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         /*
  64          * for ATA/ATAPI devices. this really doesn't belong here, ide should
  65          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  66          * private REQ_LB opcodes to differentiate what type of request this is
  67          */
  68         REQ_TYPE_ATA_TASKFILE,
  69         REQ_TYPE_ATA_PC,
  70 };
  71
  72 #define BLK_MAX_CDB     16
  73
  74 /*
  75  * try to put the fields that are referenced together in the same cacheline.
  76  * if you modify this structure, be sure to check block/blk-core.c:rq_init()
  77  * as well!
  78  */
  79 struct request {
  80         struct list_head queuelist;
  81         struct call_single_data csd;
  82
  83         struct request_queue *q;
  84
  85         unsigned int cmd_flags;
  86         enum rq_cmd_type_bits cmd_type;
  87         unsigned long atomic_flags;
  88
  89         int cpu;
  90
  91         /* the following two fields are internal, NEVER access directly */
  92         unsigned int __data_len;        /* total data len */
  93         sector_t __sector;              /* sector cursor */
  94
  95         struct bio *bio;
  96         struct bio *biotail;
  97
  98         struct hlist_node hash; /* merge hash */
  99         /*
 100          * The rb_node is only used inside the io scheduler, requests
 101          * are pruned when moved to the dispatch queue. So let the
 102          * completion_data share space with the rb_node.
 103          */
 104         union {
 105                 struct rb_node rb_node; /* sort/lookup */
 106                 void *completion_data;
 107         };
 108
 109         /*
 110          * Three pointers are available for the IO schedulers, if they need
 111          * more they have to dynamically allocate it.  Flush requests are
 112          * never put on the IO scheduler. So let the flush fields share
 113          * space with the three elevator_private pointers.
 114          */
 115         union {
 116                 void *elevator_private[3];
 117                 struct {
 118                         unsigned int            seq;
 119                         struct list_head        list;
 120                 } flush;
 121         };
 122
 123         struct gendisk *rq_disk;
 124         unsigned long start_time;
 125 #ifdef CONFIG_BLK_CGROUP
 126         unsigned long long start_time_ns;
 127         unsigned long long io_start_time_ns;    /* when passed to hardware */
 128 #endif
 129         /* Number of scatter-gather DMA addr+len pairs after
 130          * physical address coalescing is performed.
 131          */
 132         unsigned short nr_phys_segments;
 133 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 134         unsigned short nr_integrity_segments;
 135 #endif
 136
 137         unsigned short ioprio;
 138
 139         int ref_count;
 140
 141         void *special;          /* opaque pointer available for LLD use */
 142         char *buffer;           /* kaddr of the current segment if available */
 143
 144         int tag;
 145         int errors;
 146
 147         /*
 148          * when request is used as a packet command carrier
 149          */
 150         unsigned char __cmd[BLK_MAX_CDB];
 151         unsigned char *cmd;
 152         unsigned short cmd_len;
 153
 154         unsigned int extra_len; /* length of alignment and padding */
 155         unsigned int sense_len;
 156         unsigned int resid_len; /* residual count */
 157         void *sense;
 158
 159         unsigned long deadline;
 160         struct list_head timeout_list;
 161         unsigned int timeout;
 162         int retries;
 163
 164         /*
 165          * completion callback.
 166          */
 167         rq_end_io_fn *end_io;
 168         void *end_io_data;
 169
 170         /* for bidi */
 171         struct request *next_rq;
 172 };
 173
 174 static inline unsigned short req_get_ioprio(struct request *req)
 175 {
 176         return req->ioprio;
 177 }
 178
 179 /*
 180  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 181  * requests. Some step values could eventually be made generic.
