include/linux/blkdev.h

   1 #ifndef _LINUX_BLKDEV_H
   2 #define _LINUX_BLKDEV_H
   3
   4 #ifdef CONFIG_BLOCK
   5
   6 #include <linux/sched.h>
   7 #include <linux/major.h>
   8 #include <linux/genhd.h>
   9 #include <linux/list.h>
  10 #include <linux/timer.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/backing-dev.h>
  14 #include <linux/wait.h>
  15 #include <linux/mempool.h>
  16 #include <linux/bio.h>
  17 #include <linux/module.h>
  18 #include <linux/stringify.h>
  19 #include <linux/gfp.h>
  20 #include <linux/bsg.h>
  21 #include <linux/smp.h>
  22
  23 #include <asm/scatterlist.h>
  24
  25 struct scsi_ioctl_command;
  26
  27 struct request_queue;
  28 struct elevator_queue;
  29 struct request_pm_state;
  30 struct blk_trace;
  31 struct request;
  32 struct sg_io_hdr;
  33
  34 #define BLKDEV_MIN_RQ   4
  35 #define BLKDEV_MAX_RQ   128     /* Default maximum */
  36
  37 struct request;
  38 typedef void (rq_end_io_fn)(struct request *, int);
  39
  40 struct request_list {
  41         /*
  42          * count[], starved[], and wait[] are indexed by
  43          * BLK_RW_SYNC/BLK_RW_ASYNC
  44          */
  45         int count[2];
  46         int starved[2];
  47         int elvpriv;
  48         mempool_t *rq_pool;
  49         wait_queue_head_t wait[2];
  50 };
  51
  52 /*
  53  * request command types
  54  */
  55 enum rq_cmd_type_bits {
  56         REQ_TYPE_FS             = 1,    /* fs request */
  57         REQ_TYPE_BLOCK_PC,              /* scsi command */
  58         REQ_TYPE_SENSE,                 /* sense request */
  59         REQ_TYPE_PM_SUSPEND,            /* suspend request */
  60         REQ_TYPE_PM_RESUME,             /* resume request */
  61         REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
  62         REQ_TYPE_SPECIAL,               /* driver defined type */
  63         REQ_TYPE_LINUX_BLOCK,           /* generic block layer message */
  64         /*
  65          * for ATA/ATAPI devices. this really doesn't belong here, ide should
  66          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  67          * private REQ_LB opcodes to differentiate what type of request this is
  68          */
  69         REQ_TYPE_ATA_TASKFILE,
  70         REQ_TYPE_ATA_PC,
  71 };
  72
  73 /*
  74  * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
  75  * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
  76  * SCSI cdb.
  77  *
  78  * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
  79  * typically to differentiate REQ_TYPE_SPECIAL requests.
  80  *
  81  */
  82 enum {
  83         REQ_LB_OP_EJECT = 0x40,         /* eject request */
  84         REQ_LB_OP_FLUSH = 0x41,         /* flush request */
  85         REQ_LB_OP_DISCARD = 0x42,       /* discard sectors */
  86 };
  87
  88 /*
  89  * request type modified bits. first two bits match BIO_RW* bits, important
  90  */
  91 enum rq_flag_bits {
  92         __REQ_RW,               /* not set, read. set, write */
  93         __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
  94         __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
  95         __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
  96         __REQ_DISCARD,          /* request to discard sectors */
  97         __REQ_SORTED,           /* elevator knows about this request */
  98         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
  99         __REQ_HARDBARRIER,      /* may not be passed by drive either */
 100         __REQ_FUA,              /* forced unit access */
 101         __REQ_NOMERGE,          /* don't touch this for merging */
 102         __REQ_STARTED,          /* drive already may have started this one */
 103         __REQ_DONTPREP,         /* don't call prep for this one */
 104         __REQ_QUEUED,           /* uses queueing */
 105         __REQ_ELVPRIV,          /* elevator private data attached */
 106         __REQ_FAILED,           /* set if the request failed */
 107         __REQ_QUIET,            /* don't worry about errors */
 108         __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 109         __REQ_ORDERED_COLOR,    /* is before or after barrier */
 110         __REQ_RW_SYNC,          /* request is sync (sync write or read) */
 111         __REQ_ALLOCED,          /* request came from our alloc pool */
 112         __REQ_RW_META,          /* metadata io request */
 113         __REQ_COPY_USER,        /* contains copies of user pages */
 114         __REQ_INTEGRITY,        /* integrity metadata has been remapped */
 115         __REQ_NOIDLE,           /* Don't anticipate more IO after this one */
 116         __REQ_IO_STAT,          /* account I/O stat */
 117         __REQ_NR_BITS,          /* stops here */
 118 };
 119
 120 #define REQ_RW          (1 << __REQ_RW)
 121 #define REQ_FAILFAST_DEV        (1 << __REQ_FAILFAST_DEV)
 122 #define REQ_FAILFAST_TRANSPORT  (1 << __REQ_FAILFAST_TRANSPORT)
 123 #define REQ_FAILFAST_DRIVER     (1 << __REQ_FAILFAST_DRIVER)
 124 #define REQ_DISCARD     (1 << __REQ_DISCARD)
 125 #define REQ_SORTED      (1 << __REQ_SORTED)
 126 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
 127 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
 128 #define REQ_FUA         (1 << __REQ_FUA)
 129 #define REQ_NOMERGE     (1 << __REQ_NOMERGE)
 130 #define REQ_STARTED     (1 << __REQ_STARTED)
 131 #define REQ_DONTPREP    (1 << __REQ_DONTPREP)
 132 #define REQ_QUEUED      (1 << __REQ_QUEUED)
 133 #define REQ_ELVPRIV     (1 << __REQ_ELVPRIV)
 134 #define REQ_FAILED      (1 << __REQ_FAILED)
 135 #define REQ_QUIET       (1 << __REQ_QUIET)
 136 #define REQ_PREEMPT     (1 << __REQ_PREEMPT)
 137 #define REQ_ORDERED_COLOR       (1 << __REQ_ORDERED_COLOR)
 138 #define REQ_RW_SYNC     (1 << __REQ_RW_SYNC)
 139 #define REQ_ALLOCED     (1 << __REQ_ALLOCED)
 140 #define REQ_RW_META     (1 << __REQ_RW_META)
 141 #define REQ_COPY_USER   (1 << __REQ_COPY_USER)
 142 #define REQ_INTEGRITY   (1 << __REQ_INTEGRITY)
 143 #define REQ_NOIDLE      (1 << __REQ_NOIDLE)
 144 #define REQ_IO_STAT     (1 << __REQ_IO_STAT)
 145
 146 #define BLK_MAX_CDB     16
 147
 148 /*
 149  * try to put the fields that are referenced together in the same cacheline.
