drivers/usb/gadget/storage_common.c

   1 /*
   2  * storage_common.c -- Common definitions for mass storage functionality
   3  *
   4  * Copyright (C) 2003-2008 Alan Stern
   5  * Copyeight (C) 2009 Samsung Electronics
   6  * Author: Michal Nazarewicz (mina86@mina86.com)
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  */
  13
  14 /*
  15  * This file requires the following identifiers used in USB strings to
  16  * be defined (each of type pointer to char):
  17  *  - fsg_string_interface    -- name of the interface
  18  */
  19
  20 /*
  21  * When USB_GADGET_DEBUG_FILES is defined the module param num_buffers
  22  * sets the number of pipeline buffers (length of the fsg_buffhd array).
  23  * The valid range of num_buffers is: num >= 2 && num <= 4.
  24  */
  25
  26
  27 #include <linux/usb/storage.h>
  28 #include <scsi/scsi.h>
  29 #include <asm/unaligned.h>
  30
  31
  32 /*
  33  * Thanks to NetChip Technologies for donating this product ID.
  34  *
  35  * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
  36  * Instead:  allocate your own, using normal USB-IF procedures.
  37  */
  38 #define FSG_VENDOR_ID   0x0525  /* NetChip */
  39 #define FSG_PRODUCT_ID  0xa4a5  /* Linux-USB File-backed Storage Gadget */
  40
  41
  42 /*-------------------------------------------------------------------------*/
  43
  44
  45 #ifndef DEBUG
  46 #undef VERBOSE_DEBUG
  47 #undef DUMP_MSGS
  48 #endif /* !DEBUG */
  49
  50 #ifdef VERBOSE_DEBUG
  51 #define VLDBG   LDBG
  52 #else
  53 #define VLDBG(lun, fmt, args...) do { } while (0)
  54 #endif /* VERBOSE_DEBUG */
  55
  56 #define LDBG(lun, fmt, args...)   dev_dbg(&(lun)->dev, fmt, ## args)
  57 #define LERROR(lun, fmt, args...) dev_err(&(lun)->dev, fmt, ## args)
  58 #define LWARN(lun, fmt, args...)  dev_warn(&(lun)->dev, fmt, ## args)
  59 #define LINFO(lun, fmt, args...)  dev_info(&(lun)->dev, fmt, ## args)
  60
  61
  62 #ifdef DUMP_MSGS
  63
  64 #  define dump_msg(fsg, /* const char * */ label,                       \
  65                    /* const u8 * */ buf, /* unsigned */ length) do {    \
  66         if (length < 512) {                                             \
  67                 DBG(fsg, "%s, length %u:\n", label, length);            \
  68                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET,      \
  69                                16, 1, buf, length, 0);                  \
  70         }                                                               \
  71 } while (0)
  72
  73 #  define dump_cdb(fsg) do { } while (0)
  74
  75 #else
  76
  77 #  define dump_msg(fsg, /* const char * */ label, \
  78                    /* const u8 * */ buf, /* unsigned */ length) do { } while (0)
  79
  80 #  ifdef VERBOSE_DEBUG
  81
  82 #    define dump_cdb(fsg)                                               \
  83         print_hex_dump(KERN_DEBUG, "SCSI CDB: ", DUMP_PREFIX_NONE,      \
  84                        16, 1, (fsg)->cmnd, (fsg)->cmnd_size, 0)         \
  85
  86 #  else
  87
  88 #    define dump_cdb(fsg) do { } while (0)
  89
  90 #  endif /* VERBOSE_DEBUG */
  91
  92 #endif /* DUMP_MSGS */
  93
  94 /*-------------------------------------------------------------------------*/
  95
  96 /* Length of a SCSI Command Data Block */
  97 #define MAX_COMMAND_SIZE        16
  98
  99 /* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
 100 #define SS_NO_SENSE                             0
 101 #define SS_COMMUNICATION_FAILURE                0x040800
 102 #define SS_INVALID_COMMAND                      0x052000
 103 #define SS_INVALID_FIELD_IN_CDB                 0x052400
 104 #define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE   0x052100
 105 #define SS_LOGICAL_UNIT_NOT_SUPPORTED           0x052500
 106 #define SS_MEDIUM_NOT_PRESENT                   0x023a00
 107 #define SS_MEDIUM_REMOVAL_PREVENTED             0x055302
 108 #define SS_NOT_READY_TO_READY_TRANSITION        0x062800
