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  *  -- Return sense now that rq allows it (we always auto-sense anyway).
  12  *  -- set readonly flag for CDs, set removable flag for CF readers
  13  *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
  14  *  -- verify the 13 conditions and do bulk resets
  15  *  -- highmem
  16  *  -- move top_sense and work_bcs into separate allocations (if they survive)
  17  *     for cache purists and esoteric architectures.
  18  *  -- Allocate structure for LUN 0 before the first ub_sync_tur, avoid NULL. ?
  19  *  -- prune comments, they are too volumnous
  20  *  -- Resove XXX's
  21  *  -- CLEAR, CLR2STS, CLRRS seem to be ripe for refactoring.
  22  */
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/usb.h>
  26 #include <linux/usb_usual.h>
  27 #include <linux/blkdev.h>
  28 #include <linux/timer.h>
  29 #include <linux/scatterlist.h>
  30 #include <linux/slab.h>
  31 #include <linux/mutex.h>
  32 #include <scsi/scsi.h>
  33
  34 #define DRV_NAME "ub"
  35
  36 #define UB_MAJOR 180
  37
  38 /*
  39  * The command state machine is the key model for understanding of this driver.
  40  *
  41  * The general rule is that all transitions are done towards the bottom
  42  * of the diagram, thus preventing any loops.
  43  *
  44  * An exception to that is how the STAT state is handled. A counter allows it
  45  * to be re-entered along the path marked with [C].
  46  *
  47  *       +--------+
  48  *       ! INIT   !
  49  *       +--------+
  50  *           !
  51  *        ub_scsi_cmd_start fails ->--------------------------------------\
  52  *           !                                                            !
  53  *           V                                                            !
  54  *       +--------+                                                       !
  55  *       ! CMD    !                                                       !
  56  *       +--------+                                                       !
  57  *           !                                            +--------+      !
  58  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
  59  *           !                                            +--------+      !
  60  *           !                                                !           !
  61  *         was error -->------------------------------------- ! --------->\
  62  *           !                                                !           !
  63  *  /--<-- cmd->dir == NONE ?                                 !           !
  64  *  !        !                                                !           !
  65  *  !        V                                                !           !
  66  *  !    +--------+                                           !           !
  67  *  !    ! DATA   !                                           !           !
  68  *  !    +--------+                                           !           !
  69  *  !        !                           +---------+          !           !
  70  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
  71  *  !        !                           +---------+          !           !
  72  *  !        !                                !               !           !
  73  *  !        !                              was error -->---- ! --------->\
  74  *  !      was error -->--------------------- ! ------------- ! --------->\
  75  *  !        !                                !               !           !
  76  *  !        V                                !               !           !
  77  *  \--->+--------+                           !               !           !
  78  *       ! STAT   !<--------------------------/               !           !
  79  *  /--->+--------+                                           !           !
  80  *  !        !                                                !           !
  81  * [C]     was -EPIPE -->-----------\                         !           !
  82  *  !        !                      !                         !           !
  83  *  +<---- len == 0                 !                         !           !
  84  *  !        !                      !                         !           !
  85  *  !      was error -->--------------------------------------!---------->\
  86  *  !        !                      !                         !           !
  87  *  +<---- bad CSW                  !                         !           !
  88  *  +<---- bad tag                  !                         !           !
  89  *  !        !                      V                         !           !
  90  *  !        !                 +--------+                     !           !
  91  *  !        !                 ! CLRRS  !                     !           !
  92  *  !        !                 +--------+                     !           !
  93  *  !        !                      !                         !           !
  94  *  \------- ! --------------------[C]--------\               !           !
  95  *           !                                !               !           !
  96  *         cmd->error---\                +--------+           !           !
  97  *           !          +--------------->! SENSE  !<----------/           !
  98  *         STAT_FAIL----/                +--------+                       !
  99  *           !                                !                           V
 100  *           !                                V                      +--------+
 101  *           \--------------------------------\--------------------->! DONE   !
 102  *                                                                   +--------+
 103  */
 104
 105 /*
 106  * This many LUNs per USB device.
 107  * Every one of them takes a host, see UB_MAX_HOSTS.
 108  */
 109 #define UB_MAX_LUNS   9
 110
 111 /*
 112  */
 113
 114 #define UB_PARTS_PER_LUN      8
 115
 116 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
 117
 118 #define UB_SENSE_SIZE  18
 119
 120 /*
 121  */
 122 struct ub_dev;
 123
 124 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
 125 #define UB_MAX_SECTORS 64
 126
 127 /*
 128  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
 129  * even if a webcam hogs the bus, but some devices need time to spin up.
 130  */
 131 #define UB_URB_TIMEOUT  (HZ*2)
 132 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
 133 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
 134 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
 135
 136 /*
 137  * An instance of a SCSI command in transit.
 138  */
 139 #define UB_DIR_NONE     0
 140 #define UB_DIR_READ     1
 141 #define UB_DIR_ILLEGAL2 2
 142 #define UB_DIR_WRITE    3
 143
 144 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
 145                          (((c)==UB_DIR_READ)? 'r': 'n'))
 146
 147 enum ub_scsi_cmd_state {
 148         UB_CMDST_INIT,                  /* Initial state */
 149         UB_CMDST_CMD,                   /* Command submitted */
 150         UB_CMDST_DATA,                  /* Data phase */
 151         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
 152         UB_CMDST_STAT,                  /* Status phase */
 153         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
 154         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
 155         UB_CMDST_SENSE,                 /* Sending Request Sense */
 156         UB_CMDST_DONE                   /* Final state */
 157 };
 158
 159 struct ub_scsi_cmd {
 160         unsigned char cdb[UB_MAX_CDB_SIZE];
 161         unsigned char cdb_len;
 162
 163         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
 164         enum ub_scsi_cmd_state state;
 165         unsigned int tag;
 166         struct ub_scsi_cmd *next;
 167
 168         int error;                      /* Return code - valid upon done */
 169         unsigned int act_len;           /* Return size */
 170         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
 171
 172         int stat_count;                 /* Retries getting status. */
 173         unsigned int timeo;             /* jiffies until rq->timeout changes */
 174
 175         unsigned int len;               /* Requested length */
 176         unsigned int current_sg;
 177         unsigned int nsg;               /* sgv[nsg] */
 178         struct scatterlist sgv[UB_MAX_REQ_SG];
 179
 180         struct ub_lun *lun;
 181         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
 182         void *back;
 183 };
 184
 185 struct ub_request {
 186         struct request *rq;
 187         unsigned int current_try;
 188         unsigned int nsg;               /* sgv[nsg] */
 189         struct scatterlist sgv[UB_MAX_REQ_SG];
 190 };
 191
 192 /*
 193  */
 194 struct ub_capacity {
 195         unsigned long nsec;             /* Linux size - 512 byte sectors */
 196         unsigned int bsize;             /* Linux hardsect_size */
 197         unsigned int bshift;            /* Shift between 512 and hard sects */
 198 };
 199
 200 /*
 201  * This is a direct take-off from linux/include/completion.h
 202  * The difference is that I do not wait on this thing, just poll.
 203  * When I want to wait (ub_probe), I just use the stock completion.
 204  *
 205  * Note that INIT_COMPLETION takes no lock. It is correct. But why
 206  * in the bloody hell that thing takes struct instead of pointer to struct
 207  * is quite beyond me. I just copied it from the stock completion.
 208  */
 209 struct ub_completion {
 210         unsigned int done;
 211         spinlock_t lock;
 212 };
 213
 214 static DEFINE_MUTEX(ub_mutex);
 215 static inline void ub_init_completion(struct ub_completion *x)
 216 {
 217         x->done = 0;
 218         spin_lock_init(&x->lock);
 219 }
 220
 221 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
 222
 223 static void ub_complete(struct ub_completion *x)
 224 {
 225         unsigned long flags;
 226
 227         spin_lock_irqsave(&x->lock, flags);
 228         x->done++;
 229         spin_unlock_irqrestore(&x->lock, flags);
 230 }
 231
 232 static int ub_is_completed(struct ub_completion *x)
 233 {
 234         unsigned long flags;
 235         int ret;
 236
 237         spin_lock_irqsave(&x->lock, flags);
 238         ret = x->done;
 239         spin_unlock_irqrestore(&x->lock, flags);
 240         return ret;
 241 }
 242
 243 /*
 244  */
 245 struct ub_scsi_cmd_queue {
 246         int qlen, qmax;
 247         struct ub_scsi_cmd *head, *tail;
 248 };
 249
 250 /*
 251  * The block device instance (one per LUN).
 252  */
 253 struct ub_lun {
 254         struct ub_dev *udev;
 255         struct list_head link;
 256         struct gendisk *disk;
 257         int id;                         /* Host index */
 258         int num;                        /* LUN number */
 259         char name[16];
 260
 261         int changed;                    /* Media was changed */
 262         int removable;
 263         int readonly;
 264
 265         struct ub_request urq;
 266
 267         /* Use Ingo's mempool if or when we have more than one command. */
 268         /*
 269          * Currently we never need more than one command for the whole device.
 270          * However, giving every LUN a command is a cheap and automatic way
 271          * to enforce fairness between them.
 272          */
 273         int cmda[1];
 274         struct ub_scsi_cmd cmdv[1];
 275
 276         struct ub_capacity capacity;
 277 };
 278
 279 /*
 280  * The USB device instance.
