drivers/usb/gadget/function/f_fs.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_fs.c -- user mode file system API for USB composite function controllers
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * Author: Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12
  13
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/blkdev.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/export.h>
  20 #include <linux/fs_parser.h>
  21 #include <linux/hid.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/scatterlist.h>
  25 #include <linux/sched/signal.h>
  26 #include <linux/uio.h>
  27 #include <linux/vmalloc.h>
  28 #include <asm/unaligned.h>
  29
  30 #include <linux/usb/ccid.h>
  31 #include <linux/usb/composite.h>
  32 #include <linux/usb/functionfs.h>
  33
  34 #include <linux/aio.h>
  35 #include <linux/kthread.h>
  36 #include <linux/poll.h>
  37 #include <linux/eventfd.h>
  38
  39 #include "u_fs.h"
  40 #include "u_f.h"
  41 #include "u_os_desc.h"
  42 #include "configfs.h"
  43
  44 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  45
  46 /* Reference counter handling */
  47 static void ffs_data_get(struct ffs_data *ffs);
  48 static void ffs_data_put(struct ffs_data *ffs);
  49 /* Creates new ffs_data object. */
  50 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  51         __attribute__((malloc));
  52
  53 /* Opened counter handling. */
  54 static void ffs_data_opened(struct ffs_data *ffs);
  55 static void ffs_data_closed(struct ffs_data *ffs);
  56
  57 /* Called with ffs->mutex held; take over ownership of data. */
  58 static int __must_check
  59 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  60 static int __must_check
  61 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  62
  63
  64 /* The function structure ***************************************************/
  65
  66 struct ffs_ep;
  67
  68 struct ffs_function {
  69         struct usb_configuration        *conf;
  70         struct usb_gadget               *gadget;
  71         struct ffs_data                 *ffs;
  72
  73         struct ffs_ep                   *eps;
  74         u8                              eps_revmap[16];
  75         short                           *interfaces_nums;
  76
  77         struct usb_function             function;
  78 };
  79
  80
  81 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  82 {
  83         return container_of(f, struct ffs_function, function);
  84 }
  85
  86
  87 static inline enum ffs_setup_state
  88 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  89 {
  90         return (enum ffs_setup_state)
  91                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  92 }
  93
  94
  95 static void ffs_func_eps_disable(struct ffs_function *func);
  96 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  97
  98 static int ffs_func_bind(struct usb_configuration *,
  99                          struct usb_function *);
 100 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 101 static void ffs_func_disable(struct usb_function *);
 102 static int ffs_func_setup(struct usb_function *,
 103                           const struct usb_ctrlrequest *);
 104 static bool ffs_func_req_match(struct usb_function *,
 105                                const struct usb_ctrlrequest *,
 106                                bool config0);
 107 static void ffs_func_suspend(struct usb_function *);
 108 static void ffs_func_resume(struct usb_function *);
 109
 110
 111 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 112 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 113
 114
 115 /* The endpoints structures *************************************************/
 116
 117 struct ffs_ep {
 118         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 119         struct usb_request              *req;   /* P: epfile->mutex */
 120
 121         /* [0]: full speed, [1]: high speed, [2]: super speed */
 122         struct usb_endpoint_descriptor  *descs[3];
 123
 124         u8                              num;
 125
 126         int                             status; /* P: epfile->mutex */
 127 };
 128
 129 struct ffs_epfile {
 130         /* Protects ep->ep and ep->req. */
 131         struct mutex                    mutex;
 132
 133         struct ffs_data                 *ffs;
 134         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 135
 136         struct dentry                   *dentry;
 137
 138         /*
 139          * Buffer for holding data from partial reads which may happen since
 140          * we’re rounding user read requests to a multiple of a max packet size.
 141          *
 142          * The pointer is initialised with NULL value and may be set by
 143          * __ffs_epfile_read_data function to point to a temporary buffer.
 144          *
 145          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 146          * data from said buffer and eventually free it.  Importantly, while the
 147          * function is using the buffer, it sets the pointer to NULL.  This is
 148          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 149          * can never run concurrently (they are synchronised by epfile->mutex)
 150          * so the latter will not assign a new value to the pointer.
 151          *
 152          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 153          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 154          * value is crux of the synchronisation between ffs_func_eps_disable and
 155          * __ffs_epfile_read_data.
 156          *
 157          * Once __ffs_epfile_read_data is about to finish it will try to set the
 158          * pointer back to its old value (as described above), but seeing as the
 159          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 160          * the buffer.
 161          *
 162          * == State transitions ==
 163          *
 164          * • ptr == NULL:  (initial state)
 165          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 166          *   ◦ __ffs_epfile_read_buffered:    nop
 167          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 168          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 169          * • ptr == DROP:
 170          *   ◦ __ffs_epfile_read_buffer_free: nop
 171          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 172          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 173          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 174          * • ptr == buf:
 175          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 176          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 177          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 178          *                                    is always called first
 179          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 180          * • ptr == NULL and reading:
 181          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 182          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 183          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 184          *   ◦ reading finishes and …
 185          *     … all data read:               free buf, go to ptr == NULL
 186          *     … otherwise:                   go to ptr == buf and reading
 187          * • ptr == DROP and reading:
 188          *   ◦ __ffs_epfile_read_buffer_free: nop
 189          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 190          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 191          *   ◦ reading finishes:              free buf, go to ptr == DROP
 192          */
 193         struct ffs_buffer               *read_buffer;
 194 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 195
 196         char                            name[5];
 197
 198         unsigned char                   in;     /* P: ffs->eps_lock */
 199         unsigned char                   isoc;   /* P: ffs->eps_lock */
 200
 201         unsigned char                   _pad;
 202 };
 203
 204 struct ffs_buffer {
 205         size_t length;
 206         char *data;
 207         char storage[];
 208 };
 209
 210 /*  ffs_io_data structure ***************************************************/
 211
 212 struct ffs_io_data {
 213         bool aio;
 214         bool read;
 215
 216         struct kiocb *kiocb;
 217         struct iov_iter data;
 218         const void *to_free;
 219         char *buf;
 220
 221         struct mm_struct *mm;
 222         struct work_struct work;
 223
 224         struct usb_ep *ep;
 225         struct usb_request *req;
 226         struct sg_table sgt;
 227         bool use_sg;
 228
 229         struct ffs_data *ffs;
 230 };
 231
 232 struct ffs_desc_helper {
 233         struct ffs_data *ffs;
 234         unsigned interfaces_count;
 235         unsigned eps_count;
 236 };
 237
 238 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 239 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 240
 241 static struct dentry *
 242 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 243                    const struct file_operations *fops);
 244
 245 /* Devices management *******************************************************/
 246
 247 DEFINE_MUTEX(ffs_lock);
 248 EXPORT_SYMBOL_GPL(ffs_lock);
 249
 250 static struct ffs_dev *_ffs_find_dev(const char *name);
 251 static struct ffs_dev *_ffs_alloc_dev(void);
 252 static void _ffs_free_dev(struct ffs_dev *dev);
 253 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
 254 static void ffs_release_dev(struct ffs_dev *ffs_dev);
 255 static int ffs_ready(struct ffs_data *ffs);
 256 static void ffs_closed(struct ffs_data *ffs);
 257
 258 /* Misc helper functions ****************************************************/
 259
 260 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 261         __attribute__((warn_unused_result, nonnull));
 262 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 263         __attribute__((warn_unused_result, nonnull));
 264
 265
 266 /* Control file aka ep0 *****************************************************/
 267
 268 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 269 {
 270         struct ffs_data *ffs = req->context;
 271
 272         complete(&ffs->ep0req_completion);
 273 }
 274
 275 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 276         __releases(&ffs->ev.waitq.lock)
 277 {
 278         struct usb_request *req = ffs->ep0req;
 279         int ret;
 280
 281         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 282
 283         spin_unlock_irq(&ffs->ev.waitq.lock);
 284
 285         req->buf      = data;
 286         req->length   = len;
 287
 288         /*
 289          * UDC layer requires to provide a buffer even for ZLP, but should
 290          * not use it at all. Let's provide some poisoned pointer to catch
 291          * possible bug in the driver.
 292          */
 293         if (req->buf == NULL)
 294                 req->buf = (void *)0xDEADBABE;
 295
 296         reinit_completion(&ffs->ep0req_completion);
 297
 298         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 299         if (ret < 0)
 300                 return ret;
 301
 302         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 303         if (ret) {
 304                 usb_ep_dequeue(ffs->gadget->ep0, req);
 305                 return -EINTR;
 306         }
 307
 308         ffs->setup_state = FFS_NO_SETUP;
 309         return req->status ? req->status : req->actual;
 310 }
 311
 312 static int __ffs_ep0_stall(struct ffs_data *ffs)
 313 {
 314         if (ffs->ev.can_stall) {
 315                 pr_vdebug("ep0 stall\n");
 316                 usb_ep_set_halt(ffs->gadget->ep0);
 317                 ffs->setup_state = FFS_NO_SETUP;
 318                 return -EL2HLT;
 319         } else {
 320                 pr_debug("bogus ep0 stall!\n");
 321                 return -ESRCH;
 322         }
 323 }
 324
 325 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 326                              size_t len, loff_t *ptr)
 327 {
 328         struct ffs_data *ffs = file->private_data;
 329         ssize_t ret;
 330         char *data;
 331
 332         ENTER();
 333
 334         /* Fast check if setup was canceled */
 335         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 336                 return -EIDRM;
 337
 338         /* Acquire mutex */
 339         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 340         if (ret < 0)
 341                 return ret;
 342
 343         /* Check state */
 344         switch (ffs->state) {
 345         case FFS_READ_DESCRIPTORS:
 346         case FFS_READ_STRINGS:
 347                 /* Copy data */
 348                 if (len < 16) {
 349                         ret = -EINVAL;
 350                         break;
 351                 }
 352
 353                 data = ffs_prepare_buffer(buf, len);
 354                 if (IS_ERR(data)) {
 355                         ret = PTR_ERR(data);
 356                         break;
 357                 }
 358
 359                 /* Handle data */
 360                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 361                         pr_info("read descriptors\n");
 362                         ret = __ffs_data_got_descs(ffs, data, len);
 363                         if (ret < 0)
 364                                 break;
 365
 366                         ffs->state = FFS_READ_STRINGS;
 367                         ret = len;
 368                 } else {
 369                         pr_info("read strings\n");
 370                         ret = __ffs_data_got_strings(ffs, data, len);
 371                         if (ret < 0)
 372                                 break;
 373
 374                         ret = ffs_epfiles_create(ffs);
 375                         if (ret) {
 376                                 ffs->state = FFS_CLOSING;
 377                                 break;
 378                         }
 379
 380                         ffs->state = FFS_ACTIVE;
 381                         mutex_unlock(&ffs->mutex);
 382
 383                         ret = ffs_ready(ffs);
 384                         if (ret < 0) {
 385                                 ffs->state = FFS_CLOSING;
 386                                 return ret;
 387                         }
 388
 389                         return len;
 390                 }
 391                 break;
 392
 393         case FFS_ACTIVE:
 394                 data = NULL;
 395                 /*
 396                  * We're called from user space, we can use _irq
 397                  * rather then _irqsave
 398                  */
 399                 spin_lock_irq(&ffs->ev.waitq.lock);
 400                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 401                 case FFS_SETUP_CANCELLED:
 402                         ret = -EIDRM;
 403                         goto done_spin;
 404
 405                 case FFS_NO_SETUP:
 406                         ret = -ESRCH;
 407                         goto done_spin;
 408
 409                 case FFS_SETUP_PENDING:
 410                         break;
 411                 }
 412
 413                 /* FFS_SETUP_PENDING */
 414                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 415                         spin_unlock_irq(&ffs->ev.waitq.lock);
 416                         ret = __ffs_ep0_stall(ffs);
 417                         break;
 418                 }
 419
 420                 /* FFS_SETUP_PENDING and not stall */
 421                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 422
 423                 spin_unlock_irq(&ffs->ev.waitq.lock);
 424
 425                 data = ffs_prepare_buffer(buf, len);
 426                 if (IS_ERR(data)) {
 427                         ret = PTR_ERR(data);
 428                         break;
 429                 }
 430
 431                 spin_lock_irq(&ffs->ev.waitq.lock);
 432
 433                 /*
 434                  * We are guaranteed to be still in FFS_ACTIVE state
 435                  * but the state of setup could have changed from
 436                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 437                  * to check for that.  If that happened we copied data
 438                  * from user space in vain but it's unlikely.
 439                  *
 440                  * For sure we are not in FFS_NO_SETUP since this is
 441                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 442                  * transition can be performed and it's protected by
 443                  * mutex.
 444                  */
 445                 if (ffs_setup_state_clear_cancelled(ffs) ==
 446                     FFS_SETUP_CANCELLED) {
 447                         ret = -EIDRM;
 448 done_spin:
 449                         spin_unlock_irq(&ffs->ev.waitq.lock);
 450                 } else {
 451                         /* unlocks spinlock */
 452                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 453                 }
 454                 kfree(data);
 455                 break;
 456
 457         default:
 458                 ret = -EBADFD;
 459                 break;
 460         }
 461
 462         mutex_unlock(&ffs->mutex);
 463         return ret;
 464 }
 465
 466 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 467 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 468                                      size_t n)
 469         __releases(&ffs->ev.waitq.lock)
 470 {
 471         /*
 472          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 473          * size of ffs->ev.types array (which is four) so that's how much space
 474          * we reserve.