 109 #define SS_RESET_OCCURRED                       0x062900
 110 #define SS_SAVING_PARAMETERS_NOT_SUPPORTED      0x053900
 111 #define SS_UNRECOVERED_READ_ERROR               0x031100
 112 #define SS_WRITE_ERROR                          0x030c02
 113 #define SS_WRITE_PROTECTED                      0x072700
 114
 115 #define SK(x)           ((u8) ((x) >> 16))      /* Sense Key byte, etc. */
 116 #define ASC(x)          ((u8) ((x) >> 8))
 117 #define ASCQ(x)         ((u8) (x))
 118
 119
 120 /*-------------------------------------------------------------------------*/
 121
 122
 123 struct fsg_lun {
 124         struct file     *filp;
 125         loff_t          file_length;
 126         loff_t          num_sectors;
 127
 128         unsigned int    initially_ro:1;
 129         unsigned int    ro:1;
 130         unsigned int    removable:1;
 131         unsigned int    cdrom:1;
 132         unsigned int    prevent_medium_removal:1;
 133         unsigned int    registered:1;
 134         unsigned int    info_valid:1;
 135         unsigned int    nofua:1;
 136
 137         u32             sense_data;
 138         u32             sense_data_info;
 139         u32             unit_attention_data;
 140
 141         unsigned int    blkbits;        /* Bits of logical block size of bound block device */
 142         unsigned int    blksize;        /* logical block size of bound block device */
 143         struct device   dev;
 144 #ifdef CONFIG_USB_MSC_PROFILING
 145         spinlock_t      lock;
 146         struct {
 147
 148                 unsigned long rbytes;
 149                 unsigned long wbytes;
 150                 ktime_t rtime;
 151                 ktime_t wtime;
 152         } perf;
 153
 154 #endif
 155 };
 156
 157 static inline bool fsg_lun_is_open(struct fsg_lun *curlun)
 158 {
 159         return curlun->filp != NULL;
 160 }
 161
 162 static inline struct fsg_lun *fsg_lun_from_dev(struct device *dev)
 163 {
 164         return container_of(dev, struct fsg_lun, dev);
 165 }
 166
 167
 168 /* Big enough to hold our biggest descriptor */
 169 #define EP0_BUFSIZE     256
 170 #define DELAYED_STATUS  (EP0_BUFSIZE + 999)     /* An impossibly large value */
 171
 172 #ifdef CONFIG_USB_CSW_HACK
 173 #define fsg_num_buffers         4
 174 #else
 175 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
 176
 177 static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
 178 module_param_named(num_buffers, fsg_num_buffers, uint, S_IRUGO);
 179 MODULE_PARM_DESC(num_buffers, "Number of pipeline buffers");
 180
 181 #else
 182
 183 /*
 184  * Number of buffers we will use.
 185  * 2 is usually enough for good buffering pipeline
 186  */
 187 #define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
 188
 189 #endif /* CONFIG_USB_DEBUG */
 190 #endif /* CONFIG_USB_CSW_HACK */
 191
 192 /* check if fsg_num_buffers is within a valid range */
 193 static inline int fsg_num_buffers_validate(void)
 194 {
 195         if (fsg_num_buffers >= 2 && fsg_num_buffers <= 4)
 196                 return 0;
 197         pr_err("fsg_num_buffers %u is out of range (%d to %d)\n",
 198                fsg_num_buffers, 2 , 4);
 199         return -EINVAL;
 200 }
 201
 202 /* Default size of buffer length. */
 203 #define FSG_BUFLEN      ((u32)65536)
 204
 205 /* Maximal number of LUNs supported in mass storage function */
 206 #define FSG_MAX_LUNS    8
 207
 208 enum fsg_buffer_state {
 209         BUF_STATE_EMPTY = 0,
 210         BUF_STATE_FULL,
 211         BUF_STATE_BUSY
 212 };
 213
 214 struct fsg_buffhd {
 215         void                            *buf;
 216         enum fsg_buffer_state           state;
 217         struct fsg_buffhd               *next;
 218
 219         /*
 220          * The NetChip 2280 is faster, and handles some protocol faults
 221          * better, if we don't submit any short bulk-out read requests.
 222          * So we will record the intended request length here.
