_EXT_PROP: {
2266                 struct usb_ext_prop_desc *d = data;
2267                 u32 type, pdl;
2268                 u16 pnl;
2269
2270                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2271                         return -EINVAL;
2272                 length = le32_to_cpu(d->dwSize);
2273                 if (len < length)
2274                         return -EINVAL;
2275                 type = le32_to_cpu(d->dwPropertyDataType);
2276                 if (type < USB_EXT_PROP_UNICODE ||
2277                     type > USB_EXT_PROP_UNICODE_MULTI) {
2278                         pr_vdebug("unsupported os descriptor property type: %d",
2279                                   type);
2280                         return -EINVAL;
2281                 }
2282                 pnl = le16_to_cpu(d->wPropertyNameLength);
2283                 if (length < 14 + pnl) {
2284                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2285                                   length, pnl, type);
2286                         return -EINVAL;
2287                 }
2288                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2289                 if (length != 14 + pnl + pdl) {
2290                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2291                                   length, pnl, pdl, type);
2292                         return -EINVAL;
2293                 }
2294                 ++ffs->ms_os_descs_ext_prop_count;
2295                 /* property name reported to the host as "WCHAR"s */
2296                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2297                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2298         }
2299                 break;
2300         default:
2301                 pr_vdebug("unknown descriptor: %d\n", type);
2302                 return -EINVAL;
2303         }
2304         return length;
2305 }
2306
2307 static int __ffs_data_got_descs(struct ffs_data *ffs,
2308                                 char *const _data, size_t len)
2309 {
2310         char *data = _data, *raw_descs;
2311         unsigned os_descs_count = 0, counts[3], flags;
2312         int ret = -EINVAL, i;
2313         struct ffs_desc_helper helper;
2314
2315         ENTER();
2316
2317         if (get_unaligned_le32(data + 4) != len)
2318                 goto error;
2319
2320         switch (get_unaligned_le32(data)) {
2321         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2322                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2323                 data += 8;
2324                 len  -= 8;
2325                 break;
2326         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2327                 flags = get_unaligned_le32(data + 8);
2328                 ffs->user_flags = flags;
2329                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2330                               FUNCTIONFS_HAS_HS_DESC |
2331                               FUNCTIONFS_HAS_SS_DESC |
2332                               FUNCTIONFS_HAS_MS_OS_DESC |
2333                               FUNCTIONFS_VIRTUAL_ADDR |
2334                               FUNCTIONFS_EVENTFD |
2335                               FUNCTIONFS_ALL_CTRL_RECIP |
2336                               FUNCTIONFS_CONFIG0_SETUP)) {
2337                         ret = -ENOSYS;
2338                         goto error;
2339                 }
2340                 data += 12;
2341                 len  -= 12;
2342                 break;
2343         default:
2344                 goto error;
2345         }
2346
2347         if (flags & FUNCTIONFS_EVENTFD) {
2348                 if (len < 4)
2349                         goto error;
2350                 ffs->ffs_eventfd =
2351                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2352                 if (IS_ERR(ffs->ffs_eventfd)) {
2353                         ret = PTR_ERR(ffs->ffs_eventfd);
2354                         ffs->ffs_eventfd = NULL;
2355                         goto error;
2356                 }
2357                 data += 4;
2358                 len  -= 4;
2359         }
2360
2361         /* Read fs_count, hs_count and ss_count (if present) */
2362         for (i = 0; i < 3; ++i) {
2363                 if (!(flags & (1 << i))) {
2364                         counts[i] = 0;
2365                 } else if (len < 4) {
2366                         goto error;
2367                 } else {
2368                         counts[i] = get_unaligned_le32(data);
2369                         data += 4;
2370                         len  -= 4;
2371                 }
2372         }
2373         if (flags & (1 << i)) {
2374                 if (len < 4) {
2375                         goto error;
2376                 }
2377                 os_descs_count = get_unaligned_le32(data);
2378                 data += 4;
2379                 len -= 4;
2380         };
2381
2382         /* Read descriptors */
2383         raw_descs = data;
2384         helper.ffs = ffs;
2385         for (i = 0; i < 3; ++i) {
2386                 if (!counts[i])
2387                         continue;
2388                 helper.interfaces_count = 0;
2389                 helper.eps_count = 0;
2390                 ret = ffs_do_descs(counts[i], data, len,
2391                                    __ffs_data_do_entity, &helper);
2392                 if (ret < 0)
2393                         goto error;
2394                 if (!ffs->eps_count && !ffs->interfaces_count) {
2395                         ffs->eps_count = helper.eps_count;
