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 <scsi/scsi.h>
  31
  32 #define DRV_NAME "ub"
  33
  34 #define UB_MAJOR 180
  35
  36 /*
  37  * The command state machine is the key model for understanding of this driver.
  38  *
  39  * The general rule is that all transitions are done towards the bottom
  40  * of the diagram, thus preventing any loops.
  41  *
  42  * An exception to that is how the STAT state is handled. A counter allows it
  43  * to be re-entered along the path marked with [C].
  44  *
  45  *       +--------+
  46  *       ! INIT   !
  47  *       +--------+
  48  *           !
  49  *        ub_scsi_cmd_start fails ->--------------------------------------\
  50  *           !                                                            !
  51  *           V                                                            !
  52  *       +--------+                                                       !
  53  *       ! CMD    !                                                       !
  54  *       +--------+                                                       !
  55  *           !                                            +--------+      !
  56  *         was -EPIPE -->-------------------------------->! CLEAR  !      !
  57  *           !                                            +--------+      !
  58  *           !                                                !           !
  59  *         was error -->------------------------------------- ! --------->\
  60  *           !                                                !           !
  61  *  /--<-- cmd->dir == NONE ?                                 !           !
  62  *  !        !                                                !           !
  63  *  !        V                                                !           !
  64  *  !    +--------+                                           !           !
  65  *  !    ! DATA   !                                           !           !
  66  *  !    +--------+                                           !           !
  67  *  !        !                           +---------+          !           !
  68  *  !      was -EPIPE -->--------------->! CLR2STS !          !           !
  69  *  !        !                           +---------+          !           !
  70  *  !        !                                !               !           !
  71  *  !        !                              was error -->---- ! --------->\
  72  *  !      was error -->--------------------- ! ------------- ! --------->\
  73  *  !        !                                !               !           !
  74  *  !        V                                !               !           !
  75  *  \--->+--------+                           !               !           !
  76  *       ! STAT   !<--------------------------/               !           !
  77  *  /--->+--------+                                           !           !
  78  *  !        !                                                !           !
  79  * [C]     was -EPIPE -->-----------\                         !           !
  80  *  !        !                      !                         !           !
  81  *  +<---- len == 0                 !                         !           !
  82  *  !        !                      !                         !           !
  83  *  !      was error -->--------------------------------------!---------->\
  84  *  !        !                      !                         !           !
  85  *  +<---- bad CSW                  !                         !           !
  86  *  +<---- bad tag                  !                         !           !
  87  *  !        !                      V                         !           !
  88  *  !        !                 +--------+                     !           !
  89  *  !        !                 ! CLRRS  !                     !           !
  90  *  !        !                 +--------+                     !           !
  91  *  !        !                      !                         !           !
  92  *  \------- ! --------------------[C]--------\               !           !
  93  *           !                                !               !           !
  94  *         cmd->error---\                +--------+           !           !
  95  *           !          +--------------->! SENSE  !<----------/           !
  96  *         STAT_FAIL----/                +--------+                       !
  97  *           !                                !                           V
  98  *           !                                V                      +--------+
  99  *           \--------------------------------\--------------------->! DONE   !
 100  *                                                                   +--------+
 101  */
 102
 103 /*
 104  * This many LUNs per USB device.
 105  * Every one of them takes a host, see UB_MAX_HOSTS.
 106  */
 107 #define UB_MAX_LUNS   9
 108
 109 /*
 110  */
 111
 112 #define UB_PARTS_PER_LUN      8
 113
 114 #define UB_MAX_CDB_SIZE      16         /* Corresponds to Bulk */
 115
 116 #define UB_SENSE_SIZE  18
 117
 118 /*
 119  */
 120
 121 /* command block wrapper */
 122 struct bulk_cb_wrap {
 123         __le32  Signature;              /* contains 'USBC' */
 124         u32     Tag;                    /* unique per command id */
 125         __le32  DataTransferLength;     /* size of data */
 126         u8      Flags;                  /* direction in bit 0 */
 127         u8      Lun;                    /* LUN */
 128         u8      Length;                 /* of of the CDB */
 129         u8      CDB[UB_MAX_CDB_SIZE];   /* max command */
 130 };
 131
 132 #define US_BULK_CB_WRAP_LEN     31
 133 #define US_BULK_CB_SIGN         0x43425355      /*spells out USBC */
 134 #define US_BULK_FLAG_IN         1
 135 #define US_BULK_FLAG_OUT        0
 136
 137 /* command status wrapper */
 138 struct bulk_cs_wrap {
 139         __le32  Signature;              /* should = 'USBS' */
 140         u32     Tag;                    /* same as original command */
 141         __le32  Residue;                /* amount not transferred */
 142         u8      Status;                 /* see below */
 143 };
 144
 145 #define US_BULK_CS_WRAP_LEN     13
 146 #define US_BULK_CS_SIGN         0x53425355      /* spells out 'USBS' */
 147 #define US_BULK_STAT_OK         0
 148 #define US_BULK_STAT_FAIL       1
 149 #define US_BULK_STAT_PHASE      2
 150
 151 /* bulk-only class specific requests */
 152 #define US_BULK_RESET_REQUEST   0xff
 153 #define US_BULK_GET_MAX_LUN     0xfe
 154
 155 /*
 156  */
 157 struct ub_dev;
 158
 159 #define UB_MAX_REQ_SG   9       /* cdrecord requires 32KB and maybe a header */
 160 #define UB_MAX_SECTORS 64
 161
 162 /*
 163  * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
 164  * even if a webcam hogs the bus, but some devices need time to spin up.
 165  */
 166 #define UB_URB_TIMEOUT  (HZ*2)
 167 #define UB_DATA_TIMEOUT (HZ*5)  /* ZIP does spin-ups in the data phase */
 168 #define UB_STAT_TIMEOUT (HZ*5)  /* Same spinups and eject for a dataless cmd. */
 169 #define UB_CTRL_TIMEOUT (HZ/2)  /* 500ms ought to be enough to clear a stall */
 170
 171 /*
 172  * An instance of a SCSI command in transit.
 173  */
 174 #define UB_DIR_NONE     0
 175 #define UB_DIR_READ     1
 176 #define UB_DIR_ILLEGAL2 2
 177 #define UB_DIR_WRITE    3
 178
 179 #define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
 180                          (((c)==UB_DIR_READ)? 'r': 'n'))
 181
 182 enum ub_scsi_cmd_state {
 183         UB_CMDST_INIT,                  /* Initial state */
 184         UB_CMDST_CMD,                   /* Command submitted */
 185         UB_CMDST_DATA,                  /* Data phase */
 186         UB_CMDST_CLR2STS,               /* Clearing before requesting status */
 187         UB_CMDST_STAT,                  /* Status phase */
 188         UB_CMDST_CLEAR,                 /* Clearing a stall (halt, actually) */
 189         UB_CMDST_CLRRS,                 /* Clearing before retrying status */
 190         UB_CMDST_SENSE,                 /* Sending Request Sense */
 191         UB_CMDST_DONE                   /* Final state */
 192 };
 193
 194 struct ub_scsi_cmd {
 195         unsigned char cdb[UB_MAX_CDB_SIZE];
 196         unsigned char cdb_len;
 197
 198         unsigned char dir;              /* 0 - none, 1 - read, 3 - write. */
 199         enum ub_scsi_cmd_state state;
 200         unsigned int tag;
 201         struct ub_scsi_cmd *next;
 202
 203         int error;                      /* Return code - valid upon done */
 204         unsigned int act_len;           /* Return size */
 205         unsigned char key, asc, ascq;   /* May be valid if error==-EIO */
 206
 207         int stat_count;                 /* Retries getting status. */
 208         unsigned int timeo;             /* jiffies until rq->timeout changes */
 209
 210         unsigned int len;               /* Requested length */
 211         unsigned int current_sg;
 212         unsigned int nsg;               /* sgv[nsg] */
 213         struct scatterlist sgv[UB_MAX_REQ_SG];
 214
 215         struct ub_lun *lun;
 216         void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
 217         void *back;
 218 };
 219
 220 struct ub_request {
 221         struct request *rq;
 222         unsigned int current_try;
 223         unsigned int nsg;               /* sgv[nsg] */
 224         struct scatterlist sgv[UB_MAX_REQ_SG];
 225 };
 226
 227 /*
 228  */
 229 struct ub_capacity {
 230         unsigned long nsec;             /* Linux size - 512 byte sectors */
 231         unsigned int bsize;             /* Linux hardsect_size */
 232         unsigned int bshift;            /* Shift between 512 and hard sects */
 233 };
 234
 235 /*
 236  * This is a direct take-off from linux/include/completion.h
 237  * The difference is that I do not wait on this thing, just poll.
 238  * When I want to wait (ub_probe), I just use the stock completion.
 239  *
 240  * Note that INIT_COMPLETION takes no lock. It is correct. But why
 241  * in the bloody hell that thing takes struct instead of pointer to struct
 242  * is quite beyond me. I just copied it from the stock completion.
 243  */
 244 struct ub_completion {
 245         unsigned int done;
 246         spinlock_t lock;
 247 };
 248
 249 static inline void ub_init_completion(struct ub_completion *x)
 250 {
 251         x->done = 0;
 252         spin_lock_init(&x->lock);
 253 }
 254
 255 #define UB_INIT_COMPLETION(x)   ((x).done = 0)
 256
 257 static void ub_complete(struct ub_completion *x)
 258 {
 259         unsigned long flags;
 260
 261         spin_lock_irqsave(&x->lock, flags);
 262         x->done++;
 263         spin_unlock_irqrestore(&x->lock, flags);
 264 }
 265
 266 static int ub_is_completed(struct ub_completion *x)
 267 {
 268         unsigned long flags;
 269         int ret;
 270
 271         spin_lock_irqsave(&x->lock, flags);
 272         ret = x->done;
 273         spin_unlock_irqrestore(&x->lock, flags);
 274         return ret;
 275 }
 276
 277 /*
 278  */
 279 struct ub_scsi_cmd_queue {
 280         int qlen, qmax;
 281         struct ub_scsi_cmd *head, *tail;
 282 };
 283
 284 /*
 285  * The block device instance (one per LUN).