 281  */
 282 struct ub_dev {
 283         spinlock_t *lock;
 284         atomic_t poison;                /* The USB device is disconnected */
 285         int openc;                      /* protected by ub_lock! */
 286                                         /* kref is too implicit for our taste */
 287         int reset;                      /* Reset is running */
 288         int bad_resid;
 289         unsigned int tagcnt;
 290         char name[12];
 291         struct usb_device *dev;
 292         struct usb_interface *intf;
 293
 294         struct list_head luns;
 295
 296         unsigned int send_bulk_pipe;    /* cached pipe values */
 297         unsigned int recv_bulk_pipe;
 298         unsigned int send_ctrl_pipe;
 299         unsigned int recv_ctrl_pipe;
 300
 301         struct tasklet_struct tasklet;
 302
 303         struct ub_scsi_cmd_queue cmd_queue;
 304         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
 305         unsigned char top_sense[UB_SENSE_SIZE];
 306
 307         struct ub_completion work_done;
 308         struct urb work_urb;
 309         struct timer_list work_timer;
 310         int last_pipe;                  /* What might need clearing */
 311         __le32 signature;               /* Learned signature */
 312         struct bulk_cb_wrap work_bcb;
 313         struct bulk_cs_wrap work_bcs;
 314         struct usb_ctrlrequest work_cr;
 315
 316         struct work_struct reset_work;
 317         wait_queue_head_t reset_wait;
 318 };
 319
 320 /*
 321  */
 322 static void ub_cleanup(struct ub_dev *sc);
 323 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
 324 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 325     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 326 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 327     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 328 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 329 static void ub_end_rq(struct request *rq, unsigned int status);
 330 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 331     struct ub_request *urq, struct ub_scsi_cmd *cmd);
 332 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 333 static void ub_urb_complete(struct urb *urb);
 334 static void ub_scsi_action(unsigned long _dev);
 335 static void ub_scsi_dispatch(struct ub_dev *sc);
 336 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 337 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 338 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
 339 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 340 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 341 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 342 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 343 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 344     int stalled_pipe);
 345 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
 346 static void ub_reset_enter(struct ub_dev *sc, int try);
 347 static void ub_reset_task(struct work_struct *work);
 348 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
 349 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
 350     struct ub_capacity *ret);
 351 static int ub_sync_reset(struct ub_dev *sc);
 352 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe);
 353 static int ub_probe_lun(struct ub_dev *sc, int lnum);
 354
 355 /*
 356  */
 357 #ifdef CONFIG_USB_LIBUSUAL
 358
 359 #define ub_usb_ids  usb_storage_usb_ids
 360 #else
 361
 362 static const struct usb_device_id ub_usb_ids[] = {
 363         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_BULK) },
 364         { }
 365 };
 366
 367 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
 368 #endif /* CONFIG_USB_LIBUSUAL */
 369
 370 /*
 371  * Find me a way to identify "next free minor" for add_disk(),
 372  * and the array disappears the next day. However, the number of
 373  * hosts has something to do with the naming and /proc/partitions.
 374  * This has to be thought out in detail before changing.
 375  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
 376  */
 377 #define UB_MAX_HOSTS  26
 378 static char ub_hostv[UB_MAX_HOSTS];
 379
 380 #define UB_QLOCK_NUM 5
 381 static spinlock_t ub_qlockv[UB_QLOCK_NUM];
 382 static int ub_qlock_next = 0;
 383
 384 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
 385
 386 /*
 387  * The id allocator.
 388  *
 389  * This also stores the host for indexing by minor, which is somewhat dirty.
 390  */
 391 static int ub_id_get(void)
 392 {
 393         unsigned long flags;
 394         int i;
 395
 396         spin_lock_irqsave(&ub_lock, flags);
 397         for (i = 0; i < UB_MAX_HOSTS; i++) {
 398                 if (ub_hostv[i] == 0) {
 399                         ub_hostv[i] = 1;
 400                         spin_unlock_irqrestore(&ub_lock, flags);
 401                         return i;
 402                 }
 403         }
 404         spin_unlock_irqrestore(&ub_lock, flags);
 405         return -1;
 406 }
 407
 408 static void ub_id_put(int id)
 409 {
 410         unsigned long flags;
 411
 412         if (id < 0 || id >= UB_MAX_HOSTS) {
 413                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 414                 return;
 415         }
 416
 417         spin_lock_irqsave(&ub_lock, flags);
 418         if (ub_hostv[id] == 0) {
 419                 spin_unlock_irqrestore(&ub_lock, flags);
 420                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 421                 return;
 422         }
 423         ub_hostv[id] = 0;
 424         spin_unlock_irqrestore(&ub_lock, flags);
 425 }
 426
 427 /*
 428  * This is necessitated by the fact that blk_cleanup_queue does not
 429  * necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
 430  * Since our blk_init_queue() passes a spinlock common with ub_dev,
 431  * we have life time issues when ub_cleanup frees ub_dev.
 432  */
 433 static spinlock_t *ub_next_lock(void)
 434 {
 435         unsigned long flags;
 436         spinlock_t *ret;
 437
 438         spin_lock_irqsave(&ub_lock, flags);
 439         ret = &ub_qlockv[ub_qlock_next];
 440         ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
 441         spin_unlock_irqrestore(&ub_lock, flags);
 442         return ret;
 443 }
 444
 445 /*
 446  * Downcount for deallocation. This rides on two assumptions:
 447  *  - once something is poisoned, its refcount cannot grow
 448  *  - opens cannot happen at this time (del_gendisk was done)
 449  * If the above is true, we can drop the lock, which we need for
 450  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 451  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 452  */
 453 static void ub_put(struct ub_dev *sc)
 454 {
 455         unsigned long flags;
 456
 457         spin_lock_irqsave(&ub_lock, flags);
 458         --sc->openc;
 459         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 460                 spin_unlock_irqrestore(&ub_lock, flags);
 461                 ub_cleanup(sc);
 462         } else {
 463                 spin_unlock_irqrestore(&ub_lock, flags);
 464         }
 465 }
 466
 467 /*
 468  * Final cleanup and deallocation.
 469  */
 470 static void ub_cleanup(struct ub_dev *sc)
 471 {
 472         struct list_head *p;
 473         struct ub_lun *lun;
 474         struct request_queue *q;
 475
 476         while (!list_empty(&sc->luns)) {
 477                 p = sc->luns.next;
 478                 lun = list_entry(p, struct ub_lun, link);
 479                 list_del(p);
 480
 481                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 482                 if ((q = lun->disk->queue) != NULL)
 483                         blk_cleanup_queue(q);
 484                 /*
 485                  * If we zero disk->private_data BEFORE put_disk, we have
 486                  * to check for NULL all over the place in open, release,
 487                  * check_media and revalidate, because the block level
 488                  * semaphore is well inside the put_disk.
 489                  * But we cannot zero after the call, because *disk is gone.
 490                  * The sd.c is blatantly racy in this area.
 491                  */
 492                 /* disk->private_data = NULL; */
 493                 put_disk(lun->disk);
 494                 lun->disk = NULL;
 495
 496                 ub_id_put(lun->id);
 497                 kfree(lun);
 498         }
 499
 500         usb_set_intfdata(sc->intf, NULL);
 501         usb_put_intf(sc->intf);
 502         usb_put_dev(sc->dev);
 503         kfree(sc);
 504 }
 505
 506 /*
 507  * The "command allocator".
 508  */
 509 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 510 {
 511         struct ub_scsi_cmd *ret;
 512
 513         if (lun->cmda[0])
 514                 return NULL;
 515         ret = &lun->cmdv[0];
 516         lun->cmda[0] = 1;
 517         return ret;
 518 }
 519
 520 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 521 {
 522         if (cmd != &lun->cmdv[0]) {
 523                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
 524                     lun->name, cmd);
 525                 return;
 526         }
 527         if (!lun->cmda[0]) {
 528                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
 529                 return;
 530         }
 531         lun->cmda[0] = 0;
 532 }
 533
 534 /*
 535  * The command queue.