 223          */
 224         unsigned int                    bulk_out_intended_length;
 225
 226         struct usb_request              *inreq;
 227         int                             inreq_busy;
 228         struct usb_request              *outreq;
 229         int                             outreq_busy;
 230 };
 231
 232 enum fsg_state {
 233         /* This one isn't used anywhere */
 234         FSG_STATE_COMMAND_PHASE = -10,
 235         FSG_STATE_DATA_PHASE,
 236         FSG_STATE_STATUS_PHASE,
 237
 238         FSG_STATE_IDLE = 0,
 239         FSG_STATE_ABORT_BULK_OUT,
 240         FSG_STATE_RESET,
 241         FSG_STATE_INTERFACE_CHANGE,
 242         FSG_STATE_CONFIG_CHANGE,
 243         FSG_STATE_DISCONNECT,
 244         FSG_STATE_EXIT,
 245         FSG_STATE_TERMINATED
 246 };
 247
 248 enum data_direction {
 249         DATA_DIR_UNKNOWN = 0,
 250         DATA_DIR_FROM_HOST,
 251         DATA_DIR_TO_HOST,
 252         DATA_DIR_NONE
 253 };
 254
 255
 256 /*-------------------------------------------------------------------------*/
 257
 258
 259 static inline u32 get_unaligned_be24(u8 *buf)
 260 {
 261         return 0xffffff & (u32) get_unaligned_be32(buf - 1);
 262 }
 263
 264
 265 /*-------------------------------------------------------------------------*/
 266
 267
 268 enum {
 269         FSG_STRING_INTERFACE
 270 };
 271
 272
 273 /* There is only one interface. */
 274
 275 static struct usb_interface_descriptor
 276 fsg_intf_desc = {
 277         .bLength =              sizeof fsg_intf_desc,
 278         .bDescriptorType =      USB_DT_INTERFACE,
 279
 280         .bNumEndpoints =        2,              /* Adjusted during fsg_bind() */
 281         .bInterfaceClass =      USB_CLASS_MASS_STORAGE,
 282         .bInterfaceSubClass =   USB_SC_SCSI,    /* Adjusted during fsg_bind() */
 283         .bInterfaceProtocol =   USB_PR_BULK,    /* Adjusted during fsg_bind() */
 284         .iInterface =           FSG_STRING_INTERFACE,
 285 };
 286
 287 /*
 288  * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
 289  * interrupt-in.
 290  */
 291
 292 static struct usb_endpoint_descriptor
 293 fsg_fs_bulk_in_desc = {
 294         .bLength =              USB_DT_ENDPOINT_SIZE,
 295         .bDescriptorType =      USB_DT_ENDPOINT,
 296
 297         .bEndpointAddress =     USB_DIR_IN,
 298         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 299         /* wMaxPacketSize set by autoconfiguration */
 300 };
 301
 302 static struct usb_endpoint_descriptor
 303 fsg_fs_bulk_out_desc = {
 304         .bLength =              USB_DT_ENDPOINT_SIZE,
 305         .bDescriptorType =      USB_DT_ENDPOINT,
 306
 307         .bEndpointAddress =     USB_DIR_OUT,
 308         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 309         /* wMaxPacketSize set by autoconfiguration */
 310 };
 311
 312 static struct usb_descriptor_header *fsg_fs_function[] = {
 313         (struct usb_descriptor_header *) &fsg_intf_desc,
 314         (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
 315         (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
 316         NULL,
 317 };
 318
 319
 320 /*
 321  * USB 2.0 devices need to expose both high speed and full speed
 322  * descriptors, unless they only run at full speed.
 323  *
 324  * That means alternate endpoint descriptors (bigger packets)
 325  * and a "device qualifier" ... plus more construction options
 326  * for the configuration descriptor.