 286  */
 287 struct ub_lun {
 288         struct ub_dev *udev;
 289         struct list_head link;
 290         struct gendisk *disk;
 291         int id;                         /* Host index */
 292         int num;                        /* LUN number */
 293         char name[16];
 294
 295         int changed;                    /* Media was changed */
 296         int removable;
 297         int readonly;
 298
 299         struct ub_request urq;
 300
 301         /* Use Ingo's mempool if or when we have more than one command. */
 302         /*
 303          * Currently we never need more than one command for the whole device.
 304          * However, giving every LUN a command is a cheap and automatic way
 305          * to enforce fairness between them.
 306          */
 307         int cmda[1];
 308         struct ub_scsi_cmd cmdv[1];
 309
 310         struct ub_capacity capacity;
 311 };
 312
 313 /*
 314  * The USB device instance.
 315  */
 316 struct ub_dev {
 317         spinlock_t *lock;
 318         atomic_t poison;                /* The USB device is disconnected */
 319         int openc;                      /* protected by ub_lock! */
 320                                         /* kref is too implicit for our taste */
 321         int reset;                      /* Reset is running */
 322         int bad_resid;
 323         unsigned int tagcnt;
 324         char name[12];
 325         struct usb_device *dev;
 326         struct usb_interface *intf;
 327
 328         struct list_head luns;
 329
 330         unsigned int send_bulk_pipe;    /* cached pipe values */
 331         unsigned int recv_bulk_pipe;
 332         unsigned int send_ctrl_pipe;
 333         unsigned int recv_ctrl_pipe;
 334
 335         struct tasklet_struct tasklet;
 336
 337         struct ub_scsi_cmd_queue cmd_queue;
 338         struct ub_scsi_cmd top_rqs_cmd; /* REQUEST SENSE */
 339         unsigned char top_sense[UB_SENSE_SIZE];
 340
 341         struct ub_completion work_done;
 342         struct urb work_urb;
 343         struct timer_list work_timer;
 344         int last_pipe;                  /* What might need clearing */
 345         __le32 signature;               /* Learned signature */
 346         struct bulk_cb_wrap work_bcb;
 347         struct bulk_cs_wrap work_bcs;
 348         struct usb_ctrlrequest work_cr;
 349
 350         struct work_struct reset_work;
 351         wait_queue_head_t reset_wait;
 352 };
 353
 354 /*
 355  */
 356 static void ub_cleanup(struct ub_dev *sc);
 357 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);
 358 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 359     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 360 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 361     struct ub_scsi_cmd *cmd, struct ub_request *urq);
 362 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 363 static void ub_end_rq(struct request *rq, unsigned int status,
 364     unsigned int cmd_len);
 365 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 366     struct ub_request *urq, struct ub_scsi_cmd *cmd);
 367 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 368 static void ub_urb_complete(struct urb *urb);
 369 static void ub_scsi_action(unsigned long _dev);
 370 static void ub_scsi_dispatch(struct ub_dev *sc);
 371 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 372 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 373 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
 374 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 375 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 376 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 377 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
 378 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
 379     int stalled_pipe);
 380 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
 381 static void ub_reset_enter(struct ub_dev *sc, int try);
 382 static void ub_reset_task(struct work_struct *work);
 383 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun);
 384 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
 385     struct ub_capacity *ret);
 386 static int ub_sync_reset(struct ub_dev *sc);
 387 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe);
 388 static int ub_probe_lun(struct ub_dev *sc, int lnum);
 389
 390 /*
 391  */
 392 #ifdef CONFIG_USB_LIBUSUAL
 393
 394 #define ub_usb_ids  usb_storage_usb_ids
 395 #else
 396
 397 static struct usb_device_id ub_usb_ids[] = {
 398         { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
 399         { }
 400 };
 401
 402 MODULE_DEVICE_TABLE(usb, ub_usb_ids);
 403 #endif /* CONFIG_USB_LIBUSUAL */
 404
 405 /*
 406  * Find me a way to identify "next free minor" for add_disk(),
 407  * and the array disappears the next day. However, the number of
 408  * hosts has something to do with the naming and /proc/partitions.
 409  * This has to be thought out in detail before changing.
 410  * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
 411  */
 412 #define UB_MAX_HOSTS  26
 413 static char ub_hostv[UB_MAX_HOSTS];
 414
 415 #define UB_QLOCK_NUM 5
 416 static spinlock_t ub_qlockv[UB_QLOCK_NUM];
 417 static int ub_qlock_next = 0;
 418
 419 static DEFINE_SPINLOCK(ub_lock);        /* Locks globals and ->openc */
 420
 421 /*
 422  * The id allocator.
 423  *
 424  * This also stores the host for indexing by minor, which is somewhat dirty.
 425  */
 426 static int ub_id_get(void)
 427 {
 428         unsigned long flags;
 429         int i;
 430
 431         spin_lock_irqsave(&ub_lock, flags);
 432         for (i = 0; i < UB_MAX_HOSTS; i++) {
 433                 if (ub_hostv[i] == 0) {
 434                         ub_hostv[i] = 1;
 435                         spin_unlock_irqrestore(&ub_lock, flags);
 436                         return i;
 437                 }
 438         }
 439         spin_unlock_irqrestore(&ub_lock, flags);
 440         return -1;
 441 }
 442
 443 static void ub_id_put(int id)
 444 {
 445         unsigned long flags;
 446
 447         if (id < 0 || id >= UB_MAX_HOSTS) {
 448                 printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
 449                 return;
 450         }
 451
 452         spin_lock_irqsave(&ub_lock, flags);
 453         if (ub_hostv[id] == 0) {
 454                 spin_unlock_irqrestore(&ub_lock, flags);
 455                 printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
 456                 return;
 457         }
 458         ub_hostv[id] = 0;
 459         spin_unlock_irqrestore(&ub_lock, flags);
 460 }
 461
 462 /*
 463  * This is necessitated by the fact that blk_cleanup_queue does not
 464  * necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
 465  * Since our blk_init_queue() passes a spinlock common with ub_dev,
 466  * we have life time issues when ub_cleanup frees ub_dev.
 467  */
 468 static spinlock_t *ub_next_lock(void)
 469 {
 470         unsigned long flags;
 471         spinlock_t *ret;
 472
 473         spin_lock_irqsave(&ub_lock, flags);
 474         ret = &ub_qlockv[ub_qlock_next];
 475         ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
 476         spin_unlock_irqrestore(&ub_lock, flags);
 477         return ret;
 478 }
 479
 480 /*
 481  * Downcount for deallocation. This rides on two assumptions:
 482  *  - once something is poisoned, its refcount cannot grow
 483  *  - opens cannot happen at this time (del_gendisk was done)
 484  * If the above is true, we can drop the lock, which we need for
 485  * blk_cleanup_queue(): the silly thing may attempt to sleep.
 486  * [Actually, it never needs to sleep for us, but it calls might_sleep()]
 487  */
 488 static void ub_put(struct ub_dev *sc)
 489 {
 490         unsigned long flags;
 491
 492         spin_lock_irqsave(&ub_lock, flags);
 493         --sc->openc;
 494         if (sc->openc == 0 && atomic_read(&sc->poison)) {
 495                 spin_unlock_irqrestore(&ub_lock, flags);
 496                 ub_cleanup(sc);
 497         } else {
 498                 spin_unlock_irqrestore(&ub_lock, flags);
 499         }
 500 }
 501
 502 /*
 503  * Final cleanup and deallocation.
 504  */
 505 static void ub_cleanup(struct ub_dev *sc)
 506 {
 507         struct list_head *p;
 508         struct ub_lun *lun;
 509         struct request_queue *q;
 510
 511         while (!list_empty(&sc->luns)) {
 512                 p = sc->luns.next;
 513                 lun = list_entry(p, struct ub_lun, link);
 514                 list_del(p);
 515
 516                 /* I don't think queue can be NULL. But... Stolen from sx8.c */
 517                 if ((q = lun->disk->queue) != NULL)
 518                         blk_cleanup_queue(q);
 519                 /*
 520                  * If we zero disk->private_data BEFORE put_disk, we have
 521                  * to check for NULL all over the place in open, release,
 522                  * check_media and revalidate, because the block level
 523                  * semaphore is well inside the put_disk.
 524                  * But we cannot zero after the call, because *disk is gone.
 525                  * The sd.c is blatantly racy in this area.
 526                  */
 527                 /* disk->private_data = NULL; */
 528                 put_disk(lun->disk);
 529                 lun->disk = NULL;
 530
 531                 ub_id_put(lun->id);
 532                 kfree(lun);
 533         }
 534
 535         usb_set_intfdata(sc->intf, NULL);
 536         usb_put_intf(sc->intf);
 537         usb_put_dev(sc->dev);
 538         kfree(sc);
 539 }
 540
 541 /*
 542  * The "command allocator".
 543  */
 544 static struct ub_scsi_cmd *ub_get_cmd(struct ub_lun *lun)
 545 {
 546         struct ub_scsi_cmd *ret;
 547
 548         if (lun->cmda[0])
 549                 return NULL;
 550         ret = &lun->cmdv[0];
 551         lun->cmda[0] = 1;
 552         return ret;
 553 }
 554
 555 static void ub_put_cmd(struct ub_lun *lun, struct ub_scsi_cmd *cmd)
 556 {
 557         if (cmd != &lun->cmdv[0]) {
 558                 printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
 559                     lun->name, cmd);
 560                 return;
 561         }
 562         if (!lun->cmda[0]) {
 563                 printk(KERN_WARNING "%s: releasing a free cmd\n", lun->name);
 564                 return;
 565         }
 566         lun->cmda[0] = 0;
 567 }
 568
 569 /*
 570  * The command queue.