2396                         ffs->interfaces_count = helper.interfaces_count;
2397                 } else {
2398                         if (ffs->eps_count != helper.eps_count) {
2399                                 ret = -EINVAL;
2400                                 goto error;
2401                         }
2402                         if (ffs->interfaces_count != helper.interfaces_count) {
2403                                 ret = -EINVAL;
2404                                 goto error;
2405                         }
2406                 }
2407                 data += ret;
2408                 len  -= ret;
2409         }
2410         if (os_descs_count) {
2411                 ret = ffs_do_os_descs(os_descs_count, data, len,
2412                                       __ffs_data_do_os_desc, ffs);
2413                 if (ret < 0)
2414                         goto error;
2415                 data += ret;
2416                 len -= ret;
2417         }
2418
2419         if (raw_descs == data || len) {
2420                 ret = -EINVAL;
2421                 goto error;
2422         }
2423
2424         ffs->raw_descs_data     = _data;
2425         ffs->raw_descs          = raw_descs;
2426         ffs->raw_descs_length   = data - raw_descs;
2427         ffs->fs_descs_count     = counts[0];
2428         ffs->hs_descs_count     = counts[1];
2429         ffs->ss_descs_count     = counts[2];
2430         ffs->ms_os_descs_count  = os_descs_count;
2431
2432         return 0;
2433
2434 error:
2435         kfree(_data);
2436         return ret;
2437 }
2438
2439 static int __ffs_data_got_strings(struct ffs_data *ffs,
2440                                   char *const _data, size_t len)
2441 {
2442         u32 str_count, needed_count, lang_count;
2443         struct usb_gadget_strings **stringtabs, *t;
2444         const char *data = _data;
2445         struct usb_string *s;
2446
2447         ENTER();
2448
2449         if (unlikely(len < 16 ||
2450                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2451                      get_unaligned_le32(data + 4) != len))
2452                 goto error;
2453         str_count  = get_unaligned_le32(data + 8);
2454         lang_count = get_unaligned_le32(data + 12);
2455
2456         /* if one is zero the other must be zero */
2457         if (unlikely(!str_count != !lang_count))
2458                 goto error;
2459
2460         /* Do we have at least as many strings as descriptors need? */
2461         needed_count = ffs->strings_count;
2462         if (unlikely(str_count < needed_count))
2463                 goto error;
2464
2465         /*
2466          * If we don't need any strings just return and free all
2467          * memory.
2468          */
2469         if (!needed_count) {
2470                 kfree(_data);
2471                 return 0;
2472         }
2473
2474         /* Allocate everything in one chunk so there's less maintenance. */
2475         {
2476                 unsigned i = 0;
2477                 vla_group(d);
2478                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2479                         lang_count + 1);
2480                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2481                 vla_item(d, struct usb_string, strings,
2482                         lang_count*(needed_count+1));
2483
2484                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2485
2486                 if (unlikely(!vlabuf)) {
2487                         kfree(_data);
2488                         return -ENOMEM;
2489                 }
2490
2491                 /* Initialize the VLA pointers */
2492                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2493                 t = vla_ptr(vlabuf, d, stringtab);
2494                 i = lang_count;
2495                 do {
2496                         *stringtabs++ = t++;
2497                 } while (--i);
2498                 *stringtabs = NULL;
2499
2500                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2501                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2502                 t = vla_ptr(vlabuf, d, stringtab);
2503                 s = vla_ptr(vlabuf, d, strings);
2504         }
2505
2506         /* For each language */
2507         data += 16;
2508         len -= 16;
2509
2510         do { /* lang_count > 0 so we can use do-while */
2511                 unsigned needed = needed_count;
2512
2513                 if (unlikely(len < 3))
2514                         goto error_free;
2515                 t->language = get_unaligned_le16(data);
2516                 t->strings  = s;
2517                 ++t;
2518
2519                 data += 2;
2520                 len -= 2;
2521
2522                 /* For each string */
2523                 do { /* str_count > 0 so we can use do-while */
2524                         size_t length = strnlen(data, len);
2525
2526                         if (unlikely(length == len))
2527                                 goto error_free;
2528
2529                         /*
2530                          * User may provide more strings then we need,
2531                          * if that's the case we simply ignore the
2532                          * rest
2533                          */
2534                         if (likely(needed)) {
2535                                 /*
2536                                  * s->id will be set while adding
2537                                  * function to configuration so for
2538                                  * now just leave garbage here.