 150  * if you modify this structure, be sure to check block/blk-core.c:rq_init()
 151  * as well!
 152  */
 153 struct request {
 154         struct list_head queuelist;
 155         struct call_single_data csd;
 156         int cpu;
 157
 158         struct request_queue *q;
 159
 160         unsigned int cmd_flags;
 161         enum rq_cmd_type_bits cmd_type;
 162         unsigned long atomic_flags;
 163
 164         /* the following two fields are internal, NEVER access directly */
 165         sector_t __sector;              /* sector cursor */
 166         unsigned int __data_len;        /* total data len */
 167
 168         struct bio *bio;
 169         struct bio *biotail;
 170
 171         struct hlist_node hash; /* merge hash */
 172         /*
 173          * The rb_node is only used inside the io scheduler, requests
 174          * are pruned when moved to the dispatch queue. So let the
 175          * completion_data share space with the rb_node.
 176          */
 177         union {
 178                 struct rb_node rb_node; /* sort/lookup */
 179                 void *completion_data;
 180         };
 181
 182         /*
 183          * two pointers are available for the IO schedulers, if they need
 184          * more they have to dynamically allocate it.
 185          */
 186         void *elevator_private;
 187         void *elevator_private2;
 188
 189         struct gendisk *rq_disk;
 190         unsigned long start_time;
 191
 192         /* Number of scatter-gather DMA addr+len pairs after
 193          * physical address coalescing is performed.
 194          */
 195         unsigned short nr_phys_segments;
 196
 197         unsigned short ioprio;
 198
 199         void *special;          /* opaque pointer available for LLD use */
 200         char *buffer;           /* kaddr of the current segment if available */
 201
 202         int tag;
 203         int errors;
 204
 205         int ref_count;
 206
 207         /*
 208          * when request is used as a packet command carrier
 209          */
 210         unsigned short cmd_len;
 211         unsigned char __cmd[BLK_MAX_CDB];
 212         unsigned char *cmd;
 213
 214         unsigned int extra_len; /* length of alignment and padding */
 215         unsigned int sense_len;
 216         unsigned int resid_len; /* residual count */
 217         void *sense;
 218
 219         unsigned long deadline;
 220         struct list_head timeout_list;
 221         unsigned int timeout;
 222         int retries;
 223
 224         /*
 225          * completion callback.
 226          */
 227         rq_end_io_fn *end_io;
 228         void *end_io_data;
 229
 230         /* for bidi */
 231         struct request *next_rq;
 232 };
 233
 234 static inline unsigned short req_get_ioprio(struct request *req)
 235 {
 236         return req->ioprio;
 237 }
 238
 239 /*
 240  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 241  * requests. Some step values could eventually be made generic.