 182  */
 183 struct request_pm_state
 184 {
 185         /* PM state machine step value, currently driver specific */
 186         int     pm_step;
 187         /* requested PM state value (S1, S2, S3, S4, ...) */
 188         u32     pm_state;
 189         void*   data;           /* for driver use */
 190 };
 191
 192 #include <linux/elevator.h>
 193
 194 typedef void (request_fn_proc) (struct request_queue *q);
 195 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
 196 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 197 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
 198 typedef void (unplug_fn) (struct request_queue *);
 199
 200 struct bio_vec;
 201 struct bvec_merge_data {
 202         struct block_device *bi_bdev;
 203         sector_t bi_sector;
 204         unsigned bi_size;
 205         unsigned long bi_rw;
 206 };
 207 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
 208                              struct bio_vec *);
 209 typedef void (softirq_done_fn)(struct request *);
 210 typedef int (dma_drain_needed_fn)(struct request *);
 211 typedef int (lld_busy_fn) (struct request_queue *q);
 212
 213 enum blk_eh_timer_return {
 214         BLK_EH_NOT_HANDLED,
 215         BLK_EH_HANDLED,
 216         BLK_EH_RESET_TIMER,
 217 };
 218
 219 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
 220
 221 enum blk_queue_state {
 222         Queue_down,
 223         Queue_up,
 224 };
 225
 226 struct blk_queue_tag {
 227         struct request **tag_index;     /* map of busy tags */
 228         unsigned long *tag_map;         /* bit map of free/busy tags */
 229         int busy;                       /* current depth */
 230         int max_depth;                  /* what we will send to device */
 231         int real_max_depth;             /* what the array can hold */
 232         atomic_t refcnt;                /* map can be shared */
 233 };
 234
 235 #define BLK_SCSI_MAX_CMDS       (256)
 236 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 237
 238 struct queue_limits {
 239         unsigned long           bounce_pfn;
 240         unsigned long           seg_boundary_mask;
 241
 242         unsigned int            max_hw_sectors;
 243         unsigned int            max_sectors;
 244         unsigned int            max_segment_size;
 245         unsigned int            physical_block_size;
 246         unsigned int            alignment_offset;
 247         unsigned int            io_min;
 248         unsigned int            io_opt;
 249         unsigned int            max_discard_sectors;
 250         unsigned int            discard_granularity;
 251         unsigned int            discard_alignment;
 252
 253         unsigned short          logical_block_size;
 254         unsigned short          max_segments;
 255         unsigned short          max_integrity_segments;
 256
 257         unsigned char           misaligned;
 258         unsigned char           discard_misaligned;
 259         unsigned char           cluster;
 260         signed char             discard_zeroes_data;
 261 };
 262
 263 struct request_queue
 264 {
 265         /*
 266          * Together with queue_head for cacheline sharing
 267          */
 268         struct list_head        queue_head;
 269         struct request          *last_merge;
 270         struct elevator_queue   *elevator;
 271
 272         /*
 273          * the queue request freelist, one for reads and one for writes
 274          */
 275         struct request_list     rq;
 276
 277         request_fn_proc         *request_fn;
 278         make_request_fn         *make_request_fn;
 279         prep_rq_fn              *prep_rq_fn;
 280         unprep_rq_fn            *unprep_rq_fn;
 281         unplug_fn               *unplug_fn;
 282         merge_bvec_fn           *merge_bvec_fn;
 283         softirq_done_fn         *softirq_done_fn;
 284         rq_timed_out_fn         *rq_timed_out_fn;
 285         dma_drain_needed_fn     *dma_drain_needed;
 286         lld_busy_fn             *lld_busy_fn;
 287
 288         /*
 289          * Dispatch queue sorting
 290          */
 291         sector_t                end_sector;
 292         struct request          *boundary_rq;
 293
 294         /*
 295          * Auto-unplugging state
 296          */
 297         struct timer_list       unplug_timer;
 298         int                     unplug_thresh;  /* After this many requests */
 299         unsigned long           unplug_delay;   /* After this many jiffies */
 300         struct work_struct      unplug_work;
 301
 302         struct backing_dev_info backing_dev_info;
 303
 304         /*
 305          * The queue owner gets to use this for whatever they like.
 306          * ll_rw_blk doesn't touch it.