 475          */
 476         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 477         const size_t size = n * sizeof *events;
 478         unsigned i = 0;
 479
 480         memset(events, 0, size);
 481
 482         do {
 483                 events[i].type = ffs->ev.types[i];
 484                 if (events[i].type == FUNCTIONFS_SETUP) {
 485                         events[i].u.setup = ffs->ev.setup;
 486                         ffs->setup_state = FFS_SETUP_PENDING;
 487                 }
 488         } while (++i < n);
 489
 490         ffs->ev.count -= n;
 491         if (ffs->ev.count)
 492                 memmove(ffs->ev.types, ffs->ev.types + n,
 493                         ffs->ev.count * sizeof *ffs->ev.types);
 494
 495         spin_unlock_irq(&ffs->ev.waitq.lock);
 496         mutex_unlock(&ffs->mutex);
 497
 498         return copy_to_user(buf, events, size) ? -EFAULT : size;
 499 }
 500
 501 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 502                             size_t len, loff_t *ptr)
 503 {
 504         struct ffs_data *ffs = file->private_data;
 505         char *data = NULL;
 506         size_t n;
 507         int ret;
 508
 509         ENTER();
 510
 511         /* Fast check if setup was canceled */
 512         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 513                 return -EIDRM;
 514
 515         /* Acquire mutex */
 516         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 517         if (ret < 0)
 518                 return ret;
 519
 520         /* Check state */
 521         if (ffs->state != FFS_ACTIVE) {
 522                 ret = -EBADFD;
 523                 goto done_mutex;
 524         }
 525
 526         /*
 527          * We're called from user space, we can use _irq rather then
 528          * _irqsave
 529          */
 530         spin_lock_irq(&ffs->ev.waitq.lock);
 531
 532         switch (ffs_setup_state_clear_cancelled(ffs)) {
 533         case FFS_SETUP_CANCELLED:
 534                 ret = -EIDRM;
 535                 break;
 536
 537         case FFS_NO_SETUP:
 538                 n = len / sizeof(struct usb_functionfs_event);
 539                 if (!n) {
 540                         ret = -EINVAL;
 541                         break;
 542                 }
 543
 544                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 545                         ret = -EAGAIN;
 546                         break;
 547                 }
 548
 549                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 550                                                         ffs->ev.count)) {
 551                         ret = -EINTR;
 552                         break;
 553                 }
 554
 555                 /* unlocks spinlock */
 556                 return __ffs_ep0_read_events(ffs, buf,
 557                                              min(n, (size_t)ffs->ev.count));
 558
 559         case FFS_SETUP_PENDING:
 560                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 561                         spin_unlock_irq(&ffs->ev.waitq.lock);
 562                         ret = __ffs_ep0_stall(ffs);
 563                         goto done_mutex;
 564                 }
 565
 566                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 567
 568                 spin_unlock_irq(&ffs->ev.waitq.lock);
 569
 570                 if (len) {
 571                         data = kmalloc(len, GFP_KERNEL);
 572                         if (!data) {
 573                                 ret = -ENOMEM;
 574                                 goto done_mutex;
 575                         }
 576                 }
 577
 578                 spin_lock_irq(&ffs->ev.waitq.lock);
 579
 580                 /* See ffs_ep0_write() */
 581                 if (ffs_setup_state_clear_cancelled(ffs) ==
 582                     FFS_SETUP_CANCELLED) {
 583                         ret = -EIDRM;
 584                         break;
 585                 }
 586
 587                 /* unlocks spinlock */
 588                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 589                 if ((ret > 0) && (copy_to_user(buf, data, len)))
 590                         ret = -EFAULT;
 591                 goto done_mutex;
 592
 593         default:
 594                 ret = -EBADFD;
 595                 break;
 596         }
 597
 598         spin_unlock_irq(&ffs->ev.waitq.lock);
 599 done_mutex:
 600         mutex_unlock(&ffs->mutex);
 601         kfree(data);
 602         return ret;
 603 }
 604
 605 static int ffs_ep0_open(struct inode *inode, struct file *file)
 606 {
 607         struct ffs_data *ffs = inode->i_private;
 608
 609         ENTER();
 610
 611         if (ffs->state == FFS_CLOSING)
 612                 return -EBUSY;
 613
 614         file->private_data = ffs;
 615         ffs_data_opened(ffs);
 616
 617         return stream_open(inode, file);
 618 }
 619
 620 static int ffs_ep0_release(struct inode *inode, struct file *file)
 621 {
 622         struct ffs_data *ffs = file->private_data;
 623
 624         ENTER();
 625
 626         ffs_data_closed(ffs);
 627
 628         return 0;
 629 }
 630
 631 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 632 {
 633         struct ffs_data *ffs = file->private_data;
 634         struct usb_gadget *gadget = ffs->gadget;
 635         long ret;
 636
 637         ENTER();
 638
 639         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 640                 struct ffs_function *func = ffs->func;
 641                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 642         } else if (gadget && gadget->ops->ioctl) {
 643                 ret = gadget->ops->ioctl(gadget, code, value);
 644         } else {
 645                 ret = -ENOTTY;
 646         }
 647
 648         return ret;
 649 }
 650
 651 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 652 {
 653         struct ffs_data *ffs = file->private_data;
 654         __poll_t mask = EPOLLWRNORM;
 655         int ret;
 656
 657         poll_wait(file, &ffs->ev.waitq, wait);
 658
 659         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 660         if (ret < 0)
 661                 return mask;
 662
 663         switch (ffs->state) {
 664         case FFS_READ_DESCRIPTORS:
 665         case FFS_READ_STRINGS:
 666                 mask |= EPOLLOUT;
 667                 break;
 668
 669         case FFS_ACTIVE:
 670                 switch (ffs->setup_state) {
 671                 case FFS_NO_SETUP:
 672                         if (ffs->ev.count)
 673                                 mask |= EPOLLIN;
 674                         break;
 675
 676                 case FFS_SETUP_PENDING:
 677                 case FFS_SETUP_CANCELLED:
 678                         mask |= (EPOLLIN | EPOLLOUT);
 679                         break;
 680                 }
 681                 break;
 682
 683         case FFS_CLOSING:
 684                 break;
 685         case FFS_DEACTIVATED:
 686                 break;
 687         }
 688
 689         mutex_unlock(&ffs->mutex);
 690
 691         return mask;
 692 }
 693
 694 static const struct file_operations ffs_ep0_operations = {
 695         .llseek =       no_llseek,
 696
 697         .open =         ffs_ep0_open,
 698         .write =        ffs_ep0_write,
 699         .read =         ffs_ep0_read,
 700         .release =      ffs_ep0_release,
 701         .unlocked_ioctl =       ffs_ep0_ioctl,
 702         .poll =         ffs_ep0_poll,
 703 };
 704
 705
 706 /* "Normal" endpoints operations ********************************************/
 707
 708 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 709 {
 710         ENTER();
 711         if (req->context) {
 712                 struct ffs_ep *ep = _ep->driver_data;
 713                 ep->status = req->status ? req->status : req->actual;
 714                 complete(req->context);
 715         }
 716 }
 717
 718 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 719 {
 720         ssize_t ret = copy_to_iter(data, data_len, iter);
 721         if (ret == data_len)
 722                 return ret;
 723
 724         if (iov_iter_count(iter))
 725                 return -EFAULT;
 726
 727         /*
 728          * Dear user space developer!
 729          *
 730          * TL;DR: To stop getting below error message in your kernel log, change
 731          * user space code using functionfs to align read buffers to a max
 732          * packet size.
 733          *
 734          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 735          * packet size.  When unaligned buffer is passed to functionfs, it
 736          * internally uses a larger, aligned buffer so that such UDCs are happy.
 737          *
 738          * Unfortunately, this means that host may send more data than was
 739          * requested in read(2) system call.  f_fs doesn’t know what to do with
 740          * that excess data so it simply drops it.
 741          *
 742          * Was the buffer aligned in the first place, no such problem would
 743          * happen.
 744          *
 745          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 746          * by splitting a request into multiple parts.  This splitting may still
 747          * be a problem though so it’s likely best to align the buffer
 748          * regardless of it being AIO or not..
 749          *
 750          * This only affects OUT endpoints, i.e. reading data with a read(2),
 751          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 752          * affected.
 753          */
 754         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 755                "Align read buffer size to max packet size to avoid the problem.\n",
 756                data_len, ret);
 757
 758         return ret;
 759 }
 760
 761 /*
 762  * allocate a virtually contiguous buffer and create a scatterlist describing it
 763  * @sg_table    - pointer to a place to be filled with sg_table contents
 764  * @size        - required buffer size
 765  */
 766 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 767 {
 768         struct page **pages;
 769         void *vaddr, *ptr;
 770         unsigned int n_pages;
 771         int i;
 772
 773         vaddr = vmalloc(sz);
 774         if (!vaddr)
 775                 return NULL;
 776
 777         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 778         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 779         if (!pages) {
 780                 vfree(vaddr);
 781
 782                 return NULL;
 783         }
 784         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 785                 pages[i] = vmalloc_to_page(ptr);
 786
 787         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 788                 kvfree(pages);
 789                 vfree(vaddr);
 790
 791                 return NULL;
 792         }
 793         kvfree(pages);
 794
 795         return vaddr;
 796 }
 797
 798 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 799         size_t data_len)
 800 {
 801         if (io_data->use_sg)
 802                 return ffs_build_sg_list(&io_data->sgt, data_len);
 803
 804         return kmalloc(data_len, GFP_KERNEL);
 805 }
 806
 807 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 808 {
 809         if (!io_data->buf)
 810                 return;
 811
 812         if (io_data->use_sg) {
 813                 sg_free_table(&io_data->sgt);
 814                 vfree(io_data->buf);
 815         } else {
 816                 kfree(io_data->buf);
 817         }
 818 }
 819
 820 static void ffs_user_copy_worker(struct work_struct *work)
 821 {
 822         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 823                                                    work);
 824         int ret = io_data->req->status ? io_data->req->status :
 825                                          io_data->req->actual;
 826         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 827
 828         if (io_data->read && ret > 0) {
 829                 kthread_use_mm(io_data->mm);
 830                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 831                 kthread_unuse_mm(io_data->mm);
 832         }
 833
 834         io_data->kiocb->ki_complete(io_data->kiocb, ret);
 835
 836         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 837                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 838
 839         usb_ep_free_request(io_data->ep, io_data->req);
 840
 841         if (io_data->read)
 842                 kfree(io_data->to_free);
 843         ffs_free_buffer(io_data);
 844         kfree(io_data);
 845 }
 846
 847 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 848                                          struct usb_request *req)
 849 {
 850         struct ffs_io_data *io_data = req->context;
 851         struct ffs_data *ffs = io_data->ffs;
 852
 853         ENTER();
 854
 855         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 856         queue_work(ffs->io_completion_wq, &io_data->work);
 857 }
 858
 859 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 860 {
 861         /*
 862          * See comment in struct ffs_epfile for full read_buffer pointer
 863          * synchronisation story.
 864          */
 865         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 866         if (buf && buf != READ_BUFFER_DROP)
 867                 kfree(buf);
 868 }
 869
 870 /* Assumes epfile->mutex is held. */
 871 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 872                                           struct iov_iter *iter)
 873 {
 874         /*
 875          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 876          * the buffer while we are using it.  See comment in struct ffs_epfile
 877          * for full read_buffer pointer synchronisation story.
 878          */
 879         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 880         ssize_t ret;
 881         if (!buf || buf == READ_BUFFER_DROP)
 882                 return 0;
 883
 884         ret = copy_to_iter(buf->data, buf->length, iter);
 885         if (buf->length == ret) {
 886                 kfree(buf);
 887                 return ret;
 888         }
 889
 890         if (iov_iter_count(iter)) {
 891                 ret = -EFAULT;
 892         } else {
 893                 buf->length -= ret;
 894                 buf->data += ret;
 895         }
 896
 897         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 898                 kfree(buf);
 899
 900         return ret;
 901 }
 902
 903 /* Assumes epfile->mutex is held. */
 904 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 905                                       void *data, int data_len,
 906                                       struct iov_iter *iter)
 907 {
 908         struct ffs_buffer *buf;
 909
 910         ssize_t ret = copy_to_iter(data, data_len, iter);
 911         if (data_len == ret)
 912                 return ret;
 913
 914         if (iov_iter_count(iter))
 915                 return -EFAULT;
 916
 917         /* See ffs_copy_to_iter for more context. */
 918         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 919                 data_len, ret);
 920
 921         data_len -= ret;
 922         buf = kmalloc(struct_size(buf, storage, data_len), GFP_KERNEL);
 923         if (!buf)
 924                 return -ENOMEM;
 925         buf->length = data_len;
 926         buf->data = buf->storage;
 927         memcpy(buf->storage, data + ret, flex_array_size(buf, storage, data_len));
 928
 929         /*
 930          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 931          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 932          * in struct ffs_epfile for full read_buffer pointer synchronisation
 933          * story.
 934          */
 935         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 936                 kfree(buf);
 937
 938         return ret;
 939 }
 940
 941 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 942 {
 943         struct ffs_epfile *epfile = file->private_data;
 944         struct usb_request *req;
 945         struct ffs_ep *ep;
 946         char *data = NULL;
 947         ssize_t ret, data_len = -EINVAL;
 948         int halt;
 949
 950         /* Are we still active? */
 951         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 952                 return -ENODEV;
 953
 954         /* Wait for endpoint to be enabled */
 955         ep = epfile->ep;
 956         if (!ep) {
 957                 if (file->f_flags & O_NONBLOCK)
 958                         return -EAGAIN;
 959
 960                 ret = wait_event_interruptible(
 961                                 epfile->ffs->wait, (ep = epfile->ep));
 962                 if (ret)
 963                         return -EINTR;
 964         }
 965
 966         /* Do we halt? */
 967         halt = (!io_data->read == !epfile->in);
 968         if (halt && epfile->isoc)
 969                 return -EINVAL;
 970
 971         /* We will be using request and read_buffer */
 972         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 973         if (ret)
 974                 goto error;
 975
 976         /* Allocate & copy */
 977         if (!halt) {
 978                 struct usb_gadget *gadget;
 979
 980                 /*
 981                  * Do we have buffered data from previous partial read?  Check
 982                  * that for synchronous case only because we do not have
 983                  * facility to ‘wake up’ a pending asynchronous read and push
 984                  * buffered data to it which we would need to make things behave
 985                  * consistently.
 986                  */
 987                 if (!io_data->aio && io_data->read) {
 988                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 989                         if (ret)
 990                                 goto error_mutex;
 991                 }
 992
 993                 /*
 994                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 995                  * before the waiting completes, so do not assign to 'gadget'
 996                  * earlier
 997                  */
 998                 gadget = epfile->ffs->gadget;
 999
1000                 spin_lock_irq(&epfile->ffs->eps_lock);
1001                 /* In the meantime, endpoint got disabled or changed. */
1002                 if (epfile->ep != ep) {
1003                         ret = -ESHUTDOWN;
1004                         goto error_lock;
1005                 }
1006                 data_len = iov_iter_count(&io_data->data);
1007                 /*
1008                  * Controller may require buffer size to be aligned to
1009                  * maxpacketsize of an out endpoint.
