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 /* CBI Interrupt data structure */
  97 struct interrupt_data {
  98         u8      bType;
  99         u8      bValue;
 100 };
 101
 102 #define CBI_INTERRUPT_DATA_LEN          2
 103
 104 /* CBI Accept Device-Specific Command request */
 105 #define USB_CBI_ADSC_REQUEST            0x00
 106
 107
 108 /* Length of a SCSI Command Data Block */
 109 #define MAX_COMMAND_SIZE        16
 110
 111 /* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
 112 #define SS_NO_SENSE                             0
 113 #define SS_COMMUNICATION_FAILURE                0x040800
 114 #define SS_INVALID_COMMAND                      0x052000
 115 #define SS_INVALID_FIELD_IN_CDB                 0x052400
 116 #define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE   0x052100
 117 #define SS_LOGICAL_UNIT_NOT_SUPPORTED           0x052500
 118 #define SS_MEDIUM_NOT_PRESENT                   0x023a00
 119 #define SS_MEDIUM_REMOVAL_PREVENTED             0x055302
 120 #define SS_NOT_READY_TO_READY_TRANSITION        0x062800
 121 #define SS_RESET_OCCURRED                       0x062900
 122 #define SS_SAVING_PARAMETERS_NOT_SUPPORTED      0x053900
 123 #define SS_UNRECOVERED_READ_ERROR               0x031100
 124 #define SS_WRITE_ERROR                          0x030c02
 125 #define SS_WRITE_PROTECTED                      0x072700
 126
 127 #define SK(x)           ((u8) ((x) >> 16))      /* Sense Key byte, etc. */
 128 #define ASC(x)          ((u8) ((x) >> 8))
 129 #define ASCQ(x)         ((u8) (x))
 130
 131
 132 /*-------------------------------------------------------------------------*/
 133
 134
 135 struct fsg_lun {
 136         struct file     *filp;
 137         loff_t          file_length;
 138         loff_t          num_sectors;
 139
 140         unsigned int    initially_ro:1;
 141         unsigned int    ro:1;
 142         unsigned int    removable:1;
 143         unsigned int    cdrom:1;
 144         unsigned int    prevent_medium_removal:1;
 145         unsigned int    registered:1;
 146         unsigned int    info_valid:1;
 147         unsigned int    nofua:1;
 148
 149         u32             sense_data;
 150         u32             sense_data_info;
 151         u32             unit_attention_data;
 152
 153         unsigned int    blkbits;        /* Bits of logical block size of bound block device */
 154         unsigned int    blksize;        /* logical block size of bound block device */
 155         struct device   dev;
 156 };
 157
 158 #define fsg_lun_is_open(curlun) ((curlun)->filp != NULL)
 159
 160 static struct fsg_lun *fsg_lun_from_dev(struct device *dev)
 161 {
 162         return container_of(dev, struct fsg_lun, dev);
 163 }
 164
 165
 166 /* Big enough to hold our biggest descriptor */
 167 #define EP0_BUFSIZE     256
 168 #define DELAYED_STATUS  (EP0_BUFSIZE + 999)     /* An impossibly large value */
 169
 170 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
 171
 172 static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
 173 module_param_named(num_buffers, fsg_num_buffers, uint, S_IRUGO);
 174 MODULE_PARM_DESC(num_buffers, "Number of pipeline buffers");
 175
 176 #else
 177
 178 /*
 179  * Number of buffers we will use.
