git.oblomov.eu Git - linux-2.6/blob - 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  *  -- Do resets with usb_device_reset (needs a thread context, use khubd)
  13  *  -- set readonly flag for CDs, set removable flag for CF readers
  14  *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
  15  *  -- special case some senses, e.g. 3a/0 -> no media present, reduce retries
  16  *  -- verify the 13 conditions and do bulk resets
  17  *  -- kill last_pipe and simply do two-state clearing on both pipes
  18  *  -- verify protocol (bulk) from USB descriptors (maybe...)
  19  *  -- highmem
  20  *  -- move top_sense and work_bcs into separate allocations (if they survive)
  21  *     for cache purists and esoteric architectures.
  22  *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
  23  *  -- prune comments, they are too volumnous
  24  *  -- Exterminate P3 printks
  25  *  -- Resove XXX's
  26  *  -- Redo "benh's retries", perhaps have spin-up code to handle them. V:D=?
  27  *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
  28  */
  29 #include <linux/kernel.h>
  30 #include <linux/module.h>
  31 #include <linux/usb.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  * Definitions which have to be scattered once we understand the layout better.
 111  */
 112
 113 /* Transport (despite PR in the name) */
 114 #define US_PR_BULK      0x50            /* bulk only */
 115
 116 /* Protocol */
 117 #define US_SC_SCSI      0x06            /* Transparent */
 118
 119 /*
 120  * This many LUNs per USB device.
 121  * Every one of them takes a host, see UB_MAX_HOSTS.
 122  */
 123 #define UB_MAX_LUNS   9
 124
 125 /*
 126  */
 127
 128 #define UB_MINORS_PER_MAJOR     8
 129
 130 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
 131
 132 #define UB_SENSE_SIZE  18
 133
 134 /*
 135  */
 136
 137 /* command block wrapper */
 138 struct bulk_cb_wrap {
 139         __le32  Signature;              /* contains 'USBC' */
 140         u32     Tag;                    /* unique per command id */
 141         __le32  DataTransferLength;     /* size of data */
 142         u8      Flags;                  /* direction in bit 0 */
 143         u8      Lun;                    /* LUN */
 144         u8      Length;                 /* of of the CDB */
 145         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
 146 };
 147
 148 #define US_BULK_CB_WRAP_LEN     31
 149 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
 150 #define US_BULK_FLAG_IN         1
 151 #define US_BULK_FLAG_OUT        0
 152
 153 /* command status wrapper */
 154 struct bulk_cs_wrap {
 155         __le32  Signature;              /* should = 'USBS' */
 156         u32     Tag;                    /* same as original command */
 157         __le32  Residue;                /* amount not transferred */
 158         u8      Status;                 /* see below */
 159 };
 160
 161 #define US_BULK_CS_WRAP_LEN     13
 162 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
 163 #define US_BULK_STAT_OK         0
 164 #define US_BULK_STAT_FAIL       1
 165 #define US_BULK_STAT_PHASE      2
 166
 167 /* bulk-only class specific requests */
 168 #define US_BULK_RESET_REQUEST   0xff
 169 #define US_BULK_GET_MAX_LUN     0xfe
 170
 171 /*
 172  */
 173 struct ub_dev;
 174
 175 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
 176 #define UB_MAX_SECTORS 64
 177
 178 /*
 179  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
 180  * even if a webcam hogs the bus, but some devices need time to spin up.
 181  */
 182 #define UB_URB_TIMEOUT  (HZ*2)
 183 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
 184 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
 185 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
 186
 187 /*
 188  * An instance of a SCSI command in transit.
 189  */
 190 #define UB_DIR_NONE     0
 191 #define UB_DIR_READ     1
 192 #define UB_DIR_ILLEGAL2 2
 193 #define UB_DIR_WRITE    3
 194
 195 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
 196                          (((c)==UB_DIR_READ)? 'r': 'n'))
 197
 198 enum ub_scsi_cmd_state {
 199         UB_CMDST_INIT,                  /* Initial state */
 200         UB_CMDST_CMD,                   /* Command submitted */
 201         UB_CMDST_DATA,                  /* Data phase */
 202         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
 203         UB_CMDST_STAT,                  /* Status phase */
 204         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
 205         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
 206         UB_CMDST_SENSE,                 /* Sending Request Sense */
 207         UB_CMDST_DONE                   /* Final state */
 208 };
 209
 210 static char *ub_scsi_cmd_stname[] = {
 211         ".  ",
 212         "Cmd",
 213         "dat",
 214         "c2s",
 215         "sts",
 216         "clr",
 217         "crs",
 218         "Sen",
 219         "fin"
 220 };
 221
 222 struct ub_scsi_cmd {
 223         unsigned char cdb[UB_MAX_CDB_SIZE];
 224         unsigned char cdb_len;
 225
 226         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
 227         unsigned char trace_index;
 228         enum ub_scsi_cmd_state state;
 229         unsigned int tag;
 230         struct ub_scsi_cmd *next;
 231
 232         int error;                      /* Return code - valid upon done */
 233         unsigned int act_len;           /* Return size */
 234         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
 235
 236         int stat_count;                 /* Retries getting status. */
 237
 238         unsigned int len;               /* Requested length */
 239         unsigned int current_sg;
 240         unsigned int nsg;               /* sgv[nsg] */
 241         struct scatterlist sgv[UB_MAX_REQ_SG];
 242
 243         struct ub_lun *lun;
 244         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
 245         void *back;
 246 };
 247
 248 /*
 249  */
 250 struct ub_capacity {
 251         unsigned long nsec;             /* Linux size - 512 byte sectors */
 252         unsigned int bsize;             /* Linux hardsect_size */
 253         unsigned int bshift;            /* Shift between 512 and hard sects */
 254 };
 255
 256 /*
 257  * The SCSI command tracing structure.
 258  */
 259
 260 #define SCMD_ST_HIST_SZ   8
 261 #define SCMD_TRACE_SZ    63             /* Less than 4KB of 61-byte lines */
 262
 263 struct ub_scsi_cmd_trace {
 264         int hcur;
 265         unsigned int tag;
 266         unsigned int req_size, act_size;
 267         unsigned char op;
 268         unsigned char dir;
 269         unsigned char key, asc, ascq;
 270         char st_hst[SCMD_ST_HIST_SZ];
 271 };
 272
 273 struct ub_scsi_trace {
 274         int cur;
 275         struct ub_scsi_cmd_trace vec[SCMD_TRACE_SZ];
 276 };
 277
 278 /*
 279  * This is a direct take-off from linux/include/completion.h
 280  * The difference is that I do not wait on this thing, just poll.
 281  * When I want to wait (ub_probe), I just use the stock completion.
 282  *
 283  * Note that INIT_COMPLETION takes no lock. It is correct. But why
 284  * in the bloody hell that thing takes struct instead of pointer to struct
 285  * is quite beyond me. I just copied it from the stock completion.
 286  */
 287 struct ub_completion {
 288         unsigned int done;
 289         spinlock_t lock;
 290 };
 291
 292 static inline void ub_init_completion(struct ub_completion *x)
 293 {
 294         x->done = 0;
 295         spin_lock_init(&x->lock);
 296 }
 297
 298 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
 299
 300 static void ub_complete(struct ub_completion *x)
 301 {
 302         unsigned long flags;
 303
 304         spin_lock_irqsave(&x->lock, flags);
 305         x->done++;
 306         spin_unlock_irqrestore(&x->lock, flags);
 307 }
 308
 309 static int ub_is_completed(struct ub_completion *x)
 310 {
 311         unsigned long flags;
 312         int ret;
 313
 314         spin_lock_irqsave(&x->lock, flags);
 315         ret = x->done;
 316         spin_unlock_irqrestore(&x->lock, flags);
 317         return ret;
 318 }
 319
 320 /*
 321  */
 322 struct ub_scsi_cmd_queue {
 323         int qlen, qmax;
 324         struct ub_scsi_cmd *head, *tail;
 325 };
 326
 327 /*
 328  * The block device instance (one per LUN).
 329  */
 330 struct ub_lun {
 331         struct ub_dev *udev;
 332         struct list_head link;
 333         struct gendisk *disk;
 334         int id;                         /* Host index */
 335         int num;                        /* LUN number */
 336         char name[16];
 337
 338         int changed;                    /* Media was changed */
 339         int removable;
 340         int readonly;
 341         int first_open;                 /* Kludge. See ub_bd_open. */
 342
 343         /* Use Ingo's mempool if or when we have more than one command. */
 344         /*
 345          * Currently we never need more than one command for the whole device.
 346          * However, giving every LUN a command is a cheap and automatic way
 347          * to enforce fairness between them.
 348          */
 349         int cmda[1];
 350         struct ub_scsi_cmd cmdv[1];
 351
 352         struct ub_capacity capacity;
 353 };
 354
 355 /*
 356  * The USB device instance.