2539                                  */
2540                                 s->s = data;
2541                                 --needed;
2542                                 ++s;
2543                         }
2544
2545                         data += length + 1;
2546                         len -= length + 1;
2547                 } while (--str_count);
2548
2549                 s->id = 0;   /* terminator */
2550                 s->s = NULL;
2551                 ++s;
2552
2553         } while (--lang_count);
2554
2555         /* Some garbage left? */
2556         if (unlikely(len))
2557                 goto error_free;
2558
2559         /* Done! */
2560         ffs->stringtabs = stringtabs;
2561         ffs->raw_strings = _data;
2562
2563         return 0;
2564
2565 error_free:
2566         kfree(stringtabs);
2567 error:
2568         kfree(_data);
2569         return -EINVAL;
2570 }
2571
2572
2573 /* Events handling and management *******************************************/
2574
2575 static void __ffs_event_add(struct ffs_data *ffs,
2576                             enum usb_functionfs_event_type type)
2577 {
2578         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2579         int neg = 0;
2580
2581         /*
2582          * Abort any unhandled setup
2583          *
2584          * We do not need to worry about some cmpxchg() changing value
2585          * of ffs->setup_state without holding the lock because when
2586          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2587          * the source does nothing.
2588          */
2589         if (ffs->setup_state == FFS_SETUP_PENDING)
2590                 ffs->setup_state = FFS_SETUP_CANCELLED;
2591
2592         /*
2593          * Logic of this function guarantees that there are at most four pending
2594          * evens on ffs->ev.types queue.  This is important because the queue
2595          * has space for four elements only and __ffs_ep0_read_events function
2596          * depends on that limit as well.  If more event types are added, those
2597          * limits have to be revisited or guaranteed to still hold.
2598          */
2599         switch (type) {
2600         case FUNCTIONFS_RESUME:
2601                 rem_type2 = FUNCTIONFS_SUSPEND;
2602                 /* FALL THROUGH */
2603         case FUNCTIONFS_SUSPEND:
2604         case FUNCTIONFS_SETUP:
2605                 rem_type1 = type;
2606                 /* Discard all similar events */
2607                 break;
2608
2609         case FUNCTIONFS_BIND:
2610         case FUNCTIONFS_UNBIND:
2611         case FUNCTIONFS_DISABLE:
2612         case FUNCTIONFS_ENABLE:
2613                 /* Discard everything other then power management. */
2614                 rem_type1 = FUNCTIONFS_SUSPEND;
2615                 rem_type2 = FUNCTIONFS_RESUME;
2616                 neg = 1;
2617                 break;
2618
2619         default:
2620                 WARN(1, "%d: unknown event, this should not happen\n", type);
2621                 return;
2622         }
2623
2624         {
2625                 u8 *ev  = ffs->ev.types, *out = ev;
2626                 unsigned n = ffs->ev.count;
2627                 for (; n; --n, ++ev)
2628                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2629                                 *out++ = *ev;
2630                         else
2631                                 pr_vdebug("purging event %d\n", *ev);
2632                 ffs->ev.count = out - ffs->ev.types;
2633         }
2634
2635         pr_vdebug("adding event %d\n", type);
2636         ffs->ev.types[ffs->ev.count++] = type;
2637         wake_up_locked(&ffs->ev.waitq);
2638         if (ffs->ffs_eventfd)
2639                 eventfd_signal(ffs->ffs_eventfd, 1);
2640 }
2641
2642 static void ffs_event_add(struct ffs_data *ffs,
2643                           enum usb_functionfs_event_type type)
2644 {
2645         unsigned long flags;
2646         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2647         __ffs_event_add(ffs, type);
2648         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2649 }
2650
2651 /* Bind/unbind USB function hooks *******************************************/
2652
2653 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2654 {
2655         int i;
2656
2657         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2658                 if (ffs->eps_addrmap[i] == endpoint_address)
2659                         return i;
2660         return -ENOENT;
2661 }
2662
2663 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2664                                     struct usb_descriptor_header *desc,
2665                                     void *priv)
2666 {
2667         struct usb_endpoint_descriptor *ds = (void *)desc;
2668         struct ffs_function *func = priv;
2669         struct ffs_ep *ffs_ep;
2670         unsigned ep_desc_id;
2671         int idx;
2672         static const char *speed_names[] = { "full", "high", "super" };
2673
2674         if (type != FFS_DESCRIPTOR)
2675                 return 0;
2676
2677         /*
2678          * If ss_descriptors is not NULL, we are reading super speed
2679          * descriptors; if hs_descriptors is not NULL, we are reading high
2680          * speed descriptors; otherwise, we are reading full speed
2681          * descriptors.