1010                  */
1011                 if (io_data->read)
1012                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1013
1014                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1015                 spin_unlock_irq(&epfile->ffs->eps_lock);
1016
1017                 data = ffs_alloc_buffer(io_data, data_len);
1018                 if (!data) {
1019                         ret = -ENOMEM;
1020                         goto error_mutex;
1021                 }
1022                 if (!io_data->read &&
1023                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1024                         ret = -EFAULT;
1025                         goto error_mutex;
1026                 }
1027         }
1028
1029         spin_lock_irq(&epfile->ffs->eps_lock);
1030
1031         if (epfile->ep != ep) {
1032                 /* In the meantime, endpoint got disabled or changed. */
1033                 ret = -ESHUTDOWN;
1034         } else if (halt) {
1035                 ret = usb_ep_set_halt(ep->ep);
1036                 if (!ret)
1037                         ret = -EBADMSG;
1038         } else if (data_len == -EINVAL) {
1039                 /*
1040                  * Sanity Check: even though data_len can't be used
1041                  * uninitialized at the time I write this comment, some
1042                  * compilers complain about this situation.
1043                  * In order to keep the code clean from warnings, data_len is
1044                  * being initialized to -EINVAL during its declaration, which
1045                  * means we can't rely on compiler anymore to warn no future
1046                  * changes won't result in data_len being used uninitialized.
1047                  * For such reason, we're adding this redundant sanity check
1048                  * here.
1049                  */
1050                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1051                 ret = -EINVAL;
1052         } else if (!io_data->aio) {
1053                 DECLARE_COMPLETION_ONSTACK(done);
1054                 bool interrupted = false;
1055
1056                 req = ep->req;
1057                 if (io_data->use_sg) {
1058                         req->buf = NULL;
1059                         req->sg = io_data->sgt.sgl;
1060                         req->num_sgs = io_data->sgt.nents;
1061                 } else {
1062                         req->buf = data;
1063                         req->num_sgs = 0;
1064                 }
1065                 req->length = data_len;
1066
1067                 io_data->buf = data;
1068
1069                 req->context  = &done;
1070                 req->complete = ffs_epfile_io_complete;
1071
1072                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1073                 if (ret < 0)
1074                         goto error_lock;
1075
1076                 spin_unlock_irq(&epfile->ffs->eps_lock);
1077
1078                 if (wait_for_completion_interruptible(&done)) {
1079                         /*
1080                          * To avoid race condition with ffs_epfile_io_complete,
1081                          * dequeue the request first then check
1082                          * status. usb_ep_dequeue API should guarantee no race
1083                          * condition with req->complete callback.
1084                          */
1085                         usb_ep_dequeue(ep->ep, req);
1086                         wait_for_completion(&done);
1087                         interrupted = ep->status < 0;
1088                 }
1089
1090                 if (interrupted)
1091                         ret = -EINTR;
1092                 else if (io_data->read && ep->status > 0)
1093                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1094                                                      &io_data->data);
1095                 else
1096                         ret = ep->status;
1097                 goto error_mutex;
1098         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1099                 ret = -ENOMEM;
1100         } else {
1101                 if (io_data->use_sg) {
1102                         req->buf = NULL;
1103                         req->sg = io_data->sgt.sgl;
1104                         req->num_sgs = io_data->sgt.nents;
1105                 } else {
1106                         req->buf = data;
1107                         req->num_sgs = 0;
1108                 }
1109                 req->length = data_len;
1110
1111                 io_data->buf = data;
1112                 io_data->ep = ep->ep;
1113                 io_data->req = req;
1114                 io_data->ffs = epfile->ffs;
1115
1116                 req->context  = io_data;
1117                 req->complete = ffs_epfile_async_io_complete;
1118
1119                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1120                 if (ret) {
1121                         io_data->req = NULL;
1122                         usb_ep_free_request(ep->ep, req);
1123                         goto error_lock;
1124                 }
1125
1126                 ret = -EIOCBQUEUED;
1127                 /*
1128                  * Do not kfree the buffer in this function.  It will be freed
1129                  * by ffs_user_copy_worker.
1130                  */
1131                 data = NULL;
1132         }
1133
1134 error_lock:
1135         spin_unlock_irq(&epfile->ffs->eps_lock);
1136 error_mutex:
1137         mutex_unlock(&epfile->mutex);
1138 error:
1139         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1140                 ffs_free_buffer(io_data);
1141         return ret;
1142 }
1143
1144 static int
1145 ffs_epfile_open(struct inode *inode, struct file *file)
1146 {
1147         struct ffs_epfile *epfile = inode->i_private;
1148
1149         ENTER();
1150
1151         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1152                 return -ENODEV;
1153
1154         file->private_data = epfile;
1155         ffs_data_opened(epfile->ffs);
1156
1157         return stream_open(inode, file);
1158 }
1159
1160 static int ffs_aio_cancel(struct kiocb *kiocb)
1161 {
1162         struct ffs_io_data *io_data = kiocb->private;
1163         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1164         unsigned long flags;
1165         int value;
1166
1167         ENTER();
1168
1169         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1170
1171         if (io_data && io_data->ep && io_data->req)
1172                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1173         else
1174                 value = -EINVAL;
1175
1176         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1177
1178         return value;
1179 }
1180
1181 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1182 {
1183         struct ffs_io_data io_data, *p = &io_data;
1184         ssize_t res;
1185
1186         ENTER();
1187
1188         if (!is_sync_kiocb(kiocb)) {
1189                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1190                 if (!p)
1191                         return -ENOMEM;
1192                 p->aio = true;
1193         } else {
1194                 memset(p, 0, sizeof(*p));
1195                 p->aio = false;
1196         }
1197
1198         p->read = false;
1199         p->kiocb = kiocb;
1200         p->data = *from;
1201         p->mm = current->mm;
1202
1203         kiocb->private = p;
1204
1205         if (p->aio)
1206                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1207
1208         res = ffs_epfile_io(kiocb->ki_filp, p);
1209         if (res == -EIOCBQUEUED)
1210                 return res;
1211         if (p->aio)
1212                 kfree(p);
1213         else
1214                 *from = p->data;
1215         return res;
1216 }
1217
1218 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1219 {
1220         struct ffs_io_data io_data, *p = &io_data;
1221         ssize_t res;
1222
1223         ENTER();
1224
1225         if (!is_sync_kiocb(kiocb)) {
1226                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1227                 if (!p)
1228                         return -ENOMEM;
1229                 p->aio = true;
1230         } else {
1231                 memset(p, 0, sizeof(*p));
1232                 p->aio = false;
1233         }
1234
1235         p->read = true;
1236         p->kiocb = kiocb;
1237         if (p->aio) {
1238                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1239                 if (!p->to_free) {
1240                         kfree(p);
1241                         return -ENOMEM;
1242                 }
1243         } else {
1244                 p->data = *to;
1245                 p->to_free = NULL;
1246         }
1247         p->mm = current->mm;
1248
1249         kiocb->private = p;
1250
1251         if (p->aio)
1252                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1253
1254         res = ffs_epfile_io(kiocb->ki_filp, p);
1255         if (res == -EIOCBQUEUED)
1256                 return res;
1257
1258         if (p->aio) {
1259                 kfree(p->to_free);
1260                 kfree(p);
1261         } else {
1262                 *to = p->data;
1263         }
1264         return res;
1265 }
1266
1267 static int
1268 ffs_epfile_release(struct inode *inode, struct file *file)
1269 {
1270         struct ffs_epfile *epfile = inode->i_private;
1271
1272         ENTER();
1273
1274         __ffs_epfile_read_buffer_free(epfile);
1275         ffs_data_closed(epfile->ffs);
1276
1277         return 0;
1278 }
1279
1280 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1281                              unsigned long value)
1282 {
1283         struct ffs_epfile *epfile = file->private_data;
1284         struct ffs_ep *ep;
1285         int ret;
1286
1287         ENTER();
1288
1289         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1290                 return -ENODEV;
1291
1292         /* Wait for endpoint to be enabled */
1293         ep = epfile->ep;
1294         if (!ep) {
1295                 if (file->f_flags & O_NONBLOCK)
1296                         return -EAGAIN;
1297
1298                 ret = wait_event_interruptible(
1299                                 epfile->ffs->wait, (ep = epfile->ep));
1300                 if (ret)
1301                         return -EINTR;
1302         }
1303
1304         spin_lock_irq(&epfile->ffs->eps_lock);
1305
1306         /* In the meantime, endpoint got disabled or changed. */
1307         if (epfile->ep != ep) {
1308                 spin_unlock_irq(&epfile->ffs->eps_lock);
1309                 return -ESHUTDOWN;
1310         }
1311
1312         switch (code) {
1313         case FUNCTIONFS_FIFO_STATUS:
1314                 ret = usb_ep_fifo_status(epfile->ep->ep);
1315                 break;
1316         case FUNCTIONFS_FIFO_FLUSH:
1317                 usb_ep_fifo_flush(epfile->ep->ep);
1318                 ret = 0;
1319                 break;
1320         case FUNCTIONFS_CLEAR_HALT:
1321                 ret = usb_ep_clear_halt(epfile->ep->ep);
1322                 break;
1323         case FUNCTIONFS_ENDPOINT_REVMAP:
1324                 ret = epfile->ep->num;
1325                 break;
1326         case FUNCTIONFS_ENDPOINT_DESC:
1327         {
1328                 int desc_idx;
1329                 struct usb_endpoint_descriptor desc1, *desc;
1330
1331                 switch (epfile->ffs->gadget->speed) {
1332                 case USB_SPEED_SUPER:
1333                 case USB_SPEED_SUPER_PLUS:
1334                         desc_idx = 2;
1335                         break;
1336                 case USB_SPEED_HIGH:
1337                         desc_idx = 1;
1338                         break;
1339                 default:
1340                         desc_idx = 0;
1341                 }
1342
1343                 desc = epfile->ep->descs[desc_idx];
1344                 memcpy(&desc1, desc, desc->bLength);
1345
1346                 spin_unlock_irq(&epfile->ffs->eps_lock);
1347                 ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
1348                 if (ret)
1349                         ret = -EFAULT;
1350                 return ret;
1351         }
1352         default:
1353                 ret = -ENOTTY;
1354         }
1355         spin_unlock_irq(&epfile->ffs->eps_lock);
1356
1357         return ret;
1358 }
1359
1360 static const struct file_operations ffs_epfile_operations = {
1361         .llseek =       no_llseek,
1362
1363         .open =         ffs_epfile_open,
1364         .write_iter =   ffs_epfile_write_iter,
1365         .read_iter =    ffs_epfile_read_iter,
1366         .release =      ffs_epfile_release,
1367         .unlocked_ioctl =       ffs_epfile_ioctl,
1368         .compat_ioctl = compat_ptr_ioctl,
1369 };
1370
1371
1372 /* File system and super block operations ***********************************/
1373
1374 /*
1375  * Mounting the file system creates a controller file, used first for
1376  * function configuration then later for event monitoring.
1377  */
1378
1379 static struct inode *__must_check
1380 ffs_sb_make_inode(struct super_block *sb, void *data,
1381                   const struct file_operations *fops,
1382                   const struct inode_operations *iops,
1383                   struct ffs_file_perms *perms)
1384 {
1385         struct inode *inode;
1386
1387         ENTER();
1388
1389         inode = new_inode(sb);
1390
1391         if (inode) {
1392                 struct timespec64 ts = current_time(inode);
1393
1394                 inode->i_ino     = get_next_ino();
1395                 inode->i_mode    = perms->mode;
1396                 inode->i_uid     = perms->uid;
1397                 inode->i_gid     = perms->gid;
1398                 inode->i_atime   = ts;
1399                 inode->i_mtime   = ts;
1400                 inode->i_ctime   = ts;
1401                 inode->i_private = data;
1402                 if (fops)
1403                         inode->i_fop = fops;
1404                 if (iops)
1405                         inode->i_op  = iops;
1406         }
1407
1408         return inode;
1409 }
1410
1411 /* Create "regular" file */
1412 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1413                                         const char *name, void *data,
1414                                         const struct file_operations *fops)
1415 {
1416         struct ffs_data *ffs = sb->s_fs_info;
1417         struct dentry   *dentry;
1418         struct inode    *inode;
1419
1420         ENTER();
1421
1422         dentry = d_alloc_name(sb->s_root, name);
1423         if (!dentry)
1424                 return NULL;
1425
1426         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1427         if (!inode) {
1428                 dput(dentry);
1429                 return NULL;
1430         }
1431
1432         d_add(dentry, inode);
1433         return dentry;
1434 }
1435
1436 /* Super block */
1437 static const struct super_operations ffs_sb_operations = {
1438         .statfs =       simple_statfs,
1439         .drop_inode =   generic_delete_inode,
1440 };
1441
1442 struct ffs_sb_fill_data {
1443         struct ffs_file_perms perms;
1444         umode_t root_mode;
1445         const char *dev_name;
1446         bool no_disconnect;
1447         struct ffs_data *ffs_data;
1448 };
1449
1450 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1451 {
1452         struct ffs_sb_fill_data *data = fc->fs_private;
1453         struct inode    *inode;
1454         struct ffs_data *ffs = data->ffs_data;
1455
1456         ENTER();
1457
1458         ffs->sb              = sb;
1459         data->ffs_data       = NULL;
1460         sb->s_fs_info        = ffs;
1461         sb->s_blocksize      = PAGE_SIZE;
1462         sb->s_blocksize_bits = PAGE_SHIFT;
1463         sb->s_magic          = FUNCTIONFS_MAGIC;
1464         sb->s_op             = &ffs_sb_operations;
1465         sb->s_time_gran      = 1;
1466
1467         /* Root inode */
1468         data->perms.mode = data->root_mode;
1469         inode = ffs_sb_make_inode(sb, NULL,
1470                                   &simple_dir_operations,
1471                                   &simple_dir_inode_operations,
1472                                   &data->perms);
1473         sb->s_root = d_make_root(inode);
1474         if (!sb->s_root)
1475                 return -ENOMEM;
1476
1477         /* EP0 file */
1478         if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
1479                 return -ENOMEM;
1480
1481         return 0;
1482 }
1483
1484 enum {
1485         Opt_no_disconnect,
1486         Opt_rmode,
1487         Opt_fmode,
1488         Opt_mode,
1489         Opt_uid,
1490         Opt_gid,
1491 };
1492
1493 static const struct fs_parameter_spec ffs_fs_fs_parameters[] = {
1494         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1495         fsparam_u32     ("rmode",               Opt_rmode),
1496         fsparam_u32     ("fmode",               Opt_fmode),
1497         fsparam_u32     ("mode",                Opt_mode),
1498         fsparam_u32     ("uid",                 Opt_uid),
1499         fsparam_u32     ("gid",                 Opt_gid),
1500         {}
1501 };
1502
1503 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1504 {
1505         struct ffs_sb_fill_data *data = fc->fs_private;
1506         struct fs_parse_result result;
1507         int opt;
1508
1509         ENTER();
1510
1511         opt = fs_parse(fc, ffs_fs_fs_parameters, param, &result);
1512         if (opt < 0)
1513                 return opt;
1514
1515         switch (opt) {
1516         case Opt_no_disconnect:
1517                 data->no_disconnect = result.boolean;
1518                 break;
1519         case Opt_rmode:
1520                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1521                 break;
1522         case Opt_fmode:
1523                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1524                 break;
1525         case Opt_mode:
1526                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1527                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1528                 break;
1529
1530         case Opt_uid:
1531                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1532                 if (!uid_valid(data->perms.uid))
1533                         goto unmapped_value;
1534                 break;
1535         case Opt_gid:
1536                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1537                 if (!gid_valid(data->perms.gid))
1538                         goto unmapped_value;
1539                 break;
1540
1541         default:
1542                 return -ENOPARAM;
1543         }
1544
1545         return 0;
1546
1547 unmapped_value:
1548         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1549 }
1550
1551 /*
1552  * Set up the superblock for a mount.