 357  */
 358 struct ub_dev {
 359         spinlock_t lock;
 360         atomic_t poison;                /* The USB device is disconnected */
 361         int openc;                      /* protected by ub_lock! */
 362                                         /* kref is too implicit for our taste */
 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         int sg_stat[6];
 391         struct ub_scsi_trace tr;
 392 };
 393
 394 /*
 395  */
 396 static void ub_cleanup(struct ub_dev *sc);
 397 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
 398 static int ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 399     struct ub_scsi_cmd *cmd, struct request *rq);
 400 static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 401     struct ub_scsi_cmd *cmd, struct request *rq);
 402 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 403 static void ub_end_rq(struct request *rq, int uptodate);
 404 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 405 static void ub_urb_complete(struct urb *urb, struct pt_regs *pt);
 406 static void ub_scsi_action(unsigned long _dev);
 407 static void ub_scsi_dispatch(struct ub_dev *sc);
 408 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 409 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 410 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
 411 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 412 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 413 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 414 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 415 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 416     int stalled_pipe);
 417 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
 418 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
 419 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
 420     struct ub_capacity *ret);
 421 static int ub_probe_lun(struct ub_dev *sc, int lnum);
 422
 423 /*
 424  */
 425 static struct usb_device_id ub_usb_ids[] = {
 426         // { USB_DEVICE_VER(0x0781, 0x0002, 0x0009, 0x0009) },  /* SDDR-31 */
 427         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
 428         { }
 429 };
 430
 431 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
 432
 433 /*
 434  * Find me a way to identify "next free minor" for add_disk(),
 435  * and the array disappears the next day. However, the number of
 436  * hosts has something to do with the naming and /proc/partitions.
 437  * This has to be thought out in detail before changing.
 438  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
 439  */
 440 #define UB_MAX_HOSTS  26
 441 static char ub_hostv[UB_MAX_HOSTS];
 442
 443 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
 444
 445 /*
 446  * The SCSI command tracing procedures.
 447  */
 448
 449 static void ub_cmdtr_new(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 450 {
 451         int n;
 452         struct ub_scsi_cmd_trace *t;
 453
 454         if ((n = sc->tr.cur + 1) == SCMD_TRACE_SZ) n = 0;
 455         t = &sc->tr.vec[n];
 456
 457         memset(t, 0, sizeof(struct ub_scsi_cmd_trace));
 458         t->tag = cmd->tag;
 459         t->op = cmd->cdb[0];
 460         t->dir = cmd->dir;
 461         t->req_size = cmd->len;
 462         t->st_hst[0] = cmd->state;
 463
 464         sc->tr.cur = n;
 465         cmd->trace_index = n;
 466 }
 467
 468 static void ub_cmdtr_state(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 469 {
 470         int n;
 471         struct ub_scsi_cmd_trace *t;
 472
 473         t = &sc->tr.vec[cmd->trace_index];
 474         if (t->tag == cmd->tag) {
 475                 if ((n = t->hcur + 1) == SCMD_ST_HIST_SZ) n = 0;
 476                 t->st_hst[n] = cmd->state;
 477                 t->hcur = n;
 478         }
 479 }
 480
 481 static void ub_cmdtr_act_len(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 482 {
 483         struct ub_scsi_cmd_trace *t;
 484
 485         t = &sc->tr.vec[cmd->trace_index];
 486         if (t->tag == cmd->tag)
 487                 t->act_size = cmd->act_len;
 488 }
 489
 490 static void ub_cmdtr_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 491     unsigned char *sense)
 492 {
 493         struct ub_scsi_cmd_trace *t;
 494
 495         t = &sc->tr.vec[cmd->trace_index];
 496         if (t->tag == cmd->tag) {
 497                 t->key = sense[2] & 0x0F;
 498                 t->asc = sense[12];
 499                 t->ascq = sense[13];
 500         }
 501 }
 502
 503 static ssize_t ub_diag_show(struct device *dev, struct device_attribute *attr,
 504     char *page)
 505 {
 506         struct usb_interface *intf;
 507         struct ub_dev *sc;
 508         struct list_head *p;
 509         struct ub_lun *lun;
 510         int cnt;
 511         unsigned long flags;
 512         int nc, nh;
 513         int i, j;
 514         struct ub_scsi_cmd_trace *t;
 515
 516         intf = to_usb_interface(dev);
 517         sc = usb_get_intfdata(intf);
 518         if (sc == NULL)
 519                 return 0;
 520
 521         cnt = 0;
 522         spin_lock_irqsave(&sc->lock, flags);
 523
 524         cnt += sprintf(page + cnt,
 525             "qlen %d qmax %d\n",
 526             sc->cmd_queue.qlen, sc->cmd_queue.qmax);
 527         cnt += sprintf(page + cnt,
 528             "sg %d %d %d %d %d .. %d\n",
 529             sc->sg_stat[0],
 530             sc->sg_stat[1],
 531             sc->sg_stat[2],
 532             sc->sg_stat[3],
 533             sc->sg_stat[4],
 534             sc->sg_stat[5]);
 535
 536         list_for_each (p, &sc->luns) {
 537                 lun = list_entry(p, struct ub_lun, link);
 538                 cnt += sprintf(page + cnt,
 539                     "lun %u changed %d removable %d readonly %d\n",
 540                     lun->num, lun->changed, lun->removable, lun->readonly);
 541         }
 542
 543         if ((nc = sc->tr.cur + 1) == SCMD_TRACE_SZ) nc = 0;
 544         for (j = 0; j < SCMD_TRACE_SZ; j++) {
 545                 t = &sc->tr.vec[nc];
 546
 547                 cnt += sprintf(page + cnt, "%08x %02x", t->tag, t->op);
 548                 if (t->op == REQUEST_SENSE) {
 549                         cnt += sprintf(page + cnt, " [sense %x %02x %02x]",
 550                                         t->key, t->asc, t->ascq);
 551                 } else {
 552                         cnt += sprintf(page + cnt, " %c", UB_DIR_CHAR(t->dir));
 553                         cnt += sprintf(page + cnt, " [%5d %5d]",
 554                                         t->req_size, t->act_size);
 555                 }
 556                 if ((nh = t->hcur + 1) == SCMD_ST_HIST_SZ) nh = 0;
 557                 for (i = 0; i < SCMD_ST_HIST_SZ; i++) {
 558                         cnt += sprintf(page + cnt, " %s",
 559                                         ub_scsi_cmd_stname[(int)t->st_hst[nh]]);
 560                         if (++nh == SCMD_ST_HIST_SZ) nh = 0;
 561                 }
 562                 cnt += sprintf(page + cnt, "\n");
 563
 564                 if (++nc == SCMD_TRACE_SZ) nc = 0;
 565         }
 566
 567         spin_unlock_irqrestore(&sc->lock, flags);
 568         return cnt;
 569 }
 570
 571 static DEVICE_ATTR(diag, S_IRUGO, ub_diag_show, NULL); /* N.B. World readable */
 572
 573 /*
 574  * The id allocator.
 575  *
 576  * This also stores the host for indexing by minor, which is somewhat dirty.
 577  */
 578 static int ub_id_get(void)
 579 {
 580         unsigned long flags;
 581         int i;
 582
 583         spin_lock_irqsave(&ub_lock, flags);
 584         for (i = 0; i < UB_MAX_HOSTS; i++) {
 585                 if (ub_hostv[i] == 0) {
 586                         ub_hostv[i] = 1;
 587                         spin_unlock_irqrestore(&ub_lock, flags);
 588                         return i;
 589                 }
 590         }
 591         spin_unlock_irqrestore(&ub_lock, flags);
 592         return -1;
 593 }
 594
 595 static void ub_id_put(int id)
 596 {
 597         unsigned long flags;
 598
 599         if (id < 0 || id >= UB_MAX_HOSTS) {
 600                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 601                 return;
 602         }
 603
 604         spin_lock_irqsave(&ub_lock, flags);
 605         if (ub_hostv[id] == 0) {
 606                 spin_unlock_irqrestore(&ub_lock, flags);
 607                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 608                 return;
 609         }
 610         ub_hostv[id] = 0;
 611         spin_unlock_irqrestore(&ub_lock, flags);
 612 }
 613
 614 /*
 615  * Downcount for deallocation. This rides on two assumptions:
 616  *  - once something is poisoned, its refcount cannot grow
 617  *  - opens cannot happen at this time (del_gendisk was done)
 618  * If the above is true, we can drop the lock, which we need for
 619  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 620  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 621  */
 622 static void ub_put(struct ub_dev *sc)
 623 {
 624         unsigned long flags;
 625
 626         spin_lock_irqsave(&ub_lock, flags);
 627         --sc->openc;
 628         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 629                 spin_unlock_irqrestore(&ub_lock, flags);
 630                 ub_cleanup(sc);
 631         } else {
 632                 spin_unlock_irqrestore(&ub_lock, flags);
 633         }
 634 }
 635
 636 /*
 637  * Final cleanup and deallocation.
 638  */
 639 static void ub_cleanup(struct ub_dev *sc)
 640 {
 641         struct list_head *p;
 642         struct ub_lun *lun;
 643         request_queue_t *q;
 644
 645         while (!list_empty(&sc->luns)) {
 646                 p = sc->luns.next;
 647                 lun = list_entry(p, struct ub_lun, link);
 648                 list_del(p);
 649
 650                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 651                 if ((q = lun->disk->queue) != NULL)
 652                         blk_cleanup_queue(q);
 653                 /*
 654                  * If we zero disk->private_data BEFORE put_disk, we have
 655                  * to check for NULL all over the place in open, release,
 656                  * check_media and revalidate, because the block level
 657                  * semaphore is well inside the put_disk.
 658                  * But we cannot zero after the call, because *disk is gone.
 659                  * The sd.c is blatantly racy in this area.
 660                  */
 661                 /* disk->private_data = NULL; */
 662                 put_disk(lun->disk);
 663                 lun->disk = NULL;
 664
 665                 ub_id_put(lun->id);
 666                 kfree(lun);
 667         }
 668
 669         kfree(sc);
 670 }
 671
 672 /*
 673  * The "command allocator".