2682          */
2683         if (func->function.ss_descriptors) {
2684                 ep_desc_id = 2;
2685                 func->function.ss_descriptors[(long)valuep] = desc;
2686         } else if (func->function.hs_descriptors) {
2687                 ep_desc_id = 1;
2688                 func->function.hs_descriptors[(long)valuep] = desc;
2689         } else {
2690                 ep_desc_id = 0;
2691                 func->function.fs_descriptors[(long)valuep]    = desc;
2692         }
2693
2694         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2695                 return 0;
2696
2697         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2698         if (idx < 0)
2699                 return idx;
2700
2701         ffs_ep = func->eps + idx;
2702
2703         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2704                 pr_err("two %sspeed descriptors for EP %d\n",
2705                           speed_names[ep_desc_id],
2706                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2707                 return -EINVAL;
2708         }
2709         ffs_ep->descs[ep_desc_id] = ds;
2710
2711         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2712         if (ffs_ep->ep) {
2713                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2714                 if (!ds->wMaxPacketSize)
2715                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2716         } else {
2717                 struct usb_request *req;
2718                 struct usb_ep *ep;
2719                 u8 bEndpointAddress;
2720
2721                 /*
2722                  * We back up bEndpointAddress because autoconfig overwrites
2723                  * it with physical endpoint address.
2724                  */
2725                 bEndpointAddress = ds->bEndpointAddress;
2726                 pr_vdebug("autoconfig\n");
2727                 ep = usb_ep_autoconfig(func->gadget, ds);
2728                 if (unlikely(!ep))
2729                         return -ENOTSUPP;
2730                 ep->driver_data = func->eps + idx;
2731
2732                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2733                 if (unlikely(!req))
2734                         return -ENOMEM;
2735
2736                 ffs_ep->ep  = ep;
2737                 ffs_ep->req = req;
2738                 func->eps_revmap[ds->bEndpointAddress &
2739                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2740                 /*
2741                  * If we use virtual address mapping, we restore
2742                  * original bEndpointAddress value.
2743                  */
2744                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2745                         ds->bEndpointAddress = bEndpointAddress;
2746         }
2747         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2748
2749         return 0;
2750 }
2751
2752 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2753                                    struct usb_descriptor_header *desc,
2754                                    void *priv)
2755 {
2756         struct ffs_function *func = priv;
2757         unsigned idx;
2758         u8 newValue;
2759
2760         switch (type) {
2761         default:
2762         case FFS_DESCRIPTOR:
2763                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2764                 return 0;
2765
2766         case FFS_INTERFACE:
2767                 idx = *valuep;
2768                 if (func->interfaces_nums[idx] < 0) {
2769                         int id = usb_interface_id(func->conf, &func->function);
2770                         if (unlikely(id < 0))
2771                                 return id;
2772                         func->interfaces_nums[idx] = id;
2773                 }
2774                 newValue = func->interfaces_nums[idx];
2775                 break;
2776
2777         case FFS_STRING:
2778                 /* String' IDs are allocated when fsf_data is bound to cdev */
2779                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2780                 break;
2781
2782         case FFS_ENDPOINT:
2783                 /*
2784                  * USB_DT_ENDPOINT are handled in
2785                  * __ffs_func_bind_do_descs().