1553  */
1554 static int ffs_fs_get_tree(struct fs_context *fc)
1555 {
1556         struct ffs_sb_fill_data *ctx = fc->fs_private;
1557         struct ffs_data *ffs;
1558         int ret;
1559
1560         ENTER();
1561
1562         if (!fc->source)
1563                 return invalf(fc, "No source specified");
1564
1565         ffs = ffs_data_new(fc->source);
1566         if (!ffs)
1567                 return -ENOMEM;
1568         ffs->file_perms = ctx->perms;
1569         ffs->no_disconnect = ctx->no_disconnect;
1570
1571         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1572         if (!ffs->dev_name) {
1573                 ffs_data_put(ffs);
1574                 return -ENOMEM;
1575         }
1576
1577         ret = ffs_acquire_dev(ffs->dev_name, ffs);
1578         if (ret) {
1579                 ffs_data_put(ffs);
1580                 return ret;
1581         }
1582
1583         ctx->ffs_data = ffs;
1584         return get_tree_nodev(fc, ffs_sb_fill);
1585 }
1586
1587 static void ffs_fs_free_fc(struct fs_context *fc)
1588 {
1589         struct ffs_sb_fill_data *ctx = fc->fs_private;
1590
1591         if (ctx) {
1592                 if (ctx->ffs_data) {
1593                         ffs_data_put(ctx->ffs_data);
1594                 }
1595
1596                 kfree(ctx);
1597         }
1598 }
1599
1600 static const struct fs_context_operations ffs_fs_context_ops = {
1601         .free           = ffs_fs_free_fc,
1602         .parse_param    = ffs_fs_parse_param,
1603         .get_tree       = ffs_fs_get_tree,
1604 };
1605
1606 static int ffs_fs_init_fs_context(struct fs_context *fc)
1607 {
1608         struct ffs_sb_fill_data *ctx;
1609
1610         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1611         if (!ctx)
1612                 return -ENOMEM;
1613
1614         ctx->perms.mode = S_IFREG | 0600;
1615         ctx->perms.uid = GLOBAL_ROOT_UID;
1616         ctx->perms.gid = GLOBAL_ROOT_GID;
1617         ctx->root_mode = S_IFDIR | 0500;
1618         ctx->no_disconnect = false;
1619
1620         fc->fs_private = ctx;
1621         fc->ops = &ffs_fs_context_ops;
1622         return 0;
1623 }
1624
1625 static void
1626 ffs_fs_kill_sb(struct super_block *sb)
1627 {
1628         ENTER();
1629
1630         kill_litter_super(sb);
1631         if (sb->s_fs_info)
1632                 ffs_data_closed(sb->s_fs_info);
1633 }
1634
1635 static struct file_system_type ffs_fs_type = {
1636         .owner          = THIS_MODULE,
1637         .name           = "functionfs",
1638         .init_fs_context = ffs_fs_init_fs_context,
1639         .parameters     = ffs_fs_fs_parameters,
1640         .kill_sb        = ffs_fs_kill_sb,
1641 };
1642 MODULE_ALIAS_FS("functionfs");
1643
1644
1645 /* Driver's main init/cleanup functions *************************************/
1646
1647 static int functionfs_init(void)
1648 {
1649         int ret;
1650
1651         ENTER();
1652
1653         ret = register_filesystem(&ffs_fs_type);
1654         if (!ret)
1655                 pr_info("file system registered\n");
1656         else
1657                 pr_err("failed registering file system (%d)\n", ret);
1658
1659         return ret;
1660 }
1661
1662 static void functionfs_cleanup(void)
1663 {
1664         ENTER();
1665
1666         pr_info("unloading\n");
1667         unregister_filesystem(&ffs_fs_type);
1668 }
1669
1670
1671 /* ffs_data and ffs_function construction and destruction code **************/
1672
1673 static void ffs_data_clear(struct ffs_data *ffs);
1674 static void ffs_data_reset(struct ffs_data *ffs);
1675
1676 static void ffs_data_get(struct ffs_data *ffs)
1677 {
1678         ENTER();
1679
1680         refcount_inc(&ffs->ref);
1681 }
1682
1683 static void ffs_data_opened(struct ffs_data *ffs)
1684 {
1685         ENTER();
1686
1687         refcount_inc(&ffs->ref);
1688         if (atomic_add_return(1, &ffs->opened) == 1 &&
1689                         ffs->state == FFS_DEACTIVATED) {
1690                 ffs->state = FFS_CLOSING;
1691                 ffs_data_reset(ffs);
1692         }
1693 }
1694
1695 static void ffs_data_put(struct ffs_data *ffs)
1696 {
1697         ENTER();
1698
1699         if (refcount_dec_and_test(&ffs->ref)) {
1700                 pr_info("%s(): freeing\n", __func__);
1701                 ffs_data_clear(ffs);
1702                 ffs_release_dev(ffs->private_data);
1703                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1704                        swait_active(&ffs->ep0req_completion.wait) ||
1705                        waitqueue_active(&ffs->wait));
1706                 destroy_workqueue(ffs->io_completion_wq);
1707                 kfree(ffs->dev_name);
1708                 kfree(ffs);
1709         }
1710 }
1711
1712 static void ffs_data_closed(struct ffs_data *ffs)
1713 {
1714         struct ffs_epfile *epfiles;
1715         unsigned long flags;
1716
1717         ENTER();
1718
1719         if (atomic_dec_and_test(&ffs->opened)) {
1720                 if (ffs->no_disconnect) {
1721                         ffs->state = FFS_DEACTIVATED;
1722                         spin_lock_irqsave(&ffs->eps_lock, flags);
1723                         epfiles = ffs->epfiles;
1724                         ffs->epfiles = NULL;
1725                         spin_unlock_irqrestore(&ffs->eps_lock,
1726                                                         flags);
1727
1728                         if (epfiles)
1729                                 ffs_epfiles_destroy(epfiles,
1730                                                  ffs->eps_count);
1731
1732                         if (ffs->setup_state == FFS_SETUP_PENDING)
1733                                 __ffs_ep0_stall(ffs);
1734                 } else {
1735                         ffs->state = FFS_CLOSING;
1736                         ffs_data_reset(ffs);
1737                 }
1738         }
1739         if (atomic_read(&ffs->opened) < 0) {
1740                 ffs->state = FFS_CLOSING;
1741                 ffs_data_reset(ffs);
1742         }
1743
1744         ffs_data_put(ffs);
1745 }
1746
1747 static struct ffs_data *ffs_data_new(const char *dev_name)
1748 {
1749         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1750         if (!ffs)
1751                 return NULL;
1752
1753         ENTER();
1754
1755         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1756         if (!ffs->io_completion_wq) {
1757                 kfree(ffs);
1758                 return NULL;
1759         }
1760
1761         refcount_set(&ffs->ref, 1);
1762         atomic_set(&ffs->opened, 0);
1763         ffs->state = FFS_READ_DESCRIPTORS;
1764         mutex_init(&ffs->mutex);
1765         spin_lock_init(&ffs->eps_lock);
1766         init_waitqueue_head(&ffs->ev.waitq);
1767         init_waitqueue_head(&ffs->wait);
1768         init_completion(&ffs->ep0req_completion);
1769
1770         /* XXX REVISIT need to update it in some places, or do we? */
1771         ffs->ev.can_stall = 1;
1772
1773         return ffs;
1774 }
1775
1776 static void ffs_data_clear(struct ffs_data *ffs)
1777 {
1778         struct ffs_epfile *epfiles;
1779         unsigned long flags;
1780
1781         ENTER();
1782
1783         ffs_closed(ffs);
1784
1785         BUG_ON(ffs->gadget);
1786
1787         spin_lock_irqsave(&ffs->eps_lock, flags);
1788         epfiles = ffs->epfiles;
1789         ffs->epfiles = NULL;
1790         spin_unlock_irqrestore(&ffs->eps_lock, flags);
1791
1792         /*
1793          * potential race possible between ffs_func_eps_disable
1794          * & ffs_epfile_release therefore maintaining a local
1795          * copy of epfile will save us from use-after-free.
1796          */
1797         if (epfiles) {
1798                 ffs_epfiles_destroy(epfiles, ffs->eps_count);
1799                 ffs->epfiles = NULL;
1800         }
1801
1802         if (ffs->ffs_eventfd) {
1803                 eventfd_ctx_put(ffs->ffs_eventfd);
1804                 ffs->ffs_eventfd = NULL;
1805         }
1806
1807         kfree(ffs->raw_descs_data);
1808         kfree(ffs->raw_strings);
1809         kfree(ffs->stringtabs);
1810 }
1811
1812 static void ffs_data_reset(struct ffs_data *ffs)
1813 {
1814         ENTER();
1815
1816         ffs_data_clear(ffs);
1817
1818         ffs->raw_descs_data = NULL;
1819         ffs->raw_descs = NULL;
1820         ffs->raw_strings = NULL;
1821         ffs->stringtabs = NULL;
1822
1823         ffs->raw_descs_length = 0;
1824         ffs->fs_descs_count = 0;
1825         ffs->hs_descs_count = 0;
1826         ffs->ss_descs_count = 0;
1827
1828         ffs->strings_count = 0;
1829         ffs->interfaces_count = 0;
1830         ffs->eps_count = 0;
1831
1832         ffs->ev.count = 0;
1833
1834         ffs->state = FFS_READ_DESCRIPTORS;
1835         ffs->setup_state = FFS_NO_SETUP;
1836         ffs->flags = 0;
1837
1838         ffs->ms_os_descs_ext_prop_count = 0;
1839         ffs->ms_os_descs_ext_prop_name_len = 0;
1840         ffs->ms_os_descs_ext_prop_data_len = 0;
1841 }
1842
1843
1844 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1845 {
1846         struct usb_gadget_strings **lang;
1847         int first_id;
1848
1849         ENTER();
1850
1851         if (WARN_ON(ffs->state != FFS_ACTIVE
1852                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1853                 return -EBADFD;
1854
1855         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1856         if (first_id < 0)
1857                 return first_id;
1858
1859         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1860         if (!ffs->ep0req)
1861                 return -ENOMEM;
1862         ffs->ep0req->complete = ffs_ep0_complete;
1863         ffs->ep0req->context = ffs;
1864
1865         lang = ffs->stringtabs;
1866         if (lang) {
1867                 for (; *lang; ++lang) {
1868                         struct usb_string *str = (*lang)->strings;
1869                         int id = first_id;
1870                         for (; str->s; ++id, ++str)
1871                                 str->id = id;
1872                 }
1873         }
1874
1875         ffs->gadget = cdev->gadget;
1876         ffs_data_get(ffs);
1877         return 0;
1878 }
1879
1880 static void functionfs_unbind(struct ffs_data *ffs)
1881 {
1882         ENTER();
1883
1884         if (!WARN_ON(!ffs->gadget)) {
1885                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1886                 ffs->ep0req = NULL;
1887                 ffs->gadget = NULL;
1888                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1889                 ffs_data_put(ffs);
1890         }
1891 }
1892
1893 static int ffs_epfiles_create(struct ffs_data *ffs)
1894 {
1895         struct ffs_epfile *epfile, *epfiles;
1896         unsigned i, count;
1897
1898         ENTER();
1899
1900         count = ffs->eps_count;
1901         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1902         if (!epfiles)
1903                 return -ENOMEM;
1904
1905         epfile = epfiles;
1906         for (i = 1; i <= count; ++i, ++epfile) {
1907                 epfile->ffs = ffs;
1908                 mutex_init(&epfile->mutex);
1909                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1910                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1911                 else
1912                         sprintf(epfile->name, "ep%u", i);
1913                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1914                                                  epfile,
1915                                                  &ffs_epfile_operations);
1916                 if (!epfile->dentry) {
1917                         ffs_epfiles_destroy(epfiles, i - 1);
1918                         return -ENOMEM;
1919                 }
1920         }
1921
1922         ffs->epfiles = epfiles;
1923         return 0;
1924 }
1925
1926 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1927 {
1928         struct ffs_epfile *epfile = epfiles;
1929
1930         ENTER();
1931
1932         for (; count; --count, ++epfile) {
1933                 BUG_ON(mutex_is_locked(&epfile->mutex));
1934                 if (epfile->dentry) {
1935                         d_delete(epfile->dentry);
1936                         dput(epfile->dentry);
1937                         epfile->dentry = NULL;
1938                 }
1939         }
1940
1941         kfree(epfiles);
1942 }
1943
1944 static void ffs_func_eps_disable(struct ffs_function *func)
1945 {
1946         struct ffs_ep *ep;
1947         struct ffs_epfile *epfile;
1948         unsigned short count;
1949         unsigned long flags;
1950
1951         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1952         count = func->ffs->eps_count;
1953         epfile = func->ffs->epfiles;
1954         ep = func->eps;
1955         while (count--) {
1956                 /* pending requests get nuked */
1957                 if (ep->ep)
1958                         usb_ep_disable(ep->ep);
1959                 ++ep;
1960
1961                 if (epfile) {
1962                         epfile->ep = NULL;
1963                         __ffs_epfile_read_buffer_free(epfile);
1964                         ++epfile;
1965                 }
1966         }
1967         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1968 }
1969
1970 static int ffs_func_eps_enable(struct ffs_function *func)
1971 {
1972         struct ffs_data *ffs;
1973         struct ffs_ep *ep;
1974         struct ffs_epfile *epfile;
1975         unsigned short count;
1976         unsigned long flags;
1977         int ret = 0;
1978
1979         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1980         ffs = func->ffs;
1981         ep = func->eps;
1982         epfile = ffs->epfiles;
1983         count = ffs->eps_count;
1984         while(count--) {
1985                 ep->ep->driver_data = ep;
1986
1987                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1988                 if (ret) {
1989                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1990                                         __func__, ep->ep->name, ret);
1991                         break;
1992                 }
1993
1994                 ret = usb_ep_enable(ep->ep);
1995                 if (!ret) {
1996                         epfile->ep = ep;
1997                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1998                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1999                 } else {
2000                         break;
2001                 }
2002
2003                 ++ep;
2004                 ++epfile;
2005         }
2006
2007         wake_up_interruptible(&ffs->wait);
2008         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
2009
2010         return ret;
2011 }
2012
2013
2014 /* Parsing and building descriptors and strings *****************************/
2015
2016 /*
2017  * This validates if data pointed by data is a valid USB descriptor as
2018  * well as record how many interfaces, endpoints and strings are
2019  * required by given configuration.  Returns address after the
2020  * descriptor or NULL if data is invalid.