 571  */
 572 static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 573 {
 574         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 575
 576         if (t->qlen++ == 0) {
 577                 t->head = cmd;
 578                 t->tail = cmd;
 579         } else {
 580                 t->tail->next = cmd;
 581                 t->tail = cmd;
 582         }
 583
 584         if (t->qlen > t->qmax)
 585                 t->qmax = t->qlen;
 586 }
 587
 588 static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 589 {
 590         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 591
 592         if (t->qlen++ == 0) {
 593                 t->head = cmd;
 594                 t->tail = cmd;
 595         } else {
 596                 cmd->next = t->head;
 597                 t->head = cmd;
 598         }
 599
 600         if (t->qlen > t->qmax)
 601                 t->qmax = t->qlen;
 602 }
 603
 604 static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
 605 {
 606         struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
 607         struct ub_scsi_cmd *cmd;
 608
 609         if (t->qlen == 0)
 610                 return NULL;
 611         if (--t->qlen == 0)
 612                 t->tail = NULL;
 613         cmd = t->head;
 614         t->head = cmd->next;
 615         cmd->next = NULL;
 616         return cmd;
 617 }
 618
 619 #define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
 620
 621 /*
 622  * The request function is our main entry point
 623  */
 624
 625 static void ub_request_fn(struct request_queue *q)
 626 {
 627         struct ub_lun *lun = q->queuedata;
 628         struct request *rq;
 629
 630         while ((rq = elv_next_request(q)) != NULL) {
 631                 if (ub_request_fn_1(lun, rq) != 0) {
 632                         blk_stop_queue(q);
 633                         break;
 634                 }
 635         }
 636 }
 637
 638 static int ub_request_fn_1(struct ub_lun *lun, struct request *rq)
 639 {
 640         struct ub_dev *sc = lun->udev;
 641         struct ub_scsi_cmd *cmd;
 642         struct ub_request *urq;
 643         int n_elem;
 644
 645         if (atomic_read(&sc->poison)) {
 646                 blkdev_dequeue_request(rq);
 647                 ub_end_rq(rq, DID_NO_CONNECT << 16, blk_rq_bytes(rq));
 648                 return 0;
 649         }
 650
 651         if (lun->changed && !blk_pc_request(rq)) {
 652                 blkdev_dequeue_request(rq);
 653                 ub_end_rq(rq, SAM_STAT_CHECK_CONDITION, blk_rq_bytes(rq));
 654                 return 0;
 655         }
 656
 657         if (lun->urq.rq != NULL)
 658                 return -1;
 659         if ((cmd = ub_get_cmd(lun)) == NULL)
 660                 return -1;
 661         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 662
 663         blkdev_dequeue_request(rq);
 664
 665         urq = &lun->urq;
 666         memset(urq, 0, sizeof(struct ub_request));
 667         urq->rq = rq;
 668
 669         /*
 670          * get scatterlist from block layer
 671          */
 672         sg_init_table(&urq->sgv[0], UB_MAX_REQ_SG);
 673         n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);
 674         if (n_elem < 0) {
 675                 /* Impossible, because blk_rq_map_sg should not hit ENOMEM. */
 676                 printk(KERN_INFO "%s: failed request map (%d)\n",
 677                     lun->name, n_elem);
 678                 goto drop;
 679         }
 680         if (n_elem > UB_MAX_REQ_SG) {   /* Paranoia */
 681                 printk(KERN_WARNING "%s: request with %d segments\n",
 682                     lun->name, n_elem);
 683                 goto drop;
 684         }
 685         urq->nsg = n_elem;
 686
 687         if (blk_pc_request(rq)) {
 688                 ub_cmd_build_packet(sc, lun, cmd, urq);
 689         } else {
 690                 ub_cmd_build_block(sc, lun, cmd, urq);
 691         }
 692         cmd->state = UB_CMDST_INIT;
 693         cmd->lun = lun;
 694         cmd->done = ub_rw_cmd_done;
 695         cmd->back = urq;
 696
 697         cmd->tag = sc->tagcnt++;
 698         if (ub_submit_scsi(sc, cmd) != 0)
 699                 goto drop;
 700
 701         return 0;
 702
 703 drop:
 704         ub_put_cmd(lun, cmd);
 705         ub_end_rq(rq, DID_ERROR << 16, blk_rq_bytes(rq));
 706         return 0;
 707 }
 708
 709 static void ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,
 710     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 711 {
 712         struct request *rq = urq->rq;
 713         unsigned int block, nblks;
 714
 715         if (rq_data_dir(rq) == WRITE)
 716                 cmd->dir = UB_DIR_WRITE;
 717         else
 718                 cmd->dir = UB_DIR_READ;
 719
 720         cmd->nsg = urq->nsg;
 721         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 722
 723         /*
 724          * build the command
 725          *
 726          * The call to blk_queue_hardsect_size() guarantees that request
 727          * is aligned, but it is given in terms of 512 byte units, always.
 728          */
 729         block = rq->sector >> lun->capacity.bshift;
 730         nblks = rq->nr_sectors >> lun->capacity.bshift;
 731
 732         cmd->cdb[0] = (cmd->dir == UB_DIR_READ)? READ_10: WRITE_10;
 733         /* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */
 734         cmd->cdb[2] = block >> 24;
 735         cmd->cdb[3] = block >> 16;
 736         cmd->cdb[4] = block >> 8;
 737         cmd->cdb[5] = block;
 738         cmd->cdb[7] = nblks >> 8;
 739         cmd->cdb[8] = nblks;
 740         cmd->cdb_len = 10;
 741
 742         cmd->len = rq->nr_sectors * 512;
 743 }
 744
 745 static void ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,
 746     struct ub_scsi_cmd *cmd, struct ub_request *urq)
 747 {
 748         struct request *rq = urq->rq;
 749
 750         if (rq->data_len == 0) {
 751                 cmd->dir = UB_DIR_NONE;
 752         } else {
 753                 if (rq_data_dir(rq) == WRITE)
 754                         cmd->dir = UB_DIR_WRITE;
 755                 else
 756                         cmd->dir = UB_DIR_READ;
 757         }
 758
 759         cmd->nsg = urq->nsg;
 760         memcpy(cmd->sgv, urq->sgv, sizeof(struct scatterlist) * cmd->nsg);
 761
 762         memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);
 763         cmd->cdb_len = rq->cmd_len;
 764
 765         cmd->len = rq->data_len;
 766
 767         /*
 768          * To reapply this to every URB is not as incorrect as it looks.
 769          * In return, we avoid any complicated tracking calculations.
 770          */
 771         cmd->timeo = rq->timeout;
 772 }
 773
 774 static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 775 {
 776         struct ub_lun *lun = cmd->lun;
 777         struct ub_request *urq = cmd->back;
 778         struct request *rq;
 779         unsigned int scsi_status;
 780         unsigned int cmd_len;
 781
 782         rq = urq->rq;
 783
 784         if (cmd->error == 0) {
 785                 if (blk_pc_request(rq)) {
 786                         if (cmd->act_len >= rq->data_len)
 787                                 rq->data_len = 0;
 788                         else
 789                                 rq->data_len -= cmd->act_len;
 790                         scsi_status = 0;
 791                 } else {
 792                         if (cmd->act_len != cmd->len) {
 793                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 794                         } else {
 795                                 scsi_status = 0;
 796                         }
 797                 }
 798         } else {
 799                 if (blk_pc_request(rq)) {
 800                         /* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */
 801                         memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);
 802                         rq->sense_len = UB_SENSE_SIZE;
 803                         if (sc->top_sense[0] != 0)
 804                                 scsi_status = SAM_STAT_CHECK_CONDITION;
 805                         else
 806                                 scsi_status = DID_ERROR << 16;
 807                 } else {
 808                         if (cmd->error == -EIO &&
 809                             (cmd->key == 0 ||
 810                              cmd->key == MEDIUM_ERROR ||
 811                              cmd->key == UNIT_ATTENTION)) {
 812                                 if (ub_rw_cmd_retry(sc, lun, urq, cmd) == 0)
 813                                         return;
 814                         }
 815                         scsi_status = SAM_STAT_CHECK_CONDITION;
 816                 }
 817         }
 818
 819         urq->rq = NULL;
 820
 821         cmd_len = cmd->len;
 822         ub_put_cmd(lun, cmd);
 823         ub_end_rq(rq, scsi_status, cmd_len);
 824         blk_start_queue(lun->disk->queue);
 825 }
 826
 827 static void ub_end_rq(struct request *rq, unsigned int scsi_status,
 828     unsigned int cmd_len)
 829 {
 830         int error;
 831         long rqlen;
 832
 833         if (scsi_status == 0) {
 834                 error = 0;
 835         } else {
 836                 error = -EIO;
 837                 rq->errors = scsi_status;
 838         }
 839         rqlen = blk_rq_bytes(rq);    /* Oddly enough, this is the residue. */
 840         if (__blk_end_request(rq, error, cmd_len)) {
 841                 printk(KERN_WARNING DRV_NAME
 842                     ": __blk_end_request blew, %s-cmd total %u rqlen %ld\n",
 843                     blk_pc_request(rq)? "pc": "fs", cmd_len, rqlen);
 844         }
 845 }
 846
 847 static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun,
 848     struct ub_request *urq, struct ub_scsi_cmd *cmd)
 849 {
 850
 851         if (atomic_read(&sc->poison))
 852                 return -ENXIO;
 853
 854         ub_reset_enter(sc, urq->current_try);
 855
 856         if (urq->current_try >= 3)
 857                 return -EIO;
 858         urq->current_try++;
 859
 860         /* Remove this if anyone complains of flooding. */
 861         printk(KERN_DEBUG "%s: dir %c len/act %d/%d "
 862             "[sense %x %02x %02x] retry %d\n",
 863             sc->name, UB_DIR_CHAR(cmd->dir), cmd->len, cmd->act_len,
 864             cmd->key, cmd->asc, cmd->ascq, urq->current_try);
 865
 866         memset(cmd, 0, sizeof(struct ub_scsi_cmd));
 867         ub_cmd_build_block(sc, lun, cmd, urq);
 868
 869         cmd->state = UB_CMDST_INIT;
 870         cmd->lun = lun;
 871         cmd->done = ub_rw_cmd_done;
 872         cmd->back = urq;
 873
 874         cmd->tag = sc->tagcnt++;
 875
 876 #if 0 /* Wasteful */
 877         return ub_submit_scsi(sc, cmd);
 878 #else
 879         ub_cmdq_add(sc, cmd);
 880         return 0;
 881 #endif
 882 }
 883
 884 /*
 885  * Submit a regular SCSI operation (not an auto-sense).
 886  *
 887  * The Iron Law of Good Submit Routine is:
 888  * Zero return - callback is done, Nonzero return - callback is not done.
 889  * No exceptions.
 890  *
 891  * Host is assumed locked.
 892  */
 893 static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 894 {
 895
 896         if (cmd->state != UB_CMDST_INIT ||
 897             (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
 898                 return -EINVAL;
 899         }
 900
 901         ub_cmdq_add(sc, cmd);
 902         /*
 903          * We can call ub_scsi_dispatch(sc) right away here, but it's a little
 904          * safer to jump to a tasklet, in case upper layers do something silly.