 674  */
 675 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 676 {
 677         struct ub_scsi_cmd *ret;
 678
 679         if (lun->cmda[0])
 680                 return NULL;
 681         ret = &lun->cmdv[0];
 682         lun->cmda[0] = 1;
 683         return ret;
 684 }
 685
 686 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 687 {
 688         if (cmd != &lun->cmdv[0]) {
 689                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
 690                     lun->name, cmd);
 691                 return;
 692         }
 693         if (!lun->cmda[0]) {
 694                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
 695                 return;
 696         }
 697         lun->cmda[0] = 0;
 698 }
 699
 700 /*
 701  * The command queue.
 702  */
 703 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 704 {
 705         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 706
 707         if (t->qlen++ == 0) {
 708                 t->head = cmd;
 709                 t->tail = cmd;
 710         } else {
 711                 t->tail->next = cmd;
 712                 t->tail = cmd;
 713         }
 714
 715         if (t->qlen > t->qmax)
 716                 t->qmax = t->qlen;
 717 }
 718
 719 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 720 {
 721         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 722
 723         if (t->qlen++ == 0) {
 724                 t->head = cmd;
 725                 t->tail = cmd;
 726         } else {
 727                 cmd->next = t->head;
 728                 t->head = cmd;
 729         }
 730
 731         if (t->qlen > t->qmax)
 732                 t->qmax = t->qlen;
 733 }
 734
 735 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
 736 {
 737         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 738         struct ub_scsi_cmd *cmd;
 739
 740         if (t->qlen == 0)
 741                 return NULL;
 742         if (--t->qlen == 0)
 743                 t->tail = NULL;
 744         cmd = t->head;
 745         t->head = cmd->next;
 746         cmd->next = NULL;
 747         return cmd;
 748 }
 749
 750 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
 751
 752 /*
 753  * The request function is our main entry point
 754  */
 755
 756 static void ub_request_fn(request_queue_t *q)
 757 {
 758         struct ub_lun *lun = q->queuedata;
 759         struct request *rq;
 760
 761         while ((rq = elv_next_request(q)) != NULL) {
 762                 if (ub_request_fn_1(lun, rq) != 0) {
 763                         blk_stop_queue(q);
 764                         break;
 765                 }
 766         }
 767 }
 768
 769 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 770 {
 771         struct ub_dev *sc = lun->udev;
 772         struct ub_scsi_cmd *cmd;
 773         int rc;
 774
 775         if (atomic_read(&sc->poison) || lun->changed) {
 776                 blkdev_dequeue_request(rq);
 777                 ub_end_rq(rq, 0);
 778                 return 0;
 779         }
 780
 781         if ((cmd = ub_get_cmd(lun)) == NULL)
 782                 return -1;
 783         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 784
 785         blkdev_dequeue_request(rq);
 786         if (blk_pc_request(rq)) {
 787                 rc = ub_cmd_build_packet(sc, lun, cmd, rq);
 788         } else {
 789                 rc = ub_cmd_build_block(sc, lun, cmd, rq);
 790         }
 791         if (rc != 0) {
 792                 ub_put_cmd(lun, cmd);
 793                 ub_end_rq(rq, 0);
 794                 return 0;
 795         }
 796         cmd->state = UB_CMDST_INIT;
 797         cmd->lun = lun;
 798         cmd->done = ub_rw_cmd_done;
 799         cmd->back = rq;
 800
 801         cmd->tag = sc->tagcnt++;
 802         if (ub_submit_scsi(sc, cmd) != 0) {
 803                 ub_put_cmd(lun, cmd);
 804                 ub_end_rq(rq, 0);
 805                 return 0;
 806         }
 807
 808         return 0;
 809 }
 810
 811 static int ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 812     struct ub_scsi_cmd *cmd, struct request *rq)
 813 {
 814         int ub_dir;
 815         int n_elem;
 816         unsigned int block, nblks;
 817
 818         if (rq_data_dir(rq) == WRITE)
 819                 ub_dir = UB_DIR_WRITE;
 820         else
 821                 ub_dir = UB_DIR_READ;
 822         cmd->dir = ub_dir;
 823
 824         /*
 825          * get scatterlist from block layer
 826          */
 827         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &cmd->sgv[0]);
 828         if (n_elem <= 0) {
 829                 printk(KERN_INFO "%s: failed request map (%d)\n",
 830                     sc->name, n_elem); /* P3 */
 831                 return -1;              /* request with no s/g entries? */
 832         }
 833         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 834                 printk(KERN_WARNING "%s: request with %d segments\n",
 835                     sc->name, n_elem);
 836                 return -1;
 837         }
 838         cmd->nsg = n_elem;
 839         sc->sg_stat[n_elem < 5 ? n_elem : 5]++;
 840
 841         /*
 842          * build the command
 843          *
 844          * The call to blk_queue_hardsect_size() guarantees that request
 845          * is aligned, but it is given in terms of 512 byte units, always.
 846          */
 847         block = rq->sector >> lun->capacity.bshift;
 848         nblks = rq->nr_sectors >> lun->capacity.bshift;
 849
 850         cmd->cdb[0] = (ub_dir == UB_DIR_READ)? READ_10: WRITE_10;
 851         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 852         cmd->cdb[2] = block >> 24;
 853         cmd->cdb[3] = block >> 16;
 854         cmd->cdb[4] = block >> 8;
 855         cmd->cdb[5] = block;
 856         cmd->cdb[7] = nblks >> 8;
 857         cmd->cdb[8] = nblks;
 858         cmd->cdb_len = 10;
 859
 860         cmd->len = rq->nr_sectors * 512;
 861
 862         return 0;
 863 }
 864
 865 static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 866     struct ub_scsi_cmd *cmd, struct request *rq)
 867 {
 868         int n_elem;
 869
 870         if (rq->data_len == 0) {
 871                 cmd->dir = UB_DIR_NONE;
 872         } else {
 873                 if (rq_data_dir(rq) == WRITE)
 874                         cmd->dir = UB_DIR_WRITE;
 875                 else
 876                         cmd->dir = UB_DIR_READ;
 877
 878         }
 879
 880         /*
 881          * get scatterlist from block layer
 882          */
 883         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &cmd->sgv[0]);
 884         if (n_elem < 0) {
 885                 printk(KERN_INFO "%s: failed request map (%d)\n",
 886                     sc->name, n_elem); /* P3 */
 887                 return -1;
 888         }
 889         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 890                 printk(KERN_WARNING "%s: request with %d segments\n",
 891                     sc->name, n_elem);
 892                 return -1;
 893         }
 894         cmd->nsg = n_elem;
 895         sc->sg_stat[n_elem < 5 ? n_elem : 5]++;
 896
 897         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 898         cmd->cdb_len = rq->cmd_len;
 899
 900         cmd->len = rq->data_len;
 901
 902         return 0;
 903 }
 904
 905 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 906 {
 907         struct request *rq = cmd->back;
 908         struct ub_lun *lun = cmd->lun;
 909         int uptodate;
 910
 911         if (cmd->error == 0) {
 912                 uptodate = 1;
 913
 914                 if (blk_pc_request(rq)) {
 915                         if (cmd->act_len >= rq->data_len)
 916                                 rq->data_len = 0;
 917                         else
 918                                 rq->data_len -= cmd->act_len;
 919                 }
 920         } else {
 921                 uptodate = 0;
 922
 923                 if (blk_pc_request(rq)) {
 924                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 925                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 926                         rq->sense_len = UB_SENSE_SIZE;
 927                         if (sc->top_sense[0] != 0)
 928                                 rq->errors = SAM_STAT_CHECK_CONDITION;
 929                         else
 930                                 rq->errors = DID_ERROR << 16;
 931                 }
 932         }
 933
 934         ub_put_cmd(lun, cmd);
 935         ub_end_rq(rq, uptodate);
 936         blk_start_queue(lun->disk->queue);
 937 }
 938
 939 static void ub_end_rq(struct request *rq, int uptodate)
 940 {
 941         int rc;
 942
 943         rc = end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
 944         // assert(rc == 0);
 945         end_that_request_last(rq);
 946 }
 947
 948 /*
 949  * Submit a regular SCSI operation (not an auto-sense).
 950  *
 951  * The Iron Law of Good Submit Routine is:
 952  * Zero return - callback is done, Nonzero return - callback is not done.
 953  * No exceptions.
 954  *
 955  * Host is assumed locked.
 956  *
 957  * XXX We only support Bulk for the moment.
 958  */
 959 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 960 {
 961
 962         if (cmd->state != UB_CMDST_INIT ||
 963             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
 964                 return -EINVAL;
 965         }
 966
 967         ub_cmdq_add(sc, cmd);
 968         /*
 969          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
 970          * safer to jump to a tasklet, in case upper layers do something silly.
 971          */
 972         tasklet_schedule(&sc->tasklet);
 973         return 0;
 974 }
 975
 976 /*
 977  * Submit the first URB for the queued command.
 978  * This function does not deal with queueing in any way.
 979  */
 980 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 981 {
 982         struct bulk_cb_wrap *bcb;
 983         int rc;
 984
 985         bcb = &sc->work_bcb;
 986
 987         /*
 988          * ``If the allocation length is eighteen or greater, and a device
 989          * server returns less than eithteen bytes of data, the application
 990          * client should assume that the bytes not transferred would have been
 991          * zeroes had the device server returned those bytes.''
 992          *
 993          * We zero sense for all commands so that when a packet request
 994          * fails it does not return a stale sense.