2021  */
2022
2023 enum ffs_entity_type {
2024         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2025 };
2026
2027 enum ffs_os_desc_type {
2028         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2029 };
2030
2031 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2032                                    u8 *valuep,
2033                                    struct usb_descriptor_header *desc,
2034                                    void *priv);
2035
2036 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2037                                     struct usb_os_desc_header *h, void *data,
2038                                     unsigned len, void *priv);
2039
2040 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2041                                            ffs_entity_callback entity,
2042                                            void *priv, int *current_class)
2043 {
2044         struct usb_descriptor_header *_ds = (void *)data;
2045         u8 length;
2046         int ret;
2047
2048         ENTER();
2049
2050         /* At least two bytes are required: length and type */
2051         if (len < 2) {
2052                 pr_vdebug("descriptor too short\n");
2053                 return -EINVAL;
2054         }
2055
2056         /* If we have at least as many bytes as the descriptor takes? */
2057         length = _ds->bLength;
2058         if (len < length) {
2059                 pr_vdebug("descriptor longer then available data\n");
2060                 return -EINVAL;
2061         }
2062
2063 #define __entity_check_INTERFACE(val)  1
2064 #define __entity_check_STRING(val)     (val)
2065 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2066 #define __entity(type, val) do {                                        \
2067                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2068                 if (!__entity_check_ ##type(val)) {                     \
2069                         pr_vdebug("invalid entity's value\n");          \
2070                         return -EINVAL;                                 \
2071                 }                                                       \
2072                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2073                 if (ret < 0) {                                          \
2074                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2075                                  (val), ret);                           \
2076                         return ret;                                     \
2077                 }                                                       \
2078         } while (0)
2079
2080         /* Parse descriptor depending on type. */
2081         switch (_ds->bDescriptorType) {
2082         case USB_DT_DEVICE:
2083         case USB_DT_CONFIG:
2084         case USB_DT_STRING:
2085         case USB_DT_DEVICE_QUALIFIER:
2086                 /* function can't have any of those */
2087                 pr_vdebug("descriptor reserved for gadget: %d\n",
2088                       _ds->bDescriptorType);
2089                 return -EINVAL;
2090
2091         case USB_DT_INTERFACE: {
2092                 struct usb_interface_descriptor *ds = (void *)_ds;
2093                 pr_vdebug("interface descriptor\n");
2094                 if (length != sizeof *ds)
2095                         goto inv_length;
2096
2097                 __entity(INTERFACE, ds->bInterfaceNumber);
2098                 if (ds->iInterface)
2099                         __entity(STRING, ds->iInterface);
2100                 *current_class = ds->bInterfaceClass;
2101         }
2102                 break;
2103
2104         case USB_DT_ENDPOINT: {
2105                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2106                 pr_vdebug("endpoint descriptor\n");
2107                 if (length != USB_DT_ENDPOINT_SIZE &&
2108                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2109                         goto inv_length;
2110                 __entity(ENDPOINT, ds->bEndpointAddress);
2111         }
2112                 break;
2113
2114         case USB_TYPE_CLASS | 0x01:
2115                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2116                         pr_vdebug("hid descriptor\n");
2117                         if (length != sizeof(struct hid_descriptor))
2118                                 goto inv_length;
2119                         break;
2120                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2121                         pr_vdebug("ccid descriptor\n");
2122                         if (length != sizeof(struct ccid_descriptor))
2123                                 goto inv_length;
2124                         break;
2125                 } else {
2126                         pr_vdebug("unknown descriptor: %d for class %d\n",
2127                               _ds->bDescriptorType, *current_class);
2128                         return -EINVAL;
2129                 }
2130
2131         case USB_DT_OTG:
2132                 if (length != sizeof(struct usb_otg_descriptor))
2133                         goto inv_length;
2134                 break;
2135
2136         case USB_DT_INTERFACE_ASSOCIATION: {
2137                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2138                 pr_vdebug("interface association descriptor\n");
2139                 if (length != sizeof *ds)
2140                         goto inv_length;
2141                 if (ds->iFunction)
2142                         __entity(STRING, ds->iFunction);
2143         }
2144                 break;
2145
2146         case USB_DT_SS_ENDPOINT_COMP:
2147                 pr_vdebug("EP SS companion descriptor\n");
2148                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2149                         goto inv_length;
2150                 break;
2151
2152         case USB_DT_OTHER_SPEED_CONFIG:
2153         case USB_DT_INTERFACE_POWER:
2154         case USB_DT_DEBUG:
2155         case USB_DT_SECURITY:
2156         case USB_DT_CS_RADIO_CONTROL:
2157                 /* TODO */
2158                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2159                 return -EINVAL;
2160
2161         default:
2162                 /* We should never be here */
2163                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2164                 return -EINVAL;
2165
2166 inv_length:
2167                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2168                           _ds->bLength, _ds->bDescriptorType);
2169                 return -EINVAL;
2170         }
2171
2172 #undef __entity
2173 #undef __entity_check_DESCRIPTOR
2174 #undef __entity_check_INTERFACE
2175 #undef __entity_check_STRING
2176 #undef __entity_check_ENDPOINT
2177
2178         return length;
2179 }
2180
2181 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2182                                      ffs_entity_callback entity, void *priv)
2183 {
2184         const unsigned _len = len;
2185         unsigned long num = 0;
2186         int current_class = -1;
2187
2188         ENTER();
2189
2190         for (;;) {
2191                 int ret;
2192
2193                 if (num == count)
2194                         data = NULL;
2195
2196                 /* Record "descriptor" entity */
2197                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2198                 if (ret < 0) {
2199                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2200                                  num, ret);
2201                         return ret;
2202                 }
2203
2204                 if (!data)
2205                         return _len - len;
2206
2207                 ret = ffs_do_single_desc(data, len, entity, priv,
2208                         &current_class);
2209                 if (ret < 0) {
2210                         pr_debug("%s returns %d\n", __func__, ret);
2211                         return ret;
2212                 }
2213
2214                 len -= ret;
2215                 data += ret;
2216                 ++num;
2217         }
2218 }
2219
2220 static int __ffs_data_do_entity(enum ffs_entity_type type,
2221                                 u8 *valuep, struct usb_descriptor_header *desc,
2222                                 void *priv)
2223 {
2224         struct ffs_desc_helper *helper = priv;
2225         struct usb_endpoint_descriptor *d;
2226
2227         ENTER();
2228
2229         switch (type) {
2230         case FFS_DESCRIPTOR:
2231                 break;
2232
2233         case FFS_INTERFACE:
2234                 /*
2235                  * Interfaces are indexed from zero so if we
2236                  * encountered interface "n" then there are at least
2237                  * "n+1" interfaces.
2238                  */
2239                 if (*valuep >= helper->interfaces_count)
2240                         helper->interfaces_count = *valuep + 1;
2241                 break;
2242
2243         case FFS_STRING:
2244                 /*
2245                  * Strings are indexed from 1 (0 is reserved
2246                  * for languages list)
2247                  */
2248                 if (*valuep > helper->ffs->strings_count)
2249                         helper->ffs->strings_count = *valuep;
2250                 break;
2251
2252         case FFS_ENDPOINT:
2253                 d = (void *)desc;
2254                 helper->eps_count++;
2255                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2256                         return -EINVAL;
2257                 /* Check if descriptors for any speed were already parsed */
2258                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2259                         helper->ffs->eps_addrmap[helper->eps_count] =
2260                                 d->bEndpointAddress;
2261                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2262                                 d->bEndpointAddress)
2263                         return -EINVAL;
2264                 break;
2265         }
2266
2267         return 0;
2268 }
2269
2270 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2271                                    struct usb_os_desc_header *desc)
2272 {
2273         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2274         u16 w_index = le16_to_cpu(desc->wIndex);
2275
2276         if (bcd_version != 1) {
2277                 pr_vdebug("unsupported os descriptors version: %d",
2278                           bcd_version);
2279                 return -EINVAL;
2280         }
2281         switch (w_index) {
2282         case 0x4:
2283                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2284                 break;
2285         case 0x5:
2286                 *next_type = FFS_OS_DESC_EXT_PROP;
2287                 break;
2288         default:
2289                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2290                 return -EINVAL;
2291         }
2292
2293         return sizeof(*desc);
2294 }
2295
2296 /*
2297  * Process all extended compatibility/extended property descriptors
2298  * of a feature descriptor
2299  */
2300 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2301                                               enum ffs_os_desc_type type,
2302                                               u16 feature_count,
2303                                               ffs_os_desc_callback entity,
2304                                               void *priv,
2305                                               struct usb_os_desc_header *h)
2306 {
2307         int ret;
2308         const unsigned _len = len;
2309
2310         ENTER();
2311
2312         /* loop over all ext compat/ext prop descriptors */
2313         while (feature_count--) {
2314                 ret = entity(type, h, data, len, priv);
2315                 if (ret < 0) {
2316                         pr_debug("bad OS descriptor, type: %d\n", type);
2317                         return ret;
2318                 }
2319                 data += ret;
2320                 len -= ret;
2321         }
2322         return _len - len;
2323 }
2324
2325 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2326 static int __must_check ffs_do_os_descs(unsigned count,
2327                                         char *data, unsigned len,
2328                                         ffs_os_desc_callback entity, void *priv)
2329 {
2330         const unsigned _len = len;
2331         unsigned long num = 0;
2332
2333         ENTER();
2334
2335         for (num = 0; num < count; ++num) {
2336                 int ret;
2337                 enum ffs_os_desc_type type;
2338                 u16 feature_count;
2339                 struct usb_os_desc_header *desc = (void *)data;
2340
2341                 if (len < sizeof(*desc))
2342                         return -EINVAL;
2343
2344                 /*
2345                  * Record "descriptor" entity.
2346                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2347                  * Move the data pointer to the beginning of extended
2348                  * compatibilities proper or extended properties proper
2349                  * portions of the data
2350                  */
2351                 if (le32_to_cpu(desc->dwLength) > len)
2352                         return -EINVAL;
2353
2354                 ret = __ffs_do_os_desc_header(&type, desc);
2355                 if (ret < 0) {
2356                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2357                                  num, ret);
2358                         return ret;
2359                 }
2360                 /*
2361                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2362                  */
2363                 feature_count = le16_to_cpu(desc->wCount);
2364                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2365                     (feature_count > 255 || desc->Reserved))
2366                                 return -EINVAL;
2367                 len -= ret;
2368                 data += ret;
2369
2370                 /*
2371                  * Process all function/property descriptors
2372                  * of this Feature Descriptor
2373                  */
2374                 ret = ffs_do_single_os_desc(data, len, type,
2375                                             feature_count, entity, priv, desc);
2376                 if (ret < 0) {
2377                         pr_debug("%s returns %d\n", __func__, ret);
2378                         return ret;
2379                 }
2380
2381                 len -= ret;
2382                 data += ret;
2383         }
2384         return _len - len;
2385 }
2386
2387 /*
2388  * Validate contents of the buffer from userspace related to OS descriptors.
2389  */
2390 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2391                                  struct usb_os_desc_header *h, void *data,
2392                                  unsigned len, void *priv)
2393 {
2394         struct ffs_data *ffs = priv;
2395         u8 length;
2396
2397         ENTER();
2398
2399         switch (type) {
2400         case FFS_OS_DESC_EXT_COMPAT: {
2401                 struct usb_ext_compat_desc *d = data;
2402                 int i;
2403
2404                 if (len < sizeof(*d) ||
2405                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2406                         return -EINVAL;
2407                 if (d->Reserved1 != 1) {
2408                         /*
2409                          * According to the spec, Reserved1 must be set to 1
2410                          * but older kernels incorrectly rejected non-zero
2411                          * values.  We fix it here to avoid returning EINVAL
2412                          * in response to values we used to accept.
