drivers/block/ub.c

   1 /*
   2  * The low performance USB storage driver (ub).
   3  *
   4  * Copyright (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   5  * Copyright (C) 2004 Pete Zaitcev (zaitcev@yahoo.com)
   6  *
   7  * This work is a part of Linux kernel, is derived from it,
   8  * and is not licensed separately. See file COPYING for details.
   9  *
  10  * TODO (sorted by decreasing priority)
  11  *  -- Kill first_open (Al Viro fixed the block layer now)
  12  *  -- set readonly flag for CDs, set removable flag for CF readers
  13  *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
  14  *  -- special case some senses, e.g. 3a/0 -> no media present, reduce retries
  15  *  -- verify the 13 conditions and do bulk resets
  16  *  -- kill last_pipe and simply do two-state clearing on both pipes
  17  *  -- verify protocol (bulk) from USB descriptors (maybe...)
  18  *  -- highmem
  19  *  -- move top_sense and work_bcs into separate allocations (if they survive)
  20  *     for cache purists and esoteric architectures.
  21  *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
  22  *  -- prune comments, they are too volumnous
  23  *  -- Exterminate P3 printks
  24  *  -- Resove XXX's
  25  *  -- Redo "benh's retries", perhaps have spin-up code to handle them. V:D=?
  26  *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
  27  */
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/usb.h>
  31 #include <linux/usb_usual.h>
  32 #include <linux/blkdev.h>
  33 #include <linux/devfs_fs_kernel.h>
  34 #include <linux/timer.h>
  35 #include <scsi/scsi.h>
  36
  37 #define DRV_NAME "ub"
  38 #define DEVFS_NAME DRV_NAME
  39
  40 #define UB_MAJOR 180
  41
  42 /*
  43  * The command state machine is the key model for understanding of this driver.
  44  *
  45  * The general rule is that all transitions are done towards the bottom
  46  * of the diagram, thus preventing any loops.
  47  *
  48  * An exception to that is how the STAT state is handled. A counter allows it
  49  * to be re-entered along the path marked with [C].
  50  *
  51  *       +--------+
  52  *       ! INIT   !
  53  *       +--------+
  54  *           !
  55  *        ub_scsi_cmd_start fails ->--------------------------------------\
  56  *           !                                                            !
  57  *           V                                                            !
  58  *       +--------+                                                       !
  59  *       ! CMD    !                                                       !
  60  *       +--------+                                                       !
  61  *           !                                            +--------+      !
  62  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
  63  *           !                                            +--------+      !
  64  *           !                                                !           !
  65  *         was error -->------------------------------------- ! --------->\
  66  *           !                                                !           !
  67  *  /--<-- cmd->dir == NONE ?                                 !           !
  68  *  !        !                                                !           !
  69  *  !        V                                                !           !
  70  *  !    +--------+                                           !           !
  71  *  !    ! DATA   !                                           !           !
  72  *  !    +--------+                                           !           !
  73  *  !        !                           +---------+          !           !
  74  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
  75  *  !        !                           +---------+          !           !
  76  *  !        !                                !               !           !
  77  *  !        !                              was error -->---- ! --------->\
  78  *  !      was error -->--------------------- ! ------------- ! --------->\
  79  *  !        !                                !               !           !
  80  *  !        V                                !               !           !
  81  *  \--->+--------+                           !               !           !
  82  *       ! STAT   !<--------------------------/               !           !
  83  *  /--->+--------+                                           !           !
  84  *  !        !                                                !           !
  85  * [C]     was -EPIPE -->-----------\                         !           !
  86  *  !        !                      !                         !           !
  87  *  +<---- len == 0                 !                         !           !
  88  *  !        !                      !                         !           !
  89  *  !      was error -->--------------------------------------!---------->\
  90  *  !        !                      !                         !           !
  91  *  +<---- bad CSW                  !                         !           !
  92  *  +<---- bad tag                  !                         !           !
  93  *  !        !                      V                         !           !
  94  *  !        !                 +--------+                     !           !
  95  *  !        !                 ! CLRRS  !                     !           !
  96  *  !        !                 +--------+                     !           !
  97  *  !        !                      !                         !           !
  98  *  \------- ! --------------------[C]--------\               !           !
  99  *           !                                !               !           !
 100  *         cmd->error---\                +--------+           !           !
 101  *           !          +--------------->! SENSE  !<----------/           !
 102  *         STAT_FAIL----/                +--------+                       !
 103  *           !                                !                           V
 104  *           !                                V                      +--------+
 105  *           \--------------------------------\--------------------->! DONE   !
 106  *                                                                   +--------+
 107  */
 108
 109 /*
 110  * This many LUNs per USB device.
 111  * Every one of them takes a host, see UB_MAX_HOSTS.
 112  */
 113 #define UB_MAX_LUNS   9
 114
 115 /*
 116  */
 117
 118 #define UB_MINORS_PER_MAJOR     8
 119
 120 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
 121
 122 #define UB_SENSE_SIZE  18
 123
 124 /*
 125  */
 126
 127 /* command block wrapper */
 128 struct bulk_cb_wrap {
 129         __le32  Signature;              /* contains 'USBC' */
 130         u32     Tag;                    /* unique per command id */
 131         __le32  DataTransferLength;     /* size of data */
 132         u8      Flags;                  /* direction in bit 0 */
 133         u8      Lun;                    /* LUN */
 134         u8      Length;                 /* of of the CDB */
 135         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
 136 };
 137
 138 #define US_BULK_CB_WRAP_LEN     31
 139 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
 140 #define US_BULK_FLAG_IN         1
 141 #define US_BULK_FLAG_OUT        0
 142
 143 /* command status wrapper */
 144 struct bulk_cs_wrap {
 145         __le32  Signature;              /* should = 'USBS' */
 146         u32     Tag;                    /* same as original command */
 147         __le32  Residue;                /* amount not transferred */
 148         u8      Status;                 /* see below */
 149 };
 150
 151 #define US_BULK_CS_WRAP_LEN     13
 152 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
 153 #define US_BULK_STAT_OK         0
 154 #define US_BULK_STAT_FAIL       1
 155 #define US_BULK_STAT_PHASE      2
 156
 157 /* bulk-only class specific requests */
 158 #define US_BULK_RESET_REQUEST   0xff
 159 #define US_BULK_GET_MAX_LUN     0xfe
 160
 161 /*
 162  */
 163 struct ub_dev;
 164
 165 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
 166 #define UB_MAX_SECTORS 64
 167
 168 /*
 169  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
 170  * even if a webcam hogs the bus, but some devices need time to spin up.
 171  */
 172 #define UB_URB_TIMEOUT  (HZ*2)
 173 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
 174 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
 175 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
 176
 177 /*
 178  * An instance of a SCSI command in transit.
 179  */
 180 #define UB_DIR_NONE     0
 181 #define UB_DIR_READ     1
 182 #define UB_DIR_ILLEGAL2 2
 183 #define UB_DIR_WRITE    3
 184
 185 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
 186                          (((c)==UB_DIR_READ)? 'r': 'n'))
 187
 188 enum ub_scsi_cmd_state {
 189         UB_CMDST_INIT,                  /* Initial state */
 190         UB_CMDST_CMD,                   /* Command submitted */
 191         UB_CMDST_DATA,                  /* Data phase */
 192         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
 193         UB_CMDST_STAT,                  /* Status phase */
 194         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
 195         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
 196         UB_CMDST_SENSE,                 /* Sending Request Sense */
 197         UB_CMDST_DONE                   /* Final state */
 198 };
 199
 200 static char *ub_scsi_cmd_stname[] = {
 201         ".  ",
 202         "Cmd",
 203         "dat",
 204         "c2s",
 205         "sts",
 206         "clr",
 207         "crs",
 208         "Sen",
 209         "fin"
 210 };
 211
 212 struct ub_scsi_cmd {
 213         unsigned char cdb[UB_MAX_CDB_SIZE];
 214         unsigned char cdb_len;
 215
 216         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
 217         unsigned char trace_index;
 218         enum ub_scsi_cmd_state state;
 219         unsigned int tag;
 220         struct ub_scsi_cmd *next;
 221
 222         int error;                      /* Return code - valid upon done */
 223         unsigned int act_len;           /* Return size */
 224         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
 225
 226         int stat_count;                 /* Retries getting status. */
 227
 228         unsigned int len;               /* Requested length */
 229         unsigned int current_sg;
 230         unsigned int nsg;               /* sgv[nsg] */
 231         struct scatterlist sgv[UB_MAX_REQ_SG];
 232
 233         struct ub_lun *lun;
 234         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
 235         void *back;
 236 };
 237
 238 struct ub_request {
 239         struct request *rq;
 240         unsigned int current_try;
 241         unsigned int nsg;               /* sgv[nsg] */
 242         struct scatterlist sgv[UB_MAX_REQ_SG];
 243 };
 244
 245 /*
 246  */
 247 struct ub_capacity {
 248         unsigned long nsec;             /* Linux size - 512 byte sectors */
 249         unsigned int bsize;             /* Linux hardsect_size */
 250         unsigned int bshift;            /* Shift between 512 and hard sects */
 251 };
 252
 253 /*
 254  * The SCSI command tracing structure.
 255  */
 256
 257 #define SCMD_ST_HIST_SZ   8
 258 #define SCMD_TRACE_SZ    63             /* Less than 4KB of 61-byte lines */
 259
 260 struct ub_scsi_cmd_trace {
 261         int hcur;
 262         unsigned int tag;
 263         unsigned int req_size, act_size;
 264         unsigned char op;
 265         unsigned char dir;
 266         unsigned char key, asc, ascq;
 267         char st_hst[SCMD_ST_HIST_SZ];
 268 };
 269
 270 struct ub_scsi_trace {
 271         int cur;
 272         struct ub_scsi_cmd_trace vec[SCMD_TRACE_SZ];
 273 };
 274
 275 /*
 276  * This is a direct take-off from linux/include/completion.h
 277  * The difference is that I do not wait on this thing, just poll.
 278  * When I want to wait (ub_probe), I just use the stock completion.
 279  *
 280  * Note that INIT_COMPLETION takes no lock. It is correct. But why
 281  * in the bloody hell that thing takes struct instead of pointer to struct
 282  * is quite beyond me. I just copied it from the stock completion.