 995          */
 996         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
 997
 998         /* set up the command wrapper */
 999         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
1000         bcb->Tag = cmd->tag;            /* Endianness is not important */
1001         bcb->DataTransferLength = cpu_to_le32(cmd->len);
1002         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
1003         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
1004         bcb->Length = cmd->cdb_len;
1005
1006         /* copy the command payload */
1007         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
1008
1009         UB_INIT_COMPLETION(sc->work_done);
1010
1011         sc->last_pipe = sc->send_bulk_pipe;
1012         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
1013             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
1014
1015         /* Fill what we shouldn't be filling, because usb-storage did so. */
1016         sc->work_urb.actual_length = 0;
1017         sc->work_urb.error_count = 0;
1018         sc->work_urb.status = 0;
1019
1020         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1021                 /* XXX Clear stalls */
1022                 ub_complete(&sc->work_done);
1023                 return rc;
1024         }
1025
1026         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
1027         add_timer(&sc->work_timer);
1028
1029         cmd->state = UB_CMDST_CMD;
1030         ub_cmdtr_state(sc, cmd);
1031         return 0;
1032 }
1033
1034 /*
1035  * Timeout handler.
1036  */
1037 static void ub_urb_timeout(unsigned long arg)
1038 {
1039         struct ub_dev *sc = (struct ub_dev *) arg;
1040         unsigned long flags;
1041
1042         spin_lock_irqsave(&sc->lock, flags);
1043         usb_unlink_urb(&sc->work_urb);
1044         spin_unlock_irqrestore(&sc->lock, flags);
1045 }
1046
1047 /*
1048  * Completion routine for the work URB.
1049  *
1050  * This can be called directly from usb_submit_urb (while we have
1051  * the sc->lock taken) and from an interrupt (while we do NOT have
1052  * the sc->lock taken). Therefore, bounce this off to a tasklet.
1053  */
1054 static void ub_urb_complete(struct urb *urb, struct pt_regs *pt)
1055 {
1056         struct ub_dev *sc = urb->context;
1057
1058         ub_complete(&sc->work_done);
1059         tasklet_schedule(&sc->tasklet);
1060 }
1061
1062 static void ub_scsi_action(unsigned long _dev)
1063 {
1064         struct ub_dev *sc = (struct ub_dev *) _dev;
1065         unsigned long flags;
1066
1067         spin_lock_irqsave(&sc->lock, flags);
1068         del_timer(&sc->work_timer);
1069         ub_scsi_dispatch(sc);
1070         spin_unlock_irqrestore(&sc->lock, flags);
1071 }
1072
1073 static void ub_scsi_dispatch(struct ub_dev *sc)
1074 {
1075         struct ub_scsi_cmd *cmd;
1076         int rc;
1077
1078         while ((cmd = ub_cmdq_peek(sc)) != NULL) {
1079                 if (cmd->state == UB_CMDST_DONE) {
1080                         ub_cmdq_pop(sc);
1081                         (*cmd->done)(sc, cmd);
1082                 } else if (cmd->state == UB_CMDST_INIT) {
1083                         ub_cmdtr_new(sc, cmd);
1084                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
1085                                 break;
1086                         cmd->error = rc;
1087                         cmd->state = UB_CMDST_DONE;
1088                         ub_cmdtr_state(sc, cmd);
1089                 } else {
1090                         if (!ub_is_completed(&sc->work_done))
1091                                 break;
1092                         ub_scsi_urb_compl(sc, cmd);
1093                 }
1094         }
1095 }
1096
1097 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1098 {
1099         struct urb *urb = &sc->work_urb;
1100         struct bulk_cs_wrap *bcs;
1101         int rc;
1102
1103         if (atomic_read(&sc->poison)) {
1104                 /* A little too simplistic, I feel... */
1105                 goto Bad_End;
1106         }
1107
1108         if (cmd->state == UB_CMDST_CLEAR) {
1109                 if (urb->status == -EPIPE) {
1110                         /*
1111                          * STALL while clearning STALL.
1112                          * The control pipe clears itself - nothing to do.
1113                          * XXX Might try to reset the device here and retry.
1114                          */
1115                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1116                             sc->name);
1117                         goto Bad_End;
1118                 }
1119
1120                 /*
1121                  * We ignore the result for the halt clear.
1122                  */
1123
1124                 /* reset the endpoint toggle */
1125                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1126                         usb_pipeout(sc->last_pipe), 0);
1127
1128                 ub_state_sense(sc, cmd);
1129
1130         } else if (cmd->state == UB_CMDST_CLR2STS) {
1131                 if (urb->status == -EPIPE) {
1132                         /*
1133                          * STALL while clearning STALL.
1134                          * The control pipe clears itself - nothing to do.
1135                          * XXX Might try to reset the device here and retry.
1136                          */
1137                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1138                             sc->name);
1139                         goto Bad_End;
1140                 }
1141
1142                 /*
1143                  * We ignore the result for the halt clear.
1144                  */
1145
1146                 /* reset the endpoint toggle */
1147                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1148                         usb_pipeout(sc->last_pipe), 0);
1149
1150                 ub_state_stat(sc, cmd);
1151
1152         } else if (cmd->state == UB_CMDST_CLRRS) {
1153                 if (urb->status == -EPIPE) {
1154                         /*
1155                          * STALL while clearning STALL.
1156                          * The control pipe clears itself - nothing to do.
1157                          * XXX Might try to reset the device here and retry.
1158                          */
1159                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1160                             sc->name);
1161                         goto Bad_End;
1162                 }
1163
1164                 /*
1165                  * We ignore the result for the halt clear.
1166                  */
1167
1168                 /* reset the endpoint toggle */
1169                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1170                         usb_pipeout(sc->last_pipe), 0);
1171
1172                 ub_state_stat_counted(sc, cmd);
1173
1174         } else if (cmd->state == UB_CMDST_CMD) {
1175                 if (urb->status == -EPIPE) {
1176                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1177                         if (rc != 0) {
1178                                 printk(KERN_NOTICE "%s: "
1179                                     "unable to submit clear (%d)\n",
1180                                     sc->name, rc);
1181                                 /*
1182                                  * This is typically ENOMEM or some other such shit.
1183                                  * Retrying is pointless. Just do Bad End on it...
1184                                  */
1185                                 goto Bad_End;
1186                         }
1187                         cmd->state = UB_CMDST_CLEAR;
1188                         ub_cmdtr_state(sc, cmd);
1189                         return;
1190                 }
1191                 if (urb->status != 0) {
1192                         goto Bad_End;
1193                 }
1194                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1195                         /* XXX Must do reset here to unconfuse the device */
1196                         goto Bad_End;
1197                 }
1198
1199                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1200                         ub_state_stat(sc, cmd);
1201                         return;
1202                 }
1203
1204                 // udelay(125);         // usb-storage has this
1205                 ub_data_start(sc, cmd);
1206
1207         } else if (cmd->state == UB_CMDST_DATA) {
1208                 if (urb->status == -EPIPE) {
1209                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1210                         if (rc != 0) {
1211                                 printk(KERN_NOTICE "%s: "
1212                                     "unable to submit clear (%d)\n",
1213                                     sc->name, rc);
1214                                 /*
1215                                  * This is typically ENOMEM or some other such shit.
1216                                  * Retrying is pointless. Just do Bad End on it...
1217                                  */
1218                                 goto Bad_End;
1219                         }
1220                         cmd->state = UB_CMDST_CLR2STS;
1221                         ub_cmdtr_state(sc, cmd);
1222                         return;
1223                 }
1224                 if (urb->status == -EOVERFLOW) {
1225                         /*
1226                          * A babble? Failure, but we must transfer CSW now.
1227                          * XXX This is going to end in perpetual babble. Reset.
1228                          */
1229                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1230                         ub_state_stat(sc, cmd);
1231                         return;
1232                 }
1233                 if (urb->status != 0)
1234                         goto Bad_End;
1235
1236                 cmd->act_len += urb->actual_length;
1237                 ub_cmdtr_act_len(sc, cmd);
1238
1239                 if (++cmd->current_sg < cmd->nsg) {
1240                         ub_data_start(sc, cmd);
1241                         return;
1242                 }
1243                 ub_state_stat(sc, cmd);
1244
1245         } else if (cmd->state == UB_CMDST_STAT) {
1246                 if (urb->status == -EPIPE) {
1247                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1248                         if (rc != 0) {
1249                                 printk(KERN_NOTICE "%s: "
1250                                     "unable to submit clear (%d)\n",
1251                                     sc->name, rc);
1252                                 /*
1253                                  * This is typically ENOMEM or some other such shit.
1254                                  * Retrying is pointless. Just do Bad End on it...
1255                                  */
1256                                 goto Bad_End;
1257                         }
1258
1259                         /*
1260                          * Having a stall when getting CSW is an error, so
1261                          * make sure uppper levels are not oblivious to it.
1262                          */
1263                         cmd->error = -EIO;              /* A cheap trick... */
1264
1265                         cmd->state = UB_CMDST_CLRRS;
1266                         ub_cmdtr_state(sc, cmd);
1267                         return;
1268                 }
1269                 if (urb->status == -EOVERFLOW) {
1270                         /*
1271                          * XXX We are screwed here. Retrying is pointless,
1272                          * because the pipelined data will not get in until
1273                          * we read with a big enough buffer. We must reset XXX.
1274                          */
1275                         goto Bad_End;
1276                 }
1277                 if (urb->status != 0)
1278                         goto Bad_End;
1279
1280                 if (urb->actual_length == 0) {
1281                         ub_state_stat_counted(sc, cmd);
1282                         return;
1283                 }
1284
1285                 /*
1286                  * Check the returned Bulk protocol status.
1287                  * The status block has to be validated first.
1288                  */
1289
1290                 bcs = &sc->work_bcs;
1291
1292                 if (sc->signature == cpu_to_le32(0)) {
1293                         /*
1294                          * This is the first reply, so do not perform the check.
1295                          * Instead, remember the signature the device uses
1296                          * for future checks. But do not allow a nul.