 307          */
 308         void                    *queuedata;
 309
 310         /*
 311          * queue needs bounce pages for pages above this limit
 312          */
 313         gfp_t                   bounce_gfp;
 314
 315         /*
 316          * various queue flags, see QUEUE_* below
 317          */
 318         unsigned long           queue_flags;
 319
 320         /*
 321          * protects queue structures from reentrancy. ->__queue_lock should
 322          * _never_ be used directly, it is queue private. always use
 323          * ->queue_lock.
 324          */
 325         spinlock_t              __queue_lock;
 326         spinlock_t              *queue_lock;
 327
 328         /*
 329          * queue kobject
 330          */
 331         struct kobject kobj;
 332
 333         /*
 334          * queue settings
 335          */
 336         unsigned long           nr_requests;    /* Max # of requests */
 337         unsigned int            nr_congestion_on;
 338         unsigned int            nr_congestion_off;
 339         unsigned int            nr_batching;
 340
 341         void                    *dma_drain_buffer;
 342         unsigned int            dma_drain_size;
 343         unsigned int            dma_pad_mask;
 344         unsigned int            dma_alignment;
 345
 346         struct blk_queue_tag    *queue_tags;
 347         struct list_head        tag_busy_list;
 348
 349         unsigned int            nr_sorted;
 350         unsigned int            in_flight[2];
 351
 352         unsigned int            rq_timeout;
 353         struct timer_list       timeout;
 354         struct list_head        timeout_list;
 355
 356         struct queue_limits     limits;
 357
 358         /*
 359          * sg stuff
 360          */
 361         unsigned int            sg_timeout;
 362         unsigned int            sg_reserved_size;
 363         int                     node;
 364 #ifdef CONFIG_BLK_DEV_IO_TRACE
 365         struct blk_trace        *blk_trace;
 366 #endif
 367         /*
 368          * for flush operations
 369          */
 370         unsigned int            flush_flags;
 371         unsigned int            flush_pending_idx:1;
 372         unsigned int            flush_running_idx:1;
 373         unsigned long           flush_pending_since;
 374         struct list_head        flush_queue[2];
 375         struct list_head        flush_data_in_flight;
 376         struct request          flush_rq;
 377
 378         struct mutex            sysfs_lock;
 379
 380 #if defined(CONFIG_BLK_DEV_BSG)
 381         struct bsg_class_device bsg_dev;
 382 #endif
 383
 384 #ifdef CONFIG_BLK_DEV_THROTTLING
 385         /* Throttle data */
 386         struct throtl_data *td;
 387 #endif
 388 };
 389
 390 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 391 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 392 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 393 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 394 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 395 #define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 396 #define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
 397 #define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 398 #define QUEUE_FLAG_BIDI         9       /* queue supports bidi requests */
 399 #define QUEUE_FLAG_NOMERGES    10       /* disable merge attempts */
 400 #define QUEUE_FLAG_SAME_COMP   11       /* force complete on same CPU */
 401 #define QUEUE_FLAG_FAIL_IO     12       /* fake timeout */
 402 #define QUEUE_FLAG_STACKABLE   13       /* supports request stacking */
 403 #define QUEUE_FLAG_NONROT      14       /* non-rotational device (SSD) */
 404 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 405 #define QUEUE_FLAG_IO_STAT     15       /* do IO stats */
 406 #define QUEUE_FLAG_DISCARD     16       /* supports DISCARD */
 407 #define QUEUE_FLAG_NOXMERGES   17       /* No extended merges */
 408 #define QUEUE_FLAG_ADD_RANDOM  18       /* Contributes to random pool */
 409 #define QUEUE_FLAG_SECDISCARD  19       /* supports SECDISCARD */
 410
 411 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 412                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
 413                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
 414                                  (1 << QUEUE_FLAG_ADD_RANDOM))
 415
 416 static inline int queue_is_locked(struct request_queue *q)
 417 {
 418 #ifdef CONFIG_SMP
 419         spinlock_t *lock = q->queue_lock;
 420         return lock && spin_is_locked(lock);
 421 #else
 422         return 1;
 423 #endif
 424 }
 425
 426 static inline void queue_flag_set_unlocked(unsigned int flag,
 427                                            struct request_queue *q)