 283  */
 284 struct ub_completion {
 285         unsigned int done;
 286         spinlock_t lock;
 287 };
 288
 289 static inline void ub_init_completion(struct ub_completion *x)
 290 {
 291         x->done = 0;
 292         spin_lock_init(&x->lock);
 293 }
 294
 295 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
 296
 297 static void ub_complete(struct ub_completion *x)
 298 {
 299         unsigned long flags;
 300
 301         spin_lock_irqsave(&x->lock, flags);
 302         x->done++;
 303         spin_unlock_irqrestore(&x->lock, flags);
 304 }
 305
 306 static int ub_is_completed(struct ub_completion *x)
 307 {
 308         unsigned long flags;
 309         int ret;
 310
 311         spin_lock_irqsave(&x->lock, flags);
 312         ret = x->done;
 313         spin_unlock_irqrestore(&x->lock, flags);
 314         return ret;
 315 }
 316
 317 /*
 318  */
 319 struct ub_scsi_cmd_queue {
 320         int qlen, qmax;
 321         struct ub_scsi_cmd *head, *tail;
 322 };
 323
 324 /*
 325  * The block device instance (one per LUN).
 326  */
 327 struct ub_lun {
 328         struct ub_dev *udev;
 329         struct list_head link;
 330         struct gendisk *disk;
 331         int id;                         /* Host index */
 332         int num;                        /* LUN number */
 333         char name[16];
 334
 335         int changed;                    /* Media was changed */
 336         int removable;
 337         int readonly;
 338         int first_open;                 /* Kludge. See ub_bd_open. */
 339
 340         struct ub_request urq;
 341
 342         /* Use Ingo's mempool if or when we have more than one command. */
 343         /*
 344          * Currently we never need more than one command for the whole device.
 345          * However, giving every LUN a command is a cheap and automatic way
 346          * to enforce fairness between them.
 347          */
 348         int cmda[1];
 349         struct ub_scsi_cmd cmdv[1];
 350
 351         struct ub_capacity capacity;
 352 };
 353
 354 /*
 355  * The USB device instance.
 356  */
 357 struct ub_dev {
 358         spinlock_t lock;
 359         atomic_t poison;                /* The USB device is disconnected */
 360         int openc;                      /* protected by ub_lock! */
 361                                         /* kref is too implicit for our taste */
 362         int reset;                      /* Reset is running */
 363         unsigned int tagcnt;
 364         char name[12];
 365         struct usb_device *dev;
 366         struct usb_interface *intf;
 367
 368         struct list_head luns;
 369
 370         unsigned int send_bulk_pipe;    /* cached pipe values */
 371         unsigned int recv_bulk_pipe;
 372         unsigned int send_ctrl_pipe;
 373         unsigned int recv_ctrl_pipe;
 374
 375         struct tasklet_struct tasklet;
 376
 377         struct ub_scsi_cmd_queue cmd_queue;
 378         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
 379         unsigned char top_sense[UB_SENSE_SIZE];
 380
 381         struct ub_completion work_done;
 382         struct urb work_urb;
 383         struct timer_list work_timer;
 384         int last_pipe;                  /* What might need clearing */
 385         __le32 signature;               /* Learned signature */
 386         struct bulk_cb_wrap work_bcb;
 387         struct bulk_cs_wrap work_bcs;
 388         struct usb_ctrlrequest work_cr;
 389
 390         struct work_struct reset_work;
 391         wait_queue_head_t reset_wait;
 392
 393         int sg_stat[6];
 394         struct ub_scsi_trace tr;
 395 };
 396
 397 /*
 398  */
 399 static void ub_cleanup(struct ub_dev *sc);
 400 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
 401 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 402     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 403 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 404     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 405 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 406 static void ub_end_rq(struct request *rq, int uptodate);
 407 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 408     struct ub_request *urq, struct ub_scsi_cmd *cmd);
 409 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 410 static void ub_urb_complete(struct urb *urb, struct pt_regs *pt);
 411 static void ub_scsi_action(unsigned long _dev);
 412 static void ub_scsi_dispatch(struct ub_dev *sc);
 413 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 414 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 415 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
 416 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 417 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 418 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 419 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 420 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 421     int stalled_pipe);
 422 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
 423 static void ub_reset_enter(struct ub_dev *sc);
 424 static void ub_reset_task(void *arg);
 425 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
 426 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
 427     struct ub_capacity *ret);
 428 static int ub_probe_lun(struct ub_dev *sc, int lnum);
 429
 430 /*
 431  */
 432 #ifdef CONFIG_USB_LIBUSUAL
 433
 434 #define ub_usb_ids  storage_usb_ids
 435 #else
 436
 437 static struct usb_device_id ub_usb_ids[] = {
 438         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
 439         { }
 440 };
 441
 442 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
 443 #endif /* CONFIG_USB_LIBUSUAL */
 444
 445 /*
 446  * Find me a way to identify "next free minor" for add_disk(),
 447  * and the array disappears the next day. However, the number of
 448  * hosts has something to do with the naming and /proc/partitions.
 449  * This has to be thought out in detail before changing.
 450  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
 451  */
 452 #define UB_MAX_HOSTS  26
 453 static char ub_hostv[UB_MAX_HOSTS];
 454
 455 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
 456
 457 /*
 458  * The SCSI command tracing procedures.
 459  */
 460
 461 static void ub_cmdtr_new(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 462 {
 463         int n;
 464         struct ub_scsi_cmd_trace *t;
 465
 466         if ((n = sc->tr.cur + 1) == SCMD_TRACE_SZ) n = 0;
 467         t = &sc->tr.vec[n];
 468
 469         memset(t, 0, sizeof(struct ub_scsi_cmd_trace));
 470         t->tag = cmd->tag;
 471         t->op = cmd->cdb[0];
 472         t->dir = cmd->dir;
 473         t->req_size = cmd->len;
 474         t->st_hst[0] = cmd->state;
 475
 476         sc->tr.cur = n;
 477         cmd->trace_index = n;
 478 }
 479
 480 static void ub_cmdtr_state(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 481 {
 482         int n;
 483         struct ub_scsi_cmd_trace *t;
 484
 485         t = &sc->tr.vec[cmd->trace_index];
 486         if (t->tag == cmd->tag) {
 487                 if ((n = t->hcur + 1) == SCMD_ST_HIST_SZ) n = 0;
 488                 t->st_hst[n] = cmd->state;
 489                 t->hcur = n;
 490         }
 491 }
 492
 493 static void ub_cmdtr_act_len(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 494 {
 495         struct ub_scsi_cmd_trace *t;
 496
 497         t = &sc->tr.vec[cmd->trace_index];
 498         if (t->tag == cmd->tag)
 499                 t->act_size = cmd->act_len;
 500 }
 501
 502 static void ub_cmdtr_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 503     unsigned char *sense)
 504 {
 505         struct ub_scsi_cmd_trace *t;
 506
 507         t = &sc->tr.vec[cmd->trace_index];
 508         if (t->tag == cmd->tag) {
 509                 t->key = sense[2] & 0x0F;
 510                 t->asc = sense[12];
 511                 t->ascq = sense[13];
 512         }
 513 }
 514
 515 static ssize_t ub_diag_show(struct device *dev, struct device_attribute *attr,
 516     char *page)
 517 {
 518         struct usb_interface *intf;
 519         struct ub_dev *sc;
 520         struct list_head *p;
 521         struct ub_lun *lun;
 522         int cnt;
 523         unsigned long flags;
 524         int nc, nh;
 525         int i, j;
 526         struct ub_scsi_cmd_trace *t;
 527
 528         intf = to_usb_interface(dev);
 529         sc = usb_get_intfdata(intf);
 530         if (sc == NULL)
 531                 return 0;
 532
 533         cnt = 0;
 534         spin_lock_irqsave(&sc->lock, flags);
 535
 536         cnt += sprintf(page + cnt,
 537             "poison %d reset %d\n",
 538             atomic_read(&sc->poison), sc->reset);
 539         cnt += sprintf(page + cnt,
 540             "qlen %d qmax %d\n",
 541             sc->cmd_queue.qlen, sc->cmd_queue.qmax);
 542         cnt += sprintf(page + cnt,
 543             "sg %d %d %d %d %d .. %d\n",
 544             sc->sg_stat[0],
 545             sc->sg_stat[1],
 546             sc->sg_stat[2],
 547             sc->sg_stat[3],
 548             sc->sg_stat[4],
 549             sc->sg_stat[5]);
 550
 551         list_for_each (p, &sc->luns) {
 552                 lun = list_entry(p, struct ub_lun, link);
 553                 cnt += sprintf(page + cnt,
 554                     "lun %u changed %d removable %d readonly %d\n",
 555                     lun->num, lun->changed, lun->removable, lun->readonly);
 556         }
 557
 558         if ((nc = sc->tr.cur + 1) == SCMD_TRACE_SZ) nc = 0;
 559         for (j = 0; j < SCMD_TRACE_SZ; j++) {
 560                 t = &sc->tr.vec[nc];
 561
 562                 cnt += sprintf(page + cnt, "%08x %02x", t->tag, t->op);
 563                 if (t->op == REQUEST_SENSE) {
 564                         cnt += sprintf(page + cnt, " [sense %x %02x %02x]",
 565                                         t->key, t->asc, t->ascq);
 566                 } else {
 567                         cnt += sprintf(page + cnt, " %c", UB_DIR_CHAR(t->dir));
 568                         cnt += sprintf(page + cnt, " [%5d %5d]",
 569                                         t->req_size, t->act_size);
 570                 }
 571                 if ((nh = t->hcur + 1) == SCMD_ST_HIST_SZ) nh = 0;
 572                 for (i = 0; i < SCMD_ST_HIST_SZ; i++) {
 573                         cnt += sprintf(page + cnt, " %s",
 574                                         ub_scsi_cmd_stname[(int)t->st_hst[nh]]);
 575                         if (++nh == SCMD_ST_HIST_SZ) nh = 0;
 576                 }
 577                 cnt += sprintf(page + cnt, "\n");
 578
 579                 if (++nc == SCMD_TRACE_SZ) nc = 0;
 580         }
 581
 582         spin_unlock_irqrestore(&sc->lock, flags);
 583         return cnt;
 584 }
 585
 586 static DEVICE_ATTR(diag, S_IRUGO, ub_diag_show, NULL); /* N.B. World readable */
 587
 588 /*
 589  * The id allocator.
 590  *
 591  * This also stores the host for indexing by minor, which is somewhat dirty.
