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   4
 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[UB_MAX_REQ_SG+1];
 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\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
 535         list_for_each (p, &sc->luns) {
 536                 lun = list_entry(p, struct ub_lun, link);
 537                 cnt += sprintf(page + cnt,
 538                     "lun %u changed %d removable %d readonly %d\n",
 539                     lun->num, lun->changed, lun->removable, lun->readonly);
 540         }
 541
 542         if ((nc = sc->tr.cur + 1) == SCMD_TRACE_SZ) nc = 0;
 543         for (j = 0; j < SCMD_TRACE_SZ; j++) {
 544                 t = &sc->tr.vec[nc];
 545
 546                 cnt += sprintf(page + cnt, "%08x %02x", t->tag, t->op);
 547                 if (t->op == REQUEST_SENSE) {
 548                         cnt += sprintf(page + cnt, " [sense %x %02x %02x]",
 549                                         t->key, t->asc, t->ascq);
 550                 } else {
 551                         cnt += sprintf(page + cnt, " %c", UB_DIR_CHAR(t->dir));
 552                         cnt += sprintf(page + cnt, " [%5d %5d]",
 553                                         t->req_size, t->act_size);
 554                 }
 555                 if ((nh = t->hcur + 1) == SCMD_ST_HIST_SZ) nh = 0;
 556                 for (i = 0; i < SCMD_ST_HIST_SZ; i++) {
 557                         cnt += sprintf(page + cnt, " %s",
 558                                         ub_scsi_cmd_stname[(int)t->st_hst[nh]]);
 559                         if (++nh == SCMD_ST_HIST_SZ) nh = 0;
 560                 }
 561                 cnt += sprintf(page + cnt, "\n");
 562
 563                 if (++nc == SCMD_TRACE_SZ) nc = 0;
 564         }
 565
 566         spin_unlock_irqrestore(&sc->lock, flags);
 567         return cnt;
 568 }
 569
 570 static DEVICE_ATTR(diag, S_IRUGO, ub_diag_show, NULL); /* N.B. World readable */
 571
 572 /*
 573  * The id allocator.
 574  *
 575  * This also stores the host for indexing by minor, which is somewhat dirty.
 576  */
 577 static int ub_id_get(void)
 578 {
 579         unsigned long flags;
 580         int i;
 581
 582         spin_lock_irqsave(&ub_lock, flags);
 583         for (i = 0; i < UB_MAX_HOSTS; i++) {
 584                 if (ub_hostv[i] == 0) {
 585                         ub_hostv[i] = 1;
 586                         spin_unlock_irqrestore(&ub_lock, flags);
 587                         return i;
 588                 }
 589         }
 590         spin_unlock_irqrestore(&ub_lock, flags);
 591         return -1;
 592 }
 593
 594 static void ub_id_put(int id)
 595 {
 596         unsigned long flags;
 597
 598         if (id < 0 || id >= UB_MAX_HOSTS) {
 599                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 600                 return;
 601         }
 602
 603         spin_lock_irqsave(&ub_lock, flags);
 604         if (ub_hostv[id] == 0) {
 605                 spin_unlock_irqrestore(&ub_lock, flags);
 606                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 607                 return;
 608         }
 609         ub_hostv[id] = 0;
 610         spin_unlock_irqrestore(&ub_lock, flags);
 611 }
 612
 613 /*
 614  * Downcount for deallocation. This rides on two assumptions:
 615  *  - once something is poisoned, its refcount cannot grow
 616  *  - opens cannot happen at this time (del_gendisk was done)
 617  * If the above is true, we can drop the lock, which we need for
 618  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 619  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 620  */
 621 static void ub_put(struct ub_dev *sc)
 622 {
 623         unsigned long flags;
 624
 625         spin_lock_irqsave(&ub_lock, flags);
 626         --sc->openc;
 627         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 628                 spin_unlock_irqrestore(&ub_lock, flags);
 629                 ub_cleanup(sc);
 630         } else {
 631                 spin_unlock_irqrestore(&ub_lock, flags);
 632         }
 633 }
 634
 635 /*
 636  * Final cleanup and deallocation.
 637  */
 638 static void ub_cleanup(struct ub_dev *sc)
 639 {
 640         struct list_head *p;
 641         struct ub_lun *lun;
 642         request_queue_t *q;
 643
 644         while (!list_empty(&sc->luns)) {
 645                 p = sc->luns.next;
 646                 lun = list_entry(p, struct ub_lun, link);
 647                 list_del(p);
 648
 649                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 650                 if ((q = lun->disk->queue) != NULL)
 651                         blk_cleanup_queue(q);
 652                 /*
 653                  * If we zero disk->private_data BEFORE put_disk, we have
 654                  * to check for NULL all over the place in open, release,
 655                  * check_media and revalidate, because the block level
 656                  * semaphore is well inside the put_disk.
 657                  * But we cannot zero after the call, because *disk is gone.
 658                  * The sd.c is blatantly racy in this area.
 659                  */
 660                 /* disk->private_data = NULL; */
 661                 put_disk(lun->disk);
 662                 lun->disk = NULL;
 663
 664                 ub_id_put(lun->id);
 665                 kfree(lun);
 666         }
 667
 668         kfree(sc);
 669 }
 670
 671 /*
 672  * The "command allocator".
 673  */
 674 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 675 {
 676         struct ub_scsi_cmd *ret;
 677
 678         if (lun->cmda[0])
 679                 return NULL;
 680         ret = &lun->cmdv[0];
 681         lun->cmda[0] = 1;
 682         return ret;
 683 }
 684
 685 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 686 {
 687         if (cmd != &lun->cmdv[0]) {
 688                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
 689                     lun->name, cmd);
 690                 return;
 691         }
 692         if (!lun->cmda[0]) {
 693                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
 694                 return;
 695         }
 696         lun->cmda[0] = 0;
 697 }
 698
 699 /*
 700  * The command queue.