2786                  */
2787                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2788                         return 0;
2789
2790                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2791                 if (unlikely(!func->eps[idx].ep))
2792                         return -EINVAL;
2793
2794                 {
2795                         struct usb_endpoint_descriptor **descs;
2796                         descs = func->eps[idx].descs;
2797                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2798                 }
2799                 break;
2800         }
2801
2802         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2803         *valuep = newValue;
2804         return 0;
2805 }
2806
2807 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2808                                       struct usb_os_desc_header *h, void *data,
2809                                       unsigned len, void *priv)
2810 {
2811         struct ffs_function *func = priv;
2812         u8 length = 0;
2813
2814         switch (type) {
2815         case FFS_OS_DESC_EXT_COMPAT: {
2816                 struct usb_ext_compat_desc *desc = data;
2817                 struct usb_os_desc_table *t;
2818
2819                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2820                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2821                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2822                        ARRAY_SIZE(desc->CompatibleID) +
2823                        ARRAY_SIZE(desc->SubCompatibleID));
2824                 length = sizeof(*desc);
2825         }
2826                 break;
2827         case FFS_OS_DESC_EXT_PROP: {
2828                 struct usb_ext_prop_desc *desc = data;
2829                 struct usb_os_desc_table *t;
2830                 struct usb_os_desc_ext_prop *ext_prop;
2831                 char *ext_prop_name;
2832                 char *ext_prop_data;
2833
2834                 t = &func->function.os_desc_table[h->interface];
2835                 t->if_id = func->interfaces_nums[h->interface];
2836
2837                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2838                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2839
2840                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2841                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2842                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2843                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2844                 length = ext_prop->name_len + ext_prop->data_len + 14;
2845
2846                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2847                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2848                         ext_prop->name_len;
2849
2850                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2851                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2852                         ext_prop->data_len;
2853                 memcpy(ext_prop_data,
2854                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2855                        ext_prop->data_len);
2856                 /* unicode data reported to the host as "WCHAR"s */
2857                 switch (ext_prop->type) {
2858                 case USB_EXT_PROP_UNICODE:
2859                 case USB_EXT_PROP_UNICODE_ENV:
2860                 case USB_EXT_PROP_UNICODE_LINK:
2861                 case USB_EXT_PROP_UNICODE_MULTI:
2862                         ext_prop->data_len *= 2;
2863                         break;
2864                 }
2865                 ext_prop->data = ext_prop_data;
2866
2867                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2868                        ext_prop->name_len);
2869                 /* property name reported to the host as "WCHAR"s */
2870                 ext_prop->name_len *= 2;
2871                 ext_prop->name = ext_prop_name;
2872
2873                 t->os_desc->ext_prop_len +=
2874                         ext_prop->name_len + ext_prop->data_len + 14;
2875                 ++t->os_desc->ext_prop_count;
2876                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2877         }
2878                 break;
2879         default:
2880                 pr_vdebug("unknown descriptor: %d\n", type);
2881         }
2882
2883         return length;
2884 }
2885
2886 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2887                                                 struct usb_configuration *c)
2888 {
2889         struct ffs_function *func = ffs_func_from_usb(f);
2890         struct f_fs_opts *ffs_opts =
2891                 container_of(f->fi, struct f_fs_opts, func_inst);
2892         int ret;
2893
2894         ENTER();
2895
2896         /*
2897          * Legacy gadget triggers binding in functionfs_ready_callback,
2898          * which already uses locking; taking the same lock here would
2899          * cause a deadlock.
2900          *
2901          * Configfs-enabled gadgets however do need ffs_dev_lock.