 428 {
 429         __set_bit(flag, &q->queue_flags);
 430 }
 431
 432 static inline int queue_flag_test_and_clear(unsigned int flag,
 433                                             struct request_queue *q)
 434 {
 435         WARN_ON_ONCE(!queue_is_locked(q));
 436
 437         if (test_bit(flag, &q->queue_flags)) {
 438                 __clear_bit(flag, &q->queue_flags);
 439                 return 1;
 440         }
 441
 442         return 0;
 443 }
 444
 445 static inline int queue_flag_test_and_set(unsigned int flag,
 446                                           struct request_queue *q)
 447 {
 448         WARN_ON_ONCE(!queue_is_locked(q));
 449
 450         if (!test_bit(flag, &q->queue_flags)) {
 451                 __set_bit(flag, &q->queue_flags);
 452                 return 0;
 453         }
 454
 455         return 1;
 456 }
 457
 458 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 459 {
 460         WARN_ON_ONCE(!queue_is_locked(q));
 461         __set_bit(flag, &q->queue_flags);
 462 }
 463
 464 static inline void queue_flag_clear_unlocked(unsigned int flag,
 465                                              struct request_queue *q)
 466 {
 467         __clear_bit(flag, &q->queue_flags);
 468 }
 469
 470 static inline int queue_in_flight(struct request_queue *q)
 471 {
 472         return q->in_flight[0] + q->in_flight[1];
 473 }
 474
 475 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 476 {
 477         WARN_ON_ONCE(!queue_is_locked(q));
 478         __clear_bit(flag, &q->queue_flags);
 479 }
 480
 481 #define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 482 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 483 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 484 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 485 #define blk_queue_noxmerges(q)  \
 486         test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
 487 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 488 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 489 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
 490 #define blk_queue_stackable(q)  \
 491         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 492 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
 493 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
 494         test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
 495
 496 #define blk_noretry_request(rq) \
 497         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
 498                              REQ_FAILFAST_DRIVER))
 499
 500 #define blk_account_rq(rq) \
 501         (((rq)->cmd_flags & REQ_STARTED) && \
 502          ((rq)->cmd_type == REQ_TYPE_FS || \
 503           ((rq)->cmd_flags & REQ_DISCARD)))
 504
 505 #define blk_pm_request(rq)      \
 506         ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
 507          (rq)->cmd_type == REQ_TYPE_PM_RESUME)
 508
 509 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 510 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 511 /* rq->queuelist of dequeued request must be list_empty() */
 512 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 513
 514 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 515
 516 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 517
 518 static inline unsigned int blk_queue_cluster(struct request_queue *q)
 519 {
 520         return q->limits.cluster;
 521 }
 522
 523 /*
 524  * We regard a request as sync, if either a read or a sync write
 525  */
 526 static inline bool rw_is_sync(unsigned int rw_flags)
 527 {
 528         return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
 529 }
 530
 531 static inline bool rq_is_sync(struct request *rq)
 532 {
 533         return rw_is_sync(rq->cmd_flags);
 534 }
 535
 536 static inline int blk_queue_full(struct request_queue *q, int sync)
 537 {
 538         if (sync)
 539                 return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
 540         return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
 541 }
 542
 543 static inline void blk_set_queue_full(struct request_queue *q, int sync)
 544 {
 545         if (sync)
 546                 queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
 547         else
 548                 queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
 549 }
 550
 551 static inline void blk_clear_queue_full(struct request_queue *q, int sync)
 552 {
 553         if (sync)
 554                 queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
 555         else
 556                 queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
 557 }
 558
 559
 560 /*
 561  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 562  * it already be started by driver.