 905          */
 906         tasklet_schedule(&sc->tasklet);
 907         return 0;
 908 }
 909
 910 /*
 911  * Submit the first URB for the queued command.
 912  * This function does not deal with queueing in any way.
 913  */
 914 static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
 915 {
 916         struct bulk_cb_wrap *bcb;
 917         int rc;
 918
 919         bcb = &sc->work_bcb;
 920
 921         /*
 922          * ``If the allocation length is eighteen or greater, and a device
 923          * server returns less than eithteen bytes of data, the application
 924          * client should assume that the bytes not transferred would have been
 925          * zeroes had the device server returned those bytes.''
 926          *
 927          * We zero sense for all commands so that when a packet request
 928          * fails it does not return a stale sense.
 929          */
 930         memset(&sc->top_sense, 0, UB_SENSE_SIZE);
 931
 932         /* set up the command wrapper */
 933         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
 934         bcb->Tag = cmd->tag;            /* Endianness is not important */
 935         bcb->DataTransferLength = cpu_to_le32(cmd->len);
 936         bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
 937         bcb->Lun = (cmd->lun != NULL) ? cmd->lun->num : 0;
 938         bcb->Length = cmd->cdb_len;
 939
 940         /* copy the command payload */
 941         memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
 942
 943         UB_INIT_COMPLETION(sc->work_done);
 944
 945         sc->last_pipe = sc->send_bulk_pipe;
 946         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
 947             bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
 948
 949         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
 950                 /* XXX Clear stalls */
 951                 ub_complete(&sc->work_done);
 952                 return rc;
 953         }
 954
 955         sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
 956         add_timer(&sc->work_timer);
 957
 958         cmd->state = UB_CMDST_CMD;
 959         return 0;
 960 }
 961
 962 /*
 963  * Timeout handler.
 964  */
 965 static void ub_urb_timeout(unsigned long arg)
 966 {
 967         struct ub_dev *sc = (struct ub_dev *) arg;
 968         unsigned long flags;
 969
 970         spin_lock_irqsave(sc->lock, flags);
 971         if (!ub_is_completed(&sc->work_done))
 972                 usb_unlink_urb(&sc->work_urb);
 973         spin_unlock_irqrestore(sc->lock, flags);
 974 }
 975
 976 /*
 977  * Completion routine for the work URB.
 978  *
 979  * This can be called directly from usb_submit_urb (while we have
 980  * the sc->lock taken) and from an interrupt (while we do NOT have
 981  * the sc->lock taken). Therefore, bounce this off to a tasklet.
 982  */
 983 static void ub_urb_complete(struct urb *urb)
 984 {
 985         struct ub_dev *sc = urb->context;
 986
 987         ub_complete(&sc->work_done);
 988         tasklet_schedule(&sc->tasklet);
 989 }
 990
 991 static void ub_scsi_action(unsigned long _dev)
 992 {
 993         struct ub_dev *sc = (struct ub_dev *) _dev;
 994         unsigned long flags;
 995
 996         spin_lock_irqsave(sc->lock, flags);
 997         ub_scsi_dispatch(sc);
 998         spin_unlock_irqrestore(sc->lock, flags);
 999 }
1000
1001 static void ub_scsi_dispatch(struct ub_dev *sc)
1002 {
1003         struct ub_scsi_cmd *cmd;
1004         int rc;
1005
1006         while (!sc->reset && (cmd = ub_cmdq_peek(sc)) != NULL) {
1007                 if (cmd->state == UB_CMDST_DONE) {
1008                         ub_cmdq_pop(sc);
1009                         (*cmd->done)(sc, cmd);
1010                 } else if (cmd->state == UB_CMDST_INIT) {
1011                         if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
1012                                 break;
1013                         cmd->error = rc;
1014                         cmd->state = UB_CMDST_DONE;
1015                 } else {
1016                         if (!ub_is_completed(&sc->work_done))
1017                                 break;
1018                         del_timer(&sc->work_timer);
1019                         ub_scsi_urb_compl(sc, cmd);
1020                 }
1021         }
1022 }
1023
1024 static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1025 {
1026         struct urb *urb = &sc->work_urb;
1027         struct bulk_cs_wrap *bcs;
1028         int len;
1029         int rc;
1030
1031         if (atomic_read(&sc->poison)) {
1032                 ub_state_done(sc, cmd, -ENODEV);
1033                 return;
1034         }
1035
1036         if (cmd->state == UB_CMDST_CLEAR) {
1037                 if (urb->status == -EPIPE) {
1038                         /*
1039                          * STALL while clearning STALL.
1040                          * The control pipe clears itself - nothing to do.
1041                          */
1042                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1043                             sc->name);
1044                         goto Bad_End;
1045                 }
1046
1047                 /*
1048                  * We ignore the result for the halt clear.
1049                  */
1050
1051                 /* reset the endpoint toggle */
1052                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1053                         usb_pipeout(sc->last_pipe), 0);
1054
1055                 ub_state_sense(sc, cmd);
1056
1057         } else if (cmd->state == UB_CMDST_CLR2STS) {
1058                 if (urb->status == -EPIPE) {
1059                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1060                             sc->name);
1061                         goto Bad_End;
1062                 }
1063
1064                 /*
1065                  * We ignore the result for the halt clear.
1066                  */
1067
1068                 /* reset the endpoint toggle */
1069                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1070                         usb_pipeout(sc->last_pipe), 0);
1071
1072                 ub_state_stat(sc, cmd);
1073
1074         } else if (cmd->state == UB_CMDST_CLRRS) {
1075                 if (urb->status == -EPIPE) {
1076                         printk(KERN_NOTICE "%s: stall on control pipe\n",
1077                             sc->name);
1078                         goto Bad_End;
1079                 }
1080
1081                 /*
1082                  * We ignore the result for the halt clear.
1083                  */
1084
1085                 /* reset the endpoint toggle */
1086                 usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
1087                         usb_pipeout(sc->last_pipe), 0);
1088
1089                 ub_state_stat_counted(sc, cmd);
1090
1091         } else if (cmd->state == UB_CMDST_CMD) {
1092                 switch (urb->status) {
1093                 case 0:
1094                         break;
1095                 case -EOVERFLOW:
1096                         goto Bad_End;
1097                 case -EPIPE:
1098                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1099                         if (rc != 0) {
1100                                 printk(KERN_NOTICE "%s: "
1101                                     "unable to submit clear (%d)\n",
1102                                     sc->name, rc);
1103                                 /*
1104                                  * This is typically ENOMEM or some other such shit.
1105                                  * Retrying is pointless. Just do Bad End on it...
1106                                  */
1107                                 ub_state_done(sc, cmd, rc);
1108                                 return;
1109                         }
1110                         cmd->state = UB_CMDST_CLEAR;
1111                         return;
1112                 case -ESHUTDOWN:        /* unplug */
1113                 case -EILSEQ:           /* unplug timeout on uhci */
1114                         ub_state_done(sc, cmd, -ENODEV);
1115                         return;
1116                 default:
1117                         goto Bad_End;
1118                 }
1119                 if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
1120                         goto Bad_End;
1121                 }
1122
1123                 if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
1124                         ub_state_stat(sc, cmd);
1125                         return;
1126                 }
1127
1128                 // udelay(125);         // usb-storage has this
1129                 ub_data_start(sc, cmd);
1130
1131         } else if (cmd->state == UB_CMDST_DATA) {
1132                 if (urb->status == -EPIPE) {
1133                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1134                         if (rc != 0) {
1135                                 printk(KERN_NOTICE "%s: "
1136                                     "unable to submit clear (%d)\n",
1137                                     sc->name, rc);
1138                                 ub_state_done(sc, cmd, rc);
1139                                 return;
1140                         }
1141                         cmd->state = UB_CMDST_CLR2STS;
1142                         return;
1143                 }
1144                 if (urb->status == -EOVERFLOW) {
1145                         /*
1146                          * A babble? Failure, but we must transfer CSW now.
1147                          */
1148                         cmd->error = -EOVERFLOW;        /* A cheap trick... */
1149                         ub_state_stat(sc, cmd);
1150                         return;
1151                 }
1152
1153                 if (cmd->dir == UB_DIR_WRITE) {
1154                         /*
1155                          * Do not continue writes in case of a failure.
1156                          * Doing so would cause sectors to be mixed up,
1157                          * which is worse than sectors lost.
1158                          *
1159                          * We must try to read the CSW, or many devices
1160                          * get confused.
1161                          */
1162                         len = urb->actual_length;
1163                         if (urb->status != 0 ||
1164                             len != cmd->sgv[cmd->current_sg].length) {
1165                                 cmd->act_len += len;
1166
1167                                 cmd->error = -EIO;
1168                                 ub_state_stat(sc, cmd);
1169                                 return;
1170                         }
1171
1172                 } else {
1173                         /*
1174                          * If an error occurs on read, we record it, and
1175                          * continue to fetch data in order to avoid bubble.
1176                          *
1177                          * As a small shortcut, we stop if we detect that
1178                          * a CSW mixed into data.
1179                          */
1180                         if (urb->status != 0)
1181                                 cmd->error = -EIO;
1182
1183                         len = urb->actual_length;
1184                         if (urb->status != 0 ||
1185                             len != cmd->sgv[cmd->current_sg].length) {
1186                                 if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
1187                                         goto Bad_End;
1188                         }
1189                 }
1190
1191                 cmd->act_len += urb->actual_length;
1192
1193                 if (++cmd->current_sg < cmd->nsg) {
1194                         ub_data_start(sc, cmd);
1195                         return;
1196                 }
1197                 ub_state_stat(sc, cmd);
1198
1199         } else if (cmd->state == UB_CMDST_STAT) {
1200                 if (urb->status == -EPIPE) {
1201                         rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
1202                         if (rc != 0) {
1203                                 printk(KERN_NOTICE "%s: "
1204                                     "unable to submit clear (%d)\n",
1205                                     sc->name, rc);
1206                                 ub_state_done(sc, cmd, rc);
1207                                 return;
1208                         }
1209
1210                         /*
1211                          * Having a stall when getting CSW is an error, so
1212                          * make sure uppper levels are not oblivious to it.