 242  */
 243 struct request_pm_state
 244 {
 245         /* PM state machine step value, currently driver specific */
 246         int     pm_step;
 247         /* requested PM state value (S1, S2, S3, S4, ...) */
 248         u32     pm_state;
 249         void*   data;           /* for driver use */
 250 };
 251
 252 #include <linux/elevator.h>
 253
 254 typedef void (request_fn_proc) (struct request_queue *q);
 255 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
 256 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 257 typedef void (unplug_fn) (struct request_queue *);
 258 typedef int (prepare_discard_fn) (struct request_queue *, struct request *);
 259
 260 struct bio_vec;
 261 struct bvec_merge_data {
 262         struct block_device *bi_bdev;
 263         sector_t bi_sector;
 264         unsigned bi_size;
 265         unsigned long bi_rw;
 266 };
 267 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
 268                              struct bio_vec *);
 269 typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
 270 typedef void (softirq_done_fn)(struct request *);
 271 typedef int (dma_drain_needed_fn)(struct request *);
 272 typedef int (lld_busy_fn) (struct request_queue *q);
 273
 274 enum blk_eh_timer_return {
 275         BLK_EH_NOT_HANDLED,
 276         BLK_EH_HANDLED,
 277         BLK_EH_RESET_TIMER,
 278 };
 279
 280 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
 281
 282 enum blk_queue_state {
 283         Queue_down,
 284         Queue_up,
 285 };
 286
 287 struct blk_queue_tag {
 288         struct request **tag_index;     /* map of busy tags */
 289         unsigned long *tag_map;         /* bit map of free/busy tags */
 290         int busy;                       /* current depth */
 291         int max_depth;                  /* what we will send to device */
 292         int real_max_depth;             /* what the array can hold */
 293         atomic_t refcnt;                /* map can be shared */
 294 };
 295
 296 #define BLK_SCSI_MAX_CMDS       (256)
 297 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 298
 299 struct queue_limits {
 300         unsigned long           bounce_pfn;
 301         unsigned long           seg_boundary_mask;
 302
 303         unsigned int            max_hw_sectors;
 304         unsigned int            max_sectors;
 305         unsigned int            max_segment_size;
 306         unsigned int            physical_block_size;
 307         unsigned int            alignment_offset;
 308         unsigned int            io_min;
 309         unsigned int            io_opt;
 310
 311         unsigned short          logical_block_size;
 312         unsigned short          max_hw_segments;
 313         unsigned short          max_phys_segments;
 314
 315         unsigned char           misaligned;
 316         unsigned char           no_cluster;
 317 };
 318
 319 struct request_queue
 320 {
 321         /*
 322          * Together with queue_head for cacheline sharing
 323          */
 324         struct list_head        queue_head;
 325         struct request          *last_merge;
 326         struct elevator_queue   *elevator;
 327
 328         /*
 329          * the queue request freelist, one for reads and one for writes
 330          */
 331         struct request_list     rq;
 332
 333         request_fn_proc         *request_fn;
 334         make_request_fn         *make_request_fn;
 335         prep_rq_fn              *prep_rq_fn;
 336         unplug_fn               *unplug_fn;
 337         prepare_discard_fn      *prepare_discard_fn;
 338         merge_bvec_fn           *merge_bvec_fn;
 339         prepare_flush_fn        *prepare_flush_fn;
 340         softirq_done_fn         *softirq_done_fn;
 341         rq_timed_out_fn         *rq_timed_out_fn;
 342         dma_drain_needed_fn     *dma_drain_needed;
 343         lld_busy_fn             *lld_busy_fn;
 344
 345         /*
 346          * Dispatch queue sorting
 347          */
 348         sector_t                end_sector;
 349         struct request          *boundary_rq;
 350
 351         /*
 352          * Auto-unplugging state
 353          */
 354         struct timer_list       unplug_timer;
 355         int                     unplug_thresh;  /* After this many requests */
 356         unsigned long           unplug_delay;   /* After this many jiffies */
 357         struct work_struct      unplug_work;
 358
 359         struct backing_dev_info backing_dev_info;
 360
 361         /*
 362          * The queue owner gets to use this for whatever they like.
 363          * ll_rw_blk doesn't touch it.
 364          */
 365         void                    *queuedata;
 366
 367         /*
 368          * queue needs bounce pages for pages above this limit
 369          */
 370         gfp_t                   bounce_gfp;
 371
 372         /*
 373          * various queue flags, see QUEUE_* below
 374          */
 375         unsigned long           queue_flags;
 376
 377         /*
 378          * protects queue structures from reentrancy. ->__queue_lock should
 379          * _never_ be used directly, it is queue private. always use
 380          * ->queue_lock.
 381          */
 382         spinlock_t              __queue_lock;
 383         spinlock_t              *queue_lock;
 384
 385         /*
 386          * queue kobject
 387          */
 388         struct kobject kobj;
 389
 390         /*
 391          * queue settings
 392          */
 393         unsigned long           nr_requests;    /* Max # of requests */
 394         unsigned int            nr_congestion_on;
 395         unsigned int            nr_congestion_off;
 396         unsigned int            nr_batching;