 536  */
 537 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 538 {
 539         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 540
 541         if (t->qlen++ == 0) {
 542                 t->head = cmd;
 543                 t->tail = cmd;
 544         } else {
 545                 t->tail->next = cmd;
 546                 t->tail = cmd;
 547         }
 548
 549         if (t->qlen > t->qmax)
 550                 t->qmax = t->qlen;
 551 }
 552
 553 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 554 {
 555         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 556
 557         if (t->qlen++ == 0) {
 558                 t->head = cmd;
 559                 t->tail = cmd;
 560         } else {
 561                 cmd->next = t->head;
 562                 t->head = cmd;
 563         }
 564
 565         if (t->qlen > t->qmax)
 566                 t->qmax = t->qlen;
 567 }
 568
 569 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
 570 {
 571         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 572         struct ub_scsi_cmd *cmd;
 573
 574         if (t->qlen == 0)
 575                 return NULL;
 576         if (--t->qlen == 0)
 577                 t->tail = NULL;
 578         cmd = t->head;
 579         t->head = cmd->next;
 580         cmd->next = NULL;
 581         return cmd;
 582 }
 583
 584 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
 585
 586 /*
 587  * The request function is our main entry point
 588  */
 589
 590 static void ub_request_fn(struct request_queue *q)
 591 {
 592         struct ub_lun *lun = q->queuedata;
 593         struct request *rq;
 594
 595         while ((rq = blk_peek_request(q)) != NULL) {
 596                 if (ub_request_fn_1(lun, rq) != 0) {
 597                         blk_stop_queue(q);
 598                         break;
 599                 }
 600         }
 601 }
 602
 603 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 604 {
 605         struct ub_dev *sc = lun->udev;
 606         struct ub_scsi_cmd *cmd;
 607         struct ub_request *urq;
 608         int n_elem;
 609
 610         if (atomic_read(&sc->poison)) {
 611                 blk_start_request(rq);
 612                 ub_end_rq(rq, DID_NO_CONNECT << 16);
 613                 return 0;
 614         }
 615
 616         if (lun->changed && rq->cmd_type != REQ_TYPE_BLOCK_PC) {
 617                 blk_start_request(rq);
 618                 ub_end_rq(rq, SAM_STAT_CHECK_CONDITION);
 619                 return 0;
 620         }
 621
 622         if (lun->urq.rq != NULL)
 623                 return -1;
 624         if ((cmd = ub_get_cmd(lun)) == NULL)
 625                 return -1;
 626         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 627
 628         blk_start_request(rq);
 629
 630         urq = &lun->urq;
 631         memset(urq, 0, sizeof(struct ub_request));
 632         urq->rq = rq;
 633
 634         /*
 635          * get scatterlist from block layer
 636          */
 637         sg_init_table(&urq->sgv[0], UB_MAX_REQ_SG);
 638         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
 639         if (n_elem < 0) {
 640                 /* Impossible, because blk_rq_map_sg should not hit ENOMEM. */
 641                 printk(KERN_INFO "%s: failed request map (%d)\n",
 642                     lun->name, n_elem);
 643                 goto drop;
 644         }
 645         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 646                 printk(KERN_WARNING "%s: request with %d segments\n",
 647                     lun->name, n_elem);
 648                 goto drop;
 649         }
 650         urq->nsg = n_elem;
 651
 652         if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
 653                 ub_cmd_build_packet(sc, lun, cmd, urq);
 654         } else {
 655                 ub_cmd_build_block(sc, lun, cmd, urq);
 656         }
 657         cmd->state = UB_CMDST_INIT;
 658         cmd->lun = lun;
 659         cmd->done = ub_rw_cmd_done;
 660         cmd->back = urq;
 661
 662         cmd->tag = sc->tagcnt++;
 663         if (ub_submit_scsi(sc, cmd) != 0)
 664                 goto drop;
 665
 666         return 0;
 667
 668 drop:
 669         ub_put_cmd(lun, cmd);
 670         ub_end_rq(rq, DID_ERROR << 16);
 671         return 0;
 672 }
 673
 674 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 675     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 676 {
 677         struct request *rq = urq->rq;
 678         unsigned int block, nblks;
 679
 680         if (rq_data_dir(rq) == WRITE)
 681                 cmd->dir = UB_DIR_WRITE;
 682         else
 683                 cmd->dir = UB_DIR_READ;
 684
 685         cmd->nsg = urq->nsg;
 686         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 687
 688         /*
 689          * build the command
 690          *
 691          * The call to blk_queue_logical_block_size() guarantees that request
 692          * is aligned, but it is given in terms of 512 byte units, always.
 693          */
 694         block = blk_rq_pos(rq) >> lun->capacity.bshift;
 695         nblks = blk_rq_sectors(rq) >> lun->capacity.bshift;
 696
 697         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
 698         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 699         cmd->cdb[2] = block >> 24;
 700         cmd->cdb[3] = block >> 16;
 701         cmd->cdb[4] = block >> 8;
 702         cmd->cdb[5] = block;
 703         cmd->cdb[7] = nblks >> 8;
 704         cmd->cdb[8] = nblks;
 705         cmd->cdb_len = 10;
 706
 707         cmd->len = blk_rq_bytes(rq);
 708 }
 709
 710 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 711     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 712 {
 713         struct request *rq = urq->rq;
 714
 715         if (blk_rq_bytes(rq) == 0) {
 716                 cmd->dir = UB_DIR_NONE;
 717         } else {
 718                 if (rq_data_dir(rq) == WRITE)
 719                         cmd->dir = UB_DIR_WRITE;
 720                 else
 721                         cmd->dir = UB_DIR_READ;
 722         }
 723
 724         cmd->nsg = urq->nsg;
 725         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 726
 727         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 728         cmd->cdb_len = rq->cmd_len;
 729
 730         cmd->len = blk_rq_bytes(rq);
 731
 732         /*
 733          * To reapply this to every URB is not as incorrect as it looks.
 734          * In return, we avoid any complicated tracking calculations.
 735          */
 736         cmd->timeo = rq->timeout;
 737 }
 738
 739 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 740 {
 741         struct ub_lun *lun = cmd->lun;
 742         struct ub_request *urq = cmd->back;
 743         struct request *rq;
 744         unsigned int scsi_status;
 745
 746         rq = urq->rq;
 747
 748         if (cmd->error == 0) {
 749                 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
 750                         if (cmd->act_len >= rq->resid_len)
 751                                 rq->resid_len = 0;
 752                         else
 753                                 rq->resid_len -= cmd->act_len;
 754                         scsi_status = 0;
 755                 } else {
 756                         if (cmd->act_len != cmd->len) {
 757                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 758                         } else {
 759                                 scsi_status = 0;
 760                         }
 761                 }
 762         } else {
 763                 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
 764                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 765                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 766                         rq->sense_len = UB_SENSE_SIZE;
 767                         if (sc->top_sense[0] != 0)
 768                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 769                         else
 770                                 scsi_status = DID_ERROR << 16;
 771                 } else {
 772                         if (cmd->error == -EIO &&
 773                             (cmd->key == 0 ||
 774                              cmd->key == MEDIUM_ERROR ||
 775                              cmd->key == UNIT_ATTENTION)) {
 776                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
 777                                         return;
 778                         }
 779                         scsi_status = SAM_STAT_CHECK_CONDITION;
 780                 }
 781         }
 782
 783         urq->rq = NULL;
 784
 785         ub_put_cmd(lun, cmd);
 786         ub_end_rq(rq, scsi_status);
 787         blk_start_queue(lun->disk->queue);
 788 }
 789
 790 static void ub_end_rq(struct request *rq, unsigned int scsi_status)
 791 {
 792         int error;
 793
 794         if (scsi_status == 0) {
 795                 error = 0;
 796         } else {
 797                 error = -EIO;
 798                 rq->errors = scsi_status;
 799         }
 800         __blk_end_request_all(rq, error);
 801 }
 802
 803 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 804     struct ub_request *urq, struct ub_scsi_cmd *cmd)
 805 {
 806
 807         if (atomic_read(&sc->poison))
 808                 return -ENXIO;
 809
 810         ub_reset_enter(sc, urq->current_try);
 811
 812         if (urq->current_try >= 3)
 813                 return -EIO;
 814         urq->current_try++;
 815
 816         /* Remove this if anyone complains of flooding. */
 817         printk(KERN_DEBUG "%s: dir %c len/act %d/%d "
 818             "[sense %x %02x %02x] retry %d\n",
 819             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
 820             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
 821
 822         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 823         ub_cmd_build_block(sc, lun, cmd, urq);
 824
 825         cmd->state = UB_CMDST_INIT;
 826         cmd->lun = lun;
 827         cmd->done = ub_rw_cmd_done;
 828         cmd->back = urq;
 829
 830         cmd->tag = sc->tagcnt++;
 831
 832 #if 0 /* Wasteful */
 833         return ub_submit_scsi(sc, cmd);
 834 #else
 835         ub_cmdq_add(sc, cmd);
 836         return 0;
 837 #endif
 838 }
 839
 840 /*
 841  * Submit a regular SCSI operation (not an auto-sense).
 842  *
 843  * The Iron Law of Good Submit Routine is:
 844  * Zero return - callback is done, Nonzero return - callback is not done.
 845  * No exceptions.
 846  *
 847  * Host is assumed locked.
 848  */
 849 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 850 {
 851
 852         if (cmd->state != UB_CMDST_INIT ||
 853             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
 854                 return -EINVAL;
 855         }
 856
 857         ub_cmdq_add(sc, cmd);
 858         /*
 859          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
 860          * safer to jump to a tasklet, in case upper layers do something silly.
 861          */
 862         tasklet_schedule(&sc->tasklet);
 863         return 0;
 864 }
 865
 866 /*
 867  * Submit the first URB for the queued command.
 868  * This function does not deal with queueing in any way.
 869  */
 870 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 871 {
 872         struct bulk_cb_wrap *bcb;
 873         int rc;
 874
 875         bcb = &sc->work_bcb;
 876
 877         /*
 878          * ``If the allocation length is eighteen or greater, and a device
 879          * server returns less than eithteen bytes of data, the application
 880          * client should assume that the bytes not transferred would have been
 881          * zeroes had the device server returned those bytes.''
 882          *
 883          * We zero sense for all commands so that when a packet request
 884          * fails it does not return a stale sense.
 885          */
 886         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
 887
 888         /* set up the command wrapper */
 889         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
 890         bcb->Tag = cmd->tag;            /* Endianness is not important */
 891         bcb->DataTransferLength = cpu_to_le32(cmd->len);
 892         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
 893         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
 894         bcb->Length = cmd->cdb_len;
 895
 896         /* copy the command payload */
 897         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
 898
 899         UB_INIT_COMPLETION(sc->work_done);
 900
 901         sc->last_pipe = sc->send_bulk_pipe;
 902         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
 903             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
 904
 905         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
 906                 /* XXX Clear stalls */
 907                 ub_complete(&sc->work_done);
 908                 return rc;
 909         }
 910
 911         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
 912         add_timer(&sc->work_timer);
 913
 914         cmd->state = UB_CMDST_CMD;
 915         return 0;
 916 }
 917
 918 /*
 919  * Timeout handler.
 920  */
 921 static void ub_urb_timeout(unsigned long arg)
 922 {
 923         struct ub_dev *sc = (struct ub_dev *) arg;
 924         unsigned long flags;
 925
 926         spin_lock_irqsave(sc->lock, flags);
 927         if (!ub_is_completed(&sc->work_done))
 928                 usb_unlink_urb(&sc->work_urb);
 929         spin_unlock_irqrestore(sc->lock, flags);
 930 }
 931
 932 /*
 933  * Completion routine for the work URB.