1297                          */
1298                         sc->signature = bcs->Signature;
1299                         if (sc->signature == cpu_to_le32(0)) {
1300                                 ub_state_stat_counted(sc, cmd);
1301                                 return;
1302                         }
1303                 } else {
1304                         if (bcs->Signature != sc->signature) {
1305                                 ub_state_stat_counted(sc, cmd);
1306                                 return;
1307                         }
1308                 }
1309
1310                 if (bcs->Tag != cmd->tag) {
1311                         /*
1312                          * This usually happens when we disagree with the
1313                          * device's microcode about something. For instance,
1314                          * a few of them throw this after timeouts. They buffer
1315                          * commands and reply at commands we timed out before.
1316                          * Without flushing these replies we loop forever.
1317                          */
1318                         ub_state_stat_counted(sc, cmd);
1319                         return;
1320                 }
1321
1322                 rc = le32_to_cpu(bcs->Residue);
1323                 if (rc != cmd->len - cmd->act_len) {
1324                         /*
1325                          * It is all right to transfer less, the caller has
1326                          * to check. But it's not all right if the device
1327                          * counts disagree with our counts.
1328                          */
1329                         /* P3 */ printk("%s: resid %d len %d act %d\n",
1330                             sc->name, rc, cmd->len, cmd->act_len);
1331                         goto Bad_End;
1332                 }
1333
1334                 switch (bcs->Status) {
1335                 case US_BULK_STAT_OK:
1336                         break;
1337                 case US_BULK_STAT_FAIL:
1338                         ub_state_sense(sc, cmd);
1339                         return;
1340                 case US_BULK_STAT_PHASE:
1341                         /* XXX We must reset the transport here */
1342                         /* P3 */ printk("%s: status PHASE\n", sc->name);
1343                         goto Bad_End;
1344                 default:
1345                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1346                             sc->name, bcs->Status);
1347                         goto Bad_End;
1348                 }
1349
1350                 /* Not zeroing error to preserve a babble indicator */
1351                 if (cmd->error != 0) {
1352                         ub_state_sense(sc, cmd);
1353                         return;
1354                 }
1355                 cmd->state = UB_CMDST_DONE;
1356                 ub_cmdtr_state(sc, cmd);
1357                 ub_cmdq_pop(sc);
1358                 (*cmd->done)(sc, cmd);
1359
1360         } else if (cmd->state == UB_CMDST_SENSE) {
1361                 ub_state_done(sc, cmd, -EIO);
1362
1363         } else {
1364                 printk(KERN_WARNING "%s: "
1365                     "wrong command state %d\n",
1366                     sc->name, cmd->state);
1367                 goto Bad_End;
1368         }
1369         return;
1370
1371 Bad_End: /* Little Excel is dead */
1372         ub_state_done(sc, cmd, -EIO);
1373 }
1374
1375 /*
1376  * Factorization helper for the command state machine:
1377  * Initiate a data segment transfer.
1378  */
1379 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1380 {
1381         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1382         int pipe;
1383         int rc;
1384
1385         UB_INIT_COMPLETION(sc->work_done);
1386
1387         if (cmd->dir == UB_DIR_READ)
1388                 pipe = sc->recv_bulk_pipe;
1389         else
1390                 pipe = sc->send_bulk_pipe;
1391         sc->last_pipe = pipe;
1392         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe,
1393             page_address(sg->page) + sg->offset, sg->length,
1394             ub_urb_complete, sc);
1395         sc->work_urb.actual_length = 0;
1396         sc->work_urb.error_count = 0;
1397         sc->work_urb.status = 0;
1398
1399         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1400                 /* XXX Clear stalls */
1401                 ub_complete(&sc->work_done);
1402                 ub_state_done(sc, cmd, rc);
1403                 return;
1404         }
1405
1406         sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1407         add_timer(&sc->work_timer);
1408
1409         cmd->state = UB_CMDST_DATA;
1410         ub_cmdtr_state(sc, cmd);
1411 }
1412
1413 /*
1414  * Factorization helper for the command state machine:
1415  * Finish the command.
1416  */
1417 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1418 {
1419
1420         cmd->error = rc;
1421         cmd->state = UB_CMDST_DONE;
1422         ub_cmdtr_state(sc, cmd);
1423         ub_cmdq_pop(sc);
1424         (*cmd->done)(sc, cmd);
1425 }
1426
1427 /*
1428  * Factorization helper for the command state machine:
1429  * Submit a CSW read.
1430  */
1431 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1432 {
1433         int rc;
1434
1435         UB_INIT_COMPLETION(sc->work_done);
1436
1437         sc->last_pipe = sc->recv_bulk_pipe;
1438         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1439             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1440         sc->work_urb.actual_length = 0;
1441         sc->work_urb.error_count = 0;
1442         sc->work_urb.status = 0;
1443
1444         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1445                 /* XXX Clear stalls */
1446                 ub_complete(&sc->work_done);
1447                 ub_state_done(sc, cmd, rc);
1448                 return -1;
1449         }
1450
1451         sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1452         add_timer(&sc->work_timer);
1453         return 0;
1454 }
1455
1456 /*
1457  * Factorization helper for the command state machine:
1458  * Submit a CSW read and go to STAT state.
1459  */
1460 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1461 {
1462
1463         if (__ub_state_stat(sc, cmd) != 0)
1464                 return;
1465
1466         cmd->stat_count = 0;
1467         cmd->state = UB_CMDST_STAT;
1468         ub_cmdtr_state(sc, cmd);
1469 }
1470
1471 /*
1472  * Factorization helper for the command state machine:
1473  * Submit a CSW read and go to STAT state with counter (along [C] path).
1474  */
1475 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1476 {
1477
1478         if (++cmd->stat_count >= 4) {
1479                 ub_state_sense(sc, cmd);
1480                 return;
1481         }
1482
1483         if (__ub_state_stat(sc, cmd) != 0)
1484                 return;
1485
1486         cmd->state = UB_CMDST_STAT;
1487         ub_cmdtr_state(sc, cmd);
1488 }
1489
1490 /*
1491  * Factorization helper for the command state machine:
1492  * Submit a REQUEST SENSE and go to SENSE state.
1493  */
1494 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1495 {
1496         struct ub_scsi_cmd *scmd;
1497         struct scatterlist *sg;
1498         int rc;
1499
1500         if (cmd->cdb[0] == REQUEST_SENSE) {
1501                 rc = -EPIPE;
1502                 goto error;
1503         }
1504
1505         scmd = &sc->top_rqs_cmd;
1506         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1507         scmd->cdb[0] = REQUEST_SENSE;
1508         scmd->cdb[4] = UB_SENSE_SIZE;
1509         scmd->cdb_len = 6;
1510         scmd->dir = UB_DIR_READ;
1511         scmd->state = UB_CMDST_INIT;
1512         scmd->nsg = 1;
1513         sg = &scmd->sgv[0];
1514         sg->page = virt_to_page(sc->top_sense);
1515         sg->offset = (unsigned long)sc->top_sense & (PAGE_SIZE-1);
1516         sg->length = UB_SENSE_SIZE;
1517         scmd->len = UB_SENSE_SIZE;
1518         scmd->lun = cmd->lun;
1519         scmd->done = ub_top_sense_done;
1520         scmd->back = cmd;
1521
1522         scmd->tag = sc->tagcnt++;
1523
1524         cmd->state = UB_CMDST_SENSE;
1525         ub_cmdtr_state(sc, cmd);
1526
1527         ub_cmdq_insert(sc, scmd);
1528         return;
1529
1530 error:
1531         ub_state_done(sc, cmd, rc);
1532 }
1533
1534 /*
1535  * A helper for the command's state machine:
1536  * Submit a stall clear.
1537  */
1538 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1539     int stalled_pipe)
1540 {
1541         int endp;
1542         struct usb_ctrlrequest *cr;
1543         int rc;
1544
1545         endp = usb_pipeendpoint(stalled_pipe);
1546         if (usb_pipein (stalled_pipe))
1547                 endp |= USB_DIR_IN;
1548
1549         cr = &sc->work_cr;
1550         cr->bRequestType = USB_RECIP_ENDPOINT;
1551         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1552         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1553         cr->wIndex = cpu_to_le16(endp);
1554         cr->wLength = cpu_to_le16(0);
1555
1556         UB_INIT_COMPLETION(sc->work_done);
1557
1558         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1559             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1560         sc->work_urb.actual_length = 0;
1561         sc->work_urb.error_count = 0;
1562         sc->work_urb.status = 0;
1563
1564         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1565                 ub_complete(&sc->work_done);
1566                 return rc;
1567         }
1568
1569         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1570         add_timer(&sc->work_timer);
1571         return 0;
1572 }
1573
1574 /*
1575  */
1576 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1577 {
1578         unsigned char *sense = sc->top_sense;
1579         struct ub_scsi_cmd *cmd;
1580
1581         /*
1582          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1583          */
1584         ub_cmdtr_sense(sc, scmd, sense);
1585
1586         /*
1587          * Find the command which triggered the unit attention or a check,
1588          * save the sense into it, and advance its state machine.
1589          */
1590         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1591                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1592                 return;
1593         }
1594         if (cmd != scmd->back) {
1595                 printk(KERN_WARNING "%s: "
1596                     "sense done for wrong command 0x%x\n",
1597                     sc->name, cmd->tag);
1598                 return;
1599         }
1600         if (cmd->state != UB_CMDST_SENSE) {
1601                 printk(KERN_WARNING "%s: "
1602                     "sense done with bad cmd state %d\n",
1603                     sc->name, cmd->state);
1604                 return;
1605         }
1606
1607         cmd->key = sense[2] & 0x0F;
1608         cmd->asc = sense[12];
1609         cmd->ascq = sense[13];
1610
1611         ub_scsi_urb_compl(sc, cmd);
1612 }
1613
1614 /*
1615  * This is called from a process context.