1213                          */
1214                         cmd->error = -EIO;              /* A cheap trick... */
1215
1216                         cmd->state = UB_CMDST_CLRRS;
1217                         return;
1218                 }
1219
1220                 /* Catch everything, including -EOVERFLOW and other nasties. */
1221                 if (urb->status != 0)
1222                         goto Bad_End;
1223
1224                 if (urb->actual_length == 0) {
1225                         ub_state_stat_counted(sc, cmd);
1226                         return;
1227                 }
1228
1229                 /*
1230                  * Check the returned Bulk protocol status.
1231                  * The status block has to be validated first.
1232                  */
1233
1234                 bcs = &sc->work_bcs;
1235
1236                 if (sc->signature == cpu_to_le32(0)) {
1237                         /*
1238                          * This is the first reply, so do not perform the check.
1239                          * Instead, remember the signature the device uses
1240                          * for future checks. But do not allow a nul.
1241                          */
1242                         sc->signature = bcs->Signature;
1243                         if (sc->signature == cpu_to_le32(0)) {
1244                                 ub_state_stat_counted(sc, cmd);
1245                                 return;
1246                         }
1247                 } else {
1248                         if (bcs->Signature != sc->signature) {
1249                                 ub_state_stat_counted(sc, cmd);
1250                                 return;
1251                         }
1252                 }
1253
1254                 if (bcs->Tag != cmd->tag) {
1255                         /*
1256                          * This usually happens when we disagree with the
1257                          * device's microcode about something. For instance,
1258                          * a few of them throw this after timeouts. They buffer
1259                          * commands and reply at commands we timed out before.
1260                          * Without flushing these replies we loop forever.
1261                          */
1262                         ub_state_stat_counted(sc, cmd);
1263                         return;
1264                 }
1265
1266                 if (!sc->bad_resid) {
1267                         len = le32_to_cpu(bcs->Residue);
1268                         if (len != cmd->len - cmd->act_len) {
1269                                 /*
1270                                  * Only start ignoring if this cmd ended well.
1271                                  */
1272                                 if (cmd->len == cmd->act_len) {
1273                                         printk(KERN_NOTICE "%s: "
1274                                             "bad residual %d of %d, ignoring\n",
1275                                             sc->name, len, cmd->len);
1276                                         sc->bad_resid = 1;
1277                                 }
1278                         }
1279                 }
1280
1281                 switch (bcs->Status) {
1282                 case US_BULK_STAT_OK:
1283                         break;
1284                 case US_BULK_STAT_FAIL:
1285                         ub_state_sense(sc, cmd);
1286                         return;
1287                 case US_BULK_STAT_PHASE:
1288                         goto Bad_End;
1289                 default:
1290                         printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
1291                             sc->name, bcs->Status);
1292                         ub_state_done(sc, cmd, -EINVAL);
1293                         return;
1294                 }
1295
1296                 /* Not zeroing error to preserve a babble indicator */
1297                 if (cmd->error != 0) {
1298                         ub_state_sense(sc, cmd);
1299                         return;
1300                 }
1301                 cmd->state = UB_CMDST_DONE;
1302                 ub_cmdq_pop(sc);
1303                 (*cmd->done)(sc, cmd);
1304
1305         } else if (cmd->state == UB_CMDST_SENSE) {
1306                 ub_state_done(sc, cmd, -EIO);
1307
1308         } else {
1309                 printk(KERN_WARNING "%s: wrong command state %d\n",
1310                     sc->name, cmd->state);
1311                 ub_state_done(sc, cmd, -EINVAL);
1312                 return;
1313         }
1314         return;
1315
1316 Bad_End: /* Little Excel is dead */
1317         ub_state_done(sc, cmd, -EIO);
1318 }
1319
1320 /*
1321  * Factorization helper for the command state machine:
1322  * Initiate a data segment transfer.
1323  */
1324 static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1325 {
1326         struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
1327         int pipe;
1328         int rc;
1329
1330         UB_INIT_COMPLETION(sc->work_done);
1331
1332         if (cmd->dir == UB_DIR_READ)
1333                 pipe = sc->recv_bulk_pipe;
1334         else
1335                 pipe = sc->send_bulk_pipe;
1336         sc->last_pipe = pipe;
1337         usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe, sg_virt(sg),
1338             sg->length, ub_urb_complete, sc);
1339
1340         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1341                 /* XXX Clear stalls */
1342                 ub_complete(&sc->work_done);
1343                 ub_state_done(sc, cmd, rc);
1344                 return;
1345         }
1346
1347         if (cmd->timeo)
1348                 sc->work_timer.expires = jiffies + cmd->timeo;
1349         else
1350                 sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
1351         add_timer(&sc->work_timer);
1352
1353         cmd->state = UB_CMDST_DATA;
1354 }
1355
1356 /*
1357  * Factorization helper for the command state machine:
1358  * Finish the command.
1359  */
1360 static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
1361 {
1362
1363         cmd->error = rc;
1364         cmd->state = UB_CMDST_DONE;
1365         ub_cmdq_pop(sc);
1366         (*cmd->done)(sc, cmd);
1367 }
1368
1369 /*
1370  * Factorization helper for the command state machine:
1371  * Submit a CSW read.
1372  */
1373 static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1374 {
1375         int rc;
1376
1377         UB_INIT_COMPLETION(sc->work_done);
1378
1379         sc->last_pipe = sc->recv_bulk_pipe;
1380         usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
1381             &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
1382
1383         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1384                 /* XXX Clear stalls */
1385                 ub_complete(&sc->work_done);
1386                 ub_state_done(sc, cmd, rc);
1387                 return -1;
1388         }
1389
1390         if (cmd->timeo)
1391                 sc->work_timer.expires = jiffies + cmd->timeo;
1392         else
1393                 sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
1394         add_timer(&sc->work_timer);
1395         return 0;
1396 }
1397
1398 /*
1399  * Factorization helper for the command state machine:
1400  * Submit a CSW read and go to STAT state.
1401  */
1402 static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1403 {
1404
1405         if (__ub_state_stat(sc, cmd) != 0)
1406                 return;
1407
1408         cmd->stat_count = 0;
1409         cmd->state = UB_CMDST_STAT;
1410 }
1411
1412 /*
1413  * Factorization helper for the command state machine:
1414  * Submit a CSW read and go to STAT state with counter (along [C] path).
1415  */
1416 static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1417 {
1418
1419         if (++cmd->stat_count >= 4) {
1420                 ub_state_sense(sc, cmd);
1421                 return;
1422         }
1423
1424         if (__ub_state_stat(sc, cmd) != 0)
1425                 return;
1426
1427         cmd->state = UB_CMDST_STAT;
1428 }
1429
1430 /*
1431  * Factorization helper for the command state machine:
1432  * Submit a REQUEST SENSE and go to SENSE state.
1433  */
1434 static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1435 {
1436         struct ub_scsi_cmd *scmd;
1437         struct scatterlist *sg;
1438         int rc;
1439
1440         if (cmd->cdb[0] == REQUEST_SENSE) {
1441                 rc = -EPIPE;
1442                 goto error;
1443         }
1444
1445         scmd = &sc->top_rqs_cmd;
1446         memset(scmd, 0, sizeof(struct ub_scsi_cmd));
1447         scmd->cdb[0] = REQUEST_SENSE;
1448         scmd->cdb[4] = UB_SENSE_SIZE;
1449         scmd->cdb_len = 6;
1450         scmd->dir = UB_DIR_READ;
1451         scmd->state = UB_CMDST_INIT;
1452         scmd->nsg = 1;
1453         sg = &scmd->sgv[0];
1454         sg_init_table(sg, UB_MAX_REQ_SG);
1455         sg_set_page(sg, virt_to_page(sc->top_sense), UB_SENSE_SIZE,
1456                         (unsigned long)sc->top_sense & (PAGE_SIZE-1));
1457         scmd->len = UB_SENSE_SIZE;
1458         scmd->lun = cmd->lun;
1459         scmd->done = ub_top_sense_done;
1460         scmd->back = cmd;
1461
1462         scmd->tag = sc->tagcnt++;
1463
1464         cmd->state = UB_CMDST_SENSE;
1465
1466         ub_cmdq_insert(sc, scmd);
1467         return;
1468
1469 error:
1470         ub_state_done(sc, cmd, rc);
1471 }
1472
1473 /*
1474  * A helper for the command's state machine:
1475  * Submit a stall clear.
1476  */
1477 static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
1478     int stalled_pipe)
1479 {
1480         int endp;
1481         struct usb_ctrlrequest *cr;
1482         int rc;
1483
1484         endp = usb_pipeendpoint(stalled_pipe);
1485         if (usb_pipein (stalled_pipe))
1486                 endp |= USB_DIR_IN;
1487
1488         cr = &sc->work_cr;
1489         cr->bRequestType = USB_RECIP_ENDPOINT;
1490         cr->bRequest = USB_REQ_CLEAR_FEATURE;
1491         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
1492         cr->wIndex = cpu_to_le16(endp);
1493         cr->wLength = cpu_to_le16(0);
1494
1495         UB_INIT_COMPLETION(sc->work_done);
1496
1497         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1498             (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
1499
1500         if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
1501                 ub_complete(&sc->work_done);
1502                 return rc;
1503         }
1504
1505         sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
1506         add_timer(&sc->work_timer);
1507         return 0;
1508 }
1509
1510 /*
1511  */
1512 static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)
1513 {
1514         unsigned char *sense = sc->top_sense;
1515         struct ub_scsi_cmd *cmd;
1516
1517         /*
1518          * Find the command which triggered the unit attention or a check,
1519          * save the sense into it, and advance its state machine.
1520          */
1521         if ((cmd = ub_cmdq_peek(sc)) == NULL) {
1522                 printk(KERN_WARNING "%s: sense done while idle\n", sc->name);
1523                 return;
1524         }
1525         if (cmd != scmd->back) {
1526                 printk(KERN_WARNING "%s: "
1527                     "sense done for wrong command 0x%x\n",
1528                     sc->name, cmd->tag);
1529                 return;
1530         }
1531         if (cmd->state != UB_CMDST_SENSE) {
1532                 printk(KERN_WARNING "%s: sense done with bad cmd state %d\n",
1533                     sc->name, cmd->state);
1534                 return;
1535         }
1536
1537         /*
1538          * Ignoring scmd->act_len, because the buffer was pre-zeroed.