 563  */
 564 #define RQ_NOMERGE_FLAGS        \
 565         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
 566 #define rq_mergeable(rq)        \
 567         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 568          (((rq)->cmd_flags & REQ_DISCARD) || \
 569           (rq)->cmd_type == REQ_TYPE_FS))
 570
 571 /*
 572  * q->prep_rq_fn return values
 573  */
 574 #define BLKPREP_OK              0       /* serve it */
 575 #define BLKPREP_KILL            1       /* fatal error, kill */
 576 #define BLKPREP_DEFER           2       /* leave on queue */
 577
 578 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 579
 580 /*
 581  * standard bounce addresses:
 582  *
 583  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 584  * BLK_BOUNCE_ANY       : don't bounce anything
 585  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 586  */
 587
 588 #if BITS_PER_LONG == 32
 589 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 590 #else
 591 #define BLK_BOUNCE_HIGH         -1ULL
 592 #endif
 593 #define BLK_BOUNCE_ANY          (-1ULL)
 594 #define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
 595
 596 /*
 597  * default timeout for SG_IO if none specified
 598  */
 599 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 600 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 601
 602 #ifdef CONFIG_BOUNCE
 603 extern int init_emergency_isa_pool(void);
 604 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 605 #else
 606 static inline int init_emergency_isa_pool(void)
 607 {
 608         return 0;
 609 }
 610 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 611 {
 612 }
 613 #endif /* CONFIG_MMU */
 614
 615 struct rq_map_data {
 616         struct page **pages;
 617         int page_order;
 618         int nr_entries;
 619         unsigned long offset;
 620         int null_mapped;
 621         int from_user;
 622 };
 623
 624 struct req_iterator {
 625         int i;
 626         struct bio *bio;
 627 };
 628
 629 /* This should not be used directly - use rq_for_each_segment */
 630 #define for_each_bio(_bio)              \
 631         for (; _bio; _bio = _bio->bi_next)
 632 #define __rq_for_each_bio(_bio, rq)     \
 633         if ((rq->bio))                  \
 634                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 635
 636 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 637         __rq_for_each_bio(_iter.bio, _rq)                       \
 638                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 639
 640 #define rq_iter_last(rq, _iter)                                 \
 641                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 642
 643 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 644 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 645 #endif
 646 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 647 extern void rq_flush_dcache_pages(struct request *rq);
 648 #else
 649 static inline void rq_flush_dcache_pages(struct request *rq)
 650 {
 651 }
 652 #endif
 653
 654 extern int blk_register_queue(struct gendisk *disk);
 655 extern void blk_unregister_queue(struct gendisk *disk);
 656 extern void register_disk(struct gendisk *dev);
 657 extern void generic_make_request(struct bio *bio);
 658 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 659 extern void blk_put_request(struct request *);
 660 extern void __blk_put_request(struct request_queue *, struct request *);
 661 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 662 extern struct request *blk_make_request(struct request_queue *, struct bio *,
 663                                         gfp_t);
 664 extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
 665 extern void blk_requeue_request(struct request_queue *, struct request *);
 666 extern void blk_add_request_payload(struct request *rq, struct page *page,
 667                 unsigned int len);
 668 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 669 extern int blk_lld_busy(struct request_queue *q);
 670 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 671                              struct bio_set *bs, gfp_t gfp_mask,
 672                              int (*bio_ctr)(struct bio *, struct bio *, void *),
 673                              void *data);
 674 extern void blk_rq_unprep_clone(struct request *rq);
 675 extern int blk_insert_cloned_request(struct request_queue *q,
 676                                      struct request *rq);
 677 extern void blk_plug_device(struct request_queue *);
 678 extern void blk_plug_device_unlocked(struct request_queue *);
 679 extern int blk_remove_plug(struct request_queue *);
 680 extern void blk_recount_segments(struct request_queue *, struct bio *);
 681 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 682                           unsigned int, void __user *);
 683 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 684                          struct scsi_ioctl_command __user *);
 685
 686 /*
 687  * A queue has just exitted congestion.  Note this in the global counter of
 688  * congested queues, and wake up anyone who was waiting for requests to be
 689  * put back.
 690  */
 691 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 692 {
 693         clear_bdi_congested(&q->backing_dev_info, sync);
 694 }
 695
 696 /*
 697  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 698  * state flags and increment the global gounter of congested queues.