 701  */
 702 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 703 {
 704         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 705
 706         if (t->qlen++ == 0) {
 707                 t->head = cmd;
 708                 t->tail = cmd;
 709         } else {
 710                 t->tail->next = cmd;
 711                 t->tail = cmd;
 712         }
 713
 714         if (t->qlen > t->qmax)
 715                 t->qmax = t->qlen;
 716 }
 717
 718 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 719 {
 720         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 721
 722         if (t->qlen++ == 0) {
 723                 t->head = cmd;
 724                 t->tail = cmd;
 725         } else {
 726                 cmd->next = t->head;
 727                 t->head = cmd;
 728         }
 729
 730         if (t->qlen > t->qmax)
 731                 t->qmax = t->qlen;
 732 }
 733
 734 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
 735 {
 736         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 737         struct ub_scsi_cmd *cmd;
 738
 739         if (t->qlen == 0)
 740                 return NULL;
 741         if (--t->qlen == 0)
 742                 t->tail = NULL;
 743         cmd = t->head;
 744         t->head = cmd->next;
 745         cmd->next = NULL;
 746         return cmd;
 747 }
 748
 749 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
 750
 751 /*
 752  * The request function is our main entry point
 753  */
 754
 755 static void ub_request_fn(request_queue_t *q)
 756 {
 757         struct ub_lun *lun = q->queuedata;
 758         struct request *rq;
 759
 760         while ((rq = elv_next_request(q)) != NULL) {
 761                 if (ub_request_fn_1(lun, rq) != 0) {
 762                         blk_stop_queue(q);
 763                         break;
 764                 }
 765         }
 766 }
 767
 768 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 769 {
 770         struct ub_dev *sc = lun->udev;
 771         struct ub_scsi_cmd *cmd;
 772         int rc;
 773
 774         if (atomic_read(&sc->poison) || lun->changed) {
 775                 blkdev_dequeue_request(rq);
 776                 ub_end_rq(rq, 0);
 777                 return 0;
 778         }
 779
 780         if ((cmd = ub_get_cmd(lun)) == NULL)
 781                 return -1;
 782         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 783
 784         blkdev_dequeue_request(rq);
 785         if (blk_pc_request(rq)) {
 786                 rc = ub_cmd_build_packet(sc, lun, cmd, rq);
 787         } else {
 788                 rc = ub_cmd_build_block(sc, lun, cmd, rq);
 789         }
 790         if (rc != 0) {
 791                 ub_put_cmd(lun, cmd);
 792                 ub_end_rq(rq, 0);
 793                 return 0;
 794         }
 795         cmd->state = UB_CMDST_INIT;
 796         cmd->lun = lun;
 797         cmd->done = ub_rw_cmd_done;
 798         cmd->back = rq;
 799
 800         cmd->tag = sc->tagcnt++;
 801         if (ub_submit_scsi(sc, cmd) != 0) {
 802                 ub_put_cmd(lun, cmd);
 803                 ub_end_rq(rq, 0);
 804                 return 0;
 805         }
 806
 807         return 0;
 808 }
 809
 810 static int ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 811     struct ub_scsi_cmd *cmd, struct request *rq)
 812 {
 813         int ub_dir;
 814         int n_elem;
 815         unsigned int block, nblks;
 816
 817         if (rq_data_dir(rq) == WRITE)
 818                 ub_dir = UB_DIR_WRITE;
 819         else
 820                 ub_dir = UB_DIR_READ;
 821         cmd->dir = ub_dir;
 822
 823         /*
 824          * get scatterlist from block layer
 825          */
 826         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &cmd->sgv[0]);
 827         if (n_elem <= 0) {
 828                 printk(KERN_INFO "%s: failed request map (%d)\n",
 829                     sc->name, n_elem); /* P3 */
 830                 return -1;              /* request with no s/g entries? */
 831         }
 832         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 833                 printk(KERN_WARNING "%s: request with %d segments\n",
 834                     sc->name, n_elem);
 835                 return -1;
 836         }
 837         cmd->nsg = n_elem;
 838         sc->sg_stat[n_elem]++;
 839
 840         /*
 841          * build the command
 842          *
 843          * The call to blk_queue_hardsect_size() guarantees that request
 844          * is aligned, but it is given in terms of 512 byte units, always.
 845          */
 846         block = rq->sector >> lun->capacity.bshift;
 847         nblks = rq->nr_sectors >> lun->capacity.bshift;
 848
 849         cmd->cdb[0] = (ub_dir == UB_DIR_READ)? READ_10: WRITE_10;
 850         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 851         cmd->cdb[2] = block >> 24;
 852         cmd->cdb[3] = block >> 16;
 853         cmd->cdb[4] = block >> 8;
 854         cmd->cdb[5] = block;
 855         cmd->cdb[7] = nblks >> 8;
 856         cmd->cdb[8] = nblks;
 857         cmd->cdb_len = 10;
 858
 859         cmd->len = rq->nr_sectors * 512;
 860
 861         return 0;
 862 }
 863
 864 static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 865     struct ub_scsi_cmd *cmd, struct request *rq)
 866 {
 867         int n_elem;
 868
 869         if (rq->data_len == 0) {
 870                 cmd->dir = UB_DIR_NONE;
 871         } else {
 872                 if (rq_data_dir(rq) == WRITE)
 873                         cmd->dir = UB_DIR_WRITE;
 874                 else
 875                         cmd->dir = UB_DIR_READ;
 876
 877         }
 878
 879         /*
 880          * get scatterlist from block layer
 881          */
 882         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &cmd->sgv[0]);
 883         if (n_elem < 0) {
 884                 printk(KERN_INFO "%s: failed request map (%d)\n",
 885                     sc->name, n_elem); /* P3 */
 886                 return -1;
 887         }
 888         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 889                 printk(KERN_WARNING "%s: request with %d segments\n",
 890                     sc->name, n_elem);
 891                 return -1;
 892         }
 893         cmd->nsg = n_elem;
 894         sc->sg_stat[n_elem]++;
 895
 896         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 897         cmd->cdb_len = rq->cmd_len;
 898
 899         cmd->len = rq->data_len;
 900
 901         return 0;
 902 }
 903
 904 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 905 {
 906         struct request *rq = cmd->back;
 907         struct ub_lun *lun = cmd->lun;
 908         int uptodate;
 909
 910         if (cmd->error == 0) {
 911                 uptodate = 1;
 912
 913                 if (blk_pc_request(rq)) {
 914                         if (cmd->act_len >= rq->data_len)
 915                                 rq->data_len = 0;
 916                         else
 917                                 rq->data_len -= cmd->act_len;
 918                 }
 919         } else {
 920                 uptodate = 0;
 921
 922                 if (blk_pc_request(rq)) {
 923                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 924                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 925                         rq->sense_len = UB_SENSE_SIZE;
 926                         if (sc->top_sense[0] != 0)
 927                                 rq->errors = SAM_STAT_CHECK_CONDITION;
 928                         else
 929                                 rq->errors = DID_ERROR << 16;
 930                 }
 931         }
 932
 933         ub_put_cmd(lun, cmd);
 934         ub_end_rq(rq, uptodate);
 935         blk_start_queue(lun->disk->queue);
 936 }
 937
 938 static void ub_end_rq(struct request *rq, int uptodate)
 939 {
 940         int rc;
 941
 942         rc = end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
 943         // assert(rc == 0);
 944         end_that_request_last(rq);
 945 }
 946
 947 /*
 948  * Submit a regular SCSI operation (not an auto-sense).
 949  *
 950  * The Iron Law of Good Submit Routine is:
 951  * Zero return - callback is done, Nonzero return - callback is not done.
 952  * No exceptions.
 953  *
 954  * Host is assumed locked.
 955  *
 956  * XXX We only support Bulk for the moment.
 957  */
 958 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 959 {
 960
 961         if (cmd->state != UB_CMDST_INIT ||
 962             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
 963                 return -EINVAL;
 964         }
 965
 966         ub_cmdq_add(sc, cmd);
 967         /*
 968          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
 969          * safer to jump to a tasklet, in case upper layers do something silly.
 970          */
 971         tasklet_schedule(&sc->tasklet);
 972         return 0;
 973 }
 974
 975 /*
 976  * Submit the first URB for the queued command.
 977  * This function does not deal with queueing in any way.
 978  */
 979 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 980 {
 981         struct bulk_cb_wrap *bcb;
 982         int rc;
 983
 984         bcb = &sc->work_bcb;
 985
 986         /*
 987          * ``If the allocation length is eighteen or greater, and a device
 988          * server returns less than eithteen bytes of data, the application
 989          * client should assume that the bytes not transferred would have been
 990          * zeroes had the device server returned those bytes.''
 991          *
 992          * We zero sense for all commands so that when a packet request
 993          * fails it does not return a stale sense.
 994          */
 995         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
 996
 997         /* set up the command wrapper */
 998         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
 999         bcb->Tag = cmd->tag;            /* Endianness is not important */
1000         bcb->DataTransferLength = cpu_to_le32(cmd->len);
1001         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
1002         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
1003         bcb->Length = cmd->cdb_len;
1004
1005         /* copy the command payload */
1006         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
1007
1008         UB_INIT_COMPLETION(sc->work_done);
1009
1010         sc->last_pipe = sc->send_bulk_pipe;
1011         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
1012             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
1013         sc->work_urb.transfer_flags = 0;
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                 printk("ub: cmd #%d start failed (%d)\n", cmd->tag, rc); /* P3 */
1023                 ub_complete(&sc->work_done);
1024                 return rc;
1025         }
1026
1027         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
1028         add_timer(&sc->work_timer);
1029
1030         cmd->state = UB_CMDST_CMD;
1031         ub_cmdtr_state(sc, cmd);
1032         return 0;
1033 }
1034
1035 /*
1036  * Timeout handler.