 592  */
 593 static int ub_id_get(void)
 594 {
 595         unsigned long flags;
 596         int i;
 597
 598         spin_lock_irqsave(&ub_lock, flags);
 599         for (i = 0; i < UB_MAX_HOSTS; i++) {
 600                 if (ub_hostv[i] == 0) {
 601                         ub_hostv[i] = 1;
 602                         spin_unlock_irqrestore(&ub_lock, flags);
 603                         return i;
 604                 }
 605         }
 606         spin_unlock_irqrestore(&ub_lock, flags);
 607         return -1;
 608 }
 609
 610 static void ub_id_put(int id)
 611 {
 612         unsigned long flags;
 613
 614         if (id < 0 || id >= UB_MAX_HOSTS) {
 615                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 616                 return;
 617         }
 618
 619         spin_lock_irqsave(&ub_lock, flags);
 620         if (ub_hostv[id] == 0) {
 621                 spin_unlock_irqrestore(&ub_lock, flags);
 622                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 623                 return;
 624         }
 625         ub_hostv[id] = 0;
 626         spin_unlock_irqrestore(&ub_lock, flags);
 627 }
 628
 629 /*
 630  * Downcount for deallocation. This rides on two assumptions:
 631  *  - once something is poisoned, its refcount cannot grow
 632  *  - opens cannot happen at this time (del_gendisk was done)
 633  * If the above is true, we can drop the lock, which we need for
 634  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 635  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 636  */
 637 static void ub_put(struct ub_dev *sc)
 638 {
 639         unsigned long flags;
 640
 641         spin_lock_irqsave(&ub_lock, flags);
 642         --sc->openc;
 643         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 644                 spin_unlock_irqrestore(&ub_lock, flags);
 645                 ub_cleanup(sc);
 646         } else {
 647                 spin_unlock_irqrestore(&ub_lock, flags);
 648         }
 649 }
 650
 651 /*
 652  * Final cleanup and deallocation.
 653  */
 654 static void ub_cleanup(struct ub_dev *sc)
 655 {
 656         struct list_head *p;
 657         struct ub_lun *lun;
 658         request_queue_t *q;
 659
 660         while (!list_empty(&sc->luns)) {
 661                 p = sc->luns.next;
 662                 lun = list_entry(p, struct ub_lun, link);
 663                 list_del(p);
 664
 665                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 666                 if ((q = lun->disk->queue) != NULL)
 667                         blk_cleanup_queue(q);
 668                 /*
 669                  * If we zero disk->private_data BEFORE put_disk, we have
 670                  * to check for NULL all over the place in open, release,
 671                  * check_media and revalidate, because the block level
 672                  * semaphore is well inside the put_disk.
 673                  * But we cannot zero after the call, because *disk is gone.
 674                  * The sd.c is blatantly racy in this area.
 675                  */
 676                 /* disk->private_data = NULL; */
 677                 put_disk(lun->disk);
 678                 lun->disk = NULL;
 679
 680                 ub_id_put(lun->id);
 681                 kfree(lun);
 682         }
 683
 684         kfree(sc);
 685 }
 686
 687 /*
 688  * The "command allocator".
 689  */
 690 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 691 {
 692         struct ub_scsi_cmd *ret;
 693
 694         if (lun->cmda[0])
 695                 return NULL;
 696         ret = &lun->cmdv[0];
 697         lun->cmda[0] = 1;
 698         return ret;
 699 }
 700
 701 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 702 {
 703         if (cmd != &lun->cmdv[0]) {
 704                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
 705                     lun->name, cmd);
 706                 return;
 707         }
 708         if (!lun->cmda[0]) {
 709                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
 710                 return;
 711         }
 712         lun->cmda[0] = 0;
 713 }
 714
 715 /*
 716  * The command queue.
 717  */
 718 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 719 {
 720         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 721
 722         if (t->qlen++ == 0) {
 723                 t->head = cmd;
 724                 t->tail = cmd;
 725         } else {
 726                 t->tail->next = cmd;
 727                 t->tail = cmd;
 728         }
 729
 730         if (t->qlen > t->qmax)
 731                 t->qmax = t->qlen;
 732 }
 733
 734 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 735 {
 736         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 737
 738         if (t->qlen++ == 0) {
 739                 t->head = cmd;
 740                 t->tail = cmd;
 741         } else {
 742                 cmd->next = t->head;
 743                 t->head = cmd;
 744         }
 745
 746         if (t->qlen > t->qmax)
 747                 t->qmax = t->qlen;
 748 }
 749
 750 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
 751 {
 752         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 753         struct ub_scsi_cmd *cmd;
 754
 755         if (t->qlen == 0)
 756                 return NULL;
 757         if (--t->qlen == 0)
 758                 t->tail = NULL;
 759         cmd = t->head;
 760         t->head = cmd->next;
 761         cmd->next = NULL;
 762         return cmd;
 763 }
 764
 765 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
 766
 767 /*
 768  * The request function is our main entry point
 769  */
 770
 771 static void ub_request_fn(request_queue_t *q)
 772 {
 773         struct ub_lun *lun = q->queuedata;
 774         struct request *rq;
 775
 776         while ((rq = elv_next_request(q)) != NULL) {
 777                 if (ub_request_fn_1(lun, rq) != 0) {
 778                         blk_stop_queue(q);
 779                         break;
 780                 }
 781         }
 782 }
 783
 784 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 785 {
 786         struct ub_dev *sc = lun->udev;
 787         struct ub_scsi_cmd *cmd;
 788         struct ub_request *urq;
 789         int n_elem;
 790
 791         if (atomic_read(&sc->poison) || lun->changed) {
 792                 blkdev_dequeue_request(rq);
 793                 ub_end_rq(rq, 0);
 794                 return 0;
 795         }
 796
 797         if (lun->urq.rq != NULL)
 798                 return -1;
 799         if ((cmd = ub_get_cmd(lun)) == NULL)
 800                 return -1;
 801         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 802
 803         blkdev_dequeue_request(rq);
 804
 805         urq = &lun->urq;
 806         memset(urq, 0, sizeof(struct ub_request));
 807         urq->rq = rq;
 808
 809         /*
 810          * get scatterlist from block layer
 811          */
 812         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
 813         if (n_elem < 0) {
 814                 printk(KERN_INFO "%s: failed request map (%d)\n",
 815                     lun->name, n_elem); /* P3 */
 816                 goto drop;
 817         }
 818         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 819                 printk(KERN_WARNING "%s: request with %d segments\n",
 820                     lun->name, n_elem);
 821                 goto drop;
 822         }
 823         urq->nsg = n_elem;
 824         sc->sg_stat[n_elem < 5 ? n_elem : 5]++;
 825
 826         if (blk_pc_request(rq)) {
 827                 ub_cmd_build_packet(sc, lun, cmd, urq);
 828         } else {
 829                 ub_cmd_build_block(sc, lun, cmd, urq);
 830         }
 831         cmd->state = UB_CMDST_INIT;
 832         cmd->lun = lun;
 833         cmd->done = ub_rw_cmd_done;
 834         cmd->back = urq;
 835
 836         cmd->tag = sc->tagcnt++;
 837         if (ub_submit_scsi(sc, cmd) != 0)
 838                 goto drop;
 839
 840         return 0;
 841
 842 drop:
 843         ub_put_cmd(lun, cmd);
 844         ub_end_rq(rq, 0);
 845         return 0;
 846 }
 847
 848 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 849     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 850 {
 851         struct request *rq = urq->rq;
 852         unsigned int block, nblks;
 853
 854         if (rq_data_dir(rq) == WRITE)
 855                 cmd->dir = UB_DIR_WRITE;
 856         else
 857                 cmd->dir = UB_DIR_READ;
 858
 859         cmd->nsg = urq->nsg;
 860         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 861
 862         /*
 863          * build the command
 864          *
 865          * The call to blk_queue_hardsect_size() guarantees that request
 866          * is aligned, but it is given in terms of 512 byte units, always.
 867          */
 868         block = rq->sector >> lun->capacity.bshift;
 869         nblks = rq->nr_sectors >> lun->capacity.bshift;
 870
 871         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
 872         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 873         cmd->cdb[2] = block >> 24;
 874         cmd->cdb[3] = block >> 16;
 875         cmd->cdb[4] = block >> 8;
 876         cmd->cdb[5] = block;
 877         cmd->cdb[7] = nblks >> 8;
 878         cmd->cdb[8] = nblks;
 879         cmd->cdb_len = 10;
 880
 881         cmd->len = rq->nr_sectors * 512;
 882 }
 883
 884 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 885     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 886 {
 887         struct request *rq = urq->rq;
 888
 889         if (rq->data_len == 0) {
 890                 cmd->dir = UB_DIR_NONE;
 891         } else {
 892                 if (rq_data_dir(rq) == WRITE)
 893                         cmd->dir = UB_DIR_WRITE;
 894                 else
 895                         cmd->dir = UB_DIR_READ;
 896         }
 897
 898         cmd->nsg = urq->nsg;
 899         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 900
 901         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 902         cmd->cdb_len = rq->cmd_len;
 903
 904         cmd->len = rq->data_len;
 905 }
 906
 907 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 908 {
 909         struct ub_lun *lun = cmd->lun;
 910         struct ub_request *urq = cmd->back;
 911         struct request *rq;
 912         int uptodate;
 913
 914         rq = urq->rq;
 915
 916         if (cmd->error == 0) {
 917                 uptodate = 1;
 918
 919                 if (blk_pc_request(rq)) {
 920                         if (cmd->act_len >= rq->data_len)
 921                                 rq->data_len = 0;
 922                         else
 923                                 rq->data_len -= cmd->act_len;
 924                 }
 925         } else {
 926                 uptodate = 0;
 927
 928                 if (blk_pc_request(rq)) {
 929                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 930                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 931                         rq->sense_len = UB_SENSE_SIZE;
 932                         if (sc->top_sense[0] != 0)
 933                                 rq->errors = SAM_STAT_CHECK_CONDITION;
 934                         else
 935                                 rq->errors = DID_ERROR << 16;
 936                 } else {
 937                         if (cmd->error == -EIO) {
 938                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
 939                                         return;
 940                         }
 941                 }
 942         }
 943
 944         urq->rq = NULL;
 945
 946         ub_put_cmd(lun, cmd);
 947         ub_end_rq(rq, uptodate);
 948         blk_start_queue(lun->disk->queue);
 949 }
 950
 951 static void ub_end_rq(struct request *rq, int uptodate)
 952 {
 953         int rc;
 954
 955         rc = end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
 956         // assert(rc == 0);
 957         end_that_request_last(rq);
 958 }
 959
 960 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 961     struct ub_request *urq, struct ub_scsi_cmd *cmd)
 962 {
 963
 964         if (atomic_read(&sc->poison))
 965                 return -ENXIO;
 966
 967         ub_reset_enter(sc);
 968
 969         if (urq->current_try >= 3)
 970                 return -EIO;
 971         urq->current_try++;
 972         /* P3 */ printk("%s: dir %c len/act %d/%d "
 973             "[sense %x %02x %02x] retry %d\n",
 974             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
 975             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
 976
 977         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 978         ub_cmd_build_block(sc, lun, cmd, urq);
 979
 980         cmd->state = UB_CMDST_INIT;
 981         cmd->lun = lun;
 982         cmd->done = ub_rw_cmd_done;
 983         cmd->back = urq;
 984
 985         cmd->tag = sc->tagcnt++;
 986
 987 #if 0 /* Wasteful */
 988         return ub_submit_scsi(sc, cmd);
 989 #else
 990         ub_cmdq_add(sc, cmd);
 991         return 0;
 992 #endif
 993 }
 994
 995 /*
 996  * Submit a regular SCSI operation (not an auto-sense).