2413                          */
2414                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2415                         d->Reserved1 = 1;
2416                 }
2417                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2418                         if (d->Reserved2[i])
2419                                 return -EINVAL;
2420
2421                 length = sizeof(struct usb_ext_compat_desc);
2422         }
2423                 break;
2424         case FFS_OS_DESC_EXT_PROP: {
2425                 struct usb_ext_prop_desc *d = data;
2426                 u32 type, pdl;
2427                 u16 pnl;
2428
2429                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2430                         return -EINVAL;
2431                 length = le32_to_cpu(d->dwSize);
2432                 if (len < length)
2433                         return -EINVAL;
2434                 type = le32_to_cpu(d->dwPropertyDataType);
2435                 if (type < USB_EXT_PROP_UNICODE ||
2436                     type > USB_EXT_PROP_UNICODE_MULTI) {
2437                         pr_vdebug("unsupported os descriptor property type: %d",
2438                                   type);
2439                         return -EINVAL;
2440                 }
2441                 pnl = le16_to_cpu(d->wPropertyNameLength);
2442                 if (length < 14 + pnl) {
2443                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2444                                   length, pnl, type);
2445                         return -EINVAL;
2446                 }
2447                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2448                 if (length != 14 + pnl + pdl) {
2449                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2450                                   length, pnl, pdl, type);
2451                         return -EINVAL;
2452                 }
2453                 ++ffs->ms_os_descs_ext_prop_count;
2454                 /* property name reported to the host as "WCHAR"s */
2455                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2456                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2457         }
2458                 break;
2459         default:
2460                 pr_vdebug("unknown descriptor: %d\n", type);
2461                 return -EINVAL;
2462         }
2463         return length;
2464 }
2465
2466 static int __ffs_data_got_descs(struct ffs_data *ffs,
2467                                 char *const _data, size_t len)
2468 {
2469         char *data = _data, *raw_descs;
2470         unsigned os_descs_count = 0, counts[3], flags;
2471         int ret = -EINVAL, i;
2472         struct ffs_desc_helper helper;
2473
2474         ENTER();
2475
2476         if (get_unaligned_le32(data + 4) != len)
2477                 goto error;
2478
2479         switch (get_unaligned_le32(data)) {
2480         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2481                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2482                 data += 8;
2483                 len  -= 8;
2484                 break;
2485         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2486                 flags = get_unaligned_le32(data + 8);
2487                 ffs->user_flags = flags;
2488                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2489                               FUNCTIONFS_HAS_HS_DESC |
2490                               FUNCTIONFS_HAS_SS_DESC |
2491                               FUNCTIONFS_HAS_MS_OS_DESC |
2492                               FUNCTIONFS_VIRTUAL_ADDR |
2493                               FUNCTIONFS_EVENTFD |
2494                               FUNCTIONFS_ALL_CTRL_RECIP |
2495                               FUNCTIONFS_CONFIG0_SETUP)) {
2496                         ret = -ENOSYS;
2497                         goto error;
2498                 }
2499                 data += 12;
2500                 len  -= 12;
2501                 break;
2502         default:
2503                 goto error;
2504         }
2505
2506         if (flags & FUNCTIONFS_EVENTFD) {
2507                 if (len < 4)
2508                         goto error;
2509                 ffs->ffs_eventfd =
2510                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2511                 if (IS_ERR(ffs->ffs_eventfd)) {
2512                         ret = PTR_ERR(ffs->ffs_eventfd);
2513                         ffs->ffs_eventfd = NULL;
2514                         goto error;
2515                 }
2516                 data += 4;
2517                 len  -= 4;
2518         }
2519
2520         /* Read fs_count, hs_count and ss_count (if present) */
2521         for (i = 0; i < 3; ++i) {
2522                 if (!(flags & (1 << i))) {
2523                         counts[i] = 0;
2524                 } else if (len < 4) {
2525                         goto error;
2526                 } else {
2527                         counts[i] = get_unaligned_le32(data);
2528                         data += 4;
2529                         len  -= 4;
2530                 }
2531         }
2532         if (flags & (1 << i)) {
2533                 if (len < 4) {
2534                         goto error;
2535                 }
2536                 os_descs_count = get_unaligned_le32(data);
2537                 data += 4;
2538                 len -= 4;
2539         }
2540
2541         /* Read descriptors */
2542         raw_descs = data;
2543         helper.ffs = ffs;
2544         for (i = 0; i < 3; ++i) {
2545                 if (!counts[i])
2546                         continue;
2547                 helper.interfaces_count = 0;
2548                 helper.eps_count = 0;
2549                 ret = ffs_do_descs(counts[i], data, len,
2550                                    __ffs_data_do_entity, &helper);
2551                 if (ret < 0)
2552                         goto error;
2553                 if (!ffs->eps_count && !ffs->interfaces_count) {
2554                         ffs->eps_count = helper.eps_count;
2555                         ffs->interfaces_count = helper.interfaces_count;
2556                 } else {
2557                         if (ffs->eps_count != helper.eps_count) {
2558                                 ret = -EINVAL;
2559                                 goto error;
2560                         }
2561                         if (ffs->interfaces_count != helper.interfaces_count) {
2562                                 ret = -EINVAL;
2563                                 goto error;
2564                         }
2565                 }
2566                 data += ret;
2567                 len  -= ret;
2568         }
2569         if (os_descs_count) {
2570                 ret = ffs_do_os_descs(os_descs_count, data, len,
2571                                       __ffs_data_do_os_desc, ffs);
2572                 if (ret < 0)
2573                         goto error;
2574                 data += ret;
2575                 len -= ret;
2576         }
2577
2578         if (raw_descs == data || len) {
2579                 ret = -EINVAL;
2580                 goto error;
2581         }
2582
2583         ffs->raw_descs_data     = _data;
2584         ffs->raw_descs          = raw_descs;
2585         ffs->raw_descs_length   = data - raw_descs;
2586         ffs->fs_descs_count     = counts[0];
2587         ffs->hs_descs_count     = counts[1];
2588         ffs->ss_descs_count     = counts[2];
2589         ffs->ms_os_descs_count  = os_descs_count;
2590
2591         return 0;
2592
2593 error:
2594         kfree(_data);
2595         return ret;
2596 }
2597
2598 static int __ffs_data_got_strings(struct ffs_data *ffs,
2599                                   char *const _data, size_t len)
2600 {
2601         u32 str_count, needed_count, lang_count;
2602         struct usb_gadget_strings **stringtabs, *t;
2603         const char *data = _data;
2604         struct usb_string *s;
2605
2606         ENTER();
2607
2608         if (len < 16 ||
2609             get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2610             get_unaligned_le32(data + 4) != len)
2611                 goto error;
2612         str_count  = get_unaligned_le32(data + 8);
2613         lang_count = get_unaligned_le32(data + 12);
2614
2615         /* if one is zero the other must be zero */
2616         if (!str_count != !lang_count)
2617                 goto error;
2618
2619         /* Do we have at least as many strings as descriptors need? */
2620         needed_count = ffs->strings_count;
2621         if (str_count < needed_count)
2622                 goto error;
2623
2624         /*
2625          * If we don't need any strings just return and free all
2626          * memory.
2627          */
2628         if (!needed_count) {
2629                 kfree(_data);
2630                 return 0;
2631         }
2632
2633         /* Allocate everything in one chunk so there's less maintenance. */
2634         {
2635                 unsigned i = 0;
2636                 vla_group(d);
2637                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2638                         lang_count + 1);
2639                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2640                 vla_item(d, struct usb_string, strings,
2641                         lang_count*(needed_count+1));
2642
2643                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2644
2645                 if (!vlabuf) {
2646                         kfree(_data);
2647                         return -ENOMEM;
2648                 }
2649
2650                 /* Initialize the VLA pointers */
2651                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2652                 t = vla_ptr(vlabuf, d, stringtab);
2653                 i = lang_count;
2654                 do {
2655                         *stringtabs++ = t++;
2656                 } while (--i);
2657                 *stringtabs = NULL;
2658
2659                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2660                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2661                 t = vla_ptr(vlabuf, d, stringtab);
2662                 s = vla_ptr(vlabuf, d, strings);
2663         }
2664
2665         /* For each language */
2666         data += 16;
2667         len -= 16;
2668
2669         do { /* lang_count > 0 so we can use do-while */
2670                 unsigned needed = needed_count;
2671                 u32 str_per_lang = str_count;
2672
2673                 if (len < 3)
2674                         goto error_free;
2675                 t->language = get_unaligned_le16(data);
2676                 t->strings  = s;
2677                 ++t;
2678
2679                 data += 2;
2680                 len -= 2;
2681
2682                 /* For each string */
2683                 do { /* str_count > 0 so we can use do-while */
2684                         size_t length = strnlen(data, len);
2685
2686                         if (length == len)
2687                                 goto error_free;
2688
2689                         /*
2690                          * User may provide more strings then we need,
2691                          * if that's the case we simply ignore the
2692                          * rest
2693                          */
2694                         if (needed) {
2695                                 /*
2696                                  * s->id will be set while adding
2697                                  * function to configuration so for
2698                                  * now just leave garbage here.
2699                                  */
2700                                 s->s = data;
2701                                 --needed;
2702                                 ++s;
2703                         }
2704
2705                         data += length + 1;
2706                         len -= length + 1;
2707                 } while (--str_per_lang);
2708
2709                 s->id = 0;   /* terminator */
2710                 s->s = NULL;
2711                 ++s;
2712
2713         } while (--lang_count);
2714
2715         /* Some garbage left? */
2716         if (len)
2717                 goto error_free;
2718
2719         /* Done! */
2720         ffs->stringtabs = stringtabs;
2721         ffs->raw_strings = _data;
2722
2723         return 0;
2724
2725 error_free:
2726         kfree(stringtabs);
2727 error:
2728         kfree(_data);
2729         return -EINVAL;
2730 }
2731
2732
2733 /* Events handling and management *******************************************/
2734
2735 static void __ffs_event_add(struct ffs_data *ffs,
2736                             enum usb_functionfs_event_type type)
2737 {
2738         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2739         int neg = 0;
2740
2741         /*
2742          * Abort any unhandled setup
2743          *
2744          * We do not need to worry about some cmpxchg() changing value
2745          * of ffs->setup_state without holding the lock because when
2746          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2747          * the source does nothing.
2748          */
2749         if (ffs->setup_state == FFS_SETUP_PENDING)
2750                 ffs->setup_state = FFS_SETUP_CANCELLED;
2751
2752         /*
2753          * Logic of this function guarantees that there are at most four pending
2754          * evens on ffs->ev.types queue.  This is important because the queue
2755          * has space for four elements only and __ffs_ep0_read_events function
2756          * depends on that limit as well.  If more event types are added, those
2757          * limits have to be revisited or guaranteed to still hold.
2758          */
2759         switch (type) {
2760         case FUNCTIONFS_RESUME:
2761                 rem_type2 = FUNCTIONFS_SUSPEND;
2762                 fallthrough;
2763         case FUNCTIONFS_SUSPEND:
2764         case FUNCTIONFS_SETUP:
2765                 rem_type1 = type;
2766                 /* Discard all similar events */
2767                 break;
2768
2769         case FUNCTIONFS_BIND:
2770         case FUNCTIONFS_UNBIND:
2771         case FUNCTIONFS_DISABLE:
2772         case FUNCTIONFS_ENABLE:
2773                 /* Discard everything other then power management. */
2774                 rem_type1 = FUNCTIONFS_SUSPEND;
2775                 rem_type2 = FUNCTIONFS_RESUME;
2776                 neg = 1;
2777                 break;
2778
2779         default:
2780                 WARN(1, "%d: unknown event, this should not happen\n", type);
2781                 return;
2782         }
2783
2784         {
2785                 u8 *ev  = ffs->ev.types, *out = ev;
2786                 unsigned n = ffs->ev.count;
2787                 for (; n; --n, ++ev)
2788                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2789                                 *out++ = *ev;
2790                         else
2791                                 pr_vdebug("purging event %d\n", *ev);
2792                 ffs->ev.count = out - ffs->ev.types;
2793         }
2794
2795         pr_vdebug("adding event %d\n", type);
2796         ffs->ev.types[ffs->ev.count++] = type;
2797         wake_up_locked(&ffs->ev.waitq);
2798         if (ffs->ffs_eventfd)
2799                 eventfd_signal(ffs->ffs_eventfd, 1);
2800 }
2801
2802 static void ffs_event_add(struct ffs_data *ffs,
2803                           enum usb_functionfs_event_type type)
2804 {
2805         unsigned long flags;
2806         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2807         __ffs_event_add(ffs, type);
2808         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2809 }
2810
2811 /* Bind/unbind USB function hooks *******************************************/
2812
2813 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2814 {
2815         int i;
2816
2817         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2818                 if (ffs->eps_addrmap[i] == endpoint_address)
2819                         return i;
2820         return -ENOENT;
2821 }
2822
2823 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2824                                     struct usb_descriptor_header *desc,
2825                                     void *priv)
2826 {
2827         struct usb_endpoint_descriptor *ds = (void *)desc;
2828         struct ffs_function *func = priv;
2829         struct ffs_ep *ffs_ep;
2830         unsigned ep_desc_id;
2831         int idx;
2832         static const char *speed_names[] = { "full", "high", "super" };
2833
2834         if (type != FFS_DESCRIPTOR)
2835                 return 0;
2836
2837         /*
2838          * If ss_descriptors is not NULL, we are reading super speed
2839          * descriptors; if hs_descriptors is not NULL, we are reading high
2840          * speed descriptors; otherwise, we are reading full speed
2841          * descriptors.
2842          */
2843         if (func->function.ss_descriptors) {
2844                 ep_desc_id = 2;
2845                 func->function.ss_descriptors[(long)valuep] = desc;
2846         } else if (func->function.hs_descriptors) {
2847                 ep_desc_id = 1;
2848                 func->function.hs_descriptors[(long)valuep] = desc;
2849         } else {
2850                 ep_desc_id = 0;
2851                 func->function.fs_descriptors[(long)valuep]    = desc;
2852         }
2853
2854         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2855                 return 0;
2856
2857         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2858         if (idx < 0)
2859                 return idx;
2860
2861         ffs_ep = func->eps + idx;
2862
2863         if (ffs_ep->descs[ep_desc_id]) {
2864                 pr_err("two %sspeed descriptors for EP %d\n",
2865                           speed_names[ep_desc_id],
2866                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2867                 return -EINVAL;
2868         }
2869         ffs_ep->descs[ep_desc_id] = ds;
2870
2871         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2872         if (ffs_ep->ep) {
2873                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2874                 if (!ds->wMaxPacketSize)
2875                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2876         } else {
2877                 struct usb_request *req;
2878                 struct usb_ep *ep;
2879                 u8 bEndpointAddress;
2880                 u16 wMaxPacketSize;
2881
2882                 /*
2883                  * We back up bEndpointAddress because autoconfig overwrites
2884                  * it with physical endpoint address.
2885                  */
2886                 bEndpointAddress = ds->bEndpointAddress;
2887                 /*
2888                  * We back up wMaxPacketSize because autoconfig treats
2889                  * endpoint descriptors as if they were full speed.
2890                  */
2891                 wMaxPacketSize = ds->wMaxPacketSize;
2892                 pr_vdebug("autoconfig\n");
2893                 ep = usb_ep_autoconfig(func->gadget, ds);
2894                 if (!ep)
2895                         return -ENOTSUPP;
2896                 ep->driver_data = func->eps + idx;
2897
2898                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2899                 if (!req)
2900                         return -ENOMEM;
2901
2902                 ffs_ep->ep  = ep;
2903                 ffs_ep->req = req;
2904                 func->eps_revmap[ds->bEndpointAddress &
2905                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2906                 /*
2907                  * If we use virtual address mapping, we restore
2908                  * original bEndpointAddress value.