1616  */
1617 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1618 {
1619
1620         lun->readonly = 0;      /* XXX Query this from the device */
1621
1622         lun->capacity.nsec = 0;
1623         lun->capacity.bsize = 512;
1624         lun->capacity.bshift = 0;
1625
1626         if (ub_sync_tur(sc, lun) != 0)
1627                 return;                 /* Not ready */
1628         lun->changed = 0;
1629
1630         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1631                 /*
1632                  * The retry here means something is wrong, either with the
1633                  * device, with the transport, or with our code.
1634                  * We keep this because sd.c has retries for capacity.
1635                  */
1636                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1637                         lun->capacity.nsec = 0;
1638                         lun->capacity.bsize = 512;
1639                         lun->capacity.bshift = 0;
1640                 }
1641         }
1642 }
1643
1644 /*
1645  * The open funcion.
1646  * This is mostly needed to keep refcounting, but also to support
1647  * media checks on removable media drives.
1648  */
1649 static int ub_bd_open(struct inode *inode, struct file *filp)
1650 {
1651         struct gendisk *disk = inode->i_bdev->bd_disk;
1652         struct ub_lun *lun;
1653         struct ub_dev *sc;
1654         unsigned long flags;
1655         int rc;
1656
1657         if ((lun = disk->private_data) == NULL)
1658                 return -ENXIO;
1659         sc = lun->udev;
1660
1661         spin_lock_irqsave(&ub_lock, flags);
1662         if (atomic_read(&sc->poison)) {
1663                 spin_unlock_irqrestore(&ub_lock, flags);
1664                 return -ENXIO;
1665         }
1666         sc->openc++;
1667         spin_unlock_irqrestore(&ub_lock, flags);
1668
1669         /*
1670          * This is a workaround for a specific problem in our block layer.
1671          * In 2.6.9, register_disk duplicates the code from rescan_partitions.
1672          * However, if we do add_disk with a device which persistently reports
1673          * a changed media, add_disk calls register_disk, which does do_open,
1674          * which will call rescan_paritions for changed media. After that,
1675          * register_disk attempts to do it all again and causes double kobject
1676          * registration and a eventually an oops on module removal.
1677          *
1678          * The bottom line is, Al Viro says that we should not allow
1679          * bdev->bd_invalidated to be set when doing add_disk no matter what.
1680          */
1681         if (lun->first_open) {
1682                 lun->first_open = 0;
1683                 if (lun->changed) {
1684                         rc = -ENOMEDIUM;
1685                         goto err_open;
1686                 }
1687         }
1688
1689         if (lun->removable || lun->readonly)
1690                 check_disk_change(inode->i_bdev);
1691
1692         /*
1693          * The sd.c considers ->media_present and ->changed not equivalent,
1694          * under some pretty murky conditions (a failure of READ CAPACITY).
1695          * We may need it one day.
1696          */
1697         if (lun->removable && lun->changed && !(filp->f_flags & O_NDELAY)) {
1698                 rc = -ENOMEDIUM;
1699                 goto err_open;
1700         }
1701
1702         if (lun->readonly && (filp->f_mode & FMODE_WRITE)) {
1703                 rc = -EROFS;
1704                 goto err_open;
1705         }
1706
1707         return 0;
1708
1709 err_open:
1710         ub_put(sc);
1711         return rc;
1712 }
1713
1714 /*
1715  */
1716 static int ub_bd_release(struct inode *inode, struct file *filp)
1717 {
1718         struct gendisk *disk = inode->i_bdev->bd_disk;
1719         struct ub_lun *lun = disk->private_data;
1720         struct ub_dev *sc = lun->udev;
1721
1722         ub_put(sc);
1723         return 0;
1724 }
1725
1726 /*
1727  * The ioctl interface.
1728  */
1729 static int ub_bd_ioctl(struct inode *inode, struct file *filp,
1730     unsigned int cmd, unsigned long arg)
1731 {
1732         struct gendisk *disk = inode->i_bdev->bd_disk;
1733         void __user *usermem = (void __user *) arg;
1734
1735         return scsi_cmd_ioctl(filp, disk, cmd, usermem);
1736 }
1737
1738 /*
1739  * This is called once a new disk was seen by the block layer or by ub_probe().
1740  * The main onjective here is to discover the features of the media such as
1741  * the capacity, read-only status, etc. USB storage generally does not
1742  * need to be spun up, but if we needed it, this would be the place.
1743  *
1744  * This call can sleep.
1745  *
1746  * The return code is not used.
1747  */
1748 static int ub_bd_revalidate(struct gendisk *disk)
1749 {
1750         struct ub_lun *lun = disk->private_data;
1751
1752         ub_revalidate(lun->udev, lun);
1753
1754         /* XXX Support sector size switching like in sr.c */
1755         blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
1756         set_capacity(disk, lun->capacity.nsec);
1757         // set_disk_ro(sdkp->disk, lun->readonly);
1758
1759         return 0;
1760 }
1761
1762 /*
1763  * The check is called by the block layer to verify if the media
1764  * is still available. It is supposed to be harmless, lightweight and
1765  * non-intrusive in case the media was not changed.
1766  *
1767  * This call can sleep.
1768  *
1769  * The return code is bool!
1770  */
1771 static int ub_bd_media_changed(struct gendisk *disk)
1772 {
1773         struct ub_lun *lun = disk->private_data;
1774
1775         if (!lun->removable)
1776                 return 0;
1777
1778         /*
1779          * We clean checks always after every command, so this is not
1780          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1781          * the device is actually not ready with operator or software
1782          * intervention required. One dangerous item might be a drive which
1783          * spins itself down, and come the time to write dirty pages, this
1784          * will fail, then block layer discards the data. Since we never
1785          * spin drives up, such devices simply cannot be used with ub anyway.
1786          */
1787         if (ub_sync_tur(lun->udev, lun) != 0) {
1788                 lun->changed = 1;
1789                 return 1;
1790         }
1791
1792         return lun->changed;
1793 }
1794
1795 static struct block_device_operations ub_bd_fops = {
1796         .owner          = THIS_MODULE,
1797         .open           = ub_bd_open,
1798         .release        = ub_bd_release,
1799         .ioctl          = ub_bd_ioctl,
1800         .media_changed  = ub_bd_media_changed,
1801         .revalidate_disk = ub_bd_revalidate,
1802 };
1803
1804 /*
1805  * Common ->done routine for commands executed synchronously.
1806  */
1807 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1808 {
1809         struct completion *cop = cmd->back;
1810         complete(cop);
1811 }
1812
1813 /*
1814  * Test if the device has a check condition on it, synchronously.
1815  */
1816 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1817 {
1818         struct ub_scsi_cmd *cmd;
1819         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1820         unsigned long flags;
1821         struct completion compl;
1822         int rc;
1823
1824         init_completion(&compl);
1825
1826         rc = -ENOMEM;
1827         if ((cmd = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1828                 goto err_alloc;
1829         memset(cmd, 0, ALLOC_SIZE);
1830
1831         cmd->cdb[0] = TEST_UNIT_READY;
1832         cmd->cdb_len = 6;
1833         cmd->dir = UB_DIR_NONE;
1834         cmd->state = UB_CMDST_INIT;
1835         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1836         cmd->done = ub_probe_done;
1837         cmd->back = &compl;
1838
1839         spin_lock_irqsave(&sc->lock, flags);
1840         cmd->tag = sc->tagcnt++;
1841
1842         rc = ub_submit_scsi(sc, cmd);
1843         spin_unlock_irqrestore(&sc->lock, flags);
1844
1845         if (rc != 0) {
1846                 printk("ub: testing ready: submit error (%d)\n", rc); /* P3 */
1847                 goto err_submit;
1848         }
1849
1850         wait_for_completion(&compl);
1851
1852         rc = cmd->error;
1853
1854         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1855                 rc = cmd->key;
1856
1857 err_submit:
1858         kfree(cmd);
1859 err_alloc:
1860         return rc;
1861 }
1862
1863 /*
1864  * Read the SCSI capacity synchronously (for probing).