 997  *
 998  * The Iron Law of Good Submit Routine is:
 999  * Zero return - callback is done, Nonzero return - callback is not done.
1000  * No exceptions.
1001  *
1002  * Host is assumed locked.
1003  *
1004  * XXX We only support Bulk for the moment.
1005  */
1006 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1007 {
1008
1009         if (cmd->state != UB_CMDST_INIT ||
1010             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
1011                 return -EINVAL;
1012         }
1013
1014         ub_cmdq_add(sc, cmd);
1015         /*
1016          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
1017          * safer to jump to a tasklet, in case upper layers do something silly.
1018          */
1019         tasklet_schedule(&sc->tasklet);
1020         return 0;
1021 }
1022
1023 /*
1024  * Submit the first URB for the queued command.
1025  * This function does not deal with queueing in any way.
1026  */
1027 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1028 {
1029         struct bulk_cb_wrap *bcb;
1030         int rc;
1031
1032         bcb = &sc->work_bcb;
1033
1034         /*
1035          * ``If the allocation length is eighteen or greater, and a device
1036          * server returns less than eithteen bytes of data, the application
1037          * client should assume that the bytes not transferred would have been
1038          * zeroes had the device server returned those bytes.''
1039          *
1040          * We zero sense for all commands so that when a packet request
1041          * fails it does not return a stale sense.
1042          */
1043         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
1044
1045         /* set up the command wrapper */
1046         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
1047         bcb->Tag = cmd->tag;            /* Endianness is not important */
1048         bcb->DataTransferLength = cpu_to_le32(cmd->len);
1049         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
1050         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
1051         bcb->Length = cmd->cdb_len;
1052
1053         /* copy the command payload */
1054         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
1055
1056         UB_INIT_COMPLETION(sc->work_done);
1057
1058         sc->last_pipe = sc->send_bulk_pipe;
1059         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
1060             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
1061
1062         /* Fill what we shouldn't be filling, because usb-storage did so. */
1063         sc->work_urb.actual_length = 0;
1064         sc->work_urb.error_count = 0;
1065         sc->work_urb.status = 0;
1066
1067         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1068                 /* XXX Clear stalls */
1069                 ub_complete(&sc->work_done);
1070                 return rc;
1071         }
1072
1073         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
1074         add_timer(&sc->work_timer);
1075
1076         cmd->state = UB_CMDST_CMD;
1077         ub_cmdtr_state(sc, cmd);
1078         return 0;
1079 }
1080
1081 /*
1082  * Timeout handler.
1083  */
1084 static void ub_urb_timeout(unsigned long arg)
1085 {
1086         struct ub_dev *sc = (struct ub_dev *) arg;
1087         unsigned long flags;
1088
1089         spin_lock_irqsave(&sc->lock, flags);
1090         usb_unlink_urb(&sc->work_urb);
1091         spin_unlock_irqrestore(&sc->lock, flags);
1092 }
1093
1094 /*
1095  * Completion routine for the work URB.
1096  *
1097  * This can be called directly from usb_submit_urb (while we have
1098  * the sc->lock taken) and from an interrupt (while we do NOT have
1099  * the sc->lock taken). Therefore, bounce this off to a tasklet.
1100  */
1101 static void ub_urb_complete(struct urb *urb, struct pt_regs *pt)
1102 {
1103         struct ub_dev *sc = urb->context;
1104
1105         ub_complete(&sc->work_done);
1106         tasklet_schedule(&sc->tasklet);
1107 }
1108
1109 static void ub_scsi_action(unsigned long _dev)
1110 {
1111         struct ub_dev *sc = (struct ub_dev *) _dev;
1112         unsigned long flags;
1113
1114         spin_lock_irqsave(&sc->lock, flags);
1115         del_timer(&sc->work_timer);
1116         ub_scsi_dispatch(sc);
1117         spin_unlock_irqrestore(&sc->lock, flags);
1118 }
1119
1120 static void ub_scsi_dispatch(struct ub_dev *sc)
1121 {
1122         struct ub_scsi_cmd *cmd;
1123         int rc;
1124
1125         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
1126                 if (cmd->state == UB_CMDST_DONE) {
1127                         ub_cmdq_pop(sc);
1128                         (*cmd->done)(sc, cmd);
1129                 } else if (cmd->state == UB_CMDST_INIT) {
1130                         ub_cmdtr_new(sc, cmd);
1131                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
1132                                 break;
1133                         cmd->error = rc;
1134                         cmd->state = UB_CMDST_DONE;
1135                         ub_cmdtr_state(sc, cmd);
1136                 } else {
1137                         if (!ub_is_completed(&sc->work_done))
1138                                 break;
1139                         ub_scsi_urb_compl(sc, cmd);
1140                 }
1141         }
1142 }
1143
1144 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1145 {
1146         struct urb *urb = &sc->work_urb;
1147         struct bulk_cs_wrap *bcs;
1148         int len;
1149         int rc;
1150
1151         if (atomic_read(&sc->poison)) {
1152                 ub_state_done(sc, cmd, -ENODEV);
1153                 return;
1154         }
1155
1156         if (cmd->state == UB_CMDST_CLEAR) {
1157                 if (urb->status == -EPIPE) {
1158                         /*
1159                          * STALL while clearning STALL.
1160                          * The control pipe clears itself - nothing to do.
1161                          */
1162                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1163                             sc->name);
1164                         goto Bad_End;
1165                 }
1166
1167                 /*
1168                  * We ignore the result for the halt clear.
1169                  */
1170
1171                 /* reset the endpoint toggle */
1172                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1173                         usb_pipeout(sc->last_pipe), 0);
1174
1175                 ub_state_sense(sc, cmd);
1176
1177         } else if (cmd->state == UB_CMDST_CLR2STS) {
1178                 if (urb->status == -EPIPE) {
1179                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1180                             sc->name);
1181                         goto Bad_End;
1182                 }
1183
1184                 /*
1185                  * We ignore the result for the halt clear.
1186                  */
1187
1188                 /* reset the endpoint toggle */
1189                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1190                         usb_pipeout(sc->last_pipe), 0);
1191
1192                 ub_state_stat(sc, cmd);
1193
1194         } else if (cmd->state == UB_CMDST_CLRRS) {
1195                 if (urb->status == -EPIPE) {
1196                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1197                             sc->name);
1198                         goto Bad_End;
1199                 }
1200
1201                 /*
1202                  * We ignore the result for the halt clear.
1203                  */
1204
1205                 /* reset the endpoint toggle */
1206                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1207                         usb_pipeout(sc->last_pipe), 0);
1208
1209                 ub_state_stat_counted(sc, cmd);
1210
1211         } else if (cmd->state == UB_CMDST_CMD) {
1212                 switch (urb->status) {
1213                 case 0:
1214                         break;
1215                 case -EOVERFLOW:
1216                         goto Bad_End;
1217                 case -EPIPE:
1218                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1219                         if (rc != 0) {
1220                                 printk(KERN_NOTICE "%s: "
1221                                     "unable to submit clear (%d)\n",
1222                                     sc->name, rc);
1223                                 /*
1224                                  * This is typically ENOMEM or some other such shit.
1225                                  * Retrying is pointless. Just do Bad End on it...
1226                                  */
1227                                 ub_state_done(sc, cmd, rc);
1228                                 return;
1229                         }
1230                         cmd->state = UB_CMDST_CLEAR;
1231                         ub_cmdtr_state(sc, cmd);
1232                         return;
1233                 case -ESHUTDOWN:        /* unplug */
1234                 case -EILSEQ:           /* unplug timeout on uhci */
1235                         ub_state_done(sc, cmd, -ENODEV);
1236                         return;
1237                 default:
1238                         goto Bad_End;
1239                 }
1240                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1241                         goto Bad_End;
1242                 }
1243
1244                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1245                         ub_state_stat(sc, cmd);
1246                         return;
1247                 }
1248
1249                 // udelay(125);         // usb-storage has this
1250                 ub_data_start(sc, cmd);
1251
1252         } else if (cmd->state == UB_CMDST_DATA) {
1253                 if (urb->status == -EPIPE) {
1254                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1255                         if (rc != 0) {
1256                                 printk(KERN_NOTICE "%s: "
1257                                     "unable to submit clear (%d)\n",
1258                                     sc->name, rc);
1259                                 ub_state_done(sc, cmd, rc);
1260                                 return;
1261                         }
1262                         cmd->state = UB_CMDST_CLR2STS;
1263                         ub_cmdtr_state(sc, cmd);
1264                         return;
1265                 }
1266                 if (urb->status == -EOVERFLOW) {
1267                         /*
1268                          * A babble? Failure, but we must transfer CSW now.
1269                          */
1270                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1271                         ub_state_stat(sc, cmd);
1272                         return;
1273                 }
1274
1275                 if (cmd->dir == UB_DIR_WRITE) {
1276                         /*
1277                          * Do not continue writes in case of a failure.
1278                          * Doing so would cause sectors to be mixed up,
1279                          * which is worse than sectors lost.
1280                          *
1281                          * We must try to read the CSW, or many devices
1282                          * get confused.
1283                          */
1284                         len = urb->actual_length;
1285                         if (urb->status != 0 ||
1286                             len != cmd->sgv[cmd->current_sg].length) {
1287                                 cmd->act_len += len;
1288                                 ub_cmdtr_act_len(sc, cmd);
1289
1290                                 cmd->error = -EIO;
1291                                 ub_state_stat(sc, cmd);
1292                                 return;
1293                         }
1294
1295                 } else {
1296                         /*
1297                          * If an error occurs on read, we record it, and
1298                          * continue to fetch data in order to avoid bubble.
1299                          *
1300                          * As a small shortcut, we stop if we detect that
1301                          * a CSW mixed into data.
1302                          */
1303                         if (urb->status != 0)
1304                                 cmd->error = -EIO;
1305
1306                         len = urb->actual_length;
1307                         if (urb->status != 0 ||
1308                             len != cmd->sgv[cmd->current_sg].length) {
1309                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1310                                         goto Bad_End;
1311                         }
1312                 }
1313
1314                 cmd->act_len += urb->actual_length;
1315                 ub_cmdtr_act_len(sc, cmd);
1316
1317                 if (++cmd->current_sg < cmd->nsg) {
1318                         ub_data_start(sc, cmd);
1319                         return;
1320                 }
1321                 ub_state_stat(sc, cmd);
1322
1323         } else if (cmd->state == UB_CMDST_STAT) {
1324                 if (urb->status == -EPIPE) {
1325                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1326                         if (rc != 0) {
1327                                 printk(KERN_NOTICE "%s: "
1328                                     "unable to submit clear (%d)\n",
1329                                     sc->name, rc);
1330                                 ub_state_done(sc, cmd, rc);
1331                                 return;
1332                         }
1333
1334                         /*
1335                          * Having a stall when getting CSW is an error, so
1336                          * make sure uppper levels are not oblivious to it.