1037  */
1038 static void ub_urb_timeout(unsigned long arg)
1039 {
1040         struct ub_dev *sc = (struct ub_dev *) arg;
1041         unsigned long flags;
1042
1043         spin_lock_irqsave(&sc->lock, flags);
1044         usb_unlink_urb(&sc->work_urb);
1045         spin_unlock_irqrestore(&sc->lock, flags);
1046 }
1047
1048 /*
1049  * Completion routine for the work URB.
1050  *
1051  * This can be called directly from usb_submit_urb (while we have
1052  * the sc->lock taken) and from an interrupt (while we do NOT have
1053  * the sc->lock taken). Therefore, bounce this off to a tasklet.
1054  */
1055 static void ub_urb_complete(struct urb *urb, struct pt_regs *pt)
1056 {
1057         struct ub_dev *sc = urb->context;
1058
1059         ub_complete(&sc->work_done);
1060         tasklet_schedule(&sc->tasklet);
1061 }
1062
1063 static void ub_scsi_action(unsigned long _dev)
1064 {
1065         struct ub_dev *sc = (struct ub_dev *) _dev;
1066         unsigned long flags;
1067
1068         spin_lock_irqsave(&sc->lock, flags);
1069         del_timer(&sc->work_timer);
1070         ub_scsi_dispatch(sc);
1071         spin_unlock_irqrestore(&sc->lock, flags);
1072 }
1073
1074 static void ub_scsi_dispatch(struct ub_dev *sc)
1075 {
1076         struct ub_scsi_cmd *cmd;
1077         int rc;
1078
1079         while ((cmd = ub_cmdq_peek(sc)) != NULL) {
1080                 if (cmd->state == UB_CMDST_DONE) {
1081                         ub_cmdq_pop(sc);
1082                         (*cmd->done)(sc, cmd);
1083                 } else if (cmd->state == UB_CMDST_INIT) {
1084                         ub_cmdtr_new(sc, cmd);
1085                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
1086                                 break;
1087                         cmd->error = rc;
1088                         cmd->state = UB_CMDST_DONE;
1089                         ub_cmdtr_state(sc, cmd);
1090                 } else {
1091                         if (!ub_is_completed(&sc->work_done))
1092                                 break;
1093                         ub_scsi_urb_compl(sc, cmd);
1094                 }
1095         }
1096 }
1097
1098 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1099 {
1100         struct urb *urb = &sc->work_urb;
1101         struct bulk_cs_wrap *bcs;
1102         int rc;
1103
1104         if (atomic_read(&sc->poison)) {
1105                 /* A little too simplistic, I feel... */
1106                 goto Bad_End;
1107         }
1108
1109         if (cmd->state == UB_CMDST_CLEAR) {
1110                 if (urb->status == -EPIPE) {
1111                         /*
1112                          * STALL while clearning STALL.
1113                          * The control pipe clears itself - nothing to do.
1114                          * XXX Might try to reset the device here and retry.
1115                          */
1116                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1117                             sc->name);
1118                         goto Bad_End;
1119                 }
1120
1121                 /*
1122                  * We ignore the result for the halt clear.
1123                  */
1124
1125                 /* reset the endpoint toggle */
1126                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1127                         usb_pipeout(sc->last_pipe), 0);
1128
1129                 ub_state_sense(sc, cmd);
1130
1131         } else if (cmd->state == UB_CMDST_CLR2STS) {
1132                 if (urb->status == -EPIPE) {
1133                         /*
1134                          * STALL while clearning STALL.
1135                          * The control pipe clears itself - nothing to do.
1136                          * XXX Might try to reset the device here and retry.
1137                          */
1138                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1139                             sc->name);
1140                         goto Bad_End;
1141                 }
1142
1143                 /*
1144                  * We ignore the result for the halt clear.
1145                  */
1146
1147                 /* reset the endpoint toggle */
1148                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1149                         usb_pipeout(sc->last_pipe), 0);
1150
1151                 ub_state_stat(sc, cmd);
1152
1153         } else if (cmd->state == UB_CMDST_CLRRS) {
1154                 if (urb->status == -EPIPE) {
1155                         /*
1156                          * STALL while clearning STALL.
1157                          * The control pipe clears itself - nothing to do.
1158                          * XXX Might try to reset the device here and retry.
1159                          */
1160                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1161                             sc->name);
1162                         goto Bad_End;
1163                 }
1164
1165                 /*
1166                  * We ignore the result for the halt clear.
1167                  */
1168
1169                 /* reset the endpoint toggle */
1170                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1171                         usb_pipeout(sc->last_pipe), 0);
1172
1173                 ub_state_stat_counted(sc, cmd);
1174
1175         } else if (cmd->state == UB_CMDST_CMD) {
1176                 if (urb->status == -EPIPE) {
1177                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1178                         if (rc != 0) {
1179                                 printk(KERN_NOTICE "%s: "
1180                                     "unable to submit clear (%d)\n",
1181                                     sc->name, rc);
1182                                 /*
1183                                  * This is typically ENOMEM or some other such shit.
1184                                  * Retrying is pointless. Just do Bad End on it...
1185                                  */
1186                                 goto Bad_End;
1187                         }
1188                         cmd->state = UB_CMDST_CLEAR;
1189                         ub_cmdtr_state(sc, cmd);
1190                         return;
1191                 }
1192                 if (urb->status != 0) {
1193                         printk("ub: cmd #%d cmd status (%d)\n", cmd->tag, urb->status); /* P3 */
1194                         goto Bad_End;
1195                 }
1196                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1197                         printk("ub: cmd #%d xferred %d\n", cmd->tag, urb->actual_length); /* P3 */
1198                         /* XXX Must do reset here to unconfuse the device */
1199                         goto Bad_End;
1200                 }
1201
1202                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1203                         ub_state_stat(sc, cmd);
1204                         return;
1205                 }
1206
1207                 // udelay(125);         // usb-storage has this
1208                 ub_data_start(sc, cmd);
1209
1210         } else if (cmd->state == UB_CMDST_DATA) {
1211                 if (urb->status == -EPIPE) {
1212                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1213                         if (rc != 0) {
1214                                 printk(KERN_NOTICE "%s: "
1215                                     "unable to submit clear (%d)\n",
1216                                     sc->name, rc);
1217                                 /*
1218                                  * This is typically ENOMEM or some other such shit.
1219                                  * Retrying is pointless. Just do Bad End on it...
1220                                  */
1221                                 goto Bad_End;
1222                         }
1223                         cmd->state = UB_CMDST_CLR2STS;
1224                         ub_cmdtr_state(sc, cmd);
1225                         return;
1226                 }
1227                 if (urb->status == -EOVERFLOW) {
1228                         /*
1229                          * A babble? Failure, but we must transfer CSW now.
1230                          * XXX This is going to end in perpetual babble. Reset.
1231                          */
1232                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1233                         ub_state_stat(sc, cmd);
1234                         return;
1235                 }
1236                 if (urb->status != 0)
1237                         goto Bad_End;
1238
1239                 cmd->act_len += urb->actual_length;
1240                 ub_cmdtr_act_len(sc, cmd);
1241
1242                 if (++cmd->current_sg < cmd->nsg) {
1243                         ub_data_start(sc, cmd);
1244                         return;
1245                 }
1246                 ub_state_stat(sc, cmd);
1247
1248         } else if (cmd->state == UB_CMDST_STAT) {
1249                 if (urb->status == -EPIPE) {
1250                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1251                         if (rc != 0) {
1252                                 printk(KERN_NOTICE "%s: "
1253                                     "unable to submit clear (%d)\n",
1254                                     sc->name, rc);
1255                                 /*
1256                                  * This is typically ENOMEM or some other such shit.
1257                                  * Retrying is pointless. Just do Bad End on it...
1258                                  */
1259                                 goto Bad_End;
1260                         }
1261
1262                         /*
1263                          * Having a stall when getting CSW is an error, so
1264                          * make sure uppper levels are not oblivious to it.