1865  */
1866 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1867     struct ub_capacity *ret)
1868 {
1869         struct ub_scsi_cmd *cmd;
1870         struct scatterlist *sg;
1871         char *p;
1872         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1873         unsigned long flags;
1874         unsigned int bsize, shift;
1875         unsigned long nsec;
1876         struct completion compl;
1877         int rc;
1878
1879         init_completion(&compl);
1880
1881         rc = -ENOMEM;
1882         if ((cmd = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1883                 goto err_alloc;
1884         memset(cmd, 0, ALLOC_SIZE);
1885         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1886
1887         cmd->cdb[0] = 0x25;
1888         cmd->cdb_len = 10;
1889         cmd->dir = UB_DIR_READ;
1890         cmd->state = UB_CMDST_INIT;
1891         cmd->nsg = 1;
1892         sg = &cmd->sgv[0];
1893         sg->page = virt_to_page(p);
1894         sg->offset = (unsigned long)p & (PAGE_SIZE-1);
1895         sg->length = 8;
1896         cmd->len = 8;
1897         cmd->lun = lun;
1898         cmd->done = ub_probe_done;
1899         cmd->back = &compl;
1900
1901         spin_lock_irqsave(&sc->lock, flags);
1902         cmd->tag = sc->tagcnt++;
1903
1904         rc = ub_submit_scsi(sc, cmd);
1905         spin_unlock_irqrestore(&sc->lock, flags);
1906
1907         if (rc != 0) {
1908                 printk("ub: reading capacity: submit error (%d)\n", rc); /* P3 */
1909                 goto err_submit;
1910         }
1911
1912         wait_for_completion(&compl);
1913
1914         if (cmd->error != 0) {
1915                 printk("ub: reading capacity: error %d\n", cmd->error); /* P3 */
1916                 rc = -EIO;
1917                 goto err_read;
1918         }
1919         if (cmd->act_len != 8) {
1920                 printk("ub: reading capacity: size %d\n", cmd->act_len); /* P3 */
1921                 rc = -EIO;
1922                 goto err_read;
1923         }
1924
1925         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1926         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1927         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1928         switch (bsize) {
1929         case 512:       shift = 0;      break;
1930         case 1024:      shift = 1;      break;
1931         case 2048:      shift = 2;      break;
1932         case 4096:      shift = 3;      break;
1933         default:
1934                 printk("ub: Bad sector size %u\n", bsize); /* P3 */
1935                 rc = -EDOM;
1936                 goto err_inv_bsize;
1937         }
1938
1939         ret->bsize = bsize;
1940         ret->bshift = shift;
1941         ret->nsec = nsec << shift;
1942         rc = 0;
1943
1944 err_inv_bsize:
1945 err_read:
1946 err_submit:
1947         kfree(cmd);
1948 err_alloc:
1949         return rc;
1950 }
1951
1952 /*
1953  */
1954 static void ub_probe_urb_complete(struct urb *urb, struct pt_regs *pt)
1955 {
1956         struct completion *cop = urb->context;
1957         complete(cop);
1958 }
1959
1960 static void ub_probe_timeout(unsigned long arg)
1961 {
1962         struct completion *cop = (struct completion *) arg;
1963         complete(cop);
1964 }
1965
1966 /*
1967  * Get number of LUNs by the way of Bulk GetMaxLUN command.
1968  */
1969 static int ub_sync_getmaxlun(struct ub_dev *sc)
1970 {
1971         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1972         unsigned char *p;
1973         enum { ALLOC_SIZE = 1 };
1974         struct usb_ctrlrequest *cr;
1975         struct completion compl;
1976         struct timer_list timer;
1977         int nluns;
1978         int rc;
1979
1980         init_completion(&compl);
1981
1982         rc = -ENOMEM;
1983         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1984                 goto err_alloc;
1985         *p = 55;
1986
1987         cr = &sc->work_cr;
1988         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1989         cr->bRequest = US_BULK_GET_MAX_LUN;
1990         cr->wValue = cpu_to_le16(0);
1991         cr->wIndex = cpu_to_le16(ifnum);
1992         cr->wLength = cpu_to_le16(1);
1993
1994         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
1995             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
1996         sc->work_urb.actual_length = 0;
1997         sc->work_urb.error_count = 0;
1998         sc->work_urb.status = 0;
1999
2000         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2001                 if (rc == -EPIPE) {
2002                         printk("%s: Stall submitting GetMaxLUN, using 1 LUN\n",
2003                              sc->name); /* P3 */
2004                 } else {
2005                         printk(KERN_NOTICE
2006                              "%s: Unable to submit GetMaxLUN (%d)\n",
2007                              sc->name, rc);
2008                 }
2009                 goto err_submit;
2010         }
2011
2012         init_timer(&timer);
2013         timer.function = ub_probe_timeout;
2014         timer.data = (unsigned long) &compl;
2015         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2016         add_timer(&timer);
2017
2018         wait_for_completion(&compl);
2019
2020         del_timer_sync(&timer);
2021         usb_kill_urb(&sc->work_urb);
2022
2023         if ((rc = sc->work_urb.status) < 0) {
2024                 if (rc == -EPIPE) {
2025                         printk("%s: Stall at GetMaxLUN, using 1 LUN\n",
2026                              sc->name); /* P3 */
2027                 } else {
2028                         printk(KERN_NOTICE
2029                              "%s: Error at GetMaxLUN (%d)\n",
2030                              sc->name, rc);
2031                 }
2032                 goto err_io;
2033         }
2034
2035         if (sc->work_urb.actual_length != 1) {
2036                 printk("%s: GetMaxLUN returned %d bytes\n", sc->name,
2037                     sc->work_urb.actual_length); /* P3 */
2038                 nluns = 0;
2039         } else {
2040                 if ((nluns = *p) == 55) {
2041                         nluns = 0;
2042                 } else {
2043                         /* GetMaxLUN returns the maximum LUN number */
2044                         nluns += 1;
2045                         if (nluns > UB_MAX_LUNS)
2046                                 nluns = UB_MAX_LUNS;
2047                 }
2048                 printk("%s: GetMaxLUN returned %d, using %d LUNs\n", sc->name,
2049                     *p, nluns); /* P3 */
2050         }
2051
2052         kfree(p);
2053         return nluns;
2054
2055 err_io:
2056 err_submit:
2057         kfree(p);
2058 err_alloc:
2059         return rc;
2060 }
2061
2062 /*
2063  * Clear initial stalls.
2064  */
2065 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2066 {
2067         int endp;
2068         struct usb_ctrlrequest *cr;
2069         struct completion compl;
2070         struct timer_list timer;
2071         int rc;
2072
2073         init_completion(&compl);
2074
2075         endp = usb_pipeendpoint(stalled_pipe);
2076         if (usb_pipein (stalled_pipe))
2077                 endp |= USB_DIR_IN;
2078
2079         cr = &sc->work_cr;
2080         cr->bRequestType = USB_RECIP_ENDPOINT;
2081         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2082         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2083         cr->wIndex = cpu_to_le16(endp);
2084         cr->wLength = cpu_to_le16(0);
2085
2086         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2087             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2088         sc->work_urb.actual_length = 0;
2089         sc->work_urb.error_count = 0;
2090         sc->work_urb.status = 0;
2091
2092         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2093                 printk(KERN_WARNING
2094                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2095                 return rc;
2096         }
2097
2098         init_timer(&timer);
2099         timer.function = ub_probe_timeout;
2100         timer.data = (unsigned long) &compl;
2101         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2102         add_timer(&timer);
2103
2104         wait_for_completion(&compl);
2105
2106         del_timer_sync(&timer);
2107         usb_kill_urb(&sc->work_urb);
2108
2109         /* reset the endpoint toggle */
2110         usb_settoggle(sc->dev, endp, usb_pipeout(sc->last_pipe), 0);
2111
2112         return 0;
2113 }
2114
2115 /*
2116  * Get the pipe settings.
2117  */
2118 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2119     struct usb_interface *intf)
2120 {
2121         struct usb_host_interface *altsetting = intf->cur_altsetting;
2122         struct usb_endpoint_descriptor *ep_in = NULL;
2123         struct usb_endpoint_descriptor *ep_out = NULL;
2124         struct usb_endpoint_descriptor *ep;
2125         int i;
2126
2127         /*
2128          * Find the endpoints we need.
2129          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2130          * We will ignore any others.
2131          */
2132         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2133                 ep = &altsetting->endpoint[i].desc;
2134
2135                 /* Is it a BULK endpoint? */
2136                 if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
2137                                 == USB_ENDPOINT_XFER_BULK) {
2138                         /* BULK in or out? */
2139                         if (ep->bEndpointAddress & USB_DIR_IN)
2140                                 ep_in = ep;
2141                         else
2142                                 ep_out = ep;
2143                 }
2144         }
2145
2146         if (ep_in == NULL || ep_out == NULL) {
2147                 printk(KERN_NOTICE "%s: failed endpoint check\n",
2148                     sc->name);
2149                 return -EIO;
2150         }
2151
2152         /* Calculate and store the pipe values */
2153         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2154         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2155         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2156                 ep_out->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2157         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2158                 ep_in->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2159
2160         return 0;
2161 }
2162
2163 /*
2164  * Probing is done in the process context, which allows us to cheat
2165  * and not to build a state machine for the discovery.
2166  */
2167 static int ub_probe(struct usb_interface *intf,
2168     const struct usb_device_id *dev_id)
2169 {
2170         struct ub_dev *sc;
2171         int nluns;
2172         int rc;
2173         int i;
2174
2175         rc = -ENOMEM;
2176         if ((sc = kmalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2177                 goto err_core;
2178         memset(sc, 0, sizeof(struct ub_dev));
2179         spin_lock_init(&sc->lock);
2180         INIT_LIST_HEAD(&sc->luns);
2181         usb_init_urb(&sc->work_urb);
2182         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2183         atomic_set(&sc->poison, 0);
2184
2185         init_timer(&sc->work_timer);
2186         sc->work_timer.data = (unsigned long) sc;
2187         sc->work_timer.function = ub_urb_timeout;
2188
2189         ub_init_completion(&sc->work_done);
2190         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2191
2192         sc->dev = interface_to_usbdev(intf);
2193         sc->intf = intf;
2194         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2195         usb_set_intfdata(intf, sc);
2196         usb_get_dev(sc->dev);
2197         // usb_get_intf(sc->intf);      /* Do we need this? */
2198
2199         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2200             sc->dev->bus->busnum, sc->dev->devnum);
2201
2202         /* XXX Verify that we can handle the device (from descriptors) */
2203
2204         ub_get_pipes(sc, sc->dev, intf);
2205
2206         if (device_create_file(&sc->intf->dev, &dev_attr_diag) != 0)
2207                 goto err_diag;
2208
2209         /*
2210          * At this point, all USB initialization is done, do upper layer.
2211          * We really hate halfway initialized structures, so from the
2212          * invariants perspective, this ub_dev is fully constructed at
2213          * this point.