2902          */
2903         if (!ffs_opts->no_configfs)
2904                 ffs_dev_lock();
2905         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2906         func->ffs = ffs_opts->dev->ffs_data;
2907         if (!ffs_opts->no_configfs)
2908                 ffs_dev_unlock();
2909         if (ret)
2910                 return ERR_PTR(ret);
2911
2912         func->conf = c;
2913         func->gadget = c->cdev->gadget;
2914
2915         /*
2916          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2917          * configurations are bound in sequence with list_for_each_entry,
2918          * in each configuration its functions are bound in sequence
2919          * with list_for_each_entry, so we assume no race condition
2920          * with regard to ffs_opts->bound access
2921          */
2922         if (!ffs_opts->refcnt) {
2923                 ret = functionfs_bind(func->ffs, c->cdev);
2924                 if (ret)
2925                         return ERR_PTR(ret);
2926         }
2927         ffs_opts->refcnt++;
2928         func->function.strings = func->ffs->stringtabs;
2929
2930         return ffs_opts;
2931 }
2932
2933 static int _ffs_func_bind(struct usb_configuration *c,
2934                           struct usb_function *f)
2935 {
2936         struct ffs_function *func = ffs_func_from_usb(f);
2937         struct ffs_data *ffs = func->ffs;
2938
2939         const int full = !!func->ffs->fs_descs_count;
2940         const int high = gadget_is_dualspeed(func->gadget) &&
2941                 func->ffs->hs_descs_count;
2942         const int super = gadget_is_superspeed(func->gadget) &&
2943                 func->ffs->ss_descs_count;
2944
2945         int fs_len, hs_len, ss_len, ret, i;
2946         struct ffs_ep *eps_ptr;
2947
2948         /* Make it a single chunk, less management later on */
2949         vla_group(d);
2950         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2951         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2952                 full ? ffs->fs_descs_count + 1 : 0);
2953         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2954                 high ? ffs->hs_descs_count + 1 : 0);
2955         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2956                 super ? ffs->ss_descs_count + 1 : 0);
2957         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2958         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2959                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2960         vla_item_with_sz(d, char[16], ext_compat,
2961                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2962         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2963                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2964         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2965                          ffs->ms_os_descs_ext_prop_count);
2966         vla_item_with_sz(d, char, ext_prop_name,
2967                          ffs->ms_os_descs_ext_prop_name_len);
2968         vla_item_with_sz(d, char, ext_prop_data,
2969                          ffs->ms_os_descs_ext_prop_data_len);
2970         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2971         char *vlabuf;
2972
2973         ENTER();
2974
2975         /* Has descriptors only for speeds gadget does not support */
2976         if (unlikely(!(full | high | super)))
2977                 return -ENOTSUPP;
2978
2979         /* Allocate a single chunk, less management later on */
2980         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2981         if (unlikely(!vlabuf))
2982                 return -ENOMEM;
2983
2984         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2985         ffs->ms_os_descs_ext_prop_name_avail =
2986                 vla_ptr(vlabuf, d, ext_prop_name);
2987         ffs->ms_os_descs_ext_prop_data_avail =
2988                 vla_ptr(vlabuf, d, ext_prop_data);
2989
2990         /* Copy descriptors  */
2991         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2992                ffs->raw_descs_length);
2993
2994         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2995         eps_ptr = vla_ptr(vlabuf, d, eps);
2996         for (i = 0; i < ffs->eps_count; i++)
2997                 eps_ptr[i].num = -1;
2998
2999         /* Save pointers
3000          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3001         */
3002         func->eps             = vla_ptr(vlabuf, d, eps);
3003         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3004
3005         /*
3006          * Go through all the endpoint descriptors and allocate
3007          * endpoints first, so that later we can rewrite the endpoint
3008          * numbers without worrying that it may be described later on.
3009          */
3010         if (likely(full)) {
3011                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3012                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3013                                       vla_ptr(vlabuf, d, raw_descs),
3014                                       d_raw_descs__sz,
3015                                       __ffs_func_bind_do_descs, func);
3016                 if (unlikely(fs_len < 0)) {
3017                         ret = fs_len;
3018                         goto error;
3019                 }
3020         } else {
3021                 fs_len = 0;
3022         }
3023
3024         if (likely(high)) {
3025                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3026                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3027                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3028                                       d_raw_descs__sz - fs_len,
3029                                       __ffs_func_bind_do_descs, func);
3030                 if (unlikely(hs_len < 0)) {
3031                         ret = hs_len;
3032                         goto error;
3033                 }
3034         } else {
3035                 hs_len = 0;
3036         }
3037
3038         if (likely(super)) {
3039                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3040                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3041                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3042                                 d_raw_descs__sz - fs_len - hs_len,
3043                                 __ffs_func_bind_do_descs, func);
3044                 if (unlikely(ss_len < 0)) {
3045                         ret = ss_len;
3046                         goto error;
3047                 }
3048         } else {
3049                 ss_len = 0;
3050         }
3051
3052         /*
3053          * Now handle interface numbers allocation and interface and
3054          * endpoint numbers rewriting.  We can do that in one go
3055          * now.
3056          */
3057         ret = ffs_do_descs(ffs->fs_descs_count +
3058                            (high ? ffs->hs_descs_count : 0) +
3059                            (super ? ffs->ss_descs_count : 0),
3060                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3061                            __ffs_func_bind_do_nums, func);
3062         if (unlikely(ret < 0))
3063                 goto error;
3064
3065         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3066         if (c->cdev->use_os_string) {
3067                 for (i = 0; i < ffs->interfaces_count; ++i) {
3068                         struct usb_os_desc *desc;