1265                          */
1266                         cmd->error = -EIO;              /* A cheap trick... */
1267
1268                         cmd->state = UB_CMDST_CLRRS;
1269                         ub_cmdtr_state(sc, cmd);
1270                         return;
1271                 }
1272                 if (urb->status == -EOVERFLOW) {
1273                         /*
1274                          * XXX We are screwed here. Retrying is pointless,
1275                          * because the pipelined data will not get in until
1276                          * we read with a big enough buffer. We must reset XXX.
1277                          */
1278                         goto Bad_End;
1279                 }
1280                 if (urb->status != 0)
1281                         goto Bad_End;
1282
1283                 if (urb->actual_length == 0) {
1284                         ub_state_stat_counted(sc, cmd);
1285                         return;
1286                 }
1287
1288                 /*
1289                  * Check the returned Bulk protocol status.
1290                  * The status block has to be validated first.
1291                  */
1292
1293                 bcs = &sc->work_bcs;
1294
1295                 if (sc->signature == cpu_to_le32(0)) {
1296                         /*
1297                          * This is the first reply, so do not perform the check.
1298                          * Instead, remember the signature the device uses
1299                          * for future checks. But do not allow a nul.
1300                          */
1301                         sc->signature = bcs->Signature;
1302                         if (sc->signature == cpu_to_le32(0)) {
1303                                 ub_state_stat_counted(sc, cmd);
1304                                 return;
1305                         }
1306                 } else {
1307                         if (bcs->Signature != sc->signature) {
1308                                 ub_state_stat_counted(sc, cmd);
1309                                 return;
1310                         }
1311                 }
1312
1313                 if (bcs->Tag != cmd->tag) {
1314                         /*
1315                          * This usually happens when we disagree with the
1316                          * device's microcode about something. For instance,
1317                          * a few of them throw this after timeouts. They buffer
1318                          * commands and reply at commands we timed out before.
1319                          * Without flushing these replies we loop forever.
1320                          */
1321                         ub_state_stat_counted(sc, cmd);
1322                         return;
1323                 }
1324
1325                 rc = le32_to_cpu(bcs->Residue);
1326                 if (rc != cmd->len - cmd->act_len) {
1327                         /*
1328                          * It is all right to transfer less, the caller has
1329                          * to check. But it's not all right if the device
1330                          * counts disagree with our counts.
1331                          */
1332                         /* P3 */ printk("%s: resid %d len %d act %d\n",
1333                             sc->name, rc, cmd->len, cmd->act_len);
1334                         goto Bad_End;
1335                 }
1336
1337                 switch (bcs->Status) {
1338                 case US_BULK_STAT_OK:
1339                         break;
1340                 case US_BULK_STAT_FAIL:
1341                         ub_state_sense(sc, cmd);
1342                         return;
1343                 case US_BULK_STAT_PHASE:
1344                         /* XXX We must reset the transport here */
1345                         /* P3 */ printk("%s: status PHASE\n", sc->name);
1346                         goto Bad_End;
1347                 default:
1348                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1349                             sc->name, bcs->Status);
1350                         goto Bad_End;
1351                 }
1352
1353                 /* Not zeroing error to preserve a babble indicator */
1354                 if (cmd->error != 0) {
1355                         ub_state_sense(sc, cmd);
1356                         return;
1357                 }
1358                 cmd->state = UB_CMDST_DONE;
1359                 ub_cmdtr_state(sc, cmd);
1360                 ub_cmdq_pop(sc);
1361                 (*cmd->done)(sc, cmd);
1362
1363         } else if (cmd->state == UB_CMDST_SENSE) {
1364                 ub_state_done(sc, cmd, -EIO);
1365
1366         } else {
1367                 printk(KERN_WARNING "%s: "
1368                     "wrong command state %d\n",
1369                     sc->name, cmd->state);
1370                 goto Bad_End;
1371         }
1372         return;
1373
1374 Bad_End: /* Little Excel is dead */
1375         ub_state_done(sc, cmd, -EIO);
1376 }
1377
1378 /*
1379  * Factorization helper for the command state machine:
1380  * Initiate a data segment transfer.
1381  */
1382 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1383 {
1384         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1385         int pipe;
1386         int rc;
1387
1388         UB_INIT_COMPLETION(sc->work_done);
1389
1390         if (cmd->dir == UB_DIR_READ)
1391                 pipe = sc->recv_bulk_pipe;
1392         else
1393                 pipe = sc->send_bulk_pipe;
1394         sc->last_pipe = pipe;
1395         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe,
1396             page_address(sg->page) + sg->offset, sg->length,
1397             ub_urb_complete, sc);
1398         sc->work_urb.transfer_flags = 0;
1399         sc->work_urb.actual_length = 0;
1400         sc->work_urb.error_count = 0;
1401         sc->work_urb.status = 0;
1402
1403         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1404                 /* XXX Clear stalls */
1405                 printk("ub: data #%d submit failed (%d)\n", cmd->tag, rc); /* P3 */
1406                 ub_complete(&sc->work_done);
1407                 ub_state_done(sc, cmd, rc);
1408                 return;
1409         }
1410
1411         sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1412         add_timer(&sc->work_timer);
1413
1414         cmd->state = UB_CMDST_DATA;
1415         ub_cmdtr_state(sc, cmd);
1416 }
1417
1418 /*
1419  * Factorization helper for the command state machine:
1420  * Finish the command.
1421  */
1422 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1423 {
1424
1425         cmd->error = rc;
1426         cmd->state = UB_CMDST_DONE;
1427         ub_cmdtr_state(sc, cmd);
1428         ub_cmdq_pop(sc);
1429         (*cmd->done)(sc, cmd);
1430 }
1431
1432 /*
1433  * Factorization helper for the command state machine:
1434  * Submit a CSW read.
1435  */
1436 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1437 {
1438         int rc;
1439
1440         UB_INIT_COMPLETION(sc->work_done);
1441
1442         sc->last_pipe = sc->recv_bulk_pipe;
1443         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1444             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1445         sc->work_urb.transfer_flags = 0;
1446         sc->work_urb.actual_length = 0;
1447         sc->work_urb.error_count = 0;
1448         sc->work_urb.status = 0;
1449
1450         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1451                 /* XXX Clear stalls */
1452                 ub_complete(&sc->work_done);
1453                 ub_state_done(sc, cmd, rc);
1454                 return -1;
1455         }
1456
1457         sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1458         add_timer(&sc->work_timer);
1459         return 0;
1460 }
1461
1462 /*
1463  * Factorization helper for the command state machine:
1464  * Submit a CSW read and go to STAT state.
1465  */
1466 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1467 {
1468
1469         if (__ub_state_stat(sc, cmd) != 0)
1470                 return;
1471
1472         cmd->stat_count = 0;
1473         cmd->state = UB_CMDST_STAT;
1474         ub_cmdtr_state(sc, cmd);
1475 }
1476
1477 /*
1478  * Factorization helper for the command state machine:
1479  * Submit a CSW read and go to STAT state with counter (along [C] path).
1480  */
1481 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1482 {
1483
1484         if (++cmd->stat_count >= 4) {
1485                 ub_state_sense(sc, cmd);
1486                 return;
1487         }
1488
1489         if (__ub_state_stat(sc, cmd) != 0)
1490                 return;
1491
1492         cmd->state = UB_CMDST_STAT;
1493         ub_cmdtr_state(sc, cmd);
1494 }
1495
1496 /*
1497  * Factorization helper for the command state machine:
1498  * Submit a REQUEST SENSE and go to SENSE state.