 397
 398         void                    *dma_drain_buffer;
 399         unsigned int            dma_drain_size;
 400         unsigned int            dma_pad_mask;
 401         unsigned int            dma_alignment;
 402
 403         struct blk_queue_tag    *queue_tags;
 404         struct list_head        tag_busy_list;
 405
 406         unsigned int            nr_sorted;
 407         unsigned int            in_flight[2];
 408
 409         unsigned int            rq_timeout;
 410         struct timer_list       timeout;
 411         struct list_head        timeout_list;
 412
 413         struct queue_limits     limits;
 414
 415         /*
 416          * sg stuff
 417          */
 418         unsigned int            sg_timeout;
 419         unsigned int            sg_reserved_size;
 420         int                     node;
 421 #ifdef CONFIG_BLK_DEV_IO_TRACE
 422         struct blk_trace        *blk_trace;
 423 #endif
 424         /*
 425          * reserved for flush operations
 426          */
 427         unsigned int            ordered, next_ordered, ordseq;
 428         int                     orderr, ordcolor;
 429         struct request          pre_flush_rq, bar_rq, post_flush_rq;
 430         struct request          *orig_bar_rq;
 431
 432         struct mutex            sysfs_lock;
 433
 434 #if defined(CONFIG_BLK_DEV_BSG)
 435         struct bsg_class_device bsg_dev;
 436 #endif
 437 };
 438
 439 #define QUEUE_FLAG_CLUSTER      0       /* cluster several segments into 1 */
 440 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 441 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 442 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 443 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 444 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 445 #define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 446 #define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
 447 #define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 448 #define QUEUE_FLAG_BIDI         9       /* queue supports bidi requests */
 449 #define QUEUE_FLAG_NOMERGES    10       /* disable merge attempts */
 450 #define QUEUE_FLAG_SAME_COMP   11       /* force complete on same CPU */
 451 #define QUEUE_FLAG_FAIL_IO     12       /* fake timeout */
 452 #define QUEUE_FLAG_STACKABLE   13       /* supports request stacking */
 453 #define QUEUE_FLAG_NONROT      14       /* non-rotational device (SSD) */
 454 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 455 #define QUEUE_FLAG_IO_STAT     15       /* do IO stats */
 456
 457 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 458                                  (1 << QUEUE_FLAG_CLUSTER) |            \
 459                                  (1 << QUEUE_FLAG_STACKABLE))
 460
 461 static inline int queue_is_locked(struct request_queue *q)
 462 {
 463 #ifdef CONFIG_SMP
 464         spinlock_t *lock = q->queue_lock;
 465         return lock && spin_is_locked(lock);
 466 #else
 467         return 1;
 468 #endif
 469 }
 470
 471 static inline void queue_flag_set_unlocked(unsigned int flag,
 472                                            struct request_queue *q)
 473 {
 474         __set_bit(flag, &q->queue_flags);
 475 }
 476
 477 static inline int queue_flag_test_and_clear(unsigned int flag,
 478                                             struct request_queue *q)
 479 {
 480         WARN_ON_ONCE(!queue_is_locked(q));
 481
 482         if (test_bit(flag, &q->queue_flags)) {
 483                 __clear_bit(flag, &q->queue_flags);
 484                 return 1;
 485         }
 486
 487         return 0;
 488 }
 489
 490 static inline int queue_flag_test_and_set(unsigned int flag,
 491                                           struct request_queue *q)
 492 {
 493         WARN_ON_ONCE(!queue_is_locked(q));
 494
 495         if (!test_bit(flag, &q->queue_flags)) {
 496                 __set_bit(flag, &q->queue_flags);
 497                 return 0;
 498         }
 499
 500         return 1;
 501 }
 502
 503 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 504 {
 505         WARN_ON_ONCE(!queue_is_locked(q));
 506         __set_bit(flag, &q->queue_flags);
 507 }
 508
 509 static inline void queue_flag_clear_unlocked(unsigned int flag,
 510                                              struct request_queue *q)
 511 {
 512         __clear_bit(flag, &q->queue_flags);
 513 }
 514
 515 static inline int queue_in_flight(struct request_queue *q)
 516 {
 517         return q->in_flight[0] + q->in_flight[1];
 518 }
 519
 520 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 521 {
 522         WARN_ON_ONCE(!queue_is_locked(q));
 523         __clear_bit(flag, &q->queue_flags);
 524 }
 525
 526 enum {
 527         /*
 528          * Hardbarrier is supported with one of the following methods.
 529          *
 530          * NONE         : hardbarrier unsupported
 531          * DRAIN        : ordering by draining is enough
 532          * DRAIN_FLUSH  : ordering by draining w/ pre and post flushes
 533          * DRAIN_FUA    : ordering by draining w/ pre flush and FUA write
 534          * TAG          : ordering by tag is enough
 535          * TAG_FLUSH    : ordering by tag w/ pre and post flushes
 536          * TAG_FUA      : ordering by tag w/ pre flush and FUA write
 537          */
 538         QUEUE_ORDERED_BY_DRAIN          = 0x01,
 539         QUEUE_ORDERED_BY_TAG            = 0x02,
 540         QUEUE_ORDERED_DO_PREFLUSH       = 0x10,
 541         QUEUE_ORDERED_DO_BAR            = 0x20,
 542         QUEUE_ORDERED_DO_POSTFLUSH      = 0x40,
 543         QUEUE_ORDERED_DO_FUA            = 0x80,
 544