 180  * 2 is usually enough for good buffering pipeline
 181  */
 182 #define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
 183
 184 #endif /* CONFIG_USB_DEBUG */
 185
 186 /* check if fsg_num_buffers is within a valid range */
 187 static inline int fsg_num_buffers_validate(void)
 188 {
 189         if (fsg_num_buffers >= 2 && fsg_num_buffers <= 4)
 190                 return 0;
 191         pr_err("fsg_num_buffers %u is out of range (%d to %d)\n",
 192                fsg_num_buffers, 2 ,4);
 193         return -EINVAL;
 194 }
 195
 196 /* Default size of buffer length. */
 197 #define FSG_BUFLEN      ((u32)16384)
 198
 199 /* Maximal number of LUNs supported in mass storage function */
 200 #define FSG_MAX_LUNS    8
 201
 202 enum fsg_buffer_state {
 203         BUF_STATE_EMPTY = 0,
 204         BUF_STATE_FULL,
 205         BUF_STATE_BUSY
 206 };
 207
 208 struct fsg_buffhd {
 209         void                            *buf;
 210         enum fsg_buffer_state           state;
 211         struct fsg_buffhd               *next;
 212
 213         /*
 214          * The NetChip 2280 is faster, and handles some protocol faults
 215          * better, if we don't submit any short bulk-out read requests.
 216          * So we will record the intended request length here.
 217          */
 218         unsigned int                    bulk_out_intended_length;
 219
 220         struct usb_request              *inreq;
 221         int                             inreq_busy;
 222         struct usb_request              *outreq;
 223         int                             outreq_busy;
 224 };
 225
 226 enum fsg_state {
 227         /* This one isn't used anywhere */
 228         FSG_STATE_COMMAND_PHASE = -10,
 229         FSG_STATE_DATA_PHASE,
 230         FSG_STATE_STATUS_PHASE,
 231
 232         FSG_STATE_IDLE = 0,
 233         FSG_STATE_ABORT_BULK_OUT,
 234         FSG_STATE_RESET,
 235         FSG_STATE_INTERFACE_CHANGE,
 236         FSG_STATE_CONFIG_CHANGE,
 237         FSG_STATE_DISCONNECT,
 238         FSG_STATE_EXIT,
 239         FSG_STATE_TERMINATED
 240 };
 241
 242 enum data_direction {
 243         DATA_DIR_UNKNOWN = 0,
 244         DATA_DIR_FROM_HOST,
 245         DATA_DIR_TO_HOST,
 246         DATA_DIR_NONE
 247 };
 248
 249
 250 /*-------------------------------------------------------------------------*/
 251
 252
 253 static inline u32 get_unaligned_be24(u8 *buf)
 254 {
 255         return 0xffffff & (u32) get_unaligned_be32(buf - 1);
 256 }
 257
 258
 259 /*-------------------------------------------------------------------------*/
 260
 261
 262 enum {
 263         FSG_STRING_INTERFACE
 264 };
 265
 266
 267 /* There is only one interface. */
 268
 269 static struct usb_interface_descriptor
 270 fsg_intf_desc = {
 271         .bLength =              sizeof fsg_intf_desc,
 272         .bDescriptorType =      USB_DT_INTERFACE,
 273
 274         .bNumEndpoints =        2,              /* Adjusted during fsg_bind() */
 275         .bInterfaceClass =      USB_CLASS_MASS_STORAGE,
 276         .bInterfaceSubClass =   USB_SC_SCSI,    /* Adjusted during fsg_bind() */
 277         .bInterfaceProtocol =   USB_PR_BULK,    /* Adjusted during fsg_bind() */
 278         .iInterface =           FSG_STRING_INTERFACE,
 279 };
 280
 281 /*
 282  * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
 283  * interrupt-in.
 284  */
 285
 286 static struct usb_endpoint_descriptor
 287 fsg_fs_bulk_in_desc = {
 288         .bLength =              USB_DT_ENDPOINT_SIZE,
 289         .bDescriptorType =      USB_DT_ENDPOINT,
 290
 291         .bEndpointAddress =     USB_DIR_IN,
 292         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 293         /* wMaxPacketSize set by autoconfiguration */
 294 };
 295
 296 static struct usb_endpoint_descriptor
 297 fsg_fs_bulk_out_desc = {
 298         .bLength =              USB_DT_ENDPOINT_SIZE,
 299         .bDescriptorType =      USB_DT_ENDPOINT,
 300
 301         .bEndpointAddress =     USB_DIR_OUT,
 302         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 303         /* wMaxPacketSize set by autoconfiguration */
 304 };
 305
 306 static struct usb_descriptor_header *fsg_fs_function[] = {
 307         (struct usb_descriptor_header *) &fsg_intf_desc,
 308         (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
 309         (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
 310         NULL,
 311 };
 312
 313
 314 /*
 315  * USB 2.0 devices need to expose both high speed and full speed
 316  * descriptors, unless they only run at full speed.