1499  */
1500 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1501 {
1502         struct ub_scsi_cmd *scmd;
1503         struct scatterlist *sg;
1504         int rc;
1505
1506         if (cmd->cdb[0] == REQUEST_SENSE) {
1507                 rc = -EPIPE;
1508                 goto error;
1509         }
1510
1511         scmd = &sc->top_rqs_cmd;
1512         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1513         scmd->cdb[0] = REQUEST_SENSE;
1514         scmd->cdb[4] = UB_SENSE_SIZE;
1515         scmd->cdb_len = 6;
1516         scmd->dir = UB_DIR_READ;
1517         scmd->state = UB_CMDST_INIT;
1518         scmd->nsg = 1;
1519         sg = &scmd->sgv[0];
1520         sg->page = virt_to_page(sc->top_sense);
1521         sg->offset = (unsigned int)sc->top_sense & (PAGE_SIZE-1);
1522         sg->length = UB_SENSE_SIZE;
1523         scmd->len = UB_SENSE_SIZE;
1524         scmd->lun = cmd->lun;
1525         scmd->done = ub_top_sense_done;
1526         scmd->back = cmd;
1527
1528         scmd->tag = sc->tagcnt++;
1529
1530         cmd->state = UB_CMDST_SENSE;
1531         ub_cmdtr_state(sc, cmd);
1532
1533         ub_cmdq_insert(sc, scmd);
1534         return;
1535
1536 error:
1537         ub_state_done(sc, cmd, rc);
1538 }
1539
1540 /*
1541  * A helper for the command's state machine:
1542  * Submit a stall clear.
1543  */
1544 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1545     int stalled_pipe)
1546 {
1547         int endp;
1548         struct usb_ctrlrequest *cr;
1549         int rc;
1550
1551         endp = usb_pipeendpoint(stalled_pipe);
1552         if (usb_pipein (stalled_pipe))
1553                 endp |= USB_DIR_IN;
1554
1555         cr = &sc->work_cr;
1556         cr->bRequestType = USB_RECIP_ENDPOINT;
1557         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1558         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1559         cr->wIndex = cpu_to_le16(endp);
1560         cr->wLength = cpu_to_le16(0);
1561
1562         UB_INIT_COMPLETION(sc->work_done);
1563
1564         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1565             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1566         sc->work_urb.transfer_flags = 0;
1567         sc->work_urb.actual_length = 0;
1568         sc->work_urb.error_count = 0;
1569         sc->work_urb.status = 0;
1570
1571         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1572                 ub_complete(&sc->work_done);
1573                 return rc;
1574         }
1575
1576         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1577         add_timer(&sc->work_timer);
1578         return 0;
1579 }
1580
1581 /*
1582  */
1583 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1584 {
1585         unsigned char *sense = sc->top_sense;
1586         struct ub_scsi_cmd *cmd;
1587
1588         /*
1589          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1590          */
1591         ub_cmdtr_sense(sc, scmd, sense);
1592
1593         /*
1594          * Find the command which triggered the unit attention or a check,
1595          * save the sense into it, and advance its state machine.
1596          */
1597         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1598                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1599                 return;
1600         }
1601         if (cmd != scmd->back) {
1602                 printk(KERN_WARNING "%s: "
1603                     "sense done for wrong command 0x%x\n",
1604                     sc->name, cmd->tag);
1605                 return;
1606         }
1607         if (cmd->state != UB_CMDST_SENSE) {
1608                 printk(KERN_WARNING "%s: "
1609                     "sense done with bad cmd state %d\n",
1610                     sc->name, cmd->state);
1611                 return;
1612         }
1613
1614         cmd->key = sense[2] & 0x0F;
1615         cmd->asc = sense[12];
1616         cmd->ascq = sense[13];
1617
1618         ub_scsi_urb_compl(sc, cmd);
1619 }
1620
1621 /*
1622  * This is called from a process context.
1623  */
1624 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1625 {
1626
1627         lun->readonly = 0;      /* XXX Query this from the device */
1628
1629         lun->capacity.nsec = 0;
1630         lun->capacity.bsize = 512;
1631         lun->capacity.bshift = 0;
1632
1633         if (ub_sync_tur(sc, lun) != 0)
1634                 return;                 /* Not ready */
1635         lun->changed = 0;
1636
1637         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1638                 /*
1639                  * The retry here means something is wrong, either with the
1640                  * device, with the transport, or with our code.
1641                  * We keep this because sd.c has retries for capacity.
1642                  */
1643                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1644                         lun->capacity.nsec = 0;
1645                         lun->capacity.bsize = 512;
1646                         lun->capacity.bshift = 0;
1647                 }
1648         }
1649 }
1650
1651 /*
1652  * The open funcion.
1653  * This is mostly needed to keep refcounting, but also to support
1654  * media checks on removable media drives.
1655  */
1656 static int ub_bd_open(struct inode *inode, struct file *filp)
1657 {
1658         struct gendisk *disk = inode->i_bdev->bd_disk;
1659         struct ub_lun *lun;
1660         struct ub_dev *sc;
1661         unsigned long flags;
1662         int rc;
1663
1664         if ((lun = disk->private_data) == NULL)
1665                 return -ENXIO;
1666         sc = lun->udev;
1667
1668         spin_lock_irqsave(&ub_lock, flags);
1669         if (atomic_read(&sc->poison)) {
1670                 spin_unlock_irqrestore(&ub_lock, flags);
1671                 return -ENXIO;
1672         }
1673         sc->openc++;
1674         spin_unlock_irqrestore(&ub_lock, flags);
1675
1676         /*
1677          * This is a workaround for a specific problem in our block layer.
1678          * In 2.6.9, register_disk duplicates the code from rescan_partitions.
1679          * However, if we do add_disk with a device which persistently reports
1680          * a changed media, add_disk calls register_disk, which does do_open,
1681          * which will call rescan_paritions for changed media. After that,
1682          * register_disk attempts to do it all again and causes double kobject
1683          * registration and a eventually an oops on module removal.
1684          *
1685          * The bottom line is, Al Viro says that we should not allow
1686          * bdev->bd_invalidated to be set when doing add_disk no matter what.
1687          */
1688         if (lun->first_open) {
1689                 lun->first_open = 0;
1690                 if (lun->changed) {
1691                         rc = -ENOMEDIUM;
1692                         goto err_open;
1693                 }
1694         }
1695
1696         if (lun->removable || lun->readonly)
1697                 check_disk_change(inode->i_bdev);
1698
1699         /*
1700          * The sd.c considers ->media_present and ->changed not equivalent,
1701          * under some pretty murky conditions (a failure of READ CAPACITY).
1702          * We may need it one day.
1703          */
1704         if (lun->removable && lun->changed && !(filp->f_flags & O_NDELAY)) {
1705                 rc = -ENOMEDIUM;
1706                 goto err_open;
1707         }
1708
1709         if (lun->readonly && (filp->f_mode & FMODE_WRITE)) {
1710                 rc = -EROFS;
1711                 goto err_open;
1712         }
1713
1714         return 0;
1715
1716 err_open:
1717         ub_put(sc);
1718         return rc;
1719 }
1720
1721 /*
1722  */
1723 static int ub_bd_release(struct inode *inode, struct file *filp)
1724 {
1725         struct gendisk *disk = inode->i_bdev->bd_disk;
1726         struct ub_lun *lun = disk->private_data;
1727         struct ub_dev *sc = lun->udev;
1728
1729         ub_put(sc);
1730         return 0;
1731 }
1732
1733 /*
1734  * The ioctl interface.
1735  */
1736 static int ub_bd_ioctl(struct inode *inode, struct file *filp,
1737     unsigned int cmd, unsigned long arg)
1738 {
1739         struct gendisk *disk = inode->i_bdev->bd_disk;
1740         void __user *usermem = (void __user *) arg;
1741
1742         return scsi_cmd_ioctl(filp, disk, cmd, usermem);
1743 }
1744
1745 /*
1746  * This is called once a new disk was seen by the block layer or by ub_probe().
1747  * The main onjective here is to discover the features of the media such as
1748  * the capacity, read-only status, etc. USB storage generally does not
1749  * need to be spun up, but if we needed it, this would be the place.
1750  *
1751  * This call can sleep.
1752  *
1753  * The return code is not used.