2214          */
2215
2216         /*
2217          * This is needed to clear toggles. It is a problem only if we do
2218          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2219          */
2220 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2221         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2222         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2223 #endif
2224
2225         /*
2226          * The way this is used by the startup code is a little specific.
2227          * A SCSI check causes a USB stall. Our common case code sees it
2228          * and clears the check, after which the device is ready for use.
2229          * But if a check was not present, any command other than
2230          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2231          *
2232          * If we neglect to clear the SCSI check, the first real command fails
2233          * (which is the capacity readout). We clear that and retry, but why
2234          * causing spurious retries for no reason.
2235          *
2236          * Revalidation may start with its own TEST_UNIT_READY, but that one
2237          * has to succeed, so we clear checks with an additional one here.
2238          * In any case it's not our business how revaliadation is implemented.
2239          */
2240         for (i = 0; i < 3; i++) {       /* Retries for benh's key */
2241                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2242                 if (rc != 0x6) break;
2243                 msleep(10);
2244         }
2245
2246         nluns = 1;
2247         for (i = 0; i < 3; i++) {
2248                 if ((rc = ub_sync_getmaxlun(sc)) < 0) {
2249                         /*
2250                          * This segment is taken from usb-storage. They say
2251                          * that ZIP-100 needs this, but my own ZIP-100 works
2252                          * fine without this.
2253                          * Still, it does not seem to hurt anything.
2254                          */
2255                         if (rc == -EPIPE) {
2256                                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2257                                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2258                         }
2259                         break;
2260                 }
2261                 if (rc != 0) {
2262                         nluns = rc;
2263                         break;
2264                 }
2265                 msleep(100);
2266         }
2267
2268         for (i = 0; i < nluns; i++) {
2269                 ub_probe_lun(sc, i);
2270         }
2271         return 0;
2272
2273         /* device_remove_file(&sc->intf->dev, &dev_attr_diag); */
2274 err_diag:
2275         usb_set_intfdata(intf, NULL);
2276         // usb_put_intf(sc->intf);
2277         usb_put_dev(sc->dev);
2278         kfree(sc);
2279 err_core:
2280         return rc;
2281 }
2282
2283 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2284 {
2285         struct ub_lun *lun;
2286         request_queue_t *q;
2287         struct gendisk *disk;
2288         int rc;
2289
2290         rc = -ENOMEM;
2291         if ((lun = kmalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2292                 goto err_alloc;
2293         memset(lun, 0, sizeof(struct ub_lun));
2294         lun->num = lnum;
2295
2296         rc = -ENOSR;
2297         if ((lun->id = ub_id_get()) == -1)
2298                 goto err_id;
2299
2300         lun->udev = sc;
2301         list_add(&lun->link, &sc->luns);
2302
2303         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2304             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2305
2306         lun->removable = 1;             /* XXX Query this from the device */
2307         lun->changed = 1;               /* ub_revalidate clears only */
2308         lun->first_open = 1;
2309         ub_revalidate(sc, lun);
2310
2311         rc = -ENOMEM;
2312         if ((disk = alloc_disk(UB_MINORS_PER_MAJOR)) == NULL)
2313                 goto err_diskalloc;
2314
2315         lun->disk = disk;
2316         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2317         sprintf(disk->devfs_name, DEVFS_NAME "/%c", lun->id + 'a');
2318         disk->major = UB_MAJOR;
2319         disk->first_minor = lun->id * UB_MINORS_PER_MAJOR;
2320         disk->fops = &ub_bd_fops;
2321         disk->private_data = lun;
2322         disk->driverfs_dev = &sc->intf->dev;
2323
2324         rc = -ENOMEM;
2325         if ((q = blk_init_queue(ub_request_fn, &sc->lock)) == NULL)
2326                 goto err_blkqinit;
2327
2328         disk->queue = q;
2329
2330         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2331         blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
2332         blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
2333         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2334         blk_queue_max_sectors(q, UB_MAX_SECTORS);
2335         blk_queue_hardsect_size(q, lun->capacity.bsize);
2336
2337         q->queuedata = lun;
2338
2339         set_capacity(disk, lun->capacity.nsec);
2340         if (lun->removable)
2341                 disk->flags |= GENHD_FL_REMOVABLE;
2342
2343         add_disk(disk);
2344
2345         return 0;
2346
2347 err_blkqinit:
2348         put_disk(disk);
2349 err_diskalloc:
2350         list_del(&lun->link);
2351         ub_id_put(lun->id);
2352 err_id:
2353         kfree(lun);
2354 err_alloc:
2355         return rc;
2356 }
2357
2358 static void ub_disconnect(struct usb_interface *intf)
2359 {
2360         struct ub_dev *sc = usb_get_intfdata(intf);
2361         struct list_head *p;
2362         struct ub_lun *lun;
2363         struct gendisk *disk;
2364         unsigned long flags;
2365
2366         /*
2367          * Prevent ub_bd_release from pulling the rug from under us.
2368          * XXX This is starting to look like a kref.
2369          * XXX Why not to take this ref at probe time?
2370          */
2371         spin_lock_irqsave(&ub_lock, flags);
2372         sc->openc++;
2373         spin_unlock_irqrestore(&ub_lock, flags);
2374
2375         /*
2376          * Fence stall clearnings, operations triggered by unlinkings and so on.
2377          * We do not attempt to unlink any URBs, because we do not trust the
2378          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2379          */
2380         atomic_set(&sc->poison, 1);
2381
2382         /*
2383          * Blow away queued commands.
2384          *
2385          * Actually, this never works, because before we get here
2386          * the HCD terminates outstanding URB(s). It causes our
2387          * SCSI command queue to advance, commands fail to submit,
2388          * and the whole queue drains. So, we just use this code to
2389          * print warnings.
2390          */
2391         spin_lock_irqsave(&sc->lock, flags);
2392         {
2393                 struct ub_scsi_cmd *cmd;
2394                 int cnt = 0;
2395                 while ((cmd = ub_cmdq_pop(sc)) != NULL) {
2396                         cmd->error = -ENOTCONN;
2397                         cmd->state = UB_CMDST_DONE;
2398                         ub_cmdtr_state(sc, cmd);
2399                         ub_cmdq_pop(sc);
2400                         (*cmd->done)(sc, cmd);
2401                         cnt++;
2402                 }
2403                 if (cnt != 0) {
2404                         printk(KERN_WARNING "%s: "
2405                             "%d was queued after shutdown\n", sc->name, cnt);
2406                 }
2407         }
2408         spin_unlock_irqrestore(&sc->lock, flags);
2409
2410         /*
2411          * Unregister the upper layer.
2412          */
2413         list_for_each (p, &sc->luns) {
2414                 lun = list_entry(p, struct ub_lun, link);
2415                 disk = lun->disk;
2416                 if (disk->flags & GENHD_FL_UP)
2417                         del_gendisk(disk);
2418                 /*
2419                  * I wish I could do:
2420                  *    set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
2421                  * As it is, we rely on our internal poisoning and let
2422                  * the upper levels to spin furiously failing all the I/O.
2423                  */
2424         }
2425
2426         /*
2427          * Taking a lock on a structure which is about to be freed
2428          * is very nonsensual. Here it is largely a way to do a debug freeze,
2429          * and a bracket which shows where the nonsensual code segment ends.
2430          *
2431          * Testing for -EINPROGRESS is always a bug, so we are bending
2432          * the rules a little.
2433          */
2434         spin_lock_irqsave(&sc->lock, flags);
2435         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2436                 printk(KERN_WARNING "%s: "
2437                     "URB is active after disconnect\n", sc->name);
2438         }
2439         spin_unlock_irqrestore(&sc->lock, flags);
2440
2441         /*
2442          * There is virtually no chance that other CPU runs times so long
2443          * after ub_urb_complete should have called del_timer, but only if HCD
2444          * didn't forget to deliver a callback on unlink.
2445          */
2446         del_timer_sync(&sc->work_timer);
2447
2448         /*
2449          * At this point there must be no commands coming from anyone
2450          * and no URBs left in transit.
2451          */
2452
2453         device_remove_file(&sc->intf->dev, &dev_attr_diag);
2454         usb_set_intfdata(intf, NULL);
2455         // usb_put_intf(sc->intf);
2456         sc->intf = NULL;
2457         usb_put_dev(sc->dev);
2458         sc->dev = NULL;
2459
2460         ub_put(sc);
2461 }
2462
2463 static struct usb_driver ub_driver = {
2464         .owner =        THIS_MODULE,
2465         .name =         "ub",
2466         .probe =        ub_probe,
2467         .disconnect =   ub_disconnect,
2468         .id_table =     ub_usb_ids,
2469 };
2470
2471 static int __init ub_init(void)
2472 {
2473         int rc;
2474
2475         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2476                 goto err_regblkdev;
2477         devfs_mk_dir(DEVFS_NAME);
2478
2479         if ((rc = usb_register(&ub_driver)) != 0)
2480                 goto err_register;
2481
2482         return 0;
2483
2484 err_register:
2485         devfs_remove(DEVFS_NAME);
2486         unregister_blkdev(UB_MAJOR, DRV_NAME);
2487 err_regblkdev:
2488         return rc;
2489 }
2490
2491 static void __exit ub_exit(void)
2492 {
2493         usb_deregister(&ub_driver);
2494
2495         devfs_remove(DEVFS_NAME);
2496         unregister_blkdev(UB_MAJOR, DRV_NAME);
2497 }
2498
2499 module_init(ub_init);
2500 module_exit(ub_exit);
2501
2502 MODULE_LICENSE("GPL");