1539          */
1540         cmd->key = sense[2] & 0x0F;
1541         cmd->asc = sense[12];
1542         cmd->ascq = sense[13];
1543
1544         ub_scsi_urb_compl(sc, cmd);
1545 }
1546
1547 /*
1548  * Reset management
1549  */
1550
1551 static void ub_reset_enter(struct ub_dev *sc, int try)
1552 {
1553
1554         if (sc->reset) {
1555                 /* This happens often on multi-LUN devices. */
1556                 return;
1557         }
1558         sc->reset = try + 1;
1559
1560 #if 0 /* Not needed because the disconnect waits for us. */
1561         unsigned long flags;
1562         spin_lock_irqsave(&ub_lock, flags);
1563         sc->openc++;
1564         spin_unlock_irqrestore(&ub_lock, flags);
1565 #endif
1566
1567 #if 0 /* We let them stop themselves. */
1568         struct ub_lun *lun;
1569         list_for_each_entry(lun, &sc->luns, link) {
1570                 blk_stop_queue(lun->disk->queue);
1571         }
1572 #endif
1573
1574         schedule_work(&sc->reset_work);
1575 }
1576
1577 static void ub_reset_task(struct work_struct *work)
1578 {
1579         struct ub_dev *sc = container_of(work, struct ub_dev, reset_work);
1580         unsigned long flags;
1581         struct ub_lun *lun;
1582         int rc;
1583
1584         if (!sc->reset) {
1585                 printk(KERN_WARNING "%s: Running reset unrequested\n",
1586                     sc->name);
1587                 return;
1588         }
1589
1590         if (atomic_read(&sc->poison)) {
1591                 ;
1592         } else if ((sc->reset & 1) == 0) {
1593                 ub_sync_reset(sc);
1594                 msleep(700);    /* usb-storage sleeps 6s (!) */
1595                 ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
1596                 ub_probe_clear_stall(sc, sc->send_bulk_pipe);
1597         } else if (sc->dev->actconfig->desc.bNumInterfaces != 1) {
1598                 ;
1599         } else {
1600                 rc = usb_lock_device_for_reset(sc->dev, sc->intf);
1601                 if (rc < 0) {
1602                         printk(KERN_NOTICE
1603                             "%s: usb_lock_device_for_reset failed (%d)\n",
1604                             sc->name, rc);
1605                 } else {
1606                         rc = usb_reset_device(sc->dev);
1607                         if (rc < 0) {
1608                                 printk(KERN_NOTICE "%s: "
1609                                     "usb_lock_device_for_reset failed (%d)\n",
1610                                     sc->name, rc);
1611                         }
1612                         usb_unlock_device(sc->dev);
1613                 }
1614         }
1615
1616         /*
1617          * In theory, no commands can be running while reset is active,
1618          * so nobody can ask for another reset, and so we do not need any
1619          * queues of resets or anything. We do need a spinlock though,
1620          * to interact with block layer.
1621          */
1622         spin_lock_irqsave(sc->lock, flags);
1623         sc->reset = 0;
1624         tasklet_schedule(&sc->tasklet);
1625         list_for_each_entry(lun, &sc->luns, link) {
1626                 blk_start_queue(lun->disk->queue);
1627         }
1628         wake_up(&sc->reset_wait);
1629         spin_unlock_irqrestore(sc->lock, flags);
1630 }
1631
1632 /*
1633  * XXX Reset brackets are too much hassle to implement, so just stub them
1634  * in order to prevent forced unbinding (which deadlocks solid when our
1635  * ->disconnect method waits for the reset to complete and this kills keventd).
1636  *
1637  * XXX Tell Alan to move usb_unlock_device inside of usb_reset_device,
1638  * or else the post_reset is invoked, and restats I/O on a locked device.
1639  */
1640 static int ub_pre_reset(struct usb_interface *iface) {
1641         return 0;
1642 }
1643
1644 static int ub_post_reset(struct usb_interface *iface) {
1645         return 0;
1646 }
1647
1648 /*
1649  * This is called from a process context.
1650  */
1651 static void ub_revalidate(struct ub_dev *sc, struct ub_lun *lun)
1652 {
1653
1654         lun->readonly = 0;      /* XXX Query this from the device */
1655
1656         lun->capacity.nsec = 0;
1657         lun->capacity.bsize = 512;
1658         lun->capacity.bshift = 0;
1659
1660         if (ub_sync_tur(sc, lun) != 0)
1661                 return;                 /* Not ready */
1662         lun->changed = 0;
1663
1664         if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1665                 /*
1666                  * The retry here means something is wrong, either with the
1667                  * device, with the transport, or with our code.
1668                  * We keep this because sd.c has retries for capacity.
1669                  */
1670                 if (ub_sync_read_cap(sc, lun, &lun->capacity) != 0) {
1671                         lun->capacity.nsec = 0;
1672                         lun->capacity.bsize = 512;
1673                         lun->capacity.bshift = 0;
1674                 }
1675         }
1676 }
1677
1678 /*
1679  * The open funcion.
1680  * This is mostly needed to keep refcounting, but also to support
1681  * media checks on removable media drives.
1682  */
1683 static int ub_bd_open(struct block_device *bdev, fmode_t mode)
1684 {
1685         struct ub_lun *lun = bdev->bd_disk->private_data;
1686         struct ub_dev *sc = lun->udev;
1687         unsigned long flags;
1688         int rc;
1689
1690         spin_lock_irqsave(&ub_lock, flags);
1691         if (atomic_read(&sc->poison)) {
1692                 spin_unlock_irqrestore(&ub_lock, flags);
1693                 return -ENXIO;
1694         }
1695         sc->openc++;
1696         spin_unlock_irqrestore(&ub_lock, flags);
1697
1698         if (lun->removable || lun->readonly)
1699                 check_disk_change(bdev);
1700
1701         /*
1702          * The sd.c considers ->media_present and ->changed not equivalent,
1703          * under some pretty murky conditions (a failure of READ CAPACITY).
1704          * We may need it one day.
1705          */
1706         if (lun->removable && lun->changed && !(mode & FMODE_NDELAY)) {
1707                 rc = -ENOMEDIUM;
1708                 goto err_open;
1709         }
1710
1711         if (lun->readonly && (mode & FMODE_WRITE)) {
1712                 rc = -EROFS;
1713                 goto err_open;
1714         }
1715
1716         return 0;
1717
1718 err_open:
1719         ub_put(sc);
1720         return rc;
1721 }
1722
1723 /*
1724  */
1725 static int ub_bd_release(struct gendisk *disk, fmode_t mode)
1726 {
1727         struct ub_lun *lun = disk->private_data;
1728         struct ub_dev *sc = lun->udev;
1729
1730         ub_put(sc);
1731         return 0;
1732 }
1733
1734 /*
1735  * The ioctl interface.
1736  */
1737 static int ub_bd_ioctl(struct block_device *bdev, fmode_t mode,
1738     unsigned int cmd, unsigned long arg)
1739 {
1740         struct gendisk *disk = bdev->bd_disk;
1741         void __user *usermem = (void __user *) arg;
1742
1743         return scsi_cmd_ioctl(disk->queue, disk, mode, cmd, usermem);
1744 }
1745
1746 /*
1747  * This is called by check_disk_change if we reported a media change.
1748  * The main onjective here is to discover the features of the media such as
1749  * the capacity, read-only status, etc. USB storage generally does not
1750  * need to be spun up, but if we needed it, this would be the place.
1751  *
1752  * This call can sleep.
1753  *
1754  * The return code is not used.
1755  */
1756 static int ub_bd_revalidate(struct gendisk *disk)
1757 {
1758         struct ub_lun *lun = disk->private_data;
1759
1760         ub_revalidate(lun->udev, lun);
1761
1762         /* XXX Support sector size switching like in sr.c */
1763         blk_queue_hardsect_size(disk->queue, lun->capacity.bsize);
1764         set_capacity(disk, lun->capacity.nsec);
1765         // set_disk_ro(sdkp->disk, lun->readonly);
1766
1767         return 0;
1768 }
1769
1770 /*
1771  * The check is called by the block layer to verify if the media
1772  * is still available. It is supposed to be harmless, lightweight and
1773  * non-intrusive in case the media was not changed.
1774  *
1775  * This call can sleep.
1776  *
1777  * The return code is bool!
1778  */
1779 static int ub_bd_media_changed(struct gendisk *disk)
1780 {
1781         struct ub_lun *lun = disk->private_data;
1782
1783         if (!lun->removable)
1784                 return 0;
1785
1786         /*
1787          * We clean checks always after every command, so this is not
1788          * as dangerous as it looks. If the TEST_UNIT_READY fails here,
1789          * the device is actually not ready with operator or software
1790          * intervention required. One dangerous item might be a drive which
1791          * spins itself down, and come the time to write dirty pages, this
1792          * will fail, then block layer discards the data. Since we never
1793          * spin drives up, such devices simply cannot be used with ub anyway.
1794          */
1795         if (ub_sync_tur(lun->udev, lun) != 0) {
1796                 lun->changed = 1;
1797                 return 1;
1798         }
1799
1800         return lun->changed;
1801 }
1802
1803 static struct block_device_operations ub_bd_fops = {
1804         .owner          = THIS_MODULE,
1805         .open           = ub_bd_open,
1806         .release        = ub_bd_release,
1807         .locked_ioctl   = ub_bd_ioctl,
1808         .media_changed  = ub_bd_media_changed,
1809         .revalidate_disk = ub_bd_revalidate,
1810 };
1811
1812 /*
1813  * Common ->done routine for commands executed synchronously.
1814  */
1815 static void ub_probe_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
1816 {
1817         struct completion *cop = cmd->back;
1818         complete(cop);
1819 }
1820
1821 /*
1822  * Test if the device has a check condition on it, synchronously.
1823  */
1824 static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
1825 {
1826         struct ub_scsi_cmd *cmd;
1827         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) };
1828         unsigned long flags;
1829         struct completion compl;
1830         int rc;
1831
1832         init_completion(&compl);
1833
1834         rc = -ENOMEM;
1835         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1836                 goto err_alloc;
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                 goto err_submit;
1854
1855         wait_for_completion(&compl);
1856
1857         rc = cmd->error;
1858
1859         if (rc == -EIO && cmd->key != 0)        /* Retries for benh's key */
1860                 rc = cmd->key;
1861
1862 err_submit:
1863         kfree(cmd);
1864 err_alloc:
1865         return rc;
1866 }
1867
1868 /*
1869  * Read the SCSI capacity synchronously (for probing).