 545         QUEUE_ORDERED_NONE              = 0x00,
 546
 547         QUEUE_ORDERED_DRAIN             = QUEUE_ORDERED_BY_DRAIN |
 548                                           QUEUE_ORDERED_DO_BAR,
 549         QUEUE_ORDERED_DRAIN_FLUSH       = QUEUE_ORDERED_DRAIN |
 550                                           QUEUE_ORDERED_DO_PREFLUSH |
 551                                           QUEUE_ORDERED_DO_POSTFLUSH,
 552         QUEUE_ORDERED_DRAIN_FUA         = QUEUE_ORDERED_DRAIN |
 553                                           QUEUE_ORDERED_DO_PREFLUSH |
 554                                           QUEUE_ORDERED_DO_FUA,
 555
 556         QUEUE_ORDERED_TAG               = QUEUE_ORDERED_BY_TAG |
 557                                           QUEUE_ORDERED_DO_BAR,
 558         QUEUE_ORDERED_TAG_FLUSH         = QUEUE_ORDERED_TAG |
 559                                           QUEUE_ORDERED_DO_PREFLUSH |
 560                                           QUEUE_ORDERED_DO_POSTFLUSH,
 561         QUEUE_ORDERED_TAG_FUA           = QUEUE_ORDERED_TAG |
 562                                           QUEUE_ORDERED_DO_PREFLUSH |
 563                                           QUEUE_ORDERED_DO_FUA,
 564
 565         /*
 566          * Ordered operation sequence
 567          */
 568         QUEUE_ORDSEQ_STARTED    = 0x01, /* flushing in progress */
 569         QUEUE_ORDSEQ_DRAIN      = 0x02, /* waiting for the queue to be drained */
 570         QUEUE_ORDSEQ_PREFLUSH   = 0x04, /* pre-flushing in progress */
 571         QUEUE_ORDSEQ_BAR        = 0x08, /* original barrier req in progress */
 572         QUEUE_ORDSEQ_POSTFLUSH  = 0x10, /* post-flushing in progress */
 573         QUEUE_ORDSEQ_DONE       = 0x20,
 574 };
 575
 576 #define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 577 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 578 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 579 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 580 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 581 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 582 #define blk_queue_flushing(q)   ((q)->ordseq)
 583 #define blk_queue_stackable(q)  \
 584         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 585
 586 #define blk_fs_request(rq)      ((rq)->cmd_type == REQ_TYPE_FS)
 587 #define blk_pc_request(rq)      ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
 588 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
 589 #define blk_sense_request(rq)   ((rq)->cmd_type == REQ_TYPE_SENSE)
 590
 591 #define blk_failfast_dev(rq)    ((rq)->cmd_flags & REQ_FAILFAST_DEV)
 592 #define blk_failfast_transport(rq) ((rq)->cmd_flags & REQ_FAILFAST_TRANSPORT)
 593 #define blk_failfast_driver(rq) ((rq)->cmd_flags & REQ_FAILFAST_DRIVER)
 594 #define blk_noretry_request(rq) (blk_failfast_dev(rq) ||        \
 595                                  blk_failfast_transport(rq) ||  \
 596                                  blk_failfast_driver(rq))
 597 #define blk_rq_started(rq)      ((rq)->cmd_flags & REQ_STARTED)
 598 #define blk_rq_io_stat(rq)      ((rq)->cmd_flags & REQ_IO_STAT)
 599 #define blk_rq_quiet(rq)        ((rq)->cmd_flags & REQ_QUIET)
 600
 601 #define blk_account_rq(rq)      (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq)))
 602
 603 #define blk_pm_suspend_request(rq)      ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
 604 #define blk_pm_resume_request(rq)       ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
 605 #define blk_pm_request(rq)      \
 606         (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
 607
 608 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 609 #define blk_sorted_rq(rq)       ((rq)->cmd_flags & REQ_SORTED)
 610 #define blk_barrier_rq(rq)      ((rq)->cmd_flags & REQ_HARDBARRIER)
 611 #define blk_fua_rq(rq)          ((rq)->cmd_flags & REQ_FUA)
 612 #define blk_discard_rq(rq)      ((rq)->cmd_flags & REQ_DISCARD)
 613 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 614 /* rq->queuelist of dequeued request must be list_empty() */
 615 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 616
 617 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 618
 619 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 620
 621 /*
 622  * We regard a request as sync, if either a read or a sync write
 623  */
 624 static inline bool rw_is_sync(unsigned int rw_flags)
 625 {
 626         return !(rw_flags & REQ_RW) || (rw_flags & REQ_RW_SYNC);
 627 }
 628
 629 static inline bool rq_is_sync(struct request *rq)
 630 {
 631         return rw_is_sync(rq->cmd_flags);
 632 }
 633
 634 #define rq_is_meta(rq)          ((rq)->cmd_flags & REQ_RW_META)
 635 #define rq_noidle(rq)           ((rq)->cmd_flags & REQ_NOIDLE)
 636
 637 static inline int blk_queue_full(struct request_queue *q, int sync)
 638 {
 639         if (sync)
 640                 return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
 641         return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
 642 }
 643
 644 static inline void blk_set_queue_full(struct request_queue *q, int sync)
 645 {
 646         if (sync)
 647                 queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
 648         else
 649                 queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
 650 }
 651
 652 static inline void blk_clear_queue_full(struct request_queue *q, int sync)
 653 {
 654         if (sync)
 655                 queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
 656         else
 657                 queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
 658 }
 659
 660
 661 /*
 662  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 663  * it already be started by driver.