 934  *
 935  * This can be called directly from usb_submit_urb (while we have
 936  * the sc->lock taken) and from an interrupt (while we do NOT have
 937  * the sc->lock taken). Therefore, bounce this off to a tasklet.
 938  */
 939 static void ub_urb_complete(struct urb *urb)
 940 {
 941         struct ub_dev *sc = urb->context;
 942
 943         ub_complete(&sc->work_done);
 944         tasklet_schedule(&sc->tasklet);
 945 }
 946
 947 static void ub_scsi_action(unsigned long _dev)
 948 {
 949         struct ub_dev *sc = (struct ub_dev *) _dev;
 950         unsigned long flags;
 951
 952         spin_lock_irqsave(sc->lock, flags);
 953         ub_scsi_dispatch(sc);
 954         spin_unlock_irqrestore(sc->lock, flags);
 955 }
 956
 957 static void ub_scsi_dispatch(struct ub_dev *sc)
 958 {
 959         struct ub_scsi_cmd *cmd;
 960         int rc;
 961
 962         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
 963                 if (cmd->state == UB_CMDST_DONE) {
 964                         ub_cmdq_pop(sc);
 965                         (*cmd->done)(sc, cmd);
 966                 } else if (cmd->state == UB_CMDST_INIT) {
 967                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
 968                                 break;
 969                         cmd->error = rc;
 970                         cmd->state = UB_CMDST_DONE;
 971                 } else {
 972                         if (!ub_is_completed(&sc->work_done))
 973                                 break;
 974                         del_timer(&sc->work_timer);
 975                         ub_scsi_urb_compl(sc, cmd);
 976                 }
 977         }
 978 }
 979
 980 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 981 {
 982         struct urb *urb = &sc->work_urb;
 983         struct bulk_cs_wrap *bcs;
 984         int endp;
 985         int len;
 986         int rc;
 987
 988         if (atomic_read(&sc->poison)) {
 989                 ub_state_done(sc, cmd, -ENODEV);
 990                 return;
 991         }
 992
 993         endp = usb_pipeendpoint(sc->last_pipe);
 994         if (usb_pipein(sc->last_pipe))
 995                 endp |= USB_DIR_IN;
 996
 997         if (cmd->state == UB_CMDST_CLEAR) {
 998                 if (urb->status == -EPIPE) {
 999                         /*
1000                          * STALL while clearning STALL.
1001                          * The control pipe clears itself - nothing to do.
1002                          */
1003                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1004                             sc->name);
1005                         goto Bad_End;
1006                 }
1007
1008                 /*
1009                  * We ignore the result for the halt clear.
1010                  */
1011
1012                 usb_reset_endpoint(sc->dev, endp);
1013
1014                 ub_state_sense(sc, cmd);
1015
1016         } else if (cmd->state == UB_CMDST_CLR2STS) {
1017                 if (urb->status == -EPIPE) {
1018                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1019                             sc->name);
1020                         goto Bad_End;
1021                 }
1022
1023                 /*
1024                  * We ignore the result for the halt clear.
1025                  */
1026
1027                 usb_reset_endpoint(sc->dev, endp);
1028
1029                 ub_state_stat(sc, cmd);
1030
1031         } else if (cmd->state == UB_CMDST_CLRRS) {
1032                 if (urb->status == -EPIPE) {
1033                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1034                             sc->name);
1035                         goto Bad_End;
1036                 }
1037
1038                 /*
1039                  * We ignore the result for the halt clear.
1040                  */
1041
1042                 usb_reset_endpoint(sc->dev, endp);
1043
1044                 ub_state_stat_counted(sc, cmd);
1045
1046         } else if (cmd->state == UB_CMDST_CMD) {
1047                 switch (urb->status) {
1048                 case 0:
1049                         break;
1050                 case -EOVERFLOW:
1051                         goto Bad_End;
1052                 case -EPIPE:
1053                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1054                         if (rc != 0) {
1055                                 printk(KERN_NOTICE "%s: "
1056                                     "unable to submit clear (%d)\n",
1057                                     sc->name, rc);
1058                                 /*
1059                                  * This is typically ENOMEM or some other such shit.
1060                                  * Retrying is pointless. Just do Bad End on it...
1061                                  */
1062                                 ub_state_done(sc, cmd, rc);
1063                                 return;
1064                         }
1065                         cmd->state = UB_CMDST_CLEAR;
1066                         return;
1067                 case -ESHUTDOWN:        /* unplug */
1068                 case -EILSEQ:           /* unplug timeout on uhci */
1069                         ub_state_done(sc, cmd, -ENODEV);
1070                         return;
1071                 default:
1072                         goto Bad_End;
1073                 }
1074                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1075                         goto Bad_End;
1076                 }
1077
1078                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1079                         ub_state_stat(sc, cmd);
1080                         return;
1081                 }
1082
1083                 // udelay(125);         // usb-storage has this
1084                 ub_data_start(sc, cmd);
1085
1086         } else if (cmd->state == UB_CMDST_DATA) {
1087                 if (urb->status == -EPIPE) {
1088                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1089                         if (rc != 0) {
1090                                 printk(KERN_NOTICE "%s: "
1091                                     "unable to submit clear (%d)\n",
1092                                     sc->name, rc);
1093                                 ub_state_done(sc, cmd, rc);
1094                                 return;
1095                         }
1096                         cmd->state = UB_CMDST_CLR2STS;
1097                         return;
1098                 }
1099                 if (urb->status == -EOVERFLOW) {
1100                         /*
1101                          * A babble? Failure, but we must transfer CSW now.
1102                          */
1103                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1104                         ub_state_stat(sc, cmd);
1105                         return;
1106                 }
1107
1108                 if (cmd->dir == UB_DIR_WRITE) {
1109                         /*
1110                          * Do not continue writes in case of a failure.
1111                          * Doing so would cause sectors to be mixed up,
1112                          * which is worse than sectors lost.
1113                          *
1114                          * We must try to read the CSW, or many devices
1115                          * get confused.
1116                          */
1117                         len = urb->actual_length;
1118                         if (urb->status != 0 ||
1119                             len != cmd->sgv[cmd->current_sg].length) {
1120                                 cmd->act_len += len;
1121
1122                                 cmd->error = -EIO;
1123                                 ub_state_stat(sc, cmd);
1124                                 return;
1125                         }
1126
1127                 } else {
1128                         /*
1129                          * If an error occurs on read, we record it, and
1130                          * continue to fetch data in order to avoid bubble.
1131                          *
1132                          * As a small shortcut, we stop if we detect that
1133                          * a CSW mixed into data.
1134                          */
1135                         if (urb->status != 0)
1136                                 cmd->error = -EIO;
1137
1138                         len = urb->actual_length;
1139                         if (urb->status != 0 ||
1140                             len != cmd->sgv[cmd->current_sg].length) {
1141                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1142                                         goto Bad_End;
1143                         }
1144                 }
1145
1146                 cmd->act_len += urb->actual_length;
1147
1148                 if (++cmd->current_sg < cmd->nsg) {
1149                         ub_data_start(sc, cmd);
1150                         return;
1151                 }
1152                 ub_state_stat(sc, cmd);
1153
1154         } else if (cmd->state == UB_CMDST_STAT) {
1155                 if (urb->status == -EPIPE) {
1156                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1157                         if (rc != 0) {
1158                                 printk(KERN_NOTICE "%s: "
1159                                     "unable to submit clear (%d)\n",
1160                                     sc->name, rc);
1161                                 ub_state_done(sc, cmd, rc);
1162                                 return;
1163                         }
1164
1165                         /*
1166                          * Having a stall when getting CSW is an error, so
1167                          * make sure uppper levels are not oblivious to it.
1168                          */
1169                         cmd->error = -EIO;              /* A cheap trick... */
1170
1171                         cmd->state = UB_CMDST_CLRRS;
1172                         return;
1173                 }
1174
1175                 /* Catch everything, including -EOVERFLOW and other nasties. */
1176                 if (urb->status != 0)
1177                         goto Bad_End;
1178
1179                 if (urb->actual_length == 0) {
1180                         ub_state_stat_counted(sc, cmd);
1181                         return;
1182                 }
1183
1184                 /*
1185                  * Check the returned Bulk protocol status.
1186                  * The status block has to be validated first.
1187                  */
1188
1189                 bcs = &sc->work_bcs;
1190
1191                 if (sc->signature == cpu_to_le32(0)) {
1192                         /*
1193                          * This is the first reply, so do not perform the check.
1194                          * Instead, remember the signature the device uses
1195                          * for future checks. But do not allow a nul.
1196                          */
1197                         sc->signature = bcs->Signature;
1198                         if (sc->signature == cpu_to_le32(0)) {
1199                                 ub_state_stat_counted(sc, cmd);
1200                                 return;
1201                         }
1202                 } else {
1203                         if (bcs->Signature != sc->signature) {
1204                                 ub_state_stat_counted(sc, cmd);
1205                                 return;
1206                         }
1207                 }
1208
1209                 if (bcs->Tag != cmd->tag) {
1210                         /*
1211                          * This usually happens when we disagree with the
1212                          * device's microcode about something. For instance,
1213                          * a few of them throw this after timeouts. They buffer
1214                          * commands and reply at commands we timed out before.
1215                          * Without flushing these replies we loop forever.
1216                          */
1217                         ub_state_stat_counted(sc, cmd);
1218                         return;
1219                 }
1220
1221                 if (!sc->bad_resid) {
1222                         len = le32_to_cpu(bcs->Residue);
1223                         if (len != cmd->len - cmd->act_len) {
1224                                 /*
1225                                  * Only start ignoring if this cmd ended well.