1754  */
1755 static int ub_bd_revalidate(struct gendisk *disk)
1756 {
1757         struct ub_lun *lun = disk->private_data;
1758
1759         ub_revalidate(lun->udev, lun);
1760
1761         /* XXX Support sector size switching like in sr.c */
1762         blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
1763         set_capacity(disk, lun->capacity.nsec);
1764         // set_disk_ro(sdkp->disk, lun->readonly);
1765
1766         return 0;
1767 }
1768
1769 /*
1770  * The check is called by the block layer to verify if the media
1771  * is still available. It is supposed to be harmless, lightweight and
1772  * non-intrusive in case the media was not changed.
1773  *
1774  * This call can sleep.
1775  *
1776  * The return code is bool!
1777  */
1778 static int ub_bd_media_changed(struct gendisk *disk)
1779 {
1780         struct ub_lun *lun = disk->private_data;
1781
1782         if (!lun->removable)
1783                 return 0;
1784
1785         /*
1786          * We clean checks always after every command, so this is not
1787          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1788          * the device is actually not ready with operator or software
1789          * intervention required. One dangerous item might be a drive which
1790          * spins itself down, and come the time to write dirty pages, this
1791          * will fail, then block layer discards the data. Since we never
1792          * spin drives up, such devices simply cannot be used with ub anyway.
1793          */
1794         if (ub_sync_tur(lun->udev, lun) != 0) {
1795                 lun->changed = 1;
1796                 return 1;
1797         }
1798
1799         return lun->changed;
1800 }
1801
1802 static struct block_device_operations ub_bd_fops = {
1803         .owner          = THIS_MODULE,
1804         .open           = ub_bd_open,
1805         .release        = ub_bd_release,
1806         .ioctl          = ub_bd_ioctl,
1807         .media_changed  = ub_bd_media_changed,
1808         .revalidate_disk = ub_bd_revalidate,
1809 };
1810
1811 /*
1812  * Common ->done routine for commands executed synchronously.
1813  */
1814 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1815 {
1816         struct completion *cop = cmd->back;
1817         complete(cop);
1818 }
1819
1820 /*
1821  * Test if the device has a check condition on it, synchronously.
1822  */
1823 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1824 {
1825         struct ub_scsi_cmd *cmd;
1826         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1827         unsigned long flags;
1828         struct completion compl;
1829         int rc;
1830
1831         init_completion(&compl);
1832
1833         rc = -ENOMEM;
1834         if ((cmd = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1835                 goto err_alloc;
1836         memset(cmd, 0, ALLOC_SIZE);
1837
1838         cmd->cdb[0] = TEST_UNIT_READY;
1839         cmd->cdb_len = 6;
1840         cmd->dir = UB_DIR_NONE;
1841         cmd->state = UB_CMDST_INIT;
1842         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1843         cmd->done = ub_probe_done;
1844         cmd->back = &compl;
1845
1846         spin_lock_irqsave(&sc->lock, flags);
1847         cmd->tag = sc->tagcnt++;
1848
1849         rc = ub_submit_scsi(sc, cmd);
1850         spin_unlock_irqrestore(&sc->lock, flags);
1851
1852         if (rc != 0) {
1853                 printk("ub: testing ready: submit error (%d)\n", rc); /* P3 */
1854                 goto err_submit;
1855         }
1856
1857         wait_for_completion(&compl);
1858
1859         rc = cmd->error;
1860
1861         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1862                 rc = cmd->key;
1863
1864 err_submit:
1865         kfree(cmd);
1866 err_alloc:
1867         return rc;
1868 }
1869
1870 /*
1871  * Read the SCSI capacity synchronously (for probing).
1872  */
1873 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1874     struct ub_capacity *ret)
1875 {
1876         struct ub_scsi_cmd *cmd;
1877         struct scatterlist *sg;
1878         char *p;
1879         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1880         unsigned long flags;
1881         unsigned int bsize, shift;
1882         unsigned long nsec;
1883         struct completion compl;
1884         int rc;
1885
1886         init_completion(&compl);
1887
1888         rc = -ENOMEM;
1889         if ((cmd = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1890                 goto err_alloc;
1891         memset(cmd, 0, ALLOC_SIZE);
1892         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1893
1894         cmd->cdb[0] = 0x25;
1895         cmd->cdb_len = 10;
1896         cmd->dir = UB_DIR_READ;
1897         cmd->state = UB_CMDST_INIT;
1898         cmd->nsg = 1;
1899         sg = &cmd->sgv[0];
1900         sg->page = virt_to_page(p);
1901         sg->offset = (unsigned int)p & (PAGE_SIZE-1);
1902         sg->length = 8;
1903         cmd->len = 8;
1904         cmd->lun = lun;
1905         cmd->done = ub_probe_done;
1906         cmd->back = &compl;
1907
1908         spin_lock_irqsave(&sc->lock, flags);
1909         cmd->tag = sc->tagcnt++;
1910
1911         rc = ub_submit_scsi(sc, cmd);
1912         spin_unlock_irqrestore(&sc->lock, flags);
1913
1914         if (rc != 0) {
1915                 printk("ub: reading capacity: submit error (%d)\n", rc); /* P3 */
1916                 goto err_submit;
1917         }
1918
1919         wait_for_completion(&compl);
1920
1921         if (cmd->error != 0) {
1922                 printk("ub: reading capacity: error %d\n", cmd->error); /* P3 */
1923                 rc = -EIO;
1924                 goto err_read;
1925         }
1926         if (cmd->act_len != 8) {
1927                 printk("ub: reading capacity: size %d\n", cmd->act_len); /* P3 */
1928                 rc = -EIO;
1929                 goto err_read;
1930         }
1931
1932         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1933         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1934         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1935         switch (bsize) {
1936         case 512:       shift = 0;      break;
1937         case 1024:      shift = 1;      break;
1938         case 2048:      shift = 2;      break;
1939         case 4096:      shift = 3;      break;
1940         default:
1941                 printk("ub: Bad sector size %u\n", bsize); /* P3 */
1942                 rc = -EDOM;
1943                 goto err_inv_bsize;
1944         }
1945
1946         ret->bsize = bsize;
1947         ret->bshift = shift;
1948         ret->nsec = nsec << shift;
1949         rc = 0;
1950
1951 err_inv_bsize:
1952 err_read:
1953 err_submit:
1954         kfree(cmd);
1955 err_alloc:
1956         return rc;
1957 }
1958
1959 /*
1960  */
1961 static void ub_probe_urb_complete(struct urb *urb, struct pt_regs *pt)
1962 {
1963         struct completion *cop = urb->context;
1964         complete(cop);
1965 }
1966
1967 static void ub_probe_timeout(unsigned long arg)
1968 {
1969         struct completion *cop = (struct completion *) arg;
1970         complete(cop);
1971 }
1972
1973 /*
1974  * Get number of LUNs by the way of Bulk GetMaxLUN command.
1975  */
1976 static int ub_sync_getmaxlun(struct ub_dev *sc)
1977 {
1978         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1979         unsigned char *p;
1980         enum { ALLOC_SIZE = 1 };
1981         struct usb_ctrlrequest *cr;
1982         struct completion compl;
1983         struct timer_list timer;
1984         int nluns;
1985         int rc;
1986
1987         init_completion(&compl);
1988
1989         rc = -ENOMEM;
1990         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1991                 goto err_alloc;
1992         *p = 55;
1993
1994         cr = &sc->work_cr;
1995         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1996         cr->bRequest = US_BULK_GET_MAX_LUN;
1997         cr->wValue = cpu_to_le16(0);
1998         cr->wIndex = cpu_to_le16(ifnum);
1999         cr->wLength = cpu_to_le16(1);
2000
2001         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2002             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2003         sc->work_urb.transfer_flags = 0;
2004         sc->work_urb.actual_length = 0;
2005         sc->work_urb.error_count = 0;
2006         sc->work_urb.status = 0;
2007
2008         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2009                 if (rc == -EPIPE) {
2010                         printk("%s: Stall at GetMaxLUN, using 1 LUN\n",
2011                              sc->name); /* P3 */
2012                 } else {
2013                         printk(KERN_WARNING
2014                              "%s: Unable to submit GetMaxLUN (%d)\n",
2015                              sc->name, rc);
2016                 }
2017                 goto err_submit;
2018         }
2019
2020         init_timer(&timer);
2021         timer.function = ub_probe_timeout;
2022         timer.data = (unsigned long) &compl;
2023         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2024         add_timer(&timer);
2025
2026         wait_for_completion(&compl);
2027
2028         del_timer_sync(&timer);
2029         usb_kill_urb(&sc->work_urb);
2030
2031         if (sc->work_urb.actual_length != 1) {
2032                 printk("%s: GetMaxLUN returned %d bytes\n", sc->name,
2033                     sc->work_urb.actual_length); /* P3 */
2034                 nluns = 0;
2035         } else {
2036                 if ((nluns = *p) == 55) {
2037                         nluns = 0;
2038                 } else {
2039                         /* GetMaxLUN returns the maximum LUN number */
2040                         nluns += 1;
2041                         if (nluns > UB_MAX_LUNS)
2042                                 nluns = UB_MAX_LUNS;
2043                 }
2044                 printk("%s: GetMaxLUN returned %d, using %d LUNs\n", sc->name,
2045                     *p, nluns); /* P3 */
2046         }
2047
2048         kfree(p);
2049         return nluns;
2050
2051 err_submit:
2052         kfree(p);
2053 err_alloc:
2054         return rc;
2055 }
2056
2057 /*
2058  * Clear initial stalls.