2909                  */
2910                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2911                         ds->bEndpointAddress = bEndpointAddress;
2912                 /*
2913                  * Restore wMaxPacketSize which was potentially
2914                  * overwritten by autoconfig.
2915                  */
2916                 ds->wMaxPacketSize = wMaxPacketSize;
2917         }
2918         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2919
2920         return 0;
2921 }
2922
2923 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2924                                    struct usb_descriptor_header *desc,
2925                                    void *priv)
2926 {
2927         struct ffs_function *func = priv;
2928         unsigned idx;
2929         u8 newValue;
2930
2931         switch (type) {
2932         default:
2933         case FFS_DESCRIPTOR:
2934                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2935                 return 0;
2936
2937         case FFS_INTERFACE:
2938                 idx = *valuep;
2939                 if (func->interfaces_nums[idx] < 0) {
2940                         int id = usb_interface_id(func->conf, &func->function);
2941                         if (id < 0)
2942                                 return id;
2943                         func->interfaces_nums[idx] = id;
2944                 }
2945                 newValue = func->interfaces_nums[idx];
2946                 break;
2947
2948         case FFS_STRING:
2949                 /* String' IDs are allocated when fsf_data is bound to cdev */
2950                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2951                 break;
2952
2953         case FFS_ENDPOINT:
2954                 /*
2955                  * USB_DT_ENDPOINT are handled in
2956                  * __ffs_func_bind_do_descs().
2957                  */
2958                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2959                         return 0;
2960
2961                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2962                 if (!func->eps[idx].ep)
2963                         return -EINVAL;
2964
2965                 {
2966                         struct usb_endpoint_descriptor **descs;
2967                         descs = func->eps[idx].descs;
2968                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2969                 }
2970                 break;
2971         }
2972
2973         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2974         *valuep = newValue;
2975         return 0;
2976 }
2977
2978 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2979                                       struct usb_os_desc_header *h, void *data,
2980                                       unsigned len, void *priv)
2981 {
2982         struct ffs_function *func = priv;
2983         u8 length = 0;
2984
2985         switch (type) {
2986         case FFS_OS_DESC_EXT_COMPAT: {
2987                 struct usb_ext_compat_desc *desc = data;
2988                 struct usb_os_desc_table *t;
2989
2990                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2991                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2992                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2993                        ARRAY_SIZE(desc->CompatibleID) +
2994                        ARRAY_SIZE(desc->SubCompatibleID));
2995                 length = sizeof(*desc);
2996         }
2997                 break;
2998         case FFS_OS_DESC_EXT_PROP: {
2999                 struct usb_ext_prop_desc *desc = data;
3000                 struct usb_os_desc_table *t;
3001                 struct usb_os_desc_ext_prop *ext_prop;
3002                 char *ext_prop_name;
3003                 char *ext_prop_data;
3004
3005                 t = &func->function.os_desc_table[h->interface];
3006                 t->if_id = func->interfaces_nums[h->interface];
3007
3008                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
3009                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
3010
3011                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
3012                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
3013                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
3014                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
3015                 length = ext_prop->name_len + ext_prop->data_len + 14;
3016
3017                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
3018                 func->ffs->ms_os_descs_ext_prop_name_avail +=
3019                         ext_prop->name_len;
3020
3021                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3022                 func->ffs->ms_os_descs_ext_prop_data_avail +=
3023                         ext_prop->data_len;
3024                 memcpy(ext_prop_data,
3025                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
3026                        ext_prop->data_len);
3027                 /* unicode data reported to the host as "WCHAR"s */
3028                 switch (ext_prop->type) {
3029                 case USB_EXT_PROP_UNICODE:
3030                 case USB_EXT_PROP_UNICODE_ENV:
3031                 case USB_EXT_PROP_UNICODE_LINK:
3032                 case USB_EXT_PROP_UNICODE_MULTI:
3033                         ext_prop->data_len *= 2;
3034                         break;
3035                 }
3036                 ext_prop->data = ext_prop_data;
3037
3038                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3039                        ext_prop->name_len);
3040                 /* property name reported to the host as "WCHAR"s */
3041                 ext_prop->name_len *= 2;
3042                 ext_prop->name = ext_prop_name;
3043
3044                 t->os_desc->ext_prop_len +=
3045                         ext_prop->name_len + ext_prop->data_len + 14;
3046                 ++t->os_desc->ext_prop_count;
3047                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3048         }
3049                 break;
3050         default:
3051                 pr_vdebug("unknown descriptor: %d\n", type);
3052         }
3053
3054         return length;
3055 }
3056
3057 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3058                                                 struct usb_configuration *c)
3059 {
3060         struct ffs_function *func = ffs_func_from_usb(f);
3061         struct f_fs_opts *ffs_opts =
3062                 container_of(f->fi, struct f_fs_opts, func_inst);
3063         struct ffs_data *ffs_data;
3064         int ret;
3065
3066         ENTER();
3067
3068         /*
3069          * Legacy gadget triggers binding in functionfs_ready_callback,
3070          * which already uses locking; taking the same lock here would
3071          * cause a deadlock.
3072          *
3073          * Configfs-enabled gadgets however do need ffs_dev_lock.
3074          */
3075         if (!ffs_opts->no_configfs)
3076                 ffs_dev_lock();
3077         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3078         ffs_data = ffs_opts->dev->ffs_data;
3079         if (!ffs_opts->no_configfs)
3080                 ffs_dev_unlock();
3081         if (ret)
3082                 return ERR_PTR(ret);
3083
3084         func->ffs = ffs_data;
3085         func->conf = c;
3086         func->gadget = c->cdev->gadget;
3087
3088         /*
3089          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3090          * configurations are bound in sequence with list_for_each_entry,
3091          * in each configuration its functions are bound in sequence
3092          * with list_for_each_entry, so we assume no race condition
3093          * with regard to ffs_opts->bound access
3094          */
3095         if (!ffs_opts->refcnt) {
3096                 ret = functionfs_bind(func->ffs, c->cdev);
3097                 if (ret)
3098                         return ERR_PTR(ret);
3099         }
3100         ffs_opts->refcnt++;
3101         func->function.strings = func->ffs->stringtabs;
3102
3103         return ffs_opts;
3104 }
3105
3106 static int _ffs_func_bind(struct usb_configuration *c,
3107                           struct usb_function *f)
3108 {
3109         struct ffs_function *func = ffs_func_from_usb(f);
3110         struct ffs_data *ffs = func->ffs;
3111
3112         const int full = !!func->ffs->fs_descs_count;
3113         const int high = !!func->ffs->hs_descs_count;
3114         const int super = !!func->ffs->ss_descs_count;
3115
3116         int fs_len, hs_len, ss_len, ret, i;
3117         struct ffs_ep *eps_ptr;
3118
3119         /* Make it a single chunk, less management later on */
3120         vla_group(d);
3121         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3122         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3123                 full ? ffs->fs_descs_count + 1 : 0);
3124         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3125                 high ? ffs->hs_descs_count + 1 : 0);
3126         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3127                 super ? ffs->ss_descs_count + 1 : 0);
3128         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3129         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3130                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3131         vla_item_with_sz(d, char[16], ext_compat,
3132                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3133         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3134                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3135         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3136                          ffs->ms_os_descs_ext_prop_count);
3137         vla_item_with_sz(d, char, ext_prop_name,
3138                          ffs->ms_os_descs_ext_prop_name_len);
3139         vla_item_with_sz(d, char, ext_prop_data,
3140                          ffs->ms_os_descs_ext_prop_data_len);
3141         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3142         char *vlabuf;
3143
3144         ENTER();
3145
3146         /* Has descriptors only for speeds gadget does not support */
3147         if (!(full | high | super))
3148                 return -ENOTSUPP;
3149
3150         /* Allocate a single chunk, less management later on */
3151         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3152         if (!vlabuf)
3153                 return -ENOMEM;
3154
3155         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3156         ffs->ms_os_descs_ext_prop_name_avail =
3157                 vla_ptr(vlabuf, d, ext_prop_name);
3158         ffs->ms_os_descs_ext_prop_data_avail =
3159                 vla_ptr(vlabuf, d, ext_prop_data);
3160
3161         /* Copy descriptors  */
3162         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3163                ffs->raw_descs_length);
3164
3165         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3166         eps_ptr = vla_ptr(vlabuf, d, eps);
3167         for (i = 0; i < ffs->eps_count; i++)
3168                 eps_ptr[i].num = -1;
3169
3170         /* Save pointers
3171          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3172         */
3173         func->eps             = vla_ptr(vlabuf, d, eps);
3174         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3175
3176         /*
3177          * Go through all the endpoint descriptors and allocate
3178          * endpoints first, so that later we can rewrite the endpoint
3179          * numbers without worrying that it may be described later on.
3180          */
3181         if (full) {
3182                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3183                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3184                                       vla_ptr(vlabuf, d, raw_descs),
3185                                       d_raw_descs__sz,
3186                                       __ffs_func_bind_do_descs, func);
3187                 if (fs_len < 0) {
3188                         ret = fs_len;
3189                         goto error;
3190                 }
3191         } else {
3192                 fs_len = 0;
3193         }
3194
3195         if (high) {
3196                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3197                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3198                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3199                                       d_raw_descs__sz - fs_len,
3200                                       __ffs_func_bind_do_descs, func);
3201                 if (hs_len < 0) {
3202                         ret = hs_len;
3203                         goto error;
3204                 }
3205         } else {
3206                 hs_len = 0;
3207         }
3208
3209         if (super) {
3210                 func->function.ss_descriptors = func->function.ssp_descriptors =
3211                         vla_ptr(vlabuf, d, ss_descs);
3212                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3213                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3214                                 d_raw_descs__sz - fs_len - hs_len,
3215                                 __ffs_func_bind_do_descs, func);
3216                 if (ss_len < 0) {
3217                         ret = ss_len;
3218                         goto error;
3219                 }
3220         } else {
3221                 ss_len = 0;
3222         }
3223
3224         /*
3225          * Now handle interface numbers allocation and interface and
3226          * endpoint numbers rewriting.  We can do that in one go
3227          * now.
3228          */
3229         ret = ffs_do_descs(ffs->fs_descs_count +
3230                            (high ? ffs->hs_descs_count : 0) +
3231                            (super ? ffs->ss_descs_count : 0),
3232                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3233                            __ffs_func_bind_do_nums, func);
3234         if (ret < 0)
3235                 goto error;
3236
3237         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3238         if (c->cdev->use_os_string) {
3239                 for (i = 0; i < ffs->interfaces_count; ++i) {
3240                         struct usb_os_desc *desc;
3241
3242                         desc = func->function.os_desc_table[i].os_desc =
3243                                 vla_ptr(vlabuf, d, os_desc) +
3244                                 i * sizeof(struct usb_os_desc);
3245                         desc->ext_compat_id =
3246                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3247                         INIT_LIST_HEAD(&desc->ext_prop);
3248                 }
3249                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3250                                       vla_ptr(vlabuf, d, raw_descs) +
3251                                       fs_len + hs_len + ss_len,
3252                                       d_raw_descs__sz - fs_len - hs_len -
3253                                       ss_len,
3254                                       __ffs_func_bind_do_os_desc, func);
3255                 if (ret < 0)
3256                         goto error;
3257         }
3258         func->function.os_desc_n =
3259                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3260
3261         /* And we're done */
3262         ffs_event_add(ffs, FUNCTIONFS_BIND);
3263         return 0;
3264
3265 error:
3266         /* XXX Do we need to release all claimed endpoints here? */
3267         return ret;
3268 }
3269
3270 static int ffs_func_bind(struct usb_configuration *c,
3271                          struct usb_function *f)
3272 {
3273         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3274         struct ffs_function *func = ffs_func_from_usb(f);
3275         int ret;
3276
3277         if (IS_ERR(ffs_opts))
3278                 return PTR_ERR(ffs_opts);
3279
3280         ret = _ffs_func_bind(c, f);
3281         if (ret && !--ffs_opts->refcnt)
3282                 functionfs_unbind(func->ffs);
3283
3284         return ret;
3285 }
3286
3287
3288 /* Other USB function hooks *************************************************/
3289
3290 static void ffs_reset_work(struct work_struct *work)
3291 {
3292         struct ffs_data *ffs = container_of(work,
3293                 struct ffs_data, reset_work);
3294         ffs_data_reset(ffs);
3295 }
3296
3297 static int ffs_func_set_alt(struct usb_function *f,
3298                             unsigned interface, unsigned alt)
3299 {
3300         struct ffs_function *func = ffs_func_from_usb(f);
3301         struct ffs_data *ffs = func->ffs;
3302         int ret = 0, intf;
3303
3304         if (alt != (unsigned)-1) {
3305                 intf = ffs_func_revmap_intf(func, interface);
3306                 if (intf < 0)
3307                         return intf;
3308         }
3309
3310         if (ffs->func)
3311                 ffs_func_eps_disable(ffs->func);
3312
3313         if (ffs->state == FFS_DEACTIVATED) {
3314                 ffs->state = FFS_CLOSING;
3315                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3316                 schedule_work(&ffs->reset_work);
3317                 return -ENODEV;
3318         }
3319
3320         if (ffs->state != FFS_ACTIVE)
3321                 return -ENODEV;
3322
3323         if (alt == (unsigned)-1) {
3324                 ffs->func = NULL;
3325                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3326                 return 0;
3327         }
3328
3329         ffs->func = func;
3330         ret = ffs_func_eps_enable(func);
3331         if (ret >= 0)
3332                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3333         return ret;
3334 }
3335
3336 static void ffs_func_disable(struct usb_function *f)
3337 {
3338         ffs_func_set_alt(f, 0, (unsigned)-1);
3339 }
3340
3341 static int ffs_func_setup(struct usb_function *f,
3342                           const struct usb_ctrlrequest *creq)
3343 {
3344         struct ffs_function *func = ffs_func_from_usb(f);
3345         struct ffs_data *ffs = func->ffs;
3346         unsigned long flags;
3347         int ret;
3348
3349         ENTER();
3350
3351         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3352         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3353         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3354         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3355         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3356
3357         /*
3358          * Most requests directed to interface go through here
3359          * (notable exceptions are set/get interface) so we need to
3360          * handle them.  All other either handled by composite or
3361          * passed to usb_configuration->setup() (if one is set).  No
3362          * matter, we will handle requests directed to endpoint here
3363          * as well (as it's straightforward).  Other request recipient
3364          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3365          * is being used.