1870  */
1871 static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
1872     struct ub_capacity *ret)
1873 {
1874         struct ub_scsi_cmd *cmd;
1875         struct scatterlist *sg;
1876         char *p;
1877         enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
1878         unsigned long flags;
1879         unsigned int bsize, shift;
1880         unsigned long nsec;
1881         struct completion compl;
1882         int rc;
1883
1884         init_completion(&compl);
1885
1886         rc = -ENOMEM;
1887         if ((cmd = kzalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
1888                 goto err_alloc;
1889         p = (char *)cmd + sizeof(struct ub_scsi_cmd);
1890
1891         cmd->cdb[0] = 0x25;
1892         cmd->cdb_len = 10;
1893         cmd->dir = UB_DIR_READ;
1894         cmd->state = UB_CMDST_INIT;
1895         cmd->nsg = 1;
1896         sg = &cmd->sgv[0];
1897         sg_init_table(sg, UB_MAX_REQ_SG);
1898         sg_set_page(sg, virt_to_page(p), 8, (unsigned long)p & (PAGE_SIZE-1));
1899         cmd->len = 8;
1900         cmd->lun = lun;
1901         cmd->done = ub_probe_done;
1902         cmd->back = &compl;
1903
1904         spin_lock_irqsave(sc->lock, flags);
1905         cmd->tag = sc->tagcnt++;
1906
1907         rc = ub_submit_scsi(sc, cmd);
1908         spin_unlock_irqrestore(sc->lock, flags);
1909
1910         if (rc != 0)
1911                 goto err_submit;
1912
1913         wait_for_completion(&compl);
1914
1915         if (cmd->error != 0) {
1916                 rc = -EIO;
1917                 goto err_read;
1918         }
1919         if (cmd->act_len != 8) {
1920                 rc = -EIO;
1921                 goto err_read;
1922         }
1923
1924         /* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
1925         nsec = be32_to_cpu(*(__be32 *)p) + 1;
1926         bsize = be32_to_cpu(*(__be32 *)(p + 4));
1927         switch (bsize) {
1928         case 512:       shift = 0;      break;
1929         case 1024:      shift = 1;      break;
1930         case 2048:      shift = 2;      break;
1931         case 4096:      shift = 3;      break;
1932         default:
1933                 rc = -EDOM;
1934                 goto err_inv_bsize;
1935         }
1936
1937         ret->bsize = bsize;
1938         ret->bshift = shift;
1939         ret->nsec = nsec << shift;
1940         rc = 0;
1941
1942 err_inv_bsize:
1943 err_read:
1944 err_submit:
1945         kfree(cmd);
1946 err_alloc:
1947         return rc;
1948 }
1949
1950 /*
1951  */
1952 static void ub_probe_urb_complete(struct urb *urb)
1953 {
1954         struct completion *cop = urb->context;
1955         complete(cop);
1956 }
1957
1958 static void ub_probe_timeout(unsigned long arg)
1959 {
1960         struct completion *cop = (struct completion *) arg;
1961         complete(cop);
1962 }
1963
1964 /*
1965  * Reset with a Bulk reset.
1966  */
1967 static int ub_sync_reset(struct ub_dev *sc)
1968 {
1969         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
1970         struct usb_ctrlrequest *cr;
1971         struct completion compl;
1972         struct timer_list timer;
1973         int rc;
1974
1975         init_completion(&compl);
1976
1977         cr = &sc->work_cr;
1978         cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
1979         cr->bRequest = US_BULK_RESET_REQUEST;
1980         cr->wValue = cpu_to_le16(0);
1981         cr->wIndex = cpu_to_le16(ifnum);
1982         cr->wLength = cpu_to_le16(0);
1983
1984         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
1985             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
1986
1987         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
1988                 printk(KERN_WARNING
1989                      "%s: Unable to submit a bulk reset (%d)\n", sc->name, rc);
1990                 return rc;
1991         }
1992
1993         init_timer(&timer);
1994         timer.function = ub_probe_timeout;
1995         timer.data = (unsigned long) &compl;
1996         timer.expires = jiffies + UB_CTRL_TIMEOUT;
1997         add_timer(&timer);
1998
1999         wait_for_completion(&compl);
2000
2001         del_timer_sync(&timer);
2002         usb_kill_urb(&sc->work_urb);
2003
2004         return sc->work_urb.status;
2005 }
2006
2007 /*
2008  * Get number of LUNs by the way of Bulk GetMaxLUN command.
2009  */
2010 static int ub_sync_getmaxlun(struct ub_dev *sc)
2011 {
2012         int ifnum = sc->intf->cur_altsetting->desc.bInterfaceNumber;
2013         unsigned char *p;
2014         enum { ALLOC_SIZE = 1 };
2015         struct usb_ctrlrequest *cr;
2016         struct completion compl;
2017         struct timer_list timer;
2018         int nluns;
2019         int rc;
2020
2021         init_completion(&compl);
2022
2023         rc = -ENOMEM;
2024         if ((p = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
2025                 goto err_alloc;
2026         *p = 55;
2027
2028         cr = &sc->work_cr;
2029         cr->bRequestType = USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
2030         cr->bRequest = US_BULK_GET_MAX_LUN;
2031         cr->wValue = cpu_to_le16(0);
2032         cr->wIndex = cpu_to_le16(ifnum);
2033         cr->wLength = cpu_to_le16(1);
2034
2035         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->recv_ctrl_pipe,
2036             (unsigned char*) cr, p, 1, ub_probe_urb_complete, &compl);
2037
2038         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0)
2039                 goto err_submit;
2040
2041         init_timer(&timer);
2042         timer.function = ub_probe_timeout;
2043         timer.data = (unsigned long) &compl;
2044         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2045         add_timer(&timer);
2046
2047         wait_for_completion(&compl);
2048
2049         del_timer_sync(&timer);
2050         usb_kill_urb(&sc->work_urb);
2051
2052         if ((rc = sc->work_urb.status) < 0)
2053                 goto err_io;
2054
2055         if (sc->work_urb.actual_length != 1) {
2056                 nluns = 0;
2057         } else {
2058                 if ((nluns = *p) == 55) {
2059                         nluns = 0;
2060                 } else {
2061                         /* GetMaxLUN returns the maximum LUN number */
2062                         nluns += 1;
2063                         if (nluns > UB_MAX_LUNS)
2064                                 nluns = UB_MAX_LUNS;
2065                 }
2066         }
2067
2068         kfree(p);
2069         return nluns;
2070
2071 err_io:
2072 err_submit:
2073         kfree(p);
2074 err_alloc:
2075         return rc;
2076 }
2077
2078 /*
2079  * Clear initial stalls.
2080  */
2081 static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
2082 {
2083         int endp;
2084         struct usb_ctrlrequest *cr;
2085         struct completion compl;
2086         struct timer_list timer;
2087         int rc;
2088
2089         init_completion(&compl);
2090
2091         endp = usb_pipeendpoint(stalled_pipe);
2092         if (usb_pipein (stalled_pipe))
2093                 endp |= USB_DIR_IN;
2094
2095         cr = &sc->work_cr;
2096         cr->bRequestType = USB_RECIP_ENDPOINT;
2097         cr->bRequest = USB_REQ_CLEAR_FEATURE;
2098         cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
2099         cr->wIndex = cpu_to_le16(endp);
2100         cr->wLength = cpu_to_le16(0);
2101
2102         usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
2103             (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
2104
2105         if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
2106                 printk(KERN_WARNING
2107                      "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
2108                 return rc;
2109         }
2110
2111         init_timer(&timer);
2112         timer.function = ub_probe_timeout;
2113         timer.data = (unsigned long) &compl;
2114         timer.expires = jiffies + UB_CTRL_TIMEOUT;
2115         add_timer(&timer);
2116
2117         wait_for_completion(&compl);
2118
2119         del_timer_sync(&timer);
2120         usb_kill_urb(&sc->work_urb);
2121
2122         /* reset the endpoint toggle */
2123         usb_settoggle(sc->dev, endp, usb_pipeout(sc->last_pipe), 0);
2124
2125         return 0;
2126 }
2127
2128 /*
2129  * Get the pipe settings.
2130  */
2131 static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
2132     struct usb_interface *intf)
2133 {
2134         struct usb_host_interface *altsetting = intf->cur_altsetting;
2135         struct usb_endpoint_descriptor *ep_in = NULL;
2136         struct usb_endpoint_descriptor *ep_out = NULL;
2137         struct usb_endpoint_descriptor *ep;
2138         int i;
2139
2140         /*
2141          * Find the endpoints we need.
2142          * We are expecting a minimum of 2 endpoints - in and out (bulk).
2143          * We will ignore any others.
2144          */
2145         for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
2146                 ep = &altsetting->endpoint[i].desc;
2147
2148                 /* Is it a BULK endpoint? */
2149                 if (usb_endpoint_xfer_bulk(ep)) {
2150                         /* BULK in or out? */
2151                         if (usb_endpoint_dir_in(ep)) {
2152                                 if (ep_in == NULL)
2153                                         ep_in = ep;
2154                         } else {
2155                                 if (ep_out == NULL)
2156                                         ep_out = ep;
2157                         }
2158                 }
2159         }
2160
2161         if (ep_in == NULL || ep_out == NULL) {
2162                 printk(KERN_NOTICE "%s: failed endpoint check\n", sc->name);
2163                 return -ENODEV;
2164         }
2165
2166         /* Calculate and store the pipe values */
2167         sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
2168         sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
2169         sc->send_bulk_pipe = usb_sndbulkpipe(dev,
2170                 usb_endpoint_num(ep_out));
2171         sc->recv_bulk_pipe = usb_rcvbulkpipe(dev,
2172                 usb_endpoint_num(ep_in));
2173
2174         return 0;
2175 }
2176
2177 /*
2178  * Probing is done in the process context, which allows us to cheat
2179  * and not to build a state machine for the discovery.