 664  */
 665 #define RQ_NOMERGE_FLAGS        \
 666         (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
 667 #define rq_mergeable(rq)        \
 668         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 669          (blk_discard_rq(rq) || blk_fs_request((rq))))
 670
 671 /*
 672  * q->prep_rq_fn return values
 673  */
 674 #define BLKPREP_OK              0       /* serve it */
 675 #define BLKPREP_KILL            1       /* fatal error, kill */
 676 #define BLKPREP_DEFER           2       /* leave on queue */
 677
 678 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 679
 680 /*
 681  * standard bounce addresses:
 682  *
 683  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 684  * BLK_BOUNCE_ANY       : don't bounce anything
 685  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 686  */
 687
 688 #if BITS_PER_LONG == 32
 689 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 690 #else
 691 #define BLK_BOUNCE_HIGH         -1ULL
 692 #endif
 693 #define BLK_BOUNCE_ANY          (-1ULL)
 694 #define BLK_BOUNCE_ISA          (ISA_DMA_THRESHOLD)
 695
 696 /*
 697  * default timeout for SG_IO if none specified
 698  */
 699 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 700 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 701
 702 #ifdef CONFIG_BOUNCE
 703 extern int init_emergency_isa_pool(void);
 704 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 705 #else
 706 static inline int init_emergency_isa_pool(void)
 707 {
 708         return 0;
 709 }
 710 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 711 {
 712 }
 713 #endif /* CONFIG_MMU */
 714
 715 struct rq_map_data {
 716         struct page **pages;
 717         int page_order;
 718         int nr_entries;
 719         unsigned long offset;
 720         int null_mapped;
 721         int from_user;
 722 };
 723
 724 struct req_iterator {
 725         int i;
 726         struct bio *bio;
 727 };
 728
 729 /* This should not be used directly - use rq_for_each_segment */
 730 #define for_each_bio(_bio)              \
 731         for (; _bio; _bio = _bio->bi_next)
 732 #define __rq_for_each_bio(_bio, rq)     \
 733         if ((rq->bio))                  \
 734                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 735
 736 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 737         __rq_for_each_bio(_iter.bio, _rq)                       \
 738                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 739
 740 #define rq_iter_last(rq, _iter)                                 \
 741                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 742
 743 extern int blk_register_queue(struct gendisk *disk);
 744 extern void blk_unregister_queue(struct gendisk *disk);
 745 extern void register_disk(struct gendisk *dev);
 746 extern void generic_make_request(struct bio *bio);
 747 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 748 extern void blk_put_request(struct request *);
 749 extern void __blk_put_request(struct request_queue *, struct request *);
 750 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 751 extern struct request *blk_make_request(struct request_queue *, struct bio *,
 752                                         gfp_t);
 753 extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
 754 extern void blk_requeue_request(struct request_queue *, struct request *);
 755 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 756 extern int blk_lld_busy(struct request_queue *q);
 757 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 758                              struct bio_set *bs, gfp_t gfp_mask,
 759                              int (*bio_ctr)(struct bio *, struct bio *, void *),
 760                              void *data);
 761 extern void blk_rq_unprep_clone(struct request *rq);
 762 extern int blk_insert_cloned_request(struct request_queue *q,
 763                                      struct request *rq);
 764 extern void blk_plug_device(struct request_queue *);
 765 extern void blk_plug_device_unlocked(struct request_queue *);
 766 extern int blk_remove_plug(struct request_queue *);
 767 extern void blk_recount_segments(struct request_queue *, struct bio *);
 768 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 769                           unsigned int, void __user *);
 770 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 771                          struct scsi_ioctl_command __user *);
 772
 773 /*
 774  * A queue has just exitted congestion.  Note this in the global counter of
 775  * congested queues, and wake up anyone who was waiting for requests to be
 776  * put back.
 777  */
 778 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 779 {
 780         clear_bdi_congested(&q->backing_dev_info, sync);
 781 }
 782
 783 /*
 784  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 785  * state flags and increment the global gounter of congested queues.
 786  */
 787 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 788 {
 789         set_bdi_congested(&q->backing_dev_info, sync);
 790 }
 791
 792 extern void blk_start_queue(struct request_queue *q);
 793 extern void blk_stop_queue(struct request_queue *q);
 794 extern void blk_sync_queue(struct request_queue *q);
 795 extern void __blk_stop_queue(struct request_queue *q);
 796 extern void __blk_run_queue(struct request_queue *);
 797 extern void blk_run_queue(struct request_queue *);
 798 extern int blk_rq_map_user(struct request_queue *, struct request *,
 799                            struct rq_map_data *, void __user *, unsigned long,
 800                            gfp_t);
 801 extern int blk_rq_unmap_user(struct bio *);
 802 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 803 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 804                                struct rq_map_data *, struct sg_iovec *, int,
 805                                unsigned int, gfp_t);
 806 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 807                           struct request *, int);
 808 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 809                                   struct request *, int, rq_end_io_fn *);
 810 extern void blk_unplug(struct request_queue *q);
 811
 812 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 813 {
 814         return bdev->bd_disk->queue;
 815 }
 816
 817 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
 818                                        struct page *page)
 819 {
 820         if (bdi && bdi->unplug_io_fn)
 821                 bdi->unplug_io_fn(bdi, page);
 822 }
 823
 824 static inline void blk_run_address_space(struct address_space *mapping)
 825 {
 826         if (mapping)
 827                 blk_run_backing_dev(mapping->backing_dev_info, NULL);
 828 }
 829
 830 /*
 831  * blk_rq_pos()         : the current sector
 832  * blk_rq_bytes()       : bytes left in the entire request
 833  * blk_rq_cur_bytes()   : bytes left in the current segment
 834  * blk_rq_sectors()     : sectors left in the entire request
 835  * blk_rq_cur_sectors() : sectors left in the current segment
 836  */
 837 static inline sector_t blk_rq_pos(const struct request *rq)
 838 {
 839         return rq->__sector;
 840 }
 841
 842 static inline unsigned int blk_rq_bytes(const struct request *rq)
 843 {
 844         return rq->__data_len;
 845 }
 846
 847 static inline int blk_rq_cur_bytes(const struct request *rq)
 848 {
 849         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 850 }
 851
 852 static inline unsigned int blk_rq_sectors(const struct request *rq)
 853 {
 854         return blk_rq_bytes(rq) >> 9;
 855 }
 856
 857 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 858 {
 859         return blk_rq_cur_bytes(rq) >> 9;
 860 }
 861
 862 /*
 863  * Request issue related functions.
 864  */
 865 extern struct request *blk_peek_request(struct request_queue *q);
 866 extern void blk_start_request(struct request *rq);
 867 extern struct request *blk_fetch_request(struct request_queue *q);
 868
 869 /*
 870  * Request completion related functions.
 871  *
 872  * blk_update_request() completes given number of bytes and updates
 873  * the request without completing it.