1337                          */
1338                         cmd->error = -EIO;              /* A cheap trick... */
1339
1340                         cmd->state = UB_CMDST_CLRRS;
1341                         ub_cmdtr_state(sc, cmd);
1342                         return;
1343                 }
1344
1345                 /* Catch everything, including -EOVERFLOW and other nasties. */
1346                 if (urb->status != 0)
1347                         goto Bad_End;
1348
1349                 if (urb->actual_length == 0) {
1350                         ub_state_stat_counted(sc, cmd);
1351                         return;
1352                 }
1353
1354                 /*
1355                  * Check the returned Bulk protocol status.
1356                  * The status block has to be validated first.
1357                  */
1358
1359                 bcs = &sc->work_bcs;
1360
1361                 if (sc->signature == cpu_to_le32(0)) {
1362                         /*
1363                          * This is the first reply, so do not perform the check.
1364                          * Instead, remember the signature the device uses
1365                          * for future checks. But do not allow a nul.
1366                          */
1367                         sc->signature = bcs->Signature;
1368                         if (sc->signature == cpu_to_le32(0)) {
1369                                 ub_state_stat_counted(sc, cmd);
1370                                 return;
1371                         }
1372                 } else {
1373                         if (bcs->Signature != sc->signature) {
1374                                 ub_state_stat_counted(sc, cmd);
1375                                 return;
1376                         }
1377                 }
1378
1379                 if (bcs->Tag != cmd->tag) {
1380                         /*
1381                          * This usually happens when we disagree with the
1382                          * device's microcode about something. For instance,
1383                          * a few of them throw this after timeouts. They buffer
1384                          * commands and reply at commands we timed out before.
1385                          * Without flushing these replies we loop forever.
1386                          */
1387                         ub_state_stat_counted(sc, cmd);
1388                         return;
1389                 }
1390
1391                 len = le32_to_cpu(bcs->Residue);
1392                 if (len != cmd->len - cmd->act_len) {
1393                         /*
1394                          * It is all right to transfer less, the caller has
1395                          * to check. But it's not all right if the device
1396                          * counts disagree with our counts.
1397                          */
1398                         /* P3 */ printk("%s: resid %d len %d act %d\n",
1399                             sc->name, len, cmd->len, cmd->act_len);
1400                         goto Bad_End;
1401                 }
1402
1403                 switch (bcs->Status) {
1404                 case US_BULK_STAT_OK:
1405                         break;
1406                 case US_BULK_STAT_FAIL:
1407                         ub_state_sense(sc, cmd);
1408                         return;
1409                 case US_BULK_STAT_PHASE:
1410                         /* P3 */ printk("%s: status PHASE\n", sc->name);
1411                         goto Bad_End;
1412                 default:
1413                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1414                             sc->name, bcs->Status);
1415                         ub_state_done(sc, cmd, -EINVAL);
1416                         return;
1417                 }
1418
1419                 /* Not zeroing error to preserve a babble indicator */
1420                 if (cmd->error != 0) {
1421                         ub_state_sense(sc, cmd);
1422                         return;
1423                 }
1424                 cmd->state = UB_CMDST_DONE;
1425                 ub_cmdtr_state(sc, cmd);
1426                 ub_cmdq_pop(sc);
1427                 (*cmd->done)(sc, cmd);
1428
1429         } else if (cmd->state == UB_CMDST_SENSE) {
1430                 ub_state_done(sc, cmd, -EIO);
1431
1432         } else {
1433                 printk(KERN_WARNING "%s: "
1434                     "wrong command state %d\n",
1435                     sc->name, cmd->state);
1436                 ub_state_done(sc, cmd, -EINVAL);
1437                 return;
1438         }
1439         return;
1440
1441 Bad_End: /* Little Excel is dead */
1442         ub_state_done(sc, cmd, -EIO);
1443 }
1444
1445 /*
1446  * Factorization helper for the command state machine:
1447  * Initiate a data segment transfer.
1448  */
1449 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1450 {
1451         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1452         int pipe;
1453         int rc;
1454
1455         UB_INIT_COMPLETION(sc->work_done);
1456
1457         if (cmd->dir == UB_DIR_READ)
1458                 pipe = sc->recv_bulk_pipe;
1459         else
1460                 pipe = sc->send_bulk_pipe;
1461         sc->last_pipe = pipe;
1462         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe,
1463             page_address(sg->page) + sg->offset, sg->length,
1464             ub_urb_complete, sc);
1465         sc->work_urb.actual_length = 0;
1466         sc->work_urb.error_count = 0;
1467         sc->work_urb.status = 0;
1468
1469         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1470                 /* XXX Clear stalls */
1471                 ub_complete(&sc->work_done);
1472                 ub_state_done(sc, cmd, rc);
1473                 return;
1474         }
1475
1476         sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1477         add_timer(&sc->work_timer);
1478
1479         cmd->state = UB_CMDST_DATA;
1480         ub_cmdtr_state(sc, cmd);
1481 }
1482
1483 /*
1484  * Factorization helper for the command state machine:
1485  * Finish the command.
1486  */
1487 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1488 {
1489
1490         cmd->error = rc;
1491         cmd->state = UB_CMDST_DONE;
1492         ub_cmdtr_state(sc, cmd);
1493         ub_cmdq_pop(sc);
1494         (*cmd->done)(sc, cmd);
1495 }
1496
1497 /*
1498  * Factorization helper for the command state machine:
1499  * Submit a CSW read.
1500  */
1501 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1502 {
1503         int rc;
1504
1505         UB_INIT_COMPLETION(sc->work_done);
1506
1507         sc->last_pipe = sc->recv_bulk_pipe;
1508         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1509             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1510         sc->work_urb.actual_length = 0;
1511         sc->work_urb.error_count = 0;
1512         sc->work_urb.status = 0;
1513
1514         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1515                 /* XXX Clear stalls */
1516                 ub_complete(&sc->work_done);
1517                 ub_state_done(sc, cmd, rc);
1518                 return -1;
1519         }
1520
1521         sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1522         add_timer(&sc->work_timer);
1523         return 0;
1524 }
1525
1526 /*
1527  * Factorization helper for the command state machine:
1528  * Submit a CSW read and go to STAT state.
1529  */
1530 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1531 {
1532
1533         if (__ub_state_stat(sc, cmd) != 0)
1534                 return;
1535
1536         cmd->stat_count = 0;
1537         cmd->state = UB_CMDST_STAT;
1538         ub_cmdtr_state(sc, cmd);
1539 }
1540
1541 /*
1542  * Factorization helper for the command state machine:
1543  * Submit a CSW read and go to STAT state with counter (along [C] path).
1544  */
1545 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1546 {
1547
1548         if (++cmd->stat_count >= 4) {
1549                 ub_state_sense(sc, cmd);
1550                 return;
1551         }
1552
1553         if (__ub_state_stat(sc, cmd) != 0)
1554                 return;
1555
1556         cmd->state = UB_CMDST_STAT;
1557         ub_cmdtr_state(sc, cmd);
1558 }
1559
1560 /*
1561  * Factorization helper for the command state machine:
1562  * Submit a REQUEST SENSE and go to SENSE state.
1563  */
1564 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1565 {
1566         struct ub_scsi_cmd *scmd;
1567         struct scatterlist *sg;
1568         int rc;
1569
1570         if (cmd->cdb[0] == REQUEST_SENSE) {
1571                 rc = -EPIPE;
1572                 goto error;
1573         }
1574
1575         scmd = &sc->top_rqs_cmd;
1576         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1577         scmd->cdb[0] = REQUEST_SENSE;
1578         scmd->cdb[4] = UB_SENSE_SIZE;
1579         scmd->cdb_len = 6;
1580         scmd->dir = UB_DIR_READ;
1581         scmd->state = UB_CMDST_INIT;
1582         scmd->nsg = 1;
1583         sg = &scmd->sgv[0];
1584         sg->page = virt_to_page(sc->top_sense);
1585         sg->offset = (unsigned long)sc->top_sense & (PAGE_SIZE-1);
1586         sg->length = UB_SENSE_SIZE;
1587         scmd->len = UB_SENSE_SIZE;
1588         scmd->lun = cmd->lun;
1589         scmd->done = ub_top_sense_done;
1590         scmd->back = cmd;
1591
1592         scmd->tag = sc->tagcnt++;
1593
1594         cmd->state = UB_CMDST_SENSE;
1595         ub_cmdtr_state(sc, cmd);
1596
1597         ub_cmdq_insert(sc, scmd);
1598         return;
1599
1600 error:
1601         ub_state_done(sc, cmd, rc);
1602 }
1603
1604 /*
1605  * A helper for the command's state machine:
1606  * Submit a stall clear.
1607  */
1608 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1609     int stalled_pipe)
1610 {
1611         int endp;
1612         struct usb_ctrlrequest *cr;
1613         int rc;
1614
1615         endp = usb_pipeendpoint(stalled_pipe);
1616         if (usb_pipein (stalled_pipe))
1617                 endp |= USB_DIR_IN;
1618
1619         cr = &sc->work_cr;
1620         cr->bRequestType = USB_RECIP_ENDPOINT;
1621         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1622         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1623         cr->wIndex = cpu_to_le16(endp);
1624         cr->wLength = cpu_to_le16(0);
1625
1626         UB_INIT_COMPLETION(sc->work_done);
1627
1628         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1629             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1630         sc->work_urb.actual_length = 0;
1631         sc->work_urb.error_count = 0;
1632         sc->work_urb.status = 0;
1633
1634         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1635                 ub_complete(&sc->work_done);
1636                 return rc;
1637         }
1638
1639         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1640         add_timer(&sc->work_timer);
1641         return 0;
1642 }
1643
1644 /*
1645  */
1646 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1647 {
1648         unsigned char *sense = sc->top_sense;
1649         struct ub_scsi_cmd *cmd;
1650
1651         /*
1652          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1653          */
1654         ub_cmdtr_sense(sc, scmd, sense);
1655
1656         /*
1657          * Find the command which triggered the unit attention or a check,
1658          * save the sense into it, and advance its state machine.