3366          */
3367         if (ffs->state != FFS_ACTIVE)
3368                 return -ENODEV;
3369
3370         switch (creq->bRequestType & USB_RECIP_MASK) {
3371         case USB_RECIP_INTERFACE:
3372                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3373                 if (ret < 0)
3374                         return ret;
3375                 break;
3376
3377         case USB_RECIP_ENDPOINT:
3378                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3379                 if (ret < 0)
3380                         return ret;
3381                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3382                         ret = func->ffs->eps_addrmap[ret];
3383                 break;
3384
3385         default:
3386                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3387                         ret = le16_to_cpu(creq->wIndex);
3388                 else
3389                         return -EOPNOTSUPP;
3390         }
3391
3392         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3393         ffs->ev.setup = *creq;
3394         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3395         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3396         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3397
3398         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3399 }
3400
3401 static bool ffs_func_req_match(struct usb_function *f,
3402                                const struct usb_ctrlrequest *creq,
3403                                bool config0)
3404 {
3405         struct ffs_function *func = ffs_func_from_usb(f);
3406
3407         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3408                 return false;
3409
3410         switch (creq->bRequestType & USB_RECIP_MASK) {
3411         case USB_RECIP_INTERFACE:
3412                 return (ffs_func_revmap_intf(func,
3413                                              le16_to_cpu(creq->wIndex)) >= 0);
3414         case USB_RECIP_ENDPOINT:
3415                 return (ffs_func_revmap_ep(func,
3416                                            le16_to_cpu(creq->wIndex)) >= 0);
3417         default:
3418                 return (bool) (func->ffs->user_flags &
3419                                FUNCTIONFS_ALL_CTRL_RECIP);
3420         }
3421 }
3422
3423 static void ffs_func_suspend(struct usb_function *f)
3424 {
3425         ENTER();
3426         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3427 }
3428
3429 static void ffs_func_resume(struct usb_function *f)
3430 {
3431         ENTER();
3432         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3433 }
3434
3435
3436 /* Endpoint and interface numbers reverse mapping ***************************/
3437
3438 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3439 {
3440         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3441         return num ? num : -EDOM;
3442 }
3443
3444 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3445 {
3446         short *nums = func->interfaces_nums;
3447         unsigned count = func->ffs->interfaces_count;
3448
3449         for (; count; --count, ++nums) {
3450                 if (*nums >= 0 && *nums == intf)
3451                         return nums - func->interfaces_nums;
3452         }
3453
3454         return -EDOM;
3455 }
3456
3457
3458 /* Devices management *******************************************************/
3459
3460 static LIST_HEAD(ffs_devices);
3461
3462 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3463 {
3464         struct ffs_dev *dev;
3465
3466         if (!name)
3467                 return NULL;
3468
3469         list_for_each_entry(dev, &ffs_devices, entry) {
3470                 if (strcmp(dev->name, name) == 0)
3471                         return dev;
3472         }
3473
3474         return NULL;
3475 }
3476
3477 /*
3478  * ffs_lock must be taken by the caller of this function
3479  */
3480 static struct ffs_dev *_ffs_get_single_dev(void)
3481 {
3482         struct ffs_dev *dev;
3483
3484         if (list_is_singular(&ffs_devices)) {
3485                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3486                 if (dev->single)
3487                         return dev;
3488         }
3489
3490         return NULL;
3491 }
3492
3493 /*
3494  * ffs_lock must be taken by the caller of this function
3495  */
3496 static struct ffs_dev *_ffs_find_dev(const char *name)
3497 {
3498         struct ffs_dev *dev;
3499
3500         dev = _ffs_get_single_dev();
3501         if (dev)
3502                 return dev;
3503
3504         return _ffs_do_find_dev(name);
3505 }
3506
3507 /* Configfs support *********************************************************/
3508
3509 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3510 {
3511         return container_of(to_config_group(item), struct f_fs_opts,
3512                             func_inst.group);
3513 }
3514
3515 static void ffs_attr_release(struct config_item *item)
3516 {
3517         struct f_fs_opts *opts = to_ffs_opts(item);
3518
3519         usb_put_function_instance(&opts->func_inst);
3520 }
3521
3522 static struct configfs_item_operations ffs_item_ops = {
3523         .release        = ffs_attr_release,
3524 };
3525
3526 static const struct config_item_type ffs_func_type = {
3527         .ct_item_ops    = &ffs_item_ops,
3528         .ct_owner       = THIS_MODULE,
3529 };
3530
3531
3532 /* Function registration interface ******************************************/
3533
3534 static void ffs_free_inst(struct usb_function_instance *f)
3535 {
3536         struct f_fs_opts *opts;
3537
3538         opts = to_f_fs_opts(f);
3539         ffs_release_dev(opts->dev);
3540         ffs_dev_lock();
3541         _ffs_free_dev(opts->dev);
3542         ffs_dev_unlock();
3543         kfree(opts);
3544 }
3545
3546 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3547 {
3548         if (strlen(name) >= sizeof_field(struct ffs_dev, name))
3549                 return -ENAMETOOLONG;
3550         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3551 }
3552
3553 static struct usb_function_instance *ffs_alloc_inst(void)
3554 {
3555         struct f_fs_opts *opts;
3556         struct ffs_dev *dev;
3557
3558         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3559         if (!opts)
3560                 return ERR_PTR(-ENOMEM);
3561
3562         opts->func_inst.set_inst_name = ffs_set_inst_name;
3563         opts->func_inst.free_func_inst = ffs_free_inst;
3564         ffs_dev_lock();
3565         dev = _ffs_alloc_dev();
3566         ffs_dev_unlock();
3567         if (IS_ERR(dev)) {
3568                 kfree(opts);
3569                 return ERR_CAST(dev);
3570         }
3571         opts->dev = dev;
3572         dev->opts = opts;
3573
3574         config_group_init_type_name(&opts->func_inst.group, "",
3575                                     &ffs_func_type);
3576         return &opts->func_inst;
3577 }
3578
3579 static void ffs_free(struct usb_function *f)
3580 {
3581         kfree(ffs_func_from_usb(f));
3582 }
3583
3584 static void ffs_func_unbind(struct usb_configuration *c,
3585                             struct usb_function *f)
3586 {
3587         struct ffs_function *func = ffs_func_from_usb(f);
3588         struct ffs_data *ffs = func->ffs;
3589         struct f_fs_opts *opts =
3590                 container_of(f->fi, struct f_fs_opts, func_inst);
3591         struct ffs_ep *ep = func->eps;
3592         unsigned count = ffs->eps_count;
3593         unsigned long flags;
3594
3595         ENTER();
3596         if (ffs->func == func) {
3597                 ffs_func_eps_disable(func);
3598                 ffs->func = NULL;
3599         }
3600
3601         /* Drain any pending AIO completions */
3602         drain_workqueue(ffs->io_completion_wq);
3603
3604         if (!--opts->refcnt)
3605                 functionfs_unbind(ffs);
3606
3607         /* cleanup after autoconfig */
3608         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3609         while (count--) {
3610                 if (ep->ep && ep->req)
3611                         usb_ep_free_request(ep->ep, ep->req);
3612                 ep->req = NULL;
3613                 ++ep;
3614         }
3615         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3616         kfree(func->eps);
3617         func->eps = NULL;
3618         /*
3619          * eps, descriptors and interfaces_nums are allocated in the
3620          * same chunk so only one free is required.
3621          */
3622         func->function.fs_descriptors = NULL;
3623         func->function.hs_descriptors = NULL;
3624         func->function.ss_descriptors = NULL;
3625         func->function.ssp_descriptors = NULL;
3626         func->interfaces_nums = NULL;
3627
3628         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3629 }
3630
3631 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3632 {
3633         struct ffs_function *func;
3634
3635         ENTER();
3636
3637         func = kzalloc(sizeof(*func), GFP_KERNEL);
3638         if (!func)
3639                 return ERR_PTR(-ENOMEM);
3640
3641         func->function.name    = "Function FS Gadget";
3642
3643         func->function.bind    = ffs_func_bind;
3644         func->function.unbind  = ffs_func_unbind;
3645         func->function.set_alt = ffs_func_set_alt;
3646         func->function.disable = ffs_func_disable;
3647         func->function.setup   = ffs_func_setup;
3648         func->function.req_match = ffs_func_req_match;
3649         func->function.suspend = ffs_func_suspend;
3650         func->function.resume  = ffs_func_resume;
3651         func->function.free_func = ffs_free;
3652
3653         return &func->function;
3654 }
3655
3656 /*
3657  * ffs_lock must be taken by the caller of this function
3658  */
3659 static struct ffs_dev *_ffs_alloc_dev(void)
3660 {
3661         struct ffs_dev *dev;
3662         int ret;
3663
3664         if (_ffs_get_single_dev())
3665                         return ERR_PTR(-EBUSY);
3666
3667         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3668         if (!dev)
3669                 return ERR_PTR(-ENOMEM);
3670
3671         if (list_empty(&ffs_devices)) {
3672                 ret = functionfs_init();
3673                 if (ret) {
3674                         kfree(dev);
3675                         return ERR_PTR(ret);
3676                 }
3677         }
3678
3679         list_add(&dev->entry, &ffs_devices);
3680
3681         return dev;
3682 }
3683
3684 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3685 {
3686         struct ffs_dev *existing;
3687         int ret = 0;
3688
3689         ffs_dev_lock();
3690
3691         existing = _ffs_do_find_dev(name);
3692         if (!existing)
3693                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3694         else if (existing != dev)
3695                 ret = -EBUSY;
3696
3697         ffs_dev_unlock();
3698
3699         return ret;
3700 }
3701 EXPORT_SYMBOL_GPL(ffs_name_dev);
3702
3703 int ffs_single_dev(struct ffs_dev *dev)
3704 {
3705         int ret;
3706
3707         ret = 0;
3708         ffs_dev_lock();
3709
3710         if (!list_is_singular(&ffs_devices))
3711                 ret = -EBUSY;
3712         else
3713                 dev->single = true;
3714
3715         ffs_dev_unlock();
3716         return ret;
3717 }
3718 EXPORT_SYMBOL_GPL(ffs_single_dev);
3719
3720 /*
3721  * ffs_lock must be taken by the caller of this function
3722  */
3723 static void _ffs_free_dev(struct ffs_dev *dev)
3724 {
3725         list_del(&dev->entry);
3726
3727         kfree(dev);
3728         if (list_empty(&ffs_devices))
3729                 functionfs_cleanup();
3730 }
3731
3732 static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
3733 {
3734         int ret = 0;
3735         struct ffs_dev *ffs_dev;
3736
3737         ENTER();
3738         ffs_dev_lock();
3739
3740         ffs_dev = _ffs_find_dev(dev_name);
3741         if (!ffs_dev) {
3742                 ret = -ENOENT;
3743         } else if (ffs_dev->mounted) {
3744                 ret = -EBUSY;
3745         } else if (ffs_dev->ffs_acquire_dev_callback &&
3746                    ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
3747                 ret = -ENOENT;
3748         } else {
3749                 ffs_dev->mounted = true;
3750                 ffs_dev->ffs_data = ffs_data;
3751                 ffs_data->private_data = ffs_dev;
3752         }
3753
3754         ffs_dev_unlock();
3755         return ret;
3756 }
3757
3758 static void ffs_release_dev(struct ffs_dev *ffs_dev)
3759 {
3760         ENTER();
3761         ffs_dev_lock();
3762
3763         if (ffs_dev && ffs_dev->mounted) {
3764                 ffs_dev->mounted = false;
3765                 if (ffs_dev->ffs_data) {
3766                         ffs_dev->ffs_data->private_data = NULL;
3767                         ffs_dev->ffs_data = NULL;
3768                 }
3769
3770                 if (ffs_dev->ffs_release_dev_callback)
3771                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3772         }
3773
3774         ffs_dev_unlock();
3775 }
3776
3777 static int ffs_ready(struct ffs_data *ffs)
3778 {
3779         struct ffs_dev *ffs_obj;
3780         int ret = 0;
3781
3782         ENTER();
3783         ffs_dev_lock();
3784
3785         ffs_obj = ffs->private_data;
3786         if (!ffs_obj) {
3787                 ret = -EINVAL;
3788                 goto done;
3789         }
3790         if (WARN_ON(ffs_obj->desc_ready)) {
3791                 ret = -EBUSY;
3792                 goto done;
3793         }
3794
3795         ffs_obj->desc_ready = true;
3796
3797         if (ffs_obj->ffs_ready_callback) {
3798                 ret = ffs_obj->ffs_ready_callback(ffs);
3799                 if (ret)
3800                         goto done;
3801         }
3802
3803         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3804 done:
3805         ffs_dev_unlock();
3806         return ret;
3807 }
3808
3809 static void ffs_closed(struct ffs_data *ffs)
3810 {
3811         struct ffs_dev *ffs_obj;
3812         struct f_fs_opts *opts;
3813         struct config_item *ci;
3814
3815         ENTER();
3816         ffs_dev_lock();
3817
3818         ffs_obj = ffs->private_data;
3819         if (!ffs_obj)
3820                 goto done;
3821
3822         ffs_obj->desc_ready = false;
3823
3824         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3825             ffs_obj->ffs_closed_callback)
3826                 ffs_obj->ffs_closed_callback(ffs);
3827
3828         if (ffs_obj->opts)
3829                 opts = ffs_obj->opts;
3830         else
3831                 goto done;
3832
3833         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3834             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3835                 goto done;
3836
3837         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3838         ffs_dev_unlock();
3839
3840         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3841                 unregister_gadget_item(ci);
3842         return;
3843 done:
3844         ffs_dev_unlock();
3845 }
3846
3847 /* Misc helper functions ****************************************************/
3848
3849 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3850 {
3851         return nonblock
3852                 ? mutex_trylock(mutex) ? 0 : -EAGAIN
3853                 : mutex_lock_interruptible(mutex);
3854 }
3855
3856 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3857 {
3858         char *data;
3859
3860         if (!len)
3861                 return NULL;
3862
3863         data = memdup_user(buf, len);
3864         if (IS_ERR(data))
3865                 return data;
3866
3867         pr_vdebug("Buffer from user space:\n");
3868         ffs_dump_mem("", data, len);
3869
3870         return data;
3871 }
3872
3873 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3874 MODULE_LICENSE("GPL");
3875 MODULE_AUTHOR("Michal Nazarewicz");