Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

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

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