1659          */
1660         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1661                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1662                 return;
1663         }
1664         if (cmd != scmd->back) {
1665                 printk(KERN_WARNING "%s: "
1666                     "sense done for wrong command 0x%x\n",
1667                     sc->name, cmd->tag);
1668                 return;
1669         }
1670         if (cmd->state != UB_CMDST_SENSE) {
1671                 printk(KERN_WARNING "%s: "
1672                     "sense done with bad cmd state %d\n",
1673                     sc->name, cmd->state);
1674                 return;
1675         }
1676
1677         cmd->key = sense[2] & 0x0F;
1678         cmd->asc = sense[12];
1679         cmd->ascq = sense[13];
1680
1681         ub_scsi_urb_compl(sc, cmd);
1682 }
1683
1684 /*
1685  * Reset management
1686  */
1687
1688 static void ub_reset_enter(struct ub_dev *sc)
1689 {
1690
1691         if (sc->reset) {
1692                 /* This happens often on multi-LUN devices. */
1693                 return;
1694         }
1695         sc->reset = 1;
1696
1697 #if 0 /* Not needed because the disconnect waits for us. */
1698         unsigned long flags;
1699         spin_lock_irqsave(&ub_lock, flags);
1700         sc->openc++;
1701         spin_unlock_irqrestore(&ub_lock, flags);
1702 #endif
1703
1704 #if 0 /* We let them stop themselves. */
1705         struct list_head *p;
1706         struct ub_lun *lun;
1707         list_for_each(p, &sc->luns) {
1708                 lun = list_entry(p, struct ub_lun, link);
1709                 blk_stop_queue(lun->disk->queue);
1710         }
1711 #endif
1712
1713         schedule_work(&sc->reset_work);
1714 }
1715
1716 static void ub_reset_task(void *arg)
1717 {
1718         struct ub_dev *sc = arg;
1719         unsigned long flags;
1720         struct list_head *p;
1721         struct ub_lun *lun;
1722         int lkr, rc;
1723
1724         if (!sc->reset) {
1725                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1726                     sc->name);
1727                 return;
1728         }
1729
1730         if (atomic_read(&sc->poison)) {
1731                 printk(KERN_NOTICE "%s: Not resetting disconnected device\n",
1732                     sc->name); /* P3 This floods. Remove soon. XXX */
1733         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1734                 printk(KERN_NOTICE "%s: Not resetting multi-interface device\n",
1735                     sc->name); /* P3 This floods. Remove soon. XXX */
1736         } else {
1737                 if ((lkr = usb_lock_device_for_reset(sc->dev, sc->intf)) < 0) {
1738                         printk(KERN_NOTICE
1739                             "%s: usb_lock_device_for_reset failed (%d)\n",
1740                             sc->name, lkr);
1741                 } else {
1742                         rc = usb_reset_device(sc->dev);
1743                         if (rc < 0) {
1744                                 printk(KERN_NOTICE "%s: "
1745                                     "usb_lock_device_for_reset failed (%d)\n",
1746                                     sc->name, rc);
1747                         }
1748
1749                         if (lkr)
1750                                 usb_unlock_device(sc->dev);
1751                 }
1752         }
1753
1754         /*
1755          * In theory, no commands can be running while reset is active,
1756          * so nobody can ask for another reset, and so we do not need any
1757          * queues of resets or anything. We do need a spinlock though,
1758          * to interact with block layer.
1759          */
1760         spin_lock_irqsave(&sc->lock, flags);
1761         sc->reset = 0;
1762         tasklet_schedule(&sc->tasklet);
1763         list_for_each(p, &sc->luns) {
1764                 lun = list_entry(p, struct ub_lun, link);
1765                 blk_start_queue(lun->disk->queue);
1766         }
1767         wake_up(&sc->reset_wait);
1768         spin_unlock_irqrestore(&sc->lock, flags);
1769 }
1770
1771 /*
1772  * This is called from a process context.
1773  */
1774 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1775 {
1776
1777         lun->readonly = 0;      /* XXX Query this from the device */
1778
1779         lun->capacity.nsec = 0;
1780         lun->capacity.bsize = 512;
1781         lun->capacity.bshift = 0;
1782
1783         if (ub_sync_tur(sc, lun) != 0)
1784                 return;                 /* Not ready */
1785         lun->changed = 0;
1786
1787         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1788                 /*
1789                  * The retry here means something is wrong, either with the
1790                  * device, with the transport, or with our code.
1791                  * We keep this because sd.c has retries for capacity.
1792                  */
1793                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1794                         lun->capacity.nsec = 0;
1795                         lun->capacity.bsize = 512;
1796                         lun->capacity.bshift = 0;
1797                 }
1798         }
1799 }
1800
1801 /*
1802  * The open funcion.
1803  * This is mostly needed to keep refcounting, but also to support
1804  * media checks on removable media drives.
1805  */
1806 static int ub_bd_open(struct inode *inode, struct file *filp)
1807 {
1808         struct gendisk *disk = inode->i_bdev->bd_disk;
1809         struct ub_lun *lun;
1810         struct ub_dev *sc;
1811         unsigned long flags;
1812         int rc;
1813
1814         if ((lun = disk->private_data) == NULL)
1815                 return -ENXIO;
1816         sc = lun->udev;
1817
1818         spin_lock_irqsave(&ub_lock, flags);
1819         if (atomic_read(&sc->poison)) {
1820                 spin_unlock_irqrestore(&ub_lock, flags);
1821                 return -ENXIO;
1822         }
1823         sc->openc++;
1824         spin_unlock_irqrestore(&ub_lock, flags);
1825
1826         /*
1827          * This is a workaround for a specific problem in our block layer.
1828          * In 2.6.9, register_disk duplicates the code from rescan_partitions.
1829          * However, if we do add_disk with a device which persistently reports
1830          * a changed media, add_disk calls register_disk, which does do_open,
1831          * which will call rescan_paritions for changed media. After that,
1832          * register_disk attempts to do it all again and causes double kobject
1833          * registration and a eventually an oops on module removal.
1834          *
1835          * The bottom line is, Al Viro says that we should not allow
1836          * bdev->bd_invalidated to be set when doing add_disk no matter what.
1837          */
1838         if (lun->first_open) {
1839                 lun->first_open = 0;
1840                 if (lun->changed) {
1841                         rc = -ENOMEDIUM;
1842                         goto err_open;
1843                 }
1844         }
1845
1846         if (lun->removable || lun->readonly)
1847                 check_disk_change(inode->i_bdev);
1848
1849         /*
1850          * The sd.c considers ->media_present and ->changed not equivalent,
1851          * under some pretty murky conditions (a failure of READ CAPACITY).
1852          * We may need it one day.
1853          */
1854         if (lun->removable && lun->changed && !(filp->f_flags & O_NDELAY)) {
1855                 rc = -ENOMEDIUM;
1856                 goto err_open;
1857         }
1858
1859         if (lun->readonly && (filp->f_mode & FMODE_WRITE)) {
1860                 rc = -EROFS;
1861                 goto err_open;
1862         }
1863
1864         return 0;
1865
1866 err_open:
1867         ub_put(sc);
1868         return rc;
1869 }
1870
1871 /*
1872  */
1873 static int ub_bd_release(struct inode *inode, struct file *filp)
1874 {
1875         struct gendisk *disk = inode->i_bdev->bd_disk;
1876         struct ub_lun *lun = disk->private_data;
1877         struct ub_dev *sc = lun->udev;
1878
1879         ub_put(sc);
1880         return 0;
1881 }
1882
1883 /*
1884  * The ioctl interface.
1885  */
1886 static int ub_bd_ioctl(struct inode *inode, struct file *filp,
1887     unsigned int cmd, unsigned long arg)
1888 {
1889         struct gendisk *disk = inode->i_bdev->bd_disk;
1890         void __user *usermem = (void __user *) arg;
1891
1892         return scsi_cmd_ioctl(filp, disk, cmd, usermem);
1893 }
1894
1895 /*
1896  * This is called once a new disk was seen by the block layer or by ub_probe().
1897  * The main onjective here is to discover the features of the media such as
1898  * the capacity, read-only status, etc. USB storage generally does not
1899  * need to be spun up, but if we needed it, this would be the place.
1900  *
1901  * This call can sleep.
1902  *
1903  * The return code is not used.
1904  */
1905 static int ub_bd_revalidate(struct gendisk *disk)
1906 {
1907         struct ub_lun *lun = disk->private_data;
1908
1909         ub_revalidate(lun->udev, lun);
1910
1911         /* XXX Support sector size switching like in sr.c */
1912         blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
1913         set_capacity(disk, lun->capacity.nsec);
1914         // set_disk_ro(sdkp->disk, lun->readonly);
1915
1916         return 0;
1917 }
1918
1919 /*
1920  * The check is called by the block layer to verify if the media
1921  * is still available. It is supposed to be harmless, lightweight and
1922  * non-intrusive in case the media was not changed.
1923  *
1924  * This call can sleep.
1925  *
1926  * The return code is bool!
1927  */
1928 static int ub_bd_media_changed(struct gendisk *disk)
1929 {
1930         struct ub_lun *lun = disk->private_data;
1931
1932         if (!lun->removable)
1933                 return 0;
1934
1935         /*
1936          * We clean checks always after every command, so this is not
1937          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1938          * the device is actually not ready with operator or software
1939          * intervention required. One dangerous item might be a drive which
1940          * spins itself down, and come the time to write dirty pages, this
1941          * will fail, then block layer discards the data. Since we never
1942          * spin drives up, such devices simply cannot be used with ub anyway.
1943          */
1944         if (ub_sync_tur(lun->udev, lun) != 0) {
1945                 lun->changed = 1;
1946                 return 1;
1947         }
1948
1949         return lun->changed;
1950 }
1951
1952 static struct block_device_operations ub_bd_fops = {
1953         .owner          = THIS_MODULE,
1954         .open           = ub_bd_open,
1955         .release        = ub_bd_release,
1956         .ioctl          = ub_bd_ioctl,
1957         .media_changed  = ub_bd_media_changed,
1958         .revalidate_disk = ub_bd_revalidate,
1959 };
1960
1961 /*
1962  * Common ->done routine for commands executed synchronously.
1963  */
1964 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1965 {
1966         struct completion *cop = cmd->back;
1967         complete(cop);
1968 }
1969
1970 /*
1971  * Test if the device has a check condition on it, synchronously.
1972  */
1973 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1974 {
1975         struct ub_scsi_cmd *cmd;
1976         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1977         unsigned long flags;
1978         struct completion compl;
1979         int rc;
1980
1981         init_completion(&compl);
1982
1983         rc = -ENOMEM;
1984         if ((cmd = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1985                 goto err_alloc;
1986         memset(cmd, 0, ALLOC_SIZE);
1987
1988         cmd->cdb[0] = TEST_UNIT_READY;
1989         cmd->cdb_len = 6;
1990         cmd->dir = UB_DIR_NONE;
1991         cmd->state = UB_CMDST_INIT;
1992         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1993         cmd->done = ub_probe_done;
1994         cmd->back = &compl;
1995
1996         spin_lock_irqsave(&sc->lock, flags);
1997         cmd->tag = sc->tagcnt++;
1998
1999         rc = ub_submit_scsi(sc, cmd);
2000         spin_unlock_irqrestore(&sc->lock, flags);
2001
2002         if (rc != 0) {
2003                 printk("ub: testing ready: submit error (%d)\n", rc); /* P3 */
2004                 goto err_submit;
2005         }
2006
2007         wait_for_completion(&compl);
2008
2009         rc = cmd->error;
2010
2011         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
2012                 rc = cmd->key;
2013
2014 err_submit:
2015         kfree(cmd);
2016 err_alloc:
2017         return rc;
2018 }
2019
2020 /*
2021  * Read the SCSI capacity synchronously (for probing).