2180  */
2181 static int ub_probe(struct usb_interface *intf,
2182     const struct usb_device_id *dev_id)
2183 {
2184         struct ub_dev *sc;
2185         int nluns;
2186         int rc;
2187         int i;
2188
2189         if (usb_usual_check_type(dev_id, USB_US_TYPE_UB))
2190                 return -ENXIO;
2191
2192         rc = -ENOMEM;
2193         if ((sc = kzalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
2194                 goto err_core;
2195         sc->lock = ub_next_lock();
2196         INIT_LIST_HEAD(&sc->luns);
2197         usb_init_urb(&sc->work_urb);
2198         tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
2199         atomic_set(&sc->poison, 0);
2200         INIT_WORK(&sc->reset_work, ub_reset_task);
2201         init_waitqueue_head(&sc->reset_wait);
2202
2203         init_timer(&sc->work_timer);
2204         sc->work_timer.data = (unsigned long) sc;
2205         sc->work_timer.function = ub_urb_timeout;
2206
2207         ub_init_completion(&sc->work_done);
2208         sc->work_done.done = 1;         /* A little yuk, but oh well... */
2209
2210         sc->dev = interface_to_usbdev(intf);
2211         sc->intf = intf;
2212         // sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
2213         usb_set_intfdata(intf, sc);
2214         usb_get_dev(sc->dev);
2215         /*
2216          * Since we give the interface struct to the block level through
2217          * disk->driverfs_dev, we have to pin it. Otherwise, block_uevent
2218          * oopses on close after a disconnect (kernels 2.6.16 and up).
2219          */
2220         usb_get_intf(sc->intf);
2221
2222         snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
2223             sc->dev->bus->busnum, sc->dev->devnum);
2224
2225         /* XXX Verify that we can handle the device (from descriptors) */
2226
2227         if (ub_get_pipes(sc, sc->dev, intf) != 0)
2228                 goto err_dev_desc;
2229
2230         /*
2231          * At this point, all USB initialization is done, do upper layer.
2232          * We really hate halfway initialized structures, so from the
2233          * invariants perspective, this ub_dev is fully constructed at
2234          * this point.
2235          */
2236
2237         /*
2238          * This is needed to clear toggles. It is a problem only if we do
2239          * `rmmod ub && modprobe ub` without disconnects, but we like that.
2240          */
2241 #if 0 /* iPod Mini fails if we do this (big white iPod works) */
2242         ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
2243         ub_probe_clear_stall(sc, sc->send_bulk_pipe);
2244 #endif
2245
2246         /*
2247          * The way this is used by the startup code is a little specific.
2248          * A SCSI check causes a USB stall. Our common case code sees it
2249          * and clears the check, after which the device is ready for use.
2250          * But if a check was not present, any command other than
2251          * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
2252          *
2253          * If we neglect to clear the SCSI check, the first real command fails
2254          * (which is the capacity readout). We clear that and retry, but why
2255          * causing spurious retries for no reason.
2256          *
2257          * Revalidation may start with its own TEST_UNIT_READY, but that one
2258          * has to succeed, so we clear checks with an additional one here.
2259          * In any case it's not our business how revaliadation is implemented.
2260          */
2261         for (i = 0; i < 3; i++) {  /* Retries for the schwag key from KS'04 */
2262                 if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
2263                 if (rc != 0x6) break;
2264                 msleep(10);
2265         }
2266
2267         nluns = 1;
2268         for (i = 0; i < 3; i++) {
2269                 if ((rc = ub_sync_getmaxlun(sc)) < 0)
2270                         break;
2271                 if (rc != 0) {
2272                         nluns = rc;
2273                         break;
2274                 }
2275                 msleep(100);
2276         }
2277
2278         for (i = 0; i < nluns; i++) {
2279                 ub_probe_lun(sc, i);
2280         }
2281         return 0;
2282
2283 err_dev_desc:
2284         usb_set_intfdata(intf, NULL);
2285         usb_put_intf(sc->intf);
2286         usb_put_dev(sc->dev);
2287         kfree(sc);
2288 err_core:
2289         return rc;
2290 }
2291
2292 static int ub_probe_lun(struct ub_dev *sc, int lnum)
2293 {
2294         struct ub_lun *lun;
2295         struct request_queue *q;
2296         struct gendisk *disk;
2297         int rc;
2298
2299         rc = -ENOMEM;
2300         if ((lun = kzalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
2301                 goto err_alloc;
2302         lun->num = lnum;
2303
2304         rc = -ENOSR;
2305         if ((lun->id = ub_id_get()) == -1)
2306                 goto err_id;
2307
2308         lun->udev = sc;
2309
2310         snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
2311             lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);
2312
2313         lun->removable = 1;             /* XXX Query this from the device */
2314         lun->changed = 1;               /* ub_revalidate clears only */
2315         ub_revalidate(sc, lun);
2316
2317         rc = -ENOMEM;
2318         if ((disk = alloc_disk(UB_PARTS_PER_LUN)) == NULL)
2319                 goto err_diskalloc;
2320
2321         sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
2322         disk->major = UB_MAJOR;
2323         disk->first_minor = lun->id * UB_PARTS_PER_LUN;
2324         disk->fops = &ub_bd_fops;
2325         disk->private_data = lun;
2326         disk->driverfs_dev = &sc->intf->dev;
2327
2328         rc = -ENOMEM;
2329         if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
2330                 goto err_blkqinit;
2331
2332         disk->queue = q;
2333
2334         blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
2335         blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
2336         blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
2337         blk_queue_segment_boundary(q, 0xffffffff);      /* Dubious. */
2338         blk_queue_max_sectors(q, UB_MAX_SECTORS);
2339         blk_queue_hardsect_size(q, lun->capacity.bsize);
2340
2341         lun->disk = disk;
2342         q->queuedata = lun;
2343         list_add(&lun->link, &sc->luns);
2344
2345         set_capacity(disk, lun->capacity.nsec);
2346         if (lun->removable)
2347                 disk->flags |= GENHD_FL_REMOVABLE;
2348
2349         add_disk(disk);
2350
2351         return 0;
2352
2353 err_blkqinit:
2354         put_disk(disk);
2355 err_diskalloc:
2356         ub_id_put(lun->id);
2357 err_id:
2358         kfree(lun);
2359 err_alloc:
2360         return rc;
2361 }
2362
2363 static void ub_disconnect(struct usb_interface *intf)
2364 {
2365         struct ub_dev *sc = usb_get_intfdata(intf);
2366         struct ub_lun *lun;
2367         unsigned long flags;
2368
2369         /*
2370          * Prevent ub_bd_release from pulling the rug from under us.
2371          * XXX This is starting to look like a kref.
2372          * XXX Why not to take this ref at probe time?
2373          */
2374         spin_lock_irqsave(&ub_lock, flags);
2375         sc->openc++;
2376         spin_unlock_irqrestore(&ub_lock, flags);
2377
2378         /*
2379          * Fence stall clearings, operations triggered by unlinkings and so on.
2380          * We do not attempt to unlink any URBs, because we do not trust the
2381          * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
2382          */
2383         atomic_set(&sc->poison, 1);
2384
2385         /*
2386          * Wait for reset to end, if any.
2387          */
2388         wait_event(sc->reset_wait, !sc->reset);
2389
2390         /*
2391          * Blow away queued commands.
2392          *
2393          * Actually, this never works, because before we get here
2394          * the HCD terminates outstanding URB(s). It causes our
2395          * SCSI command queue to advance, commands fail to submit,
2396          * and the whole queue drains. So, we just use this code to
2397          * print warnings.
2398          */
2399         spin_lock_irqsave(sc->lock, flags);
2400         {
2401                 struct ub_scsi_cmd *cmd;
2402                 int cnt = 0;
2403                 while ((cmd = ub_cmdq_peek(sc)) != NULL) {
2404                         cmd->error = -ENOTCONN;
2405                         cmd->state = UB_CMDST_DONE;
2406                         ub_cmdq_pop(sc);
2407                         (*cmd->done)(sc, cmd);
2408                         cnt++;
2409                 }
2410                 if (cnt != 0) {
2411                         printk(KERN_WARNING "%s: "
2412                             "%d was queued after shutdown\n", sc->name, cnt);
2413                 }
2414         }
2415         spin_unlock_irqrestore(sc->lock, flags);
2416
2417         /*
2418          * Unregister the upper layer.
2419          */
2420         list_for_each_entry(lun, &sc->luns, link) {
2421                 del_gendisk(lun->disk);
2422                 /*
2423                  * I wish I could do:
2424                  *    queue_flag_set(QUEUE_FLAG_DEAD, q);
2425                  * As it is, we rely on our internal poisoning and let
2426                  * the upper levels to spin furiously failing all the I/O.
2427                  */
2428         }
2429
2430         /*
2431          * Testing for -EINPROGRESS is always a bug, so we are bending
2432          * the rules a little.
2433          */
2434         spin_lock_irqsave(sc->lock, flags);
2435         if (sc->work_urb.status == -EINPROGRESS) {      /* janitors: ignore */
2436                 printk(KERN_WARNING "%s: "
2437                     "URB is active after disconnect\n", sc->name);
2438         }
2439         spin_unlock_irqrestore(sc->lock, flags);
2440
2441         /*
2442          * There is virtually no chance that other CPU runs a timeout so long
2443          * after ub_urb_complete should have called del_timer, but only if HCD
2444          * didn't forget to deliver a callback on unlink.
2445          */
2446         del_timer_sync(&sc->work_timer);
2447
2448         /*
2449          * At this point there must be no commands coming from anyone
2450          * and no URBs left in transit.
2451          */
2452
2453         ub_put(sc);
2454 }
2455
2456 static struct usb_driver ub_driver = {
2457         .name =         "ub",
2458         .probe =        ub_probe,
2459         .disconnect =   ub_disconnect,
2460         .id_table =     ub_usb_ids,
2461         .pre_reset =    ub_pre_reset,
2462         .post_reset =   ub_post_reset,
2463 };
2464
2465 static int __init ub_init(void)
2466 {
2467         int rc;
2468         int i;
2469
2470         for (i = 0; i < UB_QLOCK_NUM; i++)
2471                 spin_lock_init(&ub_qlockv[i]);
2472
2473         if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
2474                 goto err_regblkdev;
2475
2476         if ((rc = usb_register(&ub_driver)) != 0)
2477                 goto err_register;
2478
2479         usb_usual_set_present(USB_US_TYPE_UB);
2480         return 0;
2481
2482 err_register:
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         unregister_blkdev(UB_MAJOR, DRV_NAME);
2493         usb_usual_clear_present(USB_US_TYPE_UB);
2494 }
2495
2496 module_init(ub_init);
2497 module_exit(ub_exit);
2498
2499 MODULE_LICENSE("GPL");