 699  */
 700 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 701 {
 702         set_bdi_congested(&q->backing_dev_info, sync);
 703 }
 704
 705 extern void blk_start_queue(struct request_queue *q);
 706 extern void blk_stop_queue(struct request_queue *q);
 707 extern void blk_sync_queue(struct request_queue *q);
 708 extern void __blk_stop_queue(struct request_queue *q);
 709 extern void __blk_run_queue(struct request_queue *);
 710 extern void blk_run_queue(struct request_queue *);
 711 extern int blk_rq_map_user(struct request_queue *, struct request *,
 712                            struct rq_map_data *, void __user *, unsigned long,
 713                            gfp_t);
 714 extern int blk_rq_unmap_user(struct bio *);
 715 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 716 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 717                                struct rq_map_data *, struct sg_iovec *, int,
 718                                unsigned int, gfp_t);
 719 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 720                           struct request *, int);
 721 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 722                                   struct request *, int, rq_end_io_fn *);
 723 extern void blk_unplug(struct request_queue *q);
 724
 725 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 726 {
 727         return bdev->bd_disk->queue;
 728 }
 729
 730 /*
 731  * blk_rq_pos()                 : the current sector
 732  * blk_rq_bytes()               : bytes left in the entire request
 733  * blk_rq_cur_bytes()           : bytes left in the current segment
 734  * blk_rq_err_bytes()           : bytes left till the next error boundary
 735  * blk_rq_sectors()             : sectors left in the entire request
 736  * blk_rq_cur_sectors()         : sectors left in the current segment
 737  */
 738 static inline sector_t blk_rq_pos(const struct request *rq)
 739 {
 740         return rq->__sector;
 741 }
 742
 743 static inline unsigned int blk_rq_bytes(const struct request *rq)
 744 {
 745         return rq->__data_len;
 746 }
 747
 748 static inline int blk_rq_cur_bytes(const struct request *rq)
 749 {
 750         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 751 }
 752
 753 extern unsigned int blk_rq_err_bytes(const struct request *rq);
 754
 755 static inline unsigned int blk_rq_sectors(const struct request *rq)
 756 {
 757         return blk_rq_bytes(rq) >> 9;
 758 }
 759
 760 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 761 {
 762         return blk_rq_cur_bytes(rq) >> 9;
 763 }
 764
 765 /*
 766  * Request issue related functions.
 767  */
 768 extern struct request *blk_peek_request(struct request_queue *q);
 769 extern void blk_start_request(struct request *rq);
 770 extern struct request *blk_fetch_request(struct request_queue *q);
 771
 772 /*
 773  * Request completion related functions.
 774  *
 775  * blk_update_request() completes given number of bytes and updates
 776  * the request without completing it.
 777  *
 778  * blk_end_request() and friends.  __blk_end_request() must be called
 779  * with the request queue spinlock acquired.
 780  *
 781  * Several drivers define their own end_request and call
 782  * blk_end_request() for parts of the original function.
 783  * This prevents code duplication in drivers.
 784  */
 785 extern bool blk_update_request(struct request *rq, int error,
 786                                unsigned int nr_bytes);
 787 extern bool blk_end_request(struct request *rq, int error,
 788                             unsigned int nr_bytes);
 789 extern void blk_end_request_all(struct request *rq, int error);
 790 extern bool blk_end_request_cur(struct request *rq, int error);
 791 extern bool blk_end_request_err(struct request *rq, int error);
 792 extern bool __blk_end_request(struct request *rq, int error,
 793                               unsigned int nr_bytes);
 794 extern void __blk_end_request_all(struct request *rq, int error);
 795 extern bool __blk_end_request_cur(struct request *rq, int error);
 796 extern bool __blk_end_request_err(struct request *rq, int error);
 797
 798 extern void blk_complete_request(struct request *);
 799 extern void __blk_complete_request(struct request *);
 800 extern void blk_abort_request(struct request *);
 801 extern void blk_abort_queue(struct request_queue *);
 802 extern void blk_unprep_request(struct request *);
 803
 804 /*
 805  * Access functions for manipulating queue properties
 806  */
 807 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 808                                         spinlock_t *lock, int node_id);
 809 extern struct request_queue *blk_init_allocated_queue_node(struct request_queue *,
 810                                                            request_fn_proc *,
 811                                                            spinlock_t *, int node_id);
 812 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 813 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
 814                                                       request_fn_proc *, spinlock_t *);
 815 extern void blk_cleanup_queue(struct request_queue *);
 816 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 817 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 818 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
 819 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 820 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
 821 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 822 extern void blk_queue_max_discard_sectors(struct request_queue *q,
 823                 unsigned int max_discard_sectors);