2022  */
2023 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
2024     struct ub_capacity *ret)
2025 {
2026         struct ub_scsi_cmd *cmd;
2027         struct scatterlist *sg;
2028         char *p;
2029         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
2030         unsigned long flags;
2031         unsigned int bsize, shift;
2032         unsigned long nsec;
2033         struct completion compl;
2034         int rc;
2035
2036         init_completion(&compl);
2037
2038         rc = -ENOMEM;
2039         if ((cmd = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2040                 goto err_alloc;
2041         memset(cmd, 0, ALLOC_SIZE);
2042         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
2043
2044         cmd->cdb[0] = 0x25;
2045         cmd->cdb_len = 10;
2046         cmd->dir = UB_DIR_READ;
2047         cmd->state = UB_CMDST_INIT;
2048         cmd->nsg = 1;
2049         sg = &cmd->sgv[0];
2050         sg->page = virt_to_page(p);
2051         sg->offset = (unsigned long)p & (PAGE_SIZE-1);
2052         sg->length = 8;
2053         cmd->len = 8;
2054         cmd->lun = lun;
2055         cmd->done = ub_probe_done;
2056         cmd->back = &compl;
2057
2058         spin_lock_irqsave(&sc->lock, flags);
2059         cmd->tag = sc->tagcnt++;
2060
2061         rc = ub_submit_scsi(sc, cmd);
2062         spin_unlock_irqrestore(&sc->lock, flags);
2063
2064         if (rc != 0) {
2065                 printk("ub: reading capacity: submit error (%d)\n", rc); /* P3 */
2066                 goto err_submit;
2067         }
2068
2069         wait_for_completion(&compl);
2070
2071         if (cmd->error != 0) {
2072                 printk("ub: reading capacity: error %d\n", cmd->error); /* P3 */
2073                 rc = -EIO;
2074                 goto err_read;
2075         }
2076         if (cmd->act_len != 8) {
2077                 printk("ub: reading capacity: size %d\n", cmd->act_len); /* P3 */
2078                 rc = -EIO;
2079                 goto err_read;
2080         }
2081
2082         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
2083         nsec = be32_to_cpu(*(__be32 *)p) + 1;
2084         bsize = be32_to_cpu(*(__be32 *)(p + 4));
2085         switch (bsize) {
2086         case 512:       shift = 0;      break;
2087         case 1024:      shift = 1;      break;
2088         case 2048:      shift = 2;      break;
2089         case 4096:      shift = 3;      break;
2090         default:
2091                 printk("ub: Bad sector size %u\n", bsize); /* P3 */
2092                 rc = -EDOM;
2093                 goto err_inv_bsize;
2094         }
2095
2096         ret->bsize = bsize;
2097         ret->bshift = shift;
2098         ret->nsec = nsec << shift;
2099         rc = 0;
2100
2101 err_inv_bsize:
2102 err_read:
2103 err_submit:
2104         kfree(cmd);
2105 err_alloc:
2106         return rc;
2107 }
2108
2109 /*
2110  */
2111 static void ub_probe_urb_complete(struct urb *urb, struct pt_regs *pt)
2112 {
2113         struct completion *cop = urb->context;
2114         complete(cop);
2115 }
2116
2117 static void ub_probe_timeout(unsigned long arg)
2118 {
2119         struct completion *cop = (struct completion *) arg;
2120         complete(cop);
2121 }
2122
2123 /*
2124  * Get number of LUNs by the way of Bulk GetMaxLUN command.
2125  */
2126 static int ub_sync_getmaxlun(struct ub_dev *sc)
2127 {
2128         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
2129         unsigned char *p;
2130         enum { ALLOC_SIZE = 1 };
2131         struct usb_ctrlrequest *cr;
2132         struct completion compl;
2133         struct timer_list timer;
2134         int nluns;
2135         int rc;
2136
2137         init_completion(&compl);
2138
2139         rc = -ENOMEM;
2140         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2141                 goto err_alloc;
2142         *p = 55;
2143
2144         cr = &sc->work_cr;
2145         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
2146         cr->bRequest = US_BULK_GET_MAX_LUN;
2147         cr->wValue = cpu_to_le16(0);
2148         cr->wIndex = cpu_to_le16(ifnum);
2149         cr->wLength = cpu_to_le16(1);
2150
2151         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2152             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2153         sc->work_urb.actual_length = 0;
2154         sc->work_urb.error_count = 0;
2155         sc->work_urb.status = 0;
2156
2157         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2158                 if (rc == -EPIPE) {
2159                         printk("%s: Stall submitting GetMaxLUN, using 1 LUN\n",
2160                              sc->name); /* P3 */
2161                 } else {
2162                         printk(KERN_NOTICE
2163                              "%s: Unable to submit GetMaxLUN (%d)\n",
2164                              sc->name, rc);
2165                 }
2166                 goto err_submit;
2167         }
2168
2169         init_timer(&timer);
2170         timer.function = ub_probe_timeout;
2171         timer.data = (unsigned long) &compl;
2172         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2173         add_timer(&timer);
2174
2175         wait_for_completion(&compl);
2176
2177         del_timer_sync(&timer);
2178         usb_kill_urb(&sc->work_urb);
2179
2180         if ((rc = sc->work_urb.status) < 0) {
2181                 if (rc == -EPIPE) {
2182                         printk("%s: Stall at GetMaxLUN, using 1 LUN\n",
2183                              sc->name); /* P3 */
2184                 } else {
2185                         printk(KERN_NOTICE
2186                              "%s: Error at GetMaxLUN (%d)\n",
2187                              sc->name, rc);
2188                 }
2189                 goto err_io;
2190         }
2191
2192         if (sc->work_urb.actual_length != 1) {
2193                 printk("%s: GetMaxLUN returned %d bytes\n", sc->name,
2194                     sc->work_urb.actual_length); /* P3 */
2195                 nluns = 0;
2196         } else {
2197                 if ((nluns = *p) == 55) {
2198                         nluns = 0;
2199                 } else {
2200                         /* GetMaxLUN returns the maximum LUN number */
2201                         nluns += 1;
2202                         if (nluns > UB_MAX_LUNS)
2203                                 nluns = UB_MAX_LUNS;
2204                 }
2205                 printk("%s: GetMaxLUN returned %d, using %d LUNs\n", sc->name,
2206                     *p, nluns); /* P3 */
2207         }
2208
2209         kfree(p);
2210         return nluns;
2211
2212 err_io:
2213 err_submit:
2214         kfree(p);
2215 err_alloc:
2216         return rc;
2217 }
2218
2219 /*
2220  * Clear initial stalls.
2221  */
2222 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2223 {
2224         int endp;
2225         struct usb_ctrlrequest *cr;
2226         struct completion compl;
2227         struct timer_list timer;
2228         int rc;
2229
2230         init_completion(&compl);
2231
2232         endp = usb_pipeendpoint(stalled_pipe);
2233         if (usb_pipein (stalled_pipe))
2234                 endp |= USB_DIR_IN;
2235
2236         cr = &sc->work_cr;
2237         cr->bRequestType = USB_RECIP_ENDPOINT;
2238         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2239         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2240         cr->wIndex = cpu_to_le16(endp);
2241         cr->wLength = cpu_to_le16(0);
2242
2243         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2244             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2245         sc->work_urb.actual_length = 0;
2246         sc->work_urb.error_count = 0;
2247         sc->work_urb.status = 0;
2248
2249         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2250                 printk(KERN_WARNING
2251                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2252                 return rc;
2253         }
2254
2255         init_timer(&timer);
2256         timer.function = ub_probe_timeout;
2257         timer.data = (unsigned long) &compl;
2258         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2259         add_timer(&timer);
2260
2261         wait_for_completion(&compl);
2262
2263         del_timer_sync(&timer);
2264         usb_kill_urb(&sc->work_urb);
2265
2266         /* reset the endpoint toggle */
2267         usb_settoggle(sc->dev, endp, usb_pipeout(sc->last_pipe), 0);
2268
2269         return 0;
2270 }
2271
2272 /*
2273  * Get the pipe settings.
2274  */
2275 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2276     struct usb_interface *intf)
2277 {
2278         struct usb_host_interface *altsetting = intf->cur_altsetting;
2279         struct usb_endpoint_descriptor *ep_in = NULL;
2280         struct usb_endpoint_descriptor *ep_out = NULL;
2281         struct usb_endpoint_descriptor *ep;
2282         int i;
2283
2284         /*
2285          * Find the endpoints we need.
2286          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2287          * We will ignore any others.
2288          */
2289         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2290                 ep = &altsetting->endpoint[i].desc;
2291
2292                 /* Is it a BULK endpoint? */
2293                 if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
2294                                 == USB_ENDPOINT_XFER_BULK) {
2295                         /* BULK in or out? */
2296                         if (ep->bEndpointAddress & USB_DIR_IN)
2297                                 ep_in = ep;
2298                         else
2299                                 ep_out = ep;
2300                 }
2301         }
2302
2303         if (ep_in == NULL || ep_out == NULL) {
2304                 printk(KERN_NOTICE "%s: failed endpoint check\n",
2305                     sc->name);
2306                 return -ENODEV;
2307         }
2308
2309         /* Calculate and store the pipe values */
2310         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2311         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2312         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2313                 ep_out->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2314         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2315                 ep_in->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2316
2317         return 0;
2318 }
2319
2320 /*
2321  * Probing is done in the process context, which allows us to cheat
2322  * and not to build a state machine for the discovery.