1226                                  */
1227                                 if (cmd->len == cmd->act_len) {
1228                                         printk(KERN_NOTICE "%s: "
1229                                             "bad residual %d of %d, ignoring\n",
1230                                             sc->name, len, cmd->len);
1231                                         sc->bad_resid = 1;
1232                                 }
1233                         }
1234                 }
1235
1236                 switch (bcs->Status) {
1237                 case US_BULK_STAT_OK:
1238                         break;
1239                 case US_BULK_STAT_FAIL:
1240                         ub_state_sense(sc, cmd);
1241                         return;
1242                 case US_BULK_STAT_PHASE:
1243                         goto Bad_End;
1244                 default:
1245                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1246                             sc->name, bcs->Status);
1247                         ub_state_done(sc, cmd, -EINVAL);
1248                         return;
1249                 }
1250
1251                 /* Not zeroing error to preserve a babble indicator */
1252                 if (cmd->error != 0) {
1253                         ub_state_sense(sc, cmd);
1254                         return;
1255                 }
1256                 cmd->state = UB_CMDST_DONE;
1257                 ub_cmdq_pop(sc);
1258                 (*cmd->done)(sc, cmd);
1259
1260         } else if (cmd->state == UB_CMDST_SENSE) {
1261                 ub_state_done(sc, cmd, -EIO);
1262
1263         } else {
1264                 printk(KERN_WARNING "%s: wrong command state %d\n",
1265                     sc->name, cmd->state);
1266                 ub_state_done(sc, cmd, -EINVAL);
1267                 return;
1268         }
1269         return;
1270
1271 Bad_End: /* Little Excel is dead */
1272         ub_state_done(sc, cmd, -EIO);
1273 }
1274
1275 /*
1276  * Factorization helper for the command state machine:
1277  * Initiate a data segment transfer.
1278  */
1279 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1280 {
1281         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1282         int pipe;
1283         int rc;
1284
1285         UB_INIT_COMPLETION(sc->work_done);
1286
1287         if (cmd->dir == UB_DIR_READ)
1288                 pipe = sc->recv_bulk_pipe;
1289         else
1290                 pipe = sc->send_bulk_pipe;
1291         sc->last_pipe = pipe;
1292         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe, sg_virt(sg),
1293             sg->length, ub_urb_complete, sc);
1294
1295         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1296                 /* XXX Clear stalls */
1297                 ub_complete(&sc->work_done);
1298                 ub_state_done(sc, cmd, rc);
1299                 return;
1300         }
1301
1302         if (cmd->timeo)
1303                 sc->work_timer.expires = jiffies + cmd->timeo;
1304         else
1305                 sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1306         add_timer(&sc->work_timer);
1307
1308         cmd->state = UB_CMDST_DATA;
1309 }
1310
1311 /*
1312  * Factorization helper for the command state machine:
1313  * Finish the command.
1314  */
1315 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1316 {
1317
1318         cmd->error = rc;
1319         cmd->state = UB_CMDST_DONE;
1320         ub_cmdq_pop(sc);
1321         (*cmd->done)(sc, cmd);
1322 }
1323
1324 /*
1325  * Factorization helper for the command state machine:
1326  * Submit a CSW read.
1327  */
1328 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1329 {
1330         int rc;
1331
1332         UB_INIT_COMPLETION(sc->work_done);
1333
1334         sc->last_pipe = sc->recv_bulk_pipe;
1335         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1336             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1337
1338         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1339                 /* XXX Clear stalls */
1340                 ub_complete(&sc->work_done);
1341                 ub_state_done(sc, cmd, rc);
1342                 return -1;
1343         }
1344
1345         if (cmd->timeo)
1346                 sc->work_timer.expires = jiffies + cmd->timeo;
1347         else
1348                 sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1349         add_timer(&sc->work_timer);
1350         return 0;
1351 }
1352
1353 /*
1354  * Factorization helper for the command state machine:
1355  * Submit a CSW read and go to STAT state.
1356  */
1357 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1358 {
1359
1360         if (__ub_state_stat(sc, cmd) != 0)
1361                 return;
1362
1363         cmd->stat_count = 0;
1364         cmd->state = UB_CMDST_STAT;
1365 }
1366
1367 /*
1368  * Factorization helper for the command state machine:
1369  * Submit a CSW read and go to STAT state with counter (along [C] path).
1370  */
1371 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1372 {
1373
1374         if (++cmd->stat_count >= 4) {
1375                 ub_state_sense(sc, cmd);
1376                 return;
1377         }
1378
1379         if (__ub_state_stat(sc, cmd) != 0)
1380                 return;
1381
1382         cmd->state = UB_CMDST_STAT;
1383 }
1384
1385 /*
1386  * Factorization helper for the command state machine:
1387  * Submit a REQUEST SENSE and go to SENSE state.
1388  */
1389 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1390 {
1391         struct ub_scsi_cmd *scmd;
1392         struct scatterlist *sg;
1393         int rc;
1394
1395         if (cmd->cdb[0] == REQUEST_SENSE) {
1396                 rc = -EPIPE;
1397                 goto error;
1398         }
1399
1400         scmd = &sc->top_rqs_cmd;
1401         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1402         scmd->cdb[0] = REQUEST_SENSE;
1403         scmd->cdb[4] = UB_SENSE_SIZE;
1404         scmd->cdb_len = 6;
1405         scmd->dir = UB_DIR_READ;
1406         scmd->state = UB_CMDST_INIT;
1407         scmd->nsg = 1;
1408         sg = &scmd->sgv[0];
1409         sg_init_table(sg, UB_MAX_REQ_SG);
1410         sg_set_page(sg, virt_to_page(sc->top_sense), UB_SENSE_SIZE,
1411                         (unsigned long)sc->top_sense & (PAGE_SIZE-1));
1412         scmd->len = UB_SENSE_SIZE;
1413         scmd->lun = cmd->lun;
1414         scmd->done = ub_top_sense_done;
1415         scmd->back = cmd;
1416
1417         scmd->tag = sc->tagcnt++;
1418
1419         cmd->state = UB_CMDST_SENSE;
1420
1421         ub_cmdq_insert(sc, scmd);
1422         return;
1423
1424 error:
1425         ub_state_done(sc, cmd, rc);
1426 }
1427
1428 /*
1429  * A helper for the command's state machine:
1430  * Submit a stall clear.
1431  */
1432 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1433     int stalled_pipe)
1434 {
1435         int endp;
1436         struct usb_ctrlrequest *cr;
1437         int rc;
1438
1439         endp = usb_pipeendpoint(stalled_pipe);
1440         if (usb_pipein (stalled_pipe))
1441                 endp |= USB_DIR_IN;
1442
1443         cr = &sc->work_cr;
1444         cr->bRequestType = USB_RECIP_ENDPOINT;
1445         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1446         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1447         cr->wIndex = cpu_to_le16(endp);
1448         cr->wLength = cpu_to_le16(0);
1449
1450         UB_INIT_COMPLETION(sc->work_done);
1451
1452         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1453             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1454
1455         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1456                 ub_complete(&sc->work_done);
1457                 return rc;
1458         }
1459
1460         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1461         add_timer(&sc->work_timer);
1462         return 0;
1463 }
1464
1465 /*
1466  */
1467 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1468 {
1469         unsigned char *sense = sc->top_sense;
1470         struct ub_scsi_cmd *cmd;
1471
1472         /*
1473          * Find the command which triggered the unit attention or a check,
1474          * save the sense into it, and advance its state machine.
1475          */
1476         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1477                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1478                 return;
1479         }
1480         if (cmd != scmd->back) {
1481                 printk(KERN_WARNING "%s: "
1482                     "sense done for wrong command 0x%x\n",
1483                     sc->name, cmd->tag);
1484                 return;
1485         }
1486         if (cmd->state != UB_CMDST_SENSE) {
1487                 printk(KERN_WARNING "%s: sense done with bad cmd state %d\n",
1488                     sc->name, cmd->state);
1489                 return;
1490         }
1491
1492         /*
1493          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1494          */
1495         cmd->key = sense[2] & 0x0F;
1496         cmd->asc = sense[12];
1497         cmd->ascq = sense[13];
1498
1499         ub_scsi_urb_compl(sc, cmd);
1500 }
1501
1502 /*
1503  * Reset management
1504  */
1505
1506 static void ub_reset_enter(struct ub_dev *sc, int try)
1507 {
1508
1509         if (sc->reset) {
1510                 /* This happens often on multi-LUN devices. */
1511                 return;
1512         }
1513         sc->reset = try + 1;
1514
1515 #if 0 /* Not needed because the disconnect waits for us. */
1516         unsigned long flags;
1517         spin_lock_irqsave(&ub_lock, flags);
1518         sc->openc++;
1519         spin_unlock_irqrestore(&ub_lock, flags);
1520 #endif
1521
1522 #if 0 /* We let them stop themselves. */
1523         struct ub_lun *lun;
1524         list_for_each_entry(lun, &sc->luns, link) {
1525                 blk_stop_queue(lun->disk->queue);
1526         }
1527 #endif
1528
1529         schedule_work(&sc->reset_work);
1530 }
1531
1532 static void ub_reset_task(struct work_struct *work)
1533 {
1534         struct ub_dev *sc = container_of(work, struct ub_dev, reset_work);
1535         unsigned long flags;
1536         struct ub_lun *lun;
1537         int rc;
1538
1539         if (!sc->reset) {
1540                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1541                     sc->name);
1542                 return;
1543         }
1544
1545         if (atomic_read(&sc->poison)) {
1546                 ;
1547         } else if ((sc->reset & 1) == 0) {
1548                 ub_sync_reset(sc);
1549                 msleep(700);    /* usb-storage sleeps 6s (!) */
1550                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
1551                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
1552         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1553                 ;
1554         } else {
1555                 rc = usb_lock_device_for_reset(sc->dev, sc->intf);
1556                 if (rc < 0) {
1557                         printk(KERN_NOTICE
1558                             "%s: usb_lock_device_for_reset failed (%d)\n",
1559                             sc->name, rc);
1560                 } else {
1561                         rc = usb_reset_device(sc->dev);
1562                         if (rc < 0) {
1563                                 printk(KERN_NOTICE "%s: "
1564                                     "usb_lock_device_for_reset failed (%d)\n",
1565                                     sc->name, rc);
1566                         }
1567                         usb_unlock_device(sc->dev);
1568                 }
1569         }
1570
1571         /*
1572          * In theory, no commands can be running while reset is active,
1573          * so nobody can ask for another reset, and so we do not need any
1574          * queues of resets or anything. We do need a spinlock though,
1575          * to interact with block layer.