 874  *
 875  * blk_end_request() and friends.  __blk_end_request() must be called
 876  * with the request queue spinlock acquired.
 877  *
 878  * Several drivers define their own end_request and call
 879  * blk_end_request() for parts of the original function.
 880  * This prevents code duplication in drivers.
 881  */
 882 extern bool blk_update_request(struct request *rq, int error,
 883                                unsigned int nr_bytes);
 884 extern bool blk_end_request(struct request *rq, int error,
 885                             unsigned int nr_bytes);
 886 extern void blk_end_request_all(struct request *rq, int error);
 887 extern bool blk_end_request_cur(struct request *rq, int error);
 888 extern bool __blk_end_request(struct request *rq, int error,
 889                               unsigned int nr_bytes);
 890 extern void __blk_end_request_all(struct request *rq, int error);
 891 extern bool __blk_end_request_cur(struct request *rq, int error);
 892
 893 extern void blk_complete_request(struct request *);
 894 extern void __blk_complete_request(struct request *);
 895 extern void blk_abort_request(struct request *);
 896 extern void blk_abort_queue(struct request_queue *);
 897
 898 /*
 899  * Access functions for manipulating queue properties
 900  */
 901 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 902                                         spinlock_t *lock, int node_id);
 903 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 904 extern void blk_cleanup_queue(struct request_queue *);
 905 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 906 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 907 extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
 908 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 909 extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
 910 extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
 911 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 912 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 913 extern void blk_queue_physical_block_size(struct request_queue *, unsigned short);
 914 extern void blk_queue_alignment_offset(struct request_queue *q,
 915                                        unsigned int alignment);
 916 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 917 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 918 extern void blk_set_default_limits(struct queue_limits *lim);
 919 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 920                             sector_t offset);
 921 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 922                               sector_t offset);
 923 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 924 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 925 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 926 extern int blk_queue_dma_drain(struct request_queue *q,
 927                                dma_drain_needed_fn *dma_drain_needed,
 928                                void *buf, unsigned int size);
 929 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 930 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 931 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 932 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 933 extern void blk_queue_dma_alignment(struct request_queue *, int);
 934 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 935 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 936 extern void blk_queue_set_discard(struct request_queue *, prepare_discard_fn *);
 937 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 938 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 939 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 940 extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
 941 extern bool blk_do_ordered(struct request_queue *, struct request **);
 942 extern unsigned blk_ordered_cur_seq(struct request_queue *);
 943 extern unsigned blk_ordered_req_seq(struct request *);
 944 extern bool blk_ordered_complete_seq(struct request_queue *, unsigned, int);
 945
 946 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 947 extern void blk_dump_rq_flags(struct request *, char *);
 948 extern void generic_unplug_device(struct request_queue *);
 949 extern long nr_blockdev_pages(void);
 950
 951 int blk_get_queue(struct request_queue *);
 952 struct request_queue *blk_alloc_queue(gfp_t);
 953 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 954 extern void blk_put_queue(struct request_queue *);
 955
 956 /*
 957  * tag stuff
 958  */
 959 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 960 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 961 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 962 extern void blk_queue_end_tag(struct request_queue *, struct request *);
 963 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 964 extern void blk_queue_free_tags(struct request_queue *);
 965 extern int blk_queue_resize_tags(struct request_queue *, int);
 966 extern void blk_queue_invalidate_tags(struct request_queue *);
 967 extern struct blk_queue_tag *blk_init_tags(int);
 968 extern void blk_free_tags(struct blk_queue_tag *);
 969
 970 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 971                                                 int tag)
 972 {
 973         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 974                 return NULL;
 975         return bqt->tag_index[tag];
 976 }
 977
 978 extern int blkdev_issue_flush(struct block_device *, sector_t *);
 979 extern int blkdev_issue_discard(struct block_device *,
 980                                 sector_t sector, sector_t nr_sects, gfp_t);
 981
 982 static inline int sb_issue_discard(struct super_block *sb,
 983                                    sector_t block, sector_t nr_blocks)
 984 {
 985         block <<= (sb->s_blocksize_bits - 9);
 986         nr_blocks <<= (sb->s_blocksize_bits - 9);
 987         return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, GFP_KERNEL);
 988 }
 989
 990 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
 991
 992 #define MAX_PHYS_SEGMENTS 128
 993 #define MAX_HW_SEGMENTS 128
 994 #define SAFE_MAX_SECTORS 255
 995 #define BLK_DEF_MAX_SECTORS 1024
 996
 997 #define MAX_SEGMENT_SIZE        65536
 998
 999 #define BLK_SEG_BOUNDARY_MASK   0xFFFFFFFFUL
1000
1001 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1002
1003 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1004 {
1005         return q->limits.bounce_pfn;
1006 }
1007
1008 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1009 {
1010         return q->limits.seg_boundary_mask;
1011 }
1012
1013 static inline unsigned int queue_max_sectors(struct request_queue *q)
1014 {
1015         return q->limits.max_sectors;
1016 }
1017
1018 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1019 {
1020         return q->limits.max_hw_sectors;
1021 }
1022
1023 static inline unsigned short queue_max_hw_segments(struct request_queue *q)
1024 {
1025         return q->limits.max_hw_segments;