2323  */
2324 static int ub_probe(struct usb_interface *intf,
2325     const struct usb_device_id *dev_id)
2326 {
2327         struct ub_dev *sc;
2328         int nluns;
2329         int rc;
2330         int i;
2331
2332         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2333                 return -ENXIO;
2334
2335         rc = -ENOMEM;
2336         if ((sc = kmalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2337                 goto err_core;
2338         memset(sc, 0, sizeof(struct ub_dev));
2339         spin_lock_init(&sc->lock);
2340         INIT_LIST_HEAD(&sc->luns);
2341         usb_init_urb(&sc->work_urb);
2342         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2343         atomic_set(&sc->poison, 0);
2344         INIT_WORK(&sc->reset_work, ub_reset_task, sc);
2345         init_waitqueue_head(&sc->reset_wait);
2346
2347         init_timer(&sc->work_timer);
2348         sc->work_timer.data = (unsigned long) sc;
2349         sc->work_timer.function = ub_urb_timeout;
2350
2351         ub_init_completion(&sc->work_done);
2352         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2353
2354         sc->dev = interface_to_usbdev(intf);
2355         sc->intf = intf;
2356         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2357         usb_set_intfdata(intf, sc);
2358         usb_get_dev(sc->dev);
2359         // usb_get_intf(sc->intf);      /* Do we need this? */
2360
2361         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2362             sc->dev->bus->busnum, sc->dev->devnum);
2363
2364         /* XXX Verify that we can handle the device (from descriptors) */
2365
2366         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2367                 goto err_dev_desc;
2368
2369         if (device_create_file(&sc->intf->dev, &dev_attr_diag) != 0)
2370                 goto err_diag;
2371
2372         /*
2373          * At this point, all USB initialization is done, do upper layer.
2374          * We really hate halfway initialized structures, so from the
2375          * invariants perspective, this ub_dev is fully constructed at
2376          * this point.
2377          */
2378
2379         /*
2380          * This is needed to clear toggles. It is a problem only if we do
2381          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2382          */
2383 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2384         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2385         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2386 #endif
2387
2388         /*
2389          * The way this is used by the startup code is a little specific.
2390          * A SCSI check causes a USB stall. Our common case code sees it
2391          * and clears the check, after which the device is ready for use.
2392          * But if a check was not present, any command other than
2393          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2394          *
2395          * If we neglect to clear the SCSI check, the first real command fails
2396          * (which is the capacity readout). We clear that and retry, but why
2397          * causing spurious retries for no reason.
2398          *
2399          * Revalidation may start with its own TEST_UNIT_READY, but that one
2400          * has to succeed, so we clear checks with an additional one here.
2401          * In any case it's not our business how revaliadation is implemented.
2402          */
2403         for (i = 0; i < 3; i++) {       /* Retries for benh's key */
2404                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2405                 if (rc != 0x6) break;
2406                 msleep(10);
2407         }
2408
2409         nluns = 1;
2410         for (i = 0; i < 3; i++) {
2411                 if ((rc = ub_sync_getmaxlun(sc)) < 0) {
2412                         /*
2413                          * This segment is taken from usb-storage. They say
2414                          * that ZIP-100 needs this, but my own ZIP-100 works
2415                          * fine without this.
2416                          * Still, it does not seem to hurt anything.
2417                          */
2418                         if (rc == -EPIPE) {
2419                                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2420                                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2421                         }
2422                         break;
2423                 }
2424                 if (rc != 0) {
2425                         nluns = rc;
2426                         break;
2427                 }
2428                 msleep(100);
2429         }
2430
2431         for (i = 0; i < nluns; i++) {
2432                 ub_probe_lun(sc, i);
2433         }
2434         return 0;
2435
2436         /* device_remove_file(&sc->intf->dev, &dev_attr_diag); */
2437 err_diag:
2438 err_dev_desc:
2439         usb_set_intfdata(intf, NULL);
2440         // usb_put_intf(sc->intf);
2441         usb_put_dev(sc->dev);
2442         kfree(sc);
2443 err_core:
2444         return rc;
2445 }
2446
2447 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2448 {
2449         struct ub_lun *lun;
2450         request_queue_t *q;
2451         struct gendisk *disk;
2452         int rc;
2453
2454         rc = -ENOMEM;
2455         if ((lun = kmalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2456                 goto err_alloc;
2457         memset(lun, 0, sizeof(struct ub_lun));
2458         lun->num = lnum;
2459
2460         rc = -ENOSR;
2461         if ((lun->id = ub_id_get()) == -1)
2462                 goto err_id;
2463
2464         lun->udev = sc;
2465         list_add(&lun->link, &sc->luns);
2466
2467         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2468             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2469
2470         lun->removable = 1;             /* XXX Query this from the device */
2471         lun->changed = 1;               /* ub_revalidate clears only */
2472         lun->first_open = 1;
2473         ub_revalidate(sc, lun);
2474
2475         rc = -ENOMEM;
2476         if ((disk = alloc_disk(UB_MINORS_PER_MAJOR)) == NULL)
2477                 goto err_diskalloc;
2478
2479         lun->disk = disk;
2480         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2481         sprintf(disk->devfs_name, DEVFS_NAME "/%c", lun->id + 'a');
2482         disk->major = UB_MAJOR;
2483         disk->first_minor = lun->id * UB_MINORS_PER_MAJOR;
2484         disk->fops = &ub_bd_fops;
2485         disk->private_data = lun;
2486         disk->driverfs_dev = &sc->intf->dev;
2487
2488         rc = -ENOMEM;
2489         if ((q = blk_init_queue(ub_request_fn, &sc->lock)) == NULL)
2490                 goto err_blkqinit;
2491
2492         disk->queue = q;
2493
2494         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2495         blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
2496         blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
2497         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2498         blk_queue_max_sectors(q, UB_MAX_SECTORS);
2499         blk_queue_hardsect_size(q, lun->capacity.bsize);
2500
2501         q->queuedata = lun;
2502
2503         set_capacity(disk, lun->capacity.nsec);
2504         if (lun->removable)
2505                 disk->flags |= GENHD_FL_REMOVABLE;
2506
2507         add_disk(disk);
2508
2509         return 0;
2510
2511 err_blkqinit:
2512         put_disk(disk);
2513 err_diskalloc:
2514         list_del(&lun->link);
2515         ub_id_put(lun->id);
2516 err_id:
2517         kfree(lun);
2518 err_alloc:
2519         return rc;
2520 }
2521
2522 static void ub_disconnect(struct usb_interface *intf)
2523 {
2524         struct ub_dev *sc = usb_get_intfdata(intf);
2525         struct list_head *p;
2526         struct ub_lun *lun;
2527         struct gendisk *disk;
2528         unsigned long flags;
2529
2530         /*
2531          * Prevent ub_bd_release from pulling the rug from under us.
2532          * XXX This is starting to look like a kref.
2533          * XXX Why not to take this ref at probe time?
2534          */
2535         spin_lock_irqsave(&ub_lock, flags);
2536         sc->openc++;
2537         spin_unlock_irqrestore(&ub_lock, flags);
2538
2539         /*
2540          * Fence stall clearnings, operations triggered by unlinkings and so on.
2541          * We do not attempt to unlink any URBs, because we do not trust the
2542          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2543          */
2544         atomic_set(&sc->poison, 1);
2545
2546         /*
2547          * Wait for reset to end, if any.
2548          */
2549         wait_event(sc->reset_wait, !sc->reset);
2550
2551         /*
2552          * Blow away queued commands.
2553          *
2554          * Actually, this never works, because before we get here
2555          * the HCD terminates outstanding URB(s). It causes our
2556          * SCSI command queue to advance, commands fail to submit,
2557          * and the whole queue drains. So, we just use this code to
2558          * print warnings.
2559          */
2560         spin_lock_irqsave(&sc->lock, flags);
2561         {
2562                 struct ub_scsi_cmd *cmd;
2563                 int cnt = 0;
2564                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2565                         cmd->error = -ENOTCONN;
2566                         cmd->state = UB_CMDST_DONE;
2567                         ub_cmdtr_state(sc, cmd);
2568                         ub_cmdq_pop(sc);
2569                         (*cmd->done)(sc, cmd);
2570                         cnt++;
2571                 }
2572                 if (cnt != 0) {
2573                         printk(KERN_WARNING "%s: "
2574                             "%d was queued after shutdown\n", sc->name, cnt);
2575                 }
2576         }
2577         spin_unlock_irqrestore(&sc->lock, flags);
2578
2579         /*
2580          * Unregister the upper layer.
2581          */
2582         list_for_each (p, &sc->luns) {
2583                 lun = list_entry(p, struct ub_lun, link);
2584                 disk = lun->disk;
2585                 if (disk->flags & GENHD_FL_UP)
2586                         del_gendisk(disk);
2587                 /*
2588                  * I wish I could do:
2589                  *    set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
2590                  * As it is, we rely on our internal poisoning and let
2591                  * the upper levels to spin furiously failing all the I/O.
2592                  */
2593         }
2594
2595         /*
2596          * Taking a lock on a structure which is about to be freed
2597          * is very nonsensual. Here it is largely a way to do a debug freeze,
2598          * and a bracket which shows where the nonsensual code segment ends.
2599          *
2600          * Testing for -EINPROGRESS is always a bug, so we are bending
2601          * the rules a little.
2602          */
2603         spin_lock_irqsave(&sc->lock, flags);
2604         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2605                 printk(KERN_WARNING "%s: "
2606                     "URB is active after disconnect\n", sc->name);
2607         }
2608         spin_unlock_irqrestore(&sc->lock, flags);
2609
2610         /*
2611          * There is virtually no chance that other CPU runs times so long
2612          * after ub_urb_complete should have called del_timer, but only if HCD
2613          * didn't forget to deliver a callback on unlink.
2614          */
2615         del_timer_sync(&sc->work_timer);
2616
2617         /*
2618          * At this point there must be no commands coming from anyone
2619          * and no URBs left in transit.
2620          */
2621
2622         device_remove_file(&sc->intf->dev, &dev_attr_diag);
2623         usb_set_intfdata(intf, NULL);
2624         // usb_put_intf(sc->intf);
2625         sc->intf = NULL;
2626         usb_put_dev(sc->dev);
2627         sc->dev = NULL;
2628
2629         ub_put(sc);
2630 }
2631
2632 static struct usb_driver ub_driver = {
2633         .name =         "ub",
2634         .probe =        ub_probe,
2635         .disconnect =   ub_disconnect,
2636         .id_table =     ub_usb_ids,
2637 };
2638
2639 static int __init ub_init(void)
2640 {
2641         int rc;
2642
2643         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2644                 goto err_regblkdev;
2645         devfs_mk_dir(DEVFS_NAME);
2646
2647         if ((rc = usb_register(&ub_driver)) != 0)
2648                 goto err_register;
2649
2650         usb_usual_set_present(USB_US_TYPE_UB);
2651         return 0;
2652
2653 err_register:
2654         devfs_remove(DEVFS_NAME);
2655         unregister_blkdev(UB_MAJOR, DRV_NAME);
2656 err_regblkdev:
2657         return rc;
2658 }
2659
2660 static void __exit ub_exit(void)
2661 {
2662         usb_deregister(&ub_driver);
2663
2664         devfs_remove(DEVFS_NAME);
2665         unregister_blkdev(UB_MAJOR, DRV_NAME);
2666         usb_usual_clear_present(USB_US_TYPE_UB);
2667 }
2668
2669 module_init(ub_init);
2670 module_exit(ub_exit);
2671
2672 MODULE_LICENSE("GPL");