 327  */
 328 static struct usb_endpoint_descriptor
 329 fsg_hs_bulk_in_desc = {
 330         .bLength =              USB_DT_ENDPOINT_SIZE,
 331         .bDescriptorType =      USB_DT_ENDPOINT,
 332
 333         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 334         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 335         .wMaxPacketSize =       cpu_to_le16(512),
 336 };
 337
 338 static struct usb_endpoint_descriptor
 339 fsg_hs_bulk_out_desc = {
 340         .bLength =              USB_DT_ENDPOINT_SIZE,
 341         .bDescriptorType =      USB_DT_ENDPOINT,
 342
 343         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 344         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 345         .wMaxPacketSize =       cpu_to_le16(512),
 346         .bInterval =            1,      /* NAK every 1 uframe */
 347 };
 348
 349
 350 static struct usb_descriptor_header *fsg_hs_function[] = {
 351         (struct usb_descriptor_header *) &fsg_intf_desc,
 352         (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
 353         (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
 354         NULL,
 355 };
 356
 357 static struct usb_endpoint_descriptor
 358 fsg_ss_bulk_in_desc = {
 359         .bLength =              USB_DT_ENDPOINT_SIZE,
 360         .bDescriptorType =      USB_DT_ENDPOINT,
 361
 362         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 363         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 364         .wMaxPacketSize =       cpu_to_le16(1024),
 365 };
 366
 367 static struct usb_ss_ep_comp_descriptor fsg_ss_bulk_in_comp_desc = {
 368         .bLength =              sizeof(fsg_ss_bulk_in_comp_desc),
 369         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 370
 371         /*.bMaxBurst =          DYNAMIC, */
 372 };
 373
 374 static struct usb_endpoint_descriptor
 375 fsg_ss_bulk_out_desc = {
 376         .bLength =              USB_DT_ENDPOINT_SIZE,
 377         .bDescriptorType =      USB_DT_ENDPOINT,
 378
 379         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 380         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 381         .wMaxPacketSize =       cpu_to_le16(1024),
 382 };
 383
 384 static struct usb_ss_ep_comp_descriptor fsg_ss_bulk_out_comp_desc = {
 385         .bLength =              sizeof(fsg_ss_bulk_in_comp_desc),
 386         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 387
 388         /*.bMaxBurst =          DYNAMIC, */
 389 };
 390
 391 static struct usb_descriptor_header *fsg_ss_function[] = {
 392         (struct usb_descriptor_header *) &fsg_intf_desc,
 393         (struct usb_descriptor_header *) &fsg_ss_bulk_in_desc,
 394         (struct usb_descriptor_header *) &fsg_ss_bulk_in_comp_desc,
 395         (struct usb_descriptor_header *) &fsg_ss_bulk_out_desc,
 396         (struct usb_descriptor_header *) &fsg_ss_bulk_out_comp_desc,
 397         NULL,
 398 };
 399
 400 /* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
 401 static struct usb_string                fsg_strings[] = {
 402         {FSG_STRING_INTERFACE,          fsg_string_interface},
 403         {}
 404 };
 405
 406 static struct usb_gadget_strings        fsg_stringtab = {
 407         .language       = 0x0409,               /* en-us */
 408         .strings        = fsg_strings,
 409 };
 410
 411
 412  /*-------------------------------------------------------------------------*/
 413
 414 /*
 415  * If the next two routines are called while the gadget is registered,
 416  * the caller must own fsg->filesem for writing.
 417  */
 418
 419 static void fsg_lun_close(struct fsg_lun *curlun)
 420 {
 421         if (curlun->filp) {
 422                 LDBG(curlun, "close backing file\n");
 423                 fput(curlun->filp);
 424                 curlun->filp = NULL;
 425         }
 426 }
 427
 428
 429 static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 430 {
 431         int                             ro;
 432         struct file                     *filp = NULL;
 433         int                             rc = -EINVAL;
 434         struct inode                    *inode = NULL;
 435         loff_t                          size;
 436         loff_t                          num_sectors;
 437         loff_t                          min_sectors;
 438         unsigned int                    blkbits;
 439         unsigned int                    blksize;
 440
 441         /* R/W if we can, R/O if we must */
 442         ro = curlun->initially_ro;
 443         if (!ro) {
 444                 filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
 445                 if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
 446                         ro = 1;
 447         }
 448         if (ro)
 449                 filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
 450         if (IS_ERR(filp)) {
 451                 LINFO(curlun, "unable to open backing file: %s\n", filename);
 452                 return PTR_ERR(filp);
 453         }
 454
 455         if (!(filp->f_mode & FMODE_WRITE))
 456                 ro = 1;
 457
 458         inode = file_inode(filp);
 459         if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
 460                 LINFO(curlun, "invalid file type: %s\n", filename);
 461                 goto out;
 462         }
 463
 464         /*
 465          * If we can't read the file, it's no good.
 466          * If we can't write the file, use it read-only.