 317  *
 318  * That means alternate endpoint descriptors (bigger packets)
 319  * and a "device qualifier" ... plus more construction options
 320  * for the configuration descriptor.
 321  */
 322 static struct usb_endpoint_descriptor
 323 fsg_hs_bulk_in_desc = {
 324         .bLength =              USB_DT_ENDPOINT_SIZE,
 325         .bDescriptorType =      USB_DT_ENDPOINT,
 326
 327         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 328         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 329         .wMaxPacketSize =       cpu_to_le16(512),
 330 };
 331
 332 static struct usb_endpoint_descriptor
 333 fsg_hs_bulk_out_desc = {
 334         .bLength =              USB_DT_ENDPOINT_SIZE,
 335         .bDescriptorType =      USB_DT_ENDPOINT,
 336
 337         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 338         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 339         .wMaxPacketSize =       cpu_to_le16(512),
 340         .bInterval =            1,      /* NAK every 1 uframe */
 341 };
 342
 343
 344 static struct usb_descriptor_header *fsg_hs_function[] = {
 345         (struct usb_descriptor_header *) &fsg_intf_desc,
 346         (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
 347         (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
 348         NULL,
 349 };
 350
 351 static struct usb_endpoint_descriptor
 352 fsg_ss_bulk_in_desc = {
 353         .bLength =              USB_DT_ENDPOINT_SIZE,
 354         .bDescriptorType =      USB_DT_ENDPOINT,
 355
 356         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 357         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 358         .wMaxPacketSize =       cpu_to_le16(1024),
 359 };
 360
 361 static struct usb_ss_ep_comp_descriptor fsg_ss_bulk_in_comp_desc = {
 362         .bLength =              sizeof(fsg_ss_bulk_in_comp_desc),
 363         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 364
 365         /*.bMaxBurst =          DYNAMIC, */
 366 };
 367
 368 static struct usb_endpoint_descriptor
 369 fsg_ss_bulk_out_desc = {
 370         .bLength =              USB_DT_ENDPOINT_SIZE,
 371         .bDescriptorType =      USB_DT_ENDPOINT,
 372
 373         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 374         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 375         .wMaxPacketSize =       cpu_to_le16(1024),
 376 };
 377
 378 static struct usb_ss_ep_comp_descriptor fsg_ss_bulk_out_comp_desc = {
 379         .bLength =              sizeof(fsg_ss_bulk_in_comp_desc),
 380         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 381
 382         /*.bMaxBurst =          DYNAMIC, */
 383 };
 384
 385 static __maybe_unused struct usb_ext_cap_descriptor fsg_ext_cap_desc = {
 386         .bLength =              USB_DT_USB_EXT_CAP_SIZE,
 387         .bDescriptorType =      USB_DT_DEVICE_CAPABILITY,
 388         .bDevCapabilityType =   USB_CAP_TYPE_EXT,
 389
 390         .bmAttributes =         cpu_to_le32(USB_LPM_SUPPORT),
 391 };
 392
 393 static __maybe_unused struct usb_ss_cap_descriptor fsg_ss_cap_desc = {
 394         .bLength =              USB_DT_USB_SS_CAP_SIZE,
 395         .bDescriptorType =      USB_DT_DEVICE_CAPABILITY,
 396         .bDevCapabilityType =   USB_SS_CAP_TYPE,
 397
 398         /* .bmAttributes = LTM is not supported yet */
 399
 400         .wSpeedSupported =      cpu_to_le16(USB_LOW_SPEED_OPERATION
 401                 | USB_FULL_SPEED_OPERATION
 402                 | USB_HIGH_SPEED_OPERATION
 403                 | USB_5GBPS_OPERATION),
 404         .bFunctionalitySupport = USB_LOW_SPEED_OPERATION,
 405         .bU1devExitLat =        USB_DEFAULT_U1_DEV_EXIT_LAT,
 406         .bU2DevExitLat =        cpu_to_le16(USB_DEFAULT_U2_DEV_EXIT_LAT),
 407 };
 408
 409 static __maybe_unused struct usb_bos_descriptor fsg_bos_desc = {