1576          */
1577         spin_lock_irqsave(sc->lock, flags);
1578         sc->reset = 0;
1579         tasklet_schedule(&sc->tasklet);
1580         list_for_each_entry(lun, &sc->luns, link) {
1581                 blk_start_queue(lun->disk->queue);
1582         }
1583         wake_up(&sc->reset_wait);
1584         spin_unlock_irqrestore(sc->lock, flags);
1585 }
1586
1587 /*
1588  * XXX Reset brackets are too much hassle to implement, so just stub them
1589  * in order to prevent forced unbinding (which deadlocks solid when our
1590  * ->disconnect method waits for the reset to complete and this kills keventd).
1591  *
1592  * XXX Tell Alan to move usb_unlock_device inside of usb_reset_device,
1593  * or else the post_reset is invoked, and restats I/O on a locked device.
1594  */
1595 static int ub_pre_reset(struct usb_interface *iface) {
1596         return 0;
1597 }
1598
1599 static int ub_post_reset(struct usb_interface *iface) {
1600         return 0;
1601 }
1602
1603 /*
1604  * This is called from a process context.
1605  */
1606 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1607 {
1608
1609         lun->readonly = 0;      /* XXX Query this from the device */
1610
1611         lun->capacity.nsec = 0;
1612         lun->capacity.bsize = 512;
1613         lun->capacity.bshift = 0;
1614
1615         if (ub_sync_tur(sc, lun) != 0)
1616                 return;                 /* Not ready */
1617         lun->changed = 0;
1618
1619         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1620                 /*
1621                  * The retry here means something is wrong, either with the
1622                  * device, with the transport, or with our code.
1623                  * We keep this because sd.c has retries for capacity.
1624                  */
1625                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1626                         lun->capacity.nsec = 0;
1627                         lun->capacity.bsize = 512;
1628                         lun->capacity.bshift = 0;
1629                 }
1630         }
1631 }
1632
1633 /*
1634  * The open funcion.
1635  * This is mostly needed to keep refcounting, but also to support
1636  * media checks on removable media drives.
1637  */
1638 static int ub_bd_open(struct block_device *bdev, fmode_t mode)
1639 {
1640         struct ub_lun *lun = bdev->bd_disk->private_data;
1641         struct ub_dev *sc = lun->udev;
1642         unsigned long flags;
1643         int rc;
1644
1645         spin_lock_irqsave(&ub_lock, flags);
1646         if (atomic_read(&sc->poison)) {
1647                 spin_unlock_irqrestore(&ub_lock, flags);
1648                 return -ENXIO;
1649         }
1650         sc->openc++;
1651         spin_unlock_irqrestore(&ub_lock, flags);
1652
1653         if (lun->removable || lun->readonly)
1654                 check_disk_change(bdev);
1655
1656         /*
1657          * The sd.c considers ->media_present and ->changed not equivalent,
1658          * under some pretty murky conditions (a failure of READ CAPACITY).
1659          * We may need it one day.
1660          */
1661         if (lun->removable && lun->changed && !(mode & FMODE_NDELAY)) {
1662                 rc = -ENOMEDIUM;
1663                 goto err_open;
1664         }
1665
1666         if (lun->readonly && (mode & FMODE_WRITE)) {
1667                 rc = -EROFS;
1668                 goto err_open;
1669         }
1670
1671         return 0;
1672
1673 err_open:
1674         ub_put(sc);
1675         return rc;
1676 }
1677
1678 static int ub_bd_unlocked_open(struct block_device *bdev, fmode_t mode)
1679 {
1680         int ret;
1681
1682         mutex_lock(&ub_mutex);
1683         ret = ub_bd_open(bdev, mode);
1684         mutex_unlock(&ub_mutex);
1685
1686         return ret;
1687 }
1688
1689
1690 /*
1691  */
1692 static int ub_bd_release(struct gendisk *disk, fmode_t mode)
1693 {
1694         struct ub_lun *lun = disk->private_data;
1695         struct ub_dev *sc = lun->udev;
1696
1697         mutex_lock(&ub_mutex);
1698         ub_put(sc);
1699         mutex_unlock(&ub_mutex);
1700
1701         return 0;
1702 }
1703
1704 /*
1705  * The ioctl interface.
1706  */
1707 static int ub_bd_ioctl(struct block_device *bdev, fmode_t mode,
1708     unsigned int cmd, unsigned long arg)
1709 {
1710         void __user *usermem = (void __user *) arg;
1711         int ret;
1712
1713         mutex_lock(&ub_mutex);
1714         ret = scsi_cmd_blk_ioctl(bdev, mode, cmd, usermem);
1715         mutex_unlock(&ub_mutex);
1716
1717         return ret;
1718 }
1719
1720 /*
1721  * This is called by check_disk_change if we reported a media change.
1722  * The main onjective here is to discover the features of the media such as
1723  * the capacity, read-only status, etc. USB storage generally does not
1724  * need to be spun up, but if we needed it, this would be the place.
1725  *
1726  * This call can sleep.
1727  *
1728  * The return code is not used.
1729  */
1730 static int ub_bd_revalidate(struct gendisk *disk)
1731 {
1732         struct ub_lun *lun = disk->private_data;
1733
1734         ub_revalidate(lun->udev, lun);
1735
1736         /* XXX Support sector size switching like in sr.c */
1737         blk_queue_logical_block_size(disk->queue, lun->capacity.bsize);
1738         set_capacity(disk, lun->capacity.nsec);
1739         // set_disk_ro(sdkp->disk, lun->readonly);
1740
1741         return 0;
1742 }
1743
1744 /*
1745  * The check is called by the block layer to verify if the media
1746  * is still available. It is supposed to be harmless, lightweight and
1747  * non-intrusive in case the media was not changed.
1748  *
1749  * This call can sleep.
1750  *
1751  * The return code is bool!
1752  */
1753 static unsigned int ub_bd_check_events(struct gendisk *disk,
1754                                        unsigned int clearing)
1755 {
1756         struct ub_lun *lun = disk->private_data;
1757
1758         if (!lun->removable)
1759                 return 0;
1760
1761         /*
1762          * We clean checks always after every command, so this is not
1763          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1764          * the device is actually not ready with operator or software
1765          * intervention required. One dangerous item might be a drive which
1766          * spins itself down, and come the time to write dirty pages, this
1767          * will fail, then block layer discards the data. Since we never
1768          * spin drives up, such devices simply cannot be used with ub anyway.
1769          */
1770         if (ub_sync_tur(lun->udev, lun) != 0) {
1771                 lun->changed = 1;
1772                 return DISK_EVENT_MEDIA_CHANGE;
1773         }
1774
1775         return lun->changed ? DISK_EVENT_MEDIA_CHANGE : 0;
1776 }
1777
1778 static const struct block_device_operations ub_bd_fops = {
1779         .owner          = THIS_MODULE,
1780         .open           = ub_bd_unlocked_open,
1781         .release        = ub_bd_release,
1782         .ioctl          = ub_bd_ioctl,
1783         .check_events   = ub_bd_check_events,
1784         .revalidate_disk = ub_bd_revalidate,
1785 };
1786
1787 /*
1788  * Common ->done routine for commands executed synchronously.
1789  */
1790 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1791 {
1792         struct completion *cop = cmd->back;
1793         complete(cop);
1794 }
1795
1796 /*
1797  * Test if the device has a check condition on it, synchronously.
1798  */
1799 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1800 {
1801         struct ub_scsi_cmd *cmd;
1802         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1803         unsigned long flags;
1804         struct completion compl;
1805         int rc;
1806
1807         init_completion(&compl);
1808
1809         rc = -ENOMEM;
1810         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1811                 goto err_alloc;
1812
1813         cmd->cdb[0] = TEST_UNIT_READY;
1814         cmd->cdb_len = 6;
1815         cmd->dir = UB_DIR_NONE;
1816         cmd->state = UB_CMDST_INIT;
1817         cmd->lun = lun;                 /* This may be NULL, but that's ok */
1818         cmd->done = ub_probe_done;
1819         cmd->back = &compl;
1820
1821         spin_lock_irqsave(sc->lock, flags);
1822         cmd->tag = sc->tagcnt++;
1823
1824         rc = ub_submit_scsi(sc, cmd);
1825         spin_unlock_irqrestore(sc->lock, flags);
1826
1827         if (rc != 0)
1828                 goto err_submit;
1829
1830         wait_for_completion(&compl);
1831
1832         rc = cmd->error;
1833
1834         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1835                 rc = cmd->key;
1836
1837 err_submit:
1838         kfree(cmd);
1839 err_alloc:
1840         return rc;
1841 }
1842
1843 /*
1844  * Read the SCSI capacity synchronously (for probing).