 467          */
 468         if (!(filp->f_op->read || filp->f_op->aio_read)) {
 469                 LINFO(curlun, "file not readable: %s\n", filename);
 470                 goto out;
 471         }
 472         if (!(filp->f_op->write || filp->f_op->aio_write))
 473                 ro = 1;
 474
 475         size = i_size_read(inode->i_mapping->host);
 476         if (size < 0) {
 477                 LINFO(curlun, "unable to find file size: %s\n", filename);
 478                 rc = (int) size;
 479                 goto out;
 480         }
 481
 482         if (curlun->cdrom) {
 483                 blksize = 2048;
 484                 blkbits = 11;
 485         } else if (inode->i_bdev) {
 486                 blksize = bdev_logical_block_size(inode->i_bdev);
 487                 blkbits = blksize_bits(blksize);
 488         } else {
 489                 blksize = 512;
 490                 blkbits = 9;
 491         }
 492
 493         num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
 494         min_sectors = 1;
 495         if (curlun->cdrom) {
 496                 min_sectors = 300;      /* Smallest track is 300 frames */
 497                 if (num_sectors >= 256*60*75) {
 498                         num_sectors = 256*60*75 - 1;
 499                         LINFO(curlun, "file too big: %s\n", filename);
 500                         LINFO(curlun, "using only first %d blocks\n",
 501                                         (int) num_sectors);
 502                 }
 503         }
 504         if (num_sectors < min_sectors) {
 505                 LINFO(curlun, "file too small: %s\n", filename);
 506                 rc = -ETOOSMALL;
 507                 goto out;
 508         }
 509
 510         if (fsg_lun_is_open(curlun))
 511                 fsg_lun_close(curlun);
 512
 513         curlun->blksize = blksize;
 514         curlun->blkbits = blkbits;
 515         curlun->ro = ro;
 516         curlun->filp = filp;
 517         curlun->file_length = size;
 518         curlun->num_sectors = num_sectors;
 519         LDBG(curlun, "open backing file: %s\n", filename);
 520         return 0;
 521
 522 out:
 523         fput(filp);
 524         return rc;
 525 }
 526
 527
 528 /*-------------------------------------------------------------------------*/
 529
 530 /*
 531  * Sync the file data, don't bother with the metadata.
 532  * This code was copied from fs/buffer.c:sys_fdatasync().
 533  */
 534 static int fsg_lun_fsync_sub(struct fsg_lun *curlun)
 535 {
 536         struct file     *filp = curlun->filp;
 537
 538         if (curlun->ro || !filp)
 539                 return 0;
 540         return vfs_fsync(filp, 1);
 541 }
 542
 543 static void store_cdrom_address(u8 *dest, int msf, u32 addr)
 544 {
 545         if (msf) {
 546                 /* Convert to Minutes-Seconds-Frames */
 547                 addr >>= 2;             /* Convert to 2048-byte frames */
 548                 addr += 2*75;           /* Lead-in occupies 2 seconds */
 549                 dest[3] = addr % 75;    /* Frames */
 550                 addr /= 75;
 551                 dest[2] = addr % 60;    /* Seconds */
 552                 addr /= 60;
 553                 dest[1] = addr;         /* Minutes */
 554                 dest[0] = 0;            /* Reserved */
 555         } else {
 556                 /* Absolute sector */
 557                 put_unaligned_be32(addr, dest);
 558         }
 559 }
 560
 561
 562 /*-------------------------------------------------------------------------*/
 563
 564
 565 static ssize_t fsg_show_ro(struct device *dev, struct device_attribute *attr,
 566                            char *buf)
 567 {
 568         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 569
 570         return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
 571                                   ? curlun->ro
 572                                   : curlun->initially_ro);
 573 }
 574
 575 static ssize_t fsg_show_nofua(struct device *dev, struct device_attribute *attr,
 576                               char *buf)
 577 {
 578         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 579
 580         return sprintf(buf, "%u\n", curlun->nofua);
 581 }
 582
 583 #ifdef CONFIG_USB_MSC_PROFILING
 584 static ssize_t fsg_show_perf(struct device *dev, struct device_attribute *attr,
 585                               char *buf)
 586 {
 587         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 588         unsigned long rbytes, wbytes;
 589         int64_t rtime, wtime;
 590
 591         spin_lock(&curlun->lock);
 592         rbytes = curlun->perf.rbytes;
 593         wbytes = curlun->perf.wbytes;
 594         rtime = ktime_to_us(curlun->perf.rtime);
 595         wtime = ktime_to_us(curlun->perf.wtime);
 596         spin_unlock(&curlun->lock);
 597
 598         return snprintf(buf, PAGE_SIZE, "Write performance :"
 599                                         "%lu bytes in %lld microseconds\n"
 600                                         "Read performance :"
 601                                         "%lu bytes in %lld microseconds\n",