2059  */
2060 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2061 {
2062         int endp;
2063         struct usb_ctrlrequest *cr;
2064         struct completion compl;
2065         struct timer_list timer;
2066         int rc;
2067
2068         init_completion(&compl);
2069
2070         endp = usb_pipeendpoint(stalled_pipe);
2071         if (usb_pipein (stalled_pipe))
2072                 endp |= USB_DIR_IN;
2073
2074         cr = &sc->work_cr;
2075         cr->bRequestType = USB_RECIP_ENDPOINT;
2076         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2077         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2078         cr->wIndex = cpu_to_le16(endp);
2079         cr->wLength = cpu_to_le16(0);
2080
2081         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2082             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2083         sc->work_urb.transfer_flags = 0;
2084         sc->work_urb.actual_length = 0;
2085         sc->work_urb.error_count = 0;
2086         sc->work_urb.status = 0;
2087
2088         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2089                 printk(KERN_WARNING
2090                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2091                 return rc;
2092         }
2093
2094         init_timer(&timer);
2095         timer.function = ub_probe_timeout;
2096         timer.data = (unsigned long) &compl;
2097         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2098         add_timer(&timer);
2099
2100         wait_for_completion(&compl);
2101
2102         del_timer_sync(&timer);
2103         usb_kill_urb(&sc->work_urb);
2104
2105         /* reset the endpoint toggle */
2106         usb_settoggle(sc->dev, endp, usb_pipeout(sc->last_pipe), 0);
2107
2108         return 0;
2109 }
2110
2111 /*
2112  * Get the pipe settings.
2113  */
2114 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2115     struct usb_interface *intf)
2116 {
2117         struct usb_host_interface *altsetting = intf->cur_altsetting;
2118         struct usb_endpoint_descriptor *ep_in = NULL;
2119         struct usb_endpoint_descriptor *ep_out = NULL;
2120         struct usb_endpoint_descriptor *ep;
2121         int i;
2122
2123         /*
2124          * Find the endpoints we need.
2125          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2126          * We will ignore any others.
2127          */
2128         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2129                 ep = &altsetting->endpoint[i].desc;
2130
2131                 /* Is it a BULK endpoint? */
2132                 if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
2133                                 == USB_ENDPOINT_XFER_BULK) {
2134                         /* BULK in or out? */
2135                         if (ep->bEndpointAddress & USB_DIR_IN)
2136                                 ep_in = ep;
2137                         else
2138                                 ep_out = ep;
2139                 }
2140         }
2141
2142         if (ep_in == NULL || ep_out == NULL) {
2143                 printk(KERN_NOTICE "%s: failed endpoint check\n",
2144                     sc->name);
2145                 return -EIO;
2146         }
2147
2148         /* Calculate and store the pipe values */
2149         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2150         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2151         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2152                 ep_out->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2153         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2154                 ep_in->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2155
2156         return 0;
2157 }
2158
2159 /*
2160  * Probing is done in the process context, which allows us to cheat
2161  * and not to build a state machine for the discovery.
2162  */
2163 static int ub_probe(struct usb_interface *intf,
2164     const struct usb_device_id *dev_id)
2165 {
2166         struct ub_dev *sc;
2167         int nluns;
2168         int rc;
2169         int i;
2170
2171         rc = -ENOMEM;
2172         if ((sc = kmalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2173                 goto err_core;
2174         memset(sc, 0, sizeof(struct ub_dev));
2175         spin_lock_init(&sc->lock);
2176         INIT_LIST_HEAD(&sc->luns);
2177         usb_init_urb(&sc->work_urb);
2178         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2179         atomic_set(&sc->poison, 0);
2180
2181         init_timer(&sc->work_timer);
2182         sc->work_timer.data = (unsigned long) sc;
2183         sc->work_timer.function = ub_urb_timeout;
2184
2185         ub_init_completion(&sc->work_done);
2186         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2187
2188         sc->dev = interface_to_usbdev(intf);
2189         sc->intf = intf;
2190         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2191         usb_set_intfdata(intf, sc);
2192         usb_get_dev(sc->dev);
2193         // usb_get_intf(sc->intf);      /* Do we need this? */
2194
2195         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2196             sc->dev->bus->busnum, sc->dev->devnum);
2197
2198         /* XXX Verify that we can handle the device (from descriptors) */
2199
2200         ub_get_pipes(sc, sc->dev, intf);
2201
2202         if (device_create_file(&sc->intf->dev, &dev_attr_diag) != 0)
2203                 goto err_diag;
2204
2205         /*
2206          * At this point, all USB initialization is done, do upper layer.
2207          * We really hate halfway initialized structures, so from the
2208          * invariants perspective, this ub_dev is fully constructed at
2209          * this point.
2210          */
2211
2212         /*
2213          * This is needed to clear toggles. It is a problem only if we do
2214          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2215          */
2216         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2217         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2218
2219         /*
2220          * The way this is used by the startup code is a little specific.
2221          * A SCSI check causes a USB stall. Our common case code sees it
2222          * and clears the check, after which the device is ready for use.
2223          * But if a check was not present, any command other than
2224          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2225          *
2226          * If we neglect to clear the SCSI check, the first real command fails
2227          * (which is the capacity readout). We clear that and retry, but why
2228          * causing spurious retries for no reason.
2229          *
2230          * Revalidation may start with its own TEST_UNIT_READY, but that one
2231          * has to succeed, so we clear checks with an additional one here.
2232          * In any case it's not our business how revaliadation is implemented.
2233          */
2234         for (i = 0; i < 3; i++) {       /* Retries for benh's key */
2235                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2236                 if (rc != 0x6) break;
2237                 msleep(10);
2238         }
2239
2240         nluns = 1;
2241         for (i = 0; i < 3; i++) {
2242                 if ((rc = ub_sync_getmaxlun(sc)) < 0) {
2243                         /*
2244                          * Some devices (i.e. Iomega Zip100) need this --
2245                          * apparently the bulk pipes get STALLed when the
2246                          * GetMaxLUN request is processed.
2247                          * XXX I have a ZIP-100, verify it does this.