1845  */
1846 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1847     struct ub_capacity *ret)
1848 {
1849         struct ub_scsi_cmd *cmd;
1850         struct scatterlist *sg;
1851         char *p;
1852         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1853         unsigned long flags;
1854         unsigned int bsize, shift;
1855         unsigned long nsec;
1856         struct completion compl;
1857         int rc;
1858
1859         init_completion(&compl);
1860
1861         rc = -ENOMEM;
1862         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1863                 goto err_alloc;
1864         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1865
1866         cmd->cdb[0] = 0x25;
1867         cmd->cdb_len = 10;
1868         cmd->dir = UB_DIR_READ;
1869         cmd->state = UB_CMDST_INIT;
1870         cmd->nsg = 1;
1871         sg = &cmd->sgv[0];
1872         sg_init_table(sg, UB_MAX_REQ_SG);
1873         sg_set_page(sg, virt_to_page(p), 8, (unsigned long)p & (PAGE_SIZE-1));
1874         cmd->len = 8;
1875         cmd->lun = lun;
1876         cmd->done = ub_probe_done;
1877         cmd->back = &compl;
1878
1879         spin_lock_irqsave(sc->lock, flags);
1880         cmd->tag = sc->tagcnt++;
1881
1882         rc = ub_submit_scsi(sc, cmd);
1883         spin_unlock_irqrestore(sc->lock, flags);
1884
1885         if (rc != 0)
1886                 goto err_submit;
1887
1888         wait_for_completion(&compl);
1889
1890         if (cmd->error != 0) {
1891                 rc = -EIO;
1892                 goto err_read;
1893         }
1894         if (cmd->act_len != 8) {
1895                 rc = -EIO;
1896                 goto err_read;
1897         }
1898
1899         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1900         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1901         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1902         switch (bsize) {
1903         case 512:       shift = 0;      break;
1904         case 1024:      shift = 1;      break;
1905         case 2048:      shift = 2;      break;
1906         case 4096:      shift = 3;      break;
1907         default:
1908                 rc = -EDOM;
1909                 goto err_inv_bsize;
1910         }
1911
1912         ret->bsize = bsize;
1913         ret->bshift = shift;
1914         ret->nsec = nsec << shift;
1915         rc = 0;
1916
1917 err_inv_bsize:
1918 err_read:
1919 err_submit:
1920         kfree(cmd);
1921 err_alloc:
1922         return rc;
1923 }
1924
1925 /*
1926  */
1927 static void ub_probe_urb_complete(struct urb *urb)
1928 {
1929         struct completion *cop = urb->context;
1930         complete(cop);
1931 }
1932
1933 static void ub_probe_timeout(unsigned long arg)
1934 {
1935         struct completion *cop = (struct completion *) arg;
1936         complete(cop);
1937 }
1938
1939 /*
1940  * Reset with a Bulk reset.
1941  */
1942 static int ub_sync_reset(struct ub_dev *sc)
1943 {
1944         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1945         struct usb_ctrlrequest *cr;
1946         struct completion compl;
1947         struct timer_list timer;
1948         int rc;
1949
1950         init_completion(&compl);
1951
1952         cr = &sc->work_cr;
1953         cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1954         cr->bRequest = US_BULK_RESET_REQUEST;
1955         cr->wValue = cpu_to_le16(0);
1956         cr->wIndex = cpu_to_le16(ifnum);
1957         cr->wLength = cpu_to_le16(0);
1958
1959         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1960             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
1961
1962         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
1963                 printk(KERN_WARNING
1964                      "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
1965                 return rc;
1966         }
1967
1968         init_timer(&timer);
1969         timer.function = ub_probe_timeout;
1970         timer.data = (unsigned long) &compl;
1971         timer.expires = jiffies + UB_CTRL_TIMEOUT;
1972         add_timer(&timer);
1973
1974         wait_for_completion(&compl);
1975
1976         del_timer_sync(&timer);
1977         usb_kill_urb(&sc->work_urb);
1978
1979         return sc->work_urb.status;
1980 }
1981
1982 /*
1983  * Get number of LUNs by the way of Bulk GetMaxLUN command.
1984  */
1985 static int ub_sync_getmaxlun(struct ub_dev *sc)
1986 {
1987         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1988         unsigned char *p;
1989         enum { ALLOC_SIZE = 1 };
1990         struct usb_ctrlrequest *cr;
1991         struct completion compl;
1992         struct timer_list timer;
1993         int nluns;
1994         int rc;
1995
1996         init_completion(&compl);
1997
1998         rc = -ENOMEM;
1999         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2000                 goto err_alloc;
2001         *p = 55;
2002
2003         cr = &sc->work_cr;
2004         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
2005         cr->bRequest = US_BULK_GET_MAX_LUN;
2006         cr->wValue = cpu_to_le16(0);
2007         cr->wIndex = cpu_to_le16(ifnum);
2008         cr->wLength = cpu_to_le16(1);
2009
2010         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2011             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2012
2013         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0)
2014                 goto err_submit;
2015
2016         init_timer(&timer);
2017         timer.function = ub_probe_timeout;
2018         timer.data = (unsigned long) &compl;
2019         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2020         add_timer(&timer);
2021
2022         wait_for_completion(&compl);
2023
2024         del_timer_sync(&timer);
2025         usb_kill_urb(&sc->work_urb);
2026
2027         if ((rc = sc->work_urb.status) < 0)
2028                 goto err_io;
2029
2030         if (sc->work_urb.actual_length != 1) {
2031                 nluns = 0;
2032         } else {
2033                 if ((nluns = *p) == 55) {
2034                         nluns = 0;
2035                 } else {
2036                         /* GetMaxLUN returns the maximum LUN number */
2037                         nluns += 1;
2038                         if (nluns > UB_MAX_LUNS)
2039                                 nluns = UB_MAX_LUNS;
2040                 }
2041         }
2042
2043         kfree(p);
2044         return nluns;
2045
2046 err_io:
2047 err_submit:
2048         kfree(p);
2049 err_alloc:
2050         return rc;
2051 }
2052
2053 /*
2054  * Clear initial stalls.
2055  */
2056 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2057 {
2058         int endp;
2059         struct usb_ctrlrequest *cr;
2060         struct completion compl;
2061         struct timer_list timer;
2062         int rc;
2063
2064         init_completion(&compl);
2065
2066         endp = usb_pipeendpoint(stalled_pipe);
2067         if (usb_pipein (stalled_pipe))
2068                 endp |= USB_DIR_IN;
2069
2070         cr = &sc->work_cr;
2071         cr->bRequestType = USB_RECIP_ENDPOINT;
2072         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2073         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2074         cr->wIndex = cpu_to_le16(endp);
2075         cr->wLength = cpu_to_le16(0);
2076
2077         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2078             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2079
2080         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2081                 printk(KERN_WARNING
2082                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2083                 return rc;
2084         }
2085
2086         init_timer(&timer);
2087         timer.function = ub_probe_timeout;
2088         timer.data = (unsigned long) &compl;
2089         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2090         add_timer(&timer);
2091
2092         wait_for_completion(&compl);
2093
2094         del_timer_sync(&timer);
2095         usb_kill_urb(&sc->work_urb);
2096
2097         usb_reset_endpoint(sc->dev, endp);
2098
2099         return 0;
2100 }
2101
2102 /*
2103  * Get the pipe settings.
2104  */
2105 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2106     struct usb_interface *intf)
2107 {
2108         struct usb_host_interface *altsetting = intf->cur_altsetting;
2109         struct usb_endpoint_descriptor *ep_in = NULL;
2110         struct usb_endpoint_descriptor *ep_out = NULL;
2111         struct usb_endpoint_descriptor *ep;
2112         int i;
2113
2114         /*
2115          * Find the endpoints we need.
2116          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2117          * We will ignore any others.
2118          */
2119         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2120                 ep = &altsetting->endpoint[i].desc;
2121
2122                 /* Is it a BULK endpoint? */
2123                 if (usb_endpoint_xfer_bulk(ep)) {
2124                         /* BULK in or out? */
2125                         if (usb_endpoint_dir_in(ep)) {
2126                                 if (ep_in == NULL)
2127                                         ep_in = ep;
2128                         } else {
2129                                 if (ep_out == NULL)
2130                                         ep_out = ep;
2131                         }
2132                 }
2133         }
2134
2135         if (ep_in == NULL || ep_out == NULL) {
2136                 printk(KERN_NOTICE "%s: failed endpoint check\n", sc->name);
2137                 return -ENODEV;
2138         }
2139
2140         /* Calculate and store the pipe values */
2141         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2142         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2143         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2144                 usb_endpoint_num(ep_out));
2145         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2146                 usb_endpoint_num(ep_in));
2147
2148         return 0;
2149 }
2150
2151 /*
2152  * Probing is done in the process context, which allows us to cheat
2153  * and not to build a state machine for the discovery.