 602                                         wbytes, wtime, rbytes, rtime);
 603 }
 604 static ssize_t fsg_store_perf(struct device *dev, struct device_attribute *attr,
 605                         const char *buf, size_t count)
 606 {
 607         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 608         int value;
 609
 610         sscanf(buf, "%d", &value);
 611         if (!value) {
 612                 spin_lock(&curlun->lock);
 613                 memset(&curlun->perf, 0, sizeof(curlun->perf));
 614                 spin_unlock(&curlun->lock);
 615         }
 616
 617         return count;
 618 }
 619 #endif
 620 static ssize_t fsg_show_file(struct device *dev, struct device_attribute *attr,
 621                              char *buf)
 622 {
 623         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 624         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 625         char            *p;
 626         ssize_t         rc;
 627
 628         down_read(filesem);
 629         if (fsg_lun_is_open(curlun)) {  /* Get the complete pathname */
 630                 p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1);
 631                 if (IS_ERR(p))
 632                         rc = PTR_ERR(p);
 633                 else {
 634                         rc = strlen(p);
 635                         memmove(buf, p, rc);
 636                         buf[rc] = '\n';         /* Add a newline */
 637                         buf[++rc] = 0;
 638                 }
 639         } else {                                /* No file, return 0 bytes */
 640                 *buf = 0;
 641                 rc = 0;
 642         }
 643         up_read(filesem);
 644         return rc;
 645 }
 646
 647
 648 static ssize_t fsg_store_ro(struct device *dev, struct device_attribute *attr,
 649                             const char *buf, size_t count)
 650 {
 651         ssize_t         rc;
 652         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 653         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 654         unsigned        ro;
 655
 656         rc = kstrtouint(buf, 2, &ro);
 657         if (rc)
 658                 return rc;
 659
 660         /*
 661          * Allow the write-enable status to change only while the
 662          * backing file is closed.
 663          */
 664         down_read(filesem);
 665         if (fsg_lun_is_open(curlun)) {
 666                 LDBG(curlun, "read-only status change prevented\n");
 667                 rc = -EBUSY;
 668         } else {
 669                 curlun->ro = ro;
 670                 curlun->initially_ro = ro;
 671                 LDBG(curlun, "read-only status set to %d\n", curlun->ro);
 672                 rc = count;
 673         }
 674         up_read(filesem);
 675         return rc;
 676 }
 677
 678 static ssize_t fsg_store_nofua(struct device *dev,
 679                                struct device_attribute *attr,
 680                                const char *buf, size_t count)
 681 {
 682         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 683         unsigned        nofua;
 684         int             ret;
 685
 686         ret = kstrtouint(buf, 2, &nofua);
 687         if (ret)
 688                 return ret;
 689
 690         /* Sync data when switching from async mode to sync */
 691         if (!nofua && curlun->nofua)
 692                 fsg_lun_fsync_sub(curlun);
 693
 694         curlun->nofua = nofua;
 695
 696         return count;
 697 }
 698
 699 static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr,
 700                               const char *buf, size_t count)
 701 {
 702         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 703         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 704         int             rc = 0;
 705
 706 #ifndef CONFIG_USB_G_ANDROID
 707         if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
 708                 LDBG(curlun, "eject attempt prevented\n");
 709                 return -EBUSY;                          /* "Door is locked" */
 710         }
 711 #endif
 712
 713         /* Remove a trailing newline */
 714         if (count > 0 && buf[count-1] == '\n')
 715                 ((char *) buf)[count-1] = 0;            /* Ugh! */
 716
 717         /* Load new medium */
 718         down_write(filesem);
 719         if (count > 0 && buf[0]) {
 720                 LDBG(curlun, "fsg_lun_open\n");
 721                 /* fsg_lun_open() will close existing file if any. */
 722                 rc = fsg_lun_open(curlun, buf);
 723                 if (rc == 0)
 724                         curlun->unit_attention_data =
 725                                         SS_NOT_READY_TO_READY_TRANSITION;
 726         } else if (fsg_lun_is_open(curlun)) {
 727                 LDBG(curlun, "fsg_lun_open\n");
 728                 fsg_lun_close(curlun);
 729                 curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
 730         }
 731         up_write(filesem);
 732         return (rc < 0 ? rc : count);
 733 }