 410         .bLength =              USB_DT_BOS_SIZE,
 411         .bDescriptorType =      USB_DT_BOS,
 412
 413         .wTotalLength =         cpu_to_le16(USB_DT_BOS_SIZE
 414                                 + USB_DT_USB_EXT_CAP_SIZE
 415                                 + USB_DT_USB_SS_CAP_SIZE),
 416
 417         .bNumDeviceCaps =       2,
 418 };
 419
 420 static struct usb_descriptor_header *fsg_ss_function[] = {
 421         (struct usb_descriptor_header *) &fsg_intf_desc,
 422         (struct usb_descriptor_header *) &fsg_ss_bulk_in_desc,
 423         (struct usb_descriptor_header *) &fsg_ss_bulk_in_comp_desc,
 424         (struct usb_descriptor_header *) &fsg_ss_bulk_out_desc,
 425         (struct usb_descriptor_header *) &fsg_ss_bulk_out_comp_desc,
 426         NULL,
 427 };
 428
 429 /* Maxpacket and other transfer characteristics vary by speed. */
 430 static __maybe_unused struct usb_endpoint_descriptor *
 431 fsg_ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
 432                 struct usb_endpoint_descriptor *hs,
 433                 struct usb_endpoint_descriptor *ss)
 434 {
 435         if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
 436                 return ss;
 437         else if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
 438                 return hs;
 439         return fs;
 440 }
 441
 442
 443 /* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
 444 static struct usb_string                fsg_strings[] = {
 445         {FSG_STRING_INTERFACE,          fsg_string_interface},
 446         {}
 447 };
 448
 449 static struct usb_gadget_strings        fsg_stringtab = {
 450         .language       = 0x0409,               /* en-us */
 451         .strings        = fsg_strings,
 452 };
 453
 454
 455  /*-------------------------------------------------------------------------*/
 456
 457 /*
 458  * If the next two routines are called while the gadget is registered,
 459  * the caller must own fsg->filesem for writing.
 460  */
 461
 462 static void fsg_lun_close(struct fsg_lun *curlun)
 463 {
 464         if (curlun->filp) {
 465                 LDBG(curlun, "close backing file\n");
 466                 fput(curlun->filp);
 467                 curlun->filp = NULL;
 468         }
 469 }
 470
 471
 472 static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 473 {
 474         int                             ro;
 475         struct file                     *filp = NULL;
 476         int                             rc = -EINVAL;
 477         struct inode                    *inode = NULL;
 478         loff_t                          size;
 479         loff_t                          num_sectors;
 480         loff_t                          min_sectors;
 481         unsigned int                    blkbits;
 482         unsigned int                    blksize;
 483
 484         /* R/W if we can, R/O if we must */
 485         ro = curlun->initially_ro;
 486         if (!ro) {
 487                 filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
 488                 if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
 489                         ro = 1;
 490         }
 491         if (ro)
 492                 filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
 493         if (IS_ERR(filp)) {
 494                 LINFO(curlun, "unable to open backing file: %s\n", filename);
 495                 return PTR_ERR(filp);
 496         }
 497
 498         if (!(filp->f_mode & FMODE_WRITE))
 499                 ro = 1;
 500
 501         inode = filp->f_path.dentry->d_inode;
 502         if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
 503                 LINFO(curlun, "invalid file type: %s\n", filename);
 504                 goto out;
 505         }
 506
 507         /*
 508          * If we can't read the file, it's no good.