2248                          */
2249                         if (rc == -EPIPE) {
2250                                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2251                                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2252                         }
2253                         break;
2254                 }
2255                 if (rc != 0) {
2256                         nluns = rc;
2257                         break;
2258                 }
2259                 msleep(100);
2260         }
2261
2262         for (i = 0; i < nluns; i++) {
2263                 ub_probe_lun(sc, i);
2264         }
2265         return 0;
2266
2267         /* device_remove_file(&sc->intf->dev, &dev_attr_diag); */
2268 err_diag:
2269         usb_set_intfdata(intf, NULL);
2270         // usb_put_intf(sc->intf);
2271         usb_put_dev(sc->dev);
2272         kfree(sc);
2273 err_core:
2274         return rc;
2275 }
2276
2277 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2278 {
2279         struct ub_lun *lun;
2280         request_queue_t *q;
2281         struct gendisk *disk;
2282         int rc;
2283
2284         rc = -ENOMEM;
2285         if ((lun = kmalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2286                 goto err_alloc;
2287         memset(lun, 0, sizeof(struct ub_lun));
2288         lun->num = lnum;
2289
2290         rc = -ENOSR;
2291         if ((lun->id = ub_id_get()) == -1)
2292                 goto err_id;
2293
2294         lun->udev = sc;
2295         list_add(&lun->link, &sc->luns);
2296
2297         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2298             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2299
2300         lun->removable = 1;             /* XXX Query this from the device */
2301         lun->changed = 1;               /* ub_revalidate clears only */
2302         lun->first_open = 1;
2303         ub_revalidate(sc, lun);
2304
2305         rc = -ENOMEM;
2306         if ((disk = alloc_disk(UB_MINORS_PER_MAJOR)) == NULL)
2307                 goto err_diskalloc;
2308
2309         lun->disk = disk;
2310         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2311         sprintf(disk->devfs_name, DEVFS_NAME "/%c", lun->id + 'a');
2312         disk->major = UB_MAJOR;
2313         disk->first_minor = lun->id * UB_MINORS_PER_MAJOR;
2314         disk->fops = &ub_bd_fops;
2315         disk->private_data = lun;
2316         disk->driverfs_dev = &sc->intf->dev;    /* XXX Many to one ok? */
2317
2318         rc = -ENOMEM;
2319         if ((q = blk_init_queue(ub_request_fn, &sc->lock)) == NULL)
2320                 goto err_blkqinit;
2321
2322         disk->queue = q;
2323
2324         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2325         blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
2326         blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
2327         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2328         blk_queue_max_sectors(q, UB_MAX_SECTORS);
2329         blk_queue_hardsect_size(q, lun->capacity.bsize);
2330
2331         q->queuedata = lun;
2332
2333         set_capacity(disk, lun->capacity.nsec);
2334         if (lun->removable)
2335                 disk->flags |= GENHD_FL_REMOVABLE;
2336
2337         add_disk(disk);
2338
2339         return 0;
2340
2341 err_blkqinit:
2342         put_disk(disk);
2343 err_diskalloc:
2344         list_del(&lun->link);
2345         ub_id_put(lun->id);
2346 err_id:
2347         kfree(lun);
2348 err_alloc:
2349         return rc;
2350 }
2351
2352 static void ub_disconnect(struct usb_interface *intf)
2353 {
2354         struct ub_dev *sc = usb_get_intfdata(intf);
2355         struct list_head *p;
2356         struct ub_lun *lun;
2357         struct gendisk *disk;
2358         unsigned long flags;
2359
2360         /*
2361          * Prevent ub_bd_release from pulling the rug from under us.
2362          * XXX This is starting to look like a kref.
2363          * XXX Why not to take this ref at probe time?
2364          */
2365         spin_lock_irqsave(&ub_lock, flags);
2366         sc->openc++;
2367         spin_unlock_irqrestore(&ub_lock, flags);
2368
2369         /*
2370          * Fence stall clearnings, operations triggered by unlinkings and so on.
2371          * We do not attempt to unlink any URBs, because we do not trust the
2372          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2373          */
2374         atomic_set(&sc->poison, 1);
2375
2376         /*
2377          * Blow away queued commands.
2378          *
2379          * Actually, this never works, because before we get here
2380          * the HCD terminates outstanding URB(s). It causes our
2381          * SCSI command queue to advance, commands fail to submit,
2382          * and the whole queue drains. So, we just use this code to
2383          * print warnings.
2384          */
2385         spin_lock_irqsave(&sc->lock, flags);
2386         {
2387                 struct ub_scsi_cmd *cmd;
2388                 int cnt = 0;
2389                 while ((cmd = ub_cmdq_pop(sc)) != NULL) {
2390                         cmd->error = -ENOTCONN;
2391                         cmd->state = UB_CMDST_DONE;
2392                         ub_cmdtr_state(sc, cmd);
2393                         ub_cmdq_pop(sc);
2394                         (*cmd->done)(sc, cmd);
2395                         cnt++;
2396                 }
2397                 if (cnt != 0) {
2398                         printk(KERN_WARNING "%s: "
2399                             "%d was queued after shutdown\n", sc->name, cnt);
2400                 }
2401         }
2402         spin_unlock_irqrestore(&sc->lock, flags);
2403
2404         /*
2405          * Unregister the upper layer.
2406          */
2407         list_for_each (p, &sc->luns) {
2408                 lun = list_entry(p, struct ub_lun, link);
2409                 disk = lun->disk;
2410                 if (disk->flags & GENHD_FL_UP)
2411                         del_gendisk(disk);
2412                 /*
2413                  * I wish I could do:
2414                  *    set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
2415                  * As it is, we rely on our internal poisoning and let
2416                  * the upper levels to spin furiously failing all the I/O.
2417                  */
2418         }
2419
2420         /*
2421          * Taking a lock on a structure which is about to be freed
2422          * is very nonsensual. Here it is largely a way to do a debug freeze,
2423          * and a bracket which shows where the nonsensual code segment ends.
2424          *
2425          * Testing for -EINPROGRESS is always a bug, so we are bending
2426          * the rules a little.
2427          */
2428         spin_lock_irqsave(&sc->lock, flags);
2429         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2430                 printk(KERN_WARNING "%s: "
2431                     "URB is active after disconnect\n", sc->name);
2432         }
2433         spin_unlock_irqrestore(&sc->lock, flags);
2434
2435         /*
2436          * There is virtually no chance that other CPU runs times so long
2437          * after ub_urb_complete should have called del_timer, but only if HCD
2438          * didn't forget to deliver a callback on unlink.
2439          */
2440         del_timer_sync(&sc->work_timer);
2441
2442         /*
2443          * At this point there must be no commands coming from anyone
2444          * and no URBs left in transit.
2445          */
2446
2447         device_remove_file(&sc->intf->dev, &dev_attr_diag);
2448         usb_set_intfdata(intf, NULL);
2449         // usb_put_intf(sc->intf);
2450         sc->intf = NULL;
2451         usb_put_dev(sc->dev);
2452         sc->dev = NULL;
2453
2454         ub_put(sc);
2455 }
2456
2457 static struct usb_driver ub_driver = {
2458         .owner =        THIS_MODULE,
2459         .name =         "ub",
2460         .probe =        ub_probe,
2461         .disconnect =   ub_disconnect,
2462         .id_table =     ub_usb_ids,
2463 };
2464
2465 static int __init ub_init(void)
2466 {
2467         int rc;
2468
2469         /* P3 */ printk("ub: sizeof ub_scsi_cmd %zu ub_dev %zu ub_lun %zu\n",
2470                         sizeof(struct ub_scsi_cmd), sizeof(struct ub_dev), sizeof(struct ub_lun));
2471
2472         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2473                 goto err_regblkdev;
2474         devfs_mk_dir(DEVFS_NAME);
2475
2476         if ((rc = usb_register(&ub_driver)) != 0)
2477                 goto err_register;
2478
2479         return 0;
2480
2481 err_register:
2482         devfs_remove(DEVFS_NAME);
2483         unregister_blkdev(UB_MAJOR, DRV_NAME);
2484 err_regblkdev:
2485         return rc;
2486 }
2487
2488 static void __exit ub_exit(void)
2489 {
2490         usb_deregister(&ub_driver);
2491
2492         devfs_remove(DEVFS_NAME);
2493         unregister_blkdev(UB_MAJOR, DRV_NAME);
2494 }
2495
2496 module_init(ub_init);
2497 module_exit(ub_exit);
2498
2499 MODULE_LICENSE("GPL");