1026 }
1027
1028 static inline unsigned short queue_max_phys_segments(struct request_queue *q)
1029 {
1030         return q->limits.max_phys_segments;
1031 }
1032
1033 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1034 {
1035         return q->limits.max_segment_size;
1036 }
1037
1038 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1039 {
1040         int retval = 512;
1041
1042         if (q && q->limits.logical_block_size)
1043                 retval = q->limits.logical_block_size;
1044
1045         return retval;
1046 }
1047
1048 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1049 {
1050         return queue_logical_block_size(bdev_get_queue(bdev));
1051 }
1052
1053 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1054 {
1055         return q->limits.physical_block_size;
1056 }
1057
1058 static inline unsigned int queue_io_min(struct request_queue *q)
1059 {
1060         return q->limits.io_min;
1061 }
1062
1063 static inline unsigned int queue_io_opt(struct request_queue *q)
1064 {
1065         return q->limits.io_opt;
1066 }
1067
1068 static inline int queue_alignment_offset(struct request_queue *q)
1069 {
1070         if (q && q->limits.misaligned)
1071                 return -1;
1072
1073         if (q && q->limits.alignment_offset)
1074                 return q->limits.alignment_offset;
1075
1076         return 0;
1077 }
1078
1079 static inline int queue_sector_alignment_offset(struct request_queue *q,
1080                                                 sector_t sector)
1081 {
1082         return ((sector << 9) - q->limits.alignment_offset)
1083                 & (q->limits.io_min - 1);
1084 }
1085
1086 static inline int queue_dma_alignment(struct request_queue *q)
1087 {
1088         return q ? q->dma_alignment : 511;
1089 }
1090
1091 static inline int blk_rq_aligned(struct request_queue *q, void *addr,
1092                                  unsigned int len)
1093 {
1094         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1095         return !((unsigned long)addr & alignment) && !(len & alignment);
1096 }
1097
1098 /* assumes size > 256 */
1099 static inline unsigned int blksize_bits(unsigned int size)
1100 {
1101         unsigned int bits = 8;
1102         do {
1103                 bits++;
1104                 size >>= 1;
1105         } while (size > 256);
1106         return bits;
1107 }
1108
1109 static inline unsigned int block_size(struct block_device *bdev)
1110 {
1111         return bdev->bd_block_size;
1112 }
1113
1114 typedef struct {struct page *v;} Sector;
1115
1116 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1117
1118 static inline void put_dev_sector(Sector p)
1119 {
1120         page_cache_release(p.v);
1121 }
1122
1123 struct work_struct;
1124 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1125
1126 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1127         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1128 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1129         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1130
1131 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1132
1133 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1134 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1135
1136 struct blk_integrity_exchg {
1137         void                    *prot_buf;
1138         void                    *data_buf;
1139         sector_t                sector;
1140         unsigned int            data_size;
1141         unsigned short          sector_size;
1142         const char              *disk_name;
1143 };
1144
1145 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1146 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1147 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1148 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1149
1150 struct blk_integrity {
1151         integrity_gen_fn        *generate_fn;
1152         integrity_vrfy_fn       *verify_fn;
1153         integrity_set_tag_fn    *set_tag_fn;
1154         integrity_get_tag_fn    *get_tag_fn;
1155
1156         unsigned short          flags;
1157         unsigned short          tuple_size;
1158         unsigned short          sector_size;
1159         unsigned short          tag_size;
1160
1161         const char              *name;
1162
1163         struct kobject          kobj;
1164 };
1165
1166 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1167 extern void blk_integrity_unregister(struct gendisk *);
1168 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1169 extern int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
1170 extern int blk_rq_count_integrity_sg(struct request *);
1171
1172 static inline
1173 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1174 {
1175         return bdev->bd_disk->integrity;
1176 }
1177
1178 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1179 {
1180         return disk->integrity;
1181 }
1182
1183 static inline int blk_integrity_rq(struct request *rq)
1184 {
1185         if (rq->bio == NULL)
1186                 return 0;
1187
1188         return bio_integrity(rq->bio);
1189 }
1190
1191 #else /* CONFIG_BLK_DEV_INTEGRITY */
1192
1193 #define blk_integrity_rq(rq)                    (0)
1194 #define blk_rq_count_integrity_sg(a)            (0)
1195 #define blk_rq_map_integrity_sg(a, b)           (0)
1196 #define bdev_get_integrity(a)                   (0)
1197 #define blk_get_integrity(a)                    (0)
1198 #define blk_integrity_compare(a, b)             (0)
1199 #define blk_integrity_register(a, b)            (0)
1200 #define blk_integrity_unregister(a)             do { } while (0);
1201
1202 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1203
1204 struct block_device_operations {
1205         int (*open) (struct block_device *, fmode_t);
1206         int (*release) (struct gendisk *, fmode_t);
1207         int (*locked_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1208         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1209         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1210         int (*direct_access) (struct block_device *, sector_t,
1211                                                 void **, unsigned long *);
1212         int (*media_changed) (struct gendisk *);
1213         unsigned long long (*set_capacity) (struct gendisk *,
1214                                                 unsigned long long);
1215         int (*revalidate_disk) (struct gendisk *);
1216         int (*getgeo)(struct block_device *, struct hd_geometry *);
1217         struct module *owner;
1218 };
1219
1220 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1221                                  unsigned long);
1222 #else /* CONFIG_BLOCK */
1223 /*
1224  * stubs for when the block layer is configured out
1225  */
1226 #define buffer_heads_over_limit 0
1227
1228 static inline long nr_blockdev_pages(void)
1229 {
1230         return 0;
1231 }
1232
1233 #endif /* CONFIG_BLOCK */
1234
1235 #endif