 509          * If we can't write the file, use it read-only.
 510          */
 511         if (!(filp->f_op->read || filp->f_op->aio_read)) {
 512                 LINFO(curlun, "file not readable: %s\n", filename);
 513                 goto out;
 514         }
 515         if (!(filp->f_op->write || filp->f_op->aio_write))
 516                 ro = 1;
 517
 518         size = i_size_read(inode->i_mapping->host);
 519         if (size < 0) {
 520                 LINFO(curlun, "unable to find file size: %s\n", filename);
 521                 rc = (int) size;
 522                 goto out;
 523         }
 524
 525         if (curlun->cdrom) {
 526                 blksize = 2048;
 527                 blkbits = 11;
 528         } else if (inode->i_bdev) {
 529                 blksize = bdev_logical_block_size(inode->i_bdev);
 530                 blkbits = blksize_bits(blksize);
 531         } else {
 532                 blksize = 512;
 533                 blkbits = 9;
 534         }
 535
 536         num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
 537         min_sectors = 1;
 538         if (curlun->cdrom) {
 539                 min_sectors = 300;      /* Smallest track is 300 frames */
 540                 if (num_sectors >= 256*60*75) {
 541                         num_sectors = 256*60*75 - 1;
 542                         LINFO(curlun, "file too big: %s\n", filename);
 543                         LINFO(curlun, "using only first %d blocks\n",
 544                                         (int) num_sectors);
 545                 }
 546         }
 547         if (num_sectors < min_sectors) {
 548                 LINFO(curlun, "file too small: %s\n", filename);
 549                 rc = -ETOOSMALL;
 550                 goto out;
 551         }
 552
 553         if (fsg_lun_is_open(curlun))
 554                 fsg_lun_close(curlun);
 555
 556         curlun->blksize = blksize;
 557         curlun->blkbits = blkbits;
 558         curlun->ro = ro;
 559         curlun->filp = filp;
 560         curlun->file_length = size;
 561         curlun->num_sectors = num_sectors;
 562         LDBG(curlun, "open backing file: %s\n", filename);
 563         return 0;
 564
 565 out:
 566         fput(filp);
 567         return rc;
 568 }
 569
 570
 571 /*-------------------------------------------------------------------------*/
 572
 573 /*
 574  * Sync the file data, don't bother with the metadata.
 575  * This code was copied from fs/buffer.c:sys_fdatasync().
 576  */
 577 static int fsg_lun_fsync_sub(struct fsg_lun *curlun)
 578 {
 579         struct file     *filp = curlun->filp;
 580
 581         if (curlun->ro || !filp)
 582                 return 0;
 583         return vfs_fsync(filp, 1);
 584 }
 585
 586 static void store_cdrom_address(u8 *dest, int msf, u32 addr)
 587 {
 588         if (msf) {
 589                 /* Convert to Minutes-Seconds-Frames */
 590                 addr >>= 2;             /* Convert to 2048-byte frames */
 591                 addr += 2*75;           /* Lead-in occupies 2 seconds */
 592                 dest[3] = addr % 75;    /* Frames */
 593                 addr /= 75;
 594                 dest[2] = addr % 60;    /* Seconds */
 595                 addr /= 60;
 596                 dest[1] = addr;         /* Minutes */
 597                 dest[0] = 0;            /* Reserved */
 598         } else {
 599                 /* Absolute sector */
 600                 put_unaligned_be32(addr, dest);
 601         }
 602 }
 603
 604
 605 /*-------------------------------------------------------------------------*/
 606
 607
 608 static ssize_t fsg_show_ro(struct device *dev, struct device_attribute *attr,
 609                            char *buf)
 610 {
 611         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 612
 613         return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
 614                                   ? curlun->ro
 615                                   : curlun->initially_ro);
 616 }
 617
 618 static ssize_t fsg_show_nofua(struct device *dev, struct device_attribute *attr,
 619                               char *buf)
 620 {
 621         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 622
 623         return sprintf(buf, "%u\n", curlun->nofua);
 624 }
 625