2154  */
2155 static int ub_probe(struct usb_interface *intf,
2156     const struct usb_device_id *dev_id)
2157 {
2158         struct ub_dev *sc;
2159         int nluns;
2160         int rc;
2161         int i;
2162
2163         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2164                 return -ENXIO;
2165
2166         rc = -ENOMEM;
2167         if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2168                 goto err_core;
2169         sc->lock = ub_next_lock();
2170         INIT_LIST_HEAD(&sc->luns);
2171         usb_init_urb(&sc->work_urb);
2172         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2173         atomic_set(&sc->poison, 0);
2174         INIT_WORK(&sc->reset_work, ub_reset_task);
2175         init_waitqueue_head(&sc->reset_wait);
2176
2177         init_timer(&sc->work_timer);
2178         sc->work_timer.data = (unsigned long) sc;
2179         sc->work_timer.function = ub_urb_timeout;
2180
2181         ub_init_completion(&sc->work_done);
2182         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2183
2184         sc->dev = interface_to_usbdev(intf);
2185         sc->intf = intf;
2186         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2187         usb_set_intfdata(intf, sc);
2188         usb_get_dev(sc->dev);
2189         /*
2190          * Since we give the interface struct to the block level through
2191          * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent
2192          * oopses on close after a disconnect (kernels 2.6.16 and up).
2193          */
2194         usb_get_intf(sc->intf);
2195
2196         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2197             sc->dev->bus->busnum, sc->dev->devnum);
2198
2199         /* XXX Verify that we can handle the device (from descriptors) */
2200
2201         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2202                 goto err_dev_desc;
2203
2204         /*
2205          * At this point, all USB initialization is done, do upper layer.
2206          * We really hate halfway initialized structures, so from the
2207          * invariants perspective, this ub_dev is fully constructed at
2208          * this point.
2209          */
2210
2211         /*
2212          * This is needed to clear toggles. It is a problem only if we do
2213          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2214          */
2215 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2216         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2217         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2218 #endif
2219
2220         /*
2221          * The way this is used by the startup code is a little specific.
2222          * A SCSI check causes a USB stall. Our common case code sees it
2223          * and clears the check, after which the device is ready for use.
2224          * But if a check was not present, any command other than
2225          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2226          *
2227          * If we neglect to clear the SCSI check, the first real command fails
2228          * (which is the capacity readout). We clear that and retry, but why
2229          * causing spurious retries for no reason.
2230          *
2231          * Revalidation may start with its own TEST_UNIT_READY, but that one
2232          * has to succeed, so we clear checks with an additional one here.
2233          * In any case it's not our business how revaliadation is implemented.
2234          */
2235         for (i = 0; i < 3; i++) {  /* Retries for the schwag key from KS'04 */
2236                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2237                 if (rc != 0x6) break;
2238                 msleep(10);
2239         }
2240
2241         nluns = 1;
2242         for (i = 0; i < 3; i++) {
2243                 if ((rc = ub_sync_getmaxlun(sc)) < 0)
2244                         break;
2245                 if (rc != 0) {
2246                         nluns = rc;
2247                         break;
2248                 }
2249                 msleep(100);
2250         }
2251
2252         for (i = 0; i < nluns; i++) {
2253                 ub_probe_lun(sc, i);
2254         }
2255         return 0;
2256
2257 err_dev_desc:
2258         usb_set_intfdata(intf, NULL);
2259         usb_put_intf(sc->intf);
2260         usb_put_dev(sc->dev);
2261         kfree(sc);
2262 err_core:
2263         return rc;
2264 }
2265
2266 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2267 {
2268         struct ub_lun *lun;
2269         struct request_queue *q;
2270         struct gendisk *disk;
2271         int rc;
2272
2273         rc = -ENOMEM;
2274         if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2275                 goto err_alloc;
2276         lun->num = lnum;
2277
2278         rc = -ENOSR;
2279         if ((lun->id = ub_id_get()) == -1)
2280                 goto err_id;
2281
2282         lun->udev = sc;
2283
2284         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2285             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2286
2287         lun->removable = 1;             /* XXX Query this from the device */
2288         lun->changed = 1;               /* ub_revalidate clears only */
2289         ub_revalidate(sc, lun);
2290
2291         rc = -ENOMEM;
2292         if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
2293                 goto err_diskalloc;
2294
2295         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2296         disk->major = UB_MAJOR;
2297         disk->first_minor = lun->id * UB_PARTS_PER_LUN;
2298         disk->fops = &ub_bd_fops;
2299         disk->private_data = lun;
2300         disk->driverfs_dev = &sc->intf->dev;
2301
2302         rc = -ENOMEM;
2303         if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
2304                 goto err_blkqinit;
2305
2306         disk->queue = q;
2307
2308         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2309         blk_queue_max_segments(q, UB_MAX_REQ_SG);
2310         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2311         blk_queue_max_hw_sectors(q, UB_MAX_SECTORS);
2312         blk_queue_logical_block_size(q, lun->capacity.bsize);
2313
2314         lun->disk = disk;
2315         q->queuedata = lun;
2316         list_add(&lun->link, &sc->luns);
2317
2318         set_capacity(disk, lun->capacity.nsec);
2319         if (lun->removable)
2320                 disk->flags |= GENHD_FL_REMOVABLE;
2321
2322         add_disk(disk);
2323
2324         return 0;
2325
2326 err_blkqinit:
2327         put_disk(disk);
2328 err_diskalloc:
2329         ub_id_put(lun->id);
2330 err_id:
2331         kfree(lun);
2332 err_alloc:
2333         return rc;
2334 }
2335
2336 static void ub_disconnect(struct usb_interface *intf)
2337 {
2338         struct ub_dev *sc = usb_get_intfdata(intf);
2339         struct ub_lun *lun;
2340         unsigned long flags;
2341
2342         /*
2343          * Prevent ub_bd_release from pulling the rug from under us.
2344          * XXX This is starting to look like a kref.
2345          * XXX Why not to take this ref at probe time?
2346          */
2347         spin_lock_irqsave(&ub_lock, flags);
2348         sc->openc++;
2349         spin_unlock_irqrestore(&ub_lock, flags);
2350
2351         /*
2352          * Fence stall clearings, operations triggered by unlinkings and so on.
2353          * We do not attempt to unlink any URBs, because we do not trust the
2354          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2355          */
2356         atomic_set(&sc->poison, 1);
2357
2358         /*
2359          * Wait for reset to end, if any.
2360          */
2361         wait_event(sc->reset_wait, !sc->reset);
2362
2363         /*
2364          * Blow away queued commands.
2365          *
2366          * Actually, this never works, because before we get here
2367          * the HCD terminates outstanding URB(s). It causes our
2368          * SCSI command queue to advance, commands fail to submit,
2369          * and the whole queue drains. So, we just use this code to
2370          * print warnings.
2371          */
2372         spin_lock_irqsave(sc->lock, flags);
2373         {
2374                 struct ub_scsi_cmd *cmd;
2375                 int cnt = 0;
2376                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2377                         cmd->error = -ENOTCONN;
2378                         cmd->state = UB_CMDST_DONE;
2379                         ub_cmdq_pop(sc);
2380                         (*cmd->done)(sc, cmd);
2381                         cnt++;
2382                 }
2383                 if (cnt != 0) {
2384                         printk(KERN_WARNING "%s: "
2385                             "%d was queued after shutdown\n", sc->name, cnt);
2386                 }
2387         }
2388         spin_unlock_irqrestore(sc->lock, flags);
2389
2390         /*
2391          * Unregister the upper layer.
2392          */
2393         list_for_each_entry(lun, &sc->luns, link) {
2394                 del_gendisk(lun->disk);
2395                 /*
2396                  * I wish I could do:
2397                  *    queue_flag_set(QUEUE_FLAG_DEAD, q);
2398                  * As it is, we rely on our internal poisoning and let
2399                  * the upper levels to spin furiously failing all the I/O.
2400                  */
2401         }
2402
2403         /*
2404          * Testing for -EINPROGRESS is always a bug, so we are bending
2405          * the rules a little.
2406          */
2407         spin_lock_irqsave(sc->lock, flags);
2408         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2409                 printk(KERN_WARNING "%s: "
2410                     "URB is active after disconnect\n", sc->name);
2411         }
2412         spin_unlock_irqrestore(sc->lock, flags);
2413
2414         /*
2415          * There is virtually no chance that other CPU runs a timeout so long
2416          * after ub_urb_complete should have called del_timer, but only if HCD
2417          * didn't forget to deliver a callback on unlink.
2418          */
2419         del_timer_sync(&sc->work_timer);
2420
2421         /*
2422          * At this point there must be no commands coming from anyone
2423          * and no URBs left in transit.
2424          */
2425
2426         ub_put(sc);
2427 }
2428
2429 static struct usb_driver ub_driver = {
2430         .name =         "ub",
2431         .probe =        ub_probe,
2432         .disconnect =   ub_disconnect,
2433         .id_table =     ub_usb_ids,
2434         .pre_reset =    ub_pre_reset,
2435         .post_reset =   ub_post_reset,
2436 };
2437
2438 static int __init ub_init(void)
2439 {
2440         int rc;
2441         int i;
2442
2443         pr_info("'Low Performance USB Block' driver is deprecated. "
2444                         "Please switch to usb-storage\n");
2445         for (i = 0; i < UB_QLOCK_NUM; i++)
2446                 spin_lock_init(&ub_qlockv[i]);
2447
2448         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2449                 goto err_regblkdev;
2450
2451         if ((rc = usb_register(&ub_driver)) != 0)
2452                 goto err_register;
2453
2454         usb_usual_set_present(USB_US_TYPE_UB);
2455         return 0;
2456
2457 err_register:
2458         unregister_blkdev(UB_MAJOR, DRV_NAME);
2459 err_regblkdev:
2460         return rc;
2461 }
2462
2463 static void __exit ub_exit(void)
2464 {
2465         usb_deregister(&ub_driver);
2466
2467         unregister_blkdev(UB_MAJOR, DRV_NAME);
2468         usb_usual_clear_present(USB_US_TYPE_UB);
2469 }
2470
2471 module_init(ub_init);
2472 module_exit(ub_exit);
2473
2474 MODULE_LICENSE("GPL");