 626 static ssize_t fsg_show_file(struct device *dev, struct device_attribute *attr,
 627                              char *buf)
 628 {
 629         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 630         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 631         char            *p;
 632         ssize_t         rc;
 633
 634         down_read(filesem);
 635         if (fsg_lun_is_open(curlun)) {  /* Get the complete pathname */
 636                 p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1);
 637                 if (IS_ERR(p))
 638                         rc = PTR_ERR(p);
 639                 else {
 640                         rc = strlen(p);
 641                         memmove(buf, p, rc);
 642                         buf[rc] = '\n';         /* Add a newline */
 643                         buf[++rc] = 0;
 644                 }
 645         } else {                                /* No file, return 0 bytes */
 646                 *buf = 0;
 647                 rc = 0;
 648         }
 649         up_read(filesem);
 650         return rc;
 651 }
 652
 653
 654 static ssize_t fsg_store_ro(struct device *dev, struct device_attribute *attr,
 655                             const char *buf, size_t count)
 656 {
 657         ssize_t         rc;
 658         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 659         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 660         unsigned        ro;
 661
 662         rc = kstrtouint(buf, 2, &ro);
 663         if (rc)
 664                 return rc;
 665
 666         /*
 667          * Allow the write-enable status to change only while the
 668          * backing file is closed.
 669          */
 670         down_read(filesem);
 671         if (fsg_lun_is_open(curlun)) {
 672                 LDBG(curlun, "read-only status change prevented\n");
 673                 rc = -EBUSY;
 674         } else {
 675                 curlun->ro = ro;
 676                 curlun->initially_ro = ro;
 677                 LDBG(curlun, "read-only status set to %d\n", curlun->ro);
 678                 rc = count;
 679         }
 680         up_read(filesem);
 681         return rc;
 682 }
 683
 684 static ssize_t fsg_store_nofua(struct device *dev,
 685                                struct device_attribute *attr,
 686                                const char *buf, size_t count)
 687 {
 688         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 689         unsigned        nofua;
 690         int             ret;
 691
 692         ret = kstrtouint(buf, 2, &nofua);
 693         if (ret)
 694                 return ret;
 695
 696         /* Sync data when switching from async mode to sync */
 697         if (!nofua && curlun->nofua)
 698                 fsg_lun_fsync_sub(curlun);
 699
 700         curlun->nofua = nofua;
 701
 702         return count;
 703 }
 704
 705 static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr,
 706                               const char *buf, size_t count)
 707 {
 708         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 709         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 710         int             rc = 0;
 711
 712         if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
 713                 LDBG(curlun, "eject attempt prevented\n");
 714                 return -EBUSY;                          /* "Door is locked" */
 715         }
 716
 717         /* Remove a trailing newline */
 718         if (count > 0 && buf[count-1] == '\n')
 719                 ((char *) buf)[count-1] = 0;            /* Ugh! */
 720
 721         /* Load new medium */
 722         down_write(filesem);
 723         if (count > 0 && buf[0]) {
 724                 /* fsg_lun_open() will close existing file if any. */
 725                 rc = fsg_lun_open(curlun, buf);
 726                 if (rc == 0)
 727                         curlun->unit_attention_data =
 728                                         SS_NOT_READY_TO_READY_TRANSITION;
 729         } else if (fsg_lun_is_open(curlun)) {
 730                 fsg_lun_close(curlun);
 731                 curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
 732         }
 733         up_write(filesem);
 734         return (rc < 0 ? rc : count);
 735 }