 824 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 825 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
 826 extern void blk_queue_alignment_offset(struct request_queue *q,
 827                                        unsigned int alignment);
 828 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 829 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 830 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 831 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 832 extern void blk_set_default_limits(struct queue_limits *lim);
 833 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 834                             sector_t offset);
 835 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
 836                             sector_t offset);
 837 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 838                               sector_t offset);
 839 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 840 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 841 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 842 extern int blk_queue_dma_drain(struct request_queue *q,
 843                                dma_drain_needed_fn *dma_drain_needed,
 844                                void *buf, unsigned int size);
 845 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 846 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 847 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 848 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
 849 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 850 extern void blk_queue_dma_alignment(struct request_queue *, int);
 851 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 852 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 853 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 854 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 855 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
 856 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 857
 858 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 859 extern void blk_dump_rq_flags(struct request *, char *);
 860 extern void generic_unplug_device(struct request_queue *);
 861 extern long nr_blockdev_pages(void);
 862
 863 int blk_get_queue(struct request_queue *);
 864 struct request_queue *blk_alloc_queue(gfp_t);
 865 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 866 extern void blk_put_queue(struct request_queue *);
 867
 868 /*
 869  * tag stuff
 870  */
 871 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 872 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 873 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 874 extern void blk_queue_end_tag(struct request_queue *, struct request *);
 875 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 876 extern void blk_queue_free_tags(struct request_queue *);
 877 extern int blk_queue_resize_tags(struct request_queue *, int);
 878 extern void blk_queue_invalidate_tags(struct request_queue *);
 879 extern struct blk_queue_tag *blk_init_tags(int);
 880 extern void blk_free_tags(struct blk_queue_tag *);
 881
 882 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 883                                                 int tag)
 884 {
 885         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 886                 return NULL;
 887         return bqt->tag_index[tag];
 888 }
 889
 890 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
 891
 892 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
 893 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 894                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
 895 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 896                         sector_t nr_sects, gfp_t gfp_mask);
 897 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
 898                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
 899 {
 900         return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
 901                                     nr_blocks << (sb->s_blocksize_bits - 9),
 902                                     gfp_mask, flags);
 903 }
 904 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
 905                 sector_t nr_blocks, gfp_t gfp_mask)
 906 {
 907         return blkdev_issue_zeroout(sb->s_bdev,
 908                                     block << (sb->s_blocksize_bits - 9),
 909                                     nr_blocks << (sb->s_blocksize_bits - 9),
 910                                     gfp_mask);
 911 }
 912
 913 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
 914
 915 enum blk_default_limits {
 916         BLK_MAX_SEGMENTS        = 128,
 917         BLK_SAFE_MAX_SECTORS    = 255,
 918         BLK_DEF_MAX_SECTORS     = 1024,
 919         BLK_MAX_SEGMENT_SIZE    = 65536,
 920         BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
 921 };
 922
 923 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
 924
 925 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
 926 {
 927         return q->limits.bounce_pfn;
 928 }
 929
 930 static inline unsigned long queue_segment_boundary(struct request_queue *q)
 931 {
 932         return q->limits.seg_boundary_mask;
 933 }
 934
 935 static inline unsigned int queue_max_sectors(struct request_queue *q)
 936 {
 937         return q->limits.max_sectors;
 938 }
 939
 940 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
 941 {
 942         return q->limits.max_hw_sectors;
 943 }
 944
 945 static inline unsigned short queue_max_segments(struct request_queue *q)
 946 {
 947         return q->limits.max_segments;
 948 }
 949
 950 static inline unsigned int queue_max_segment_size(struct request_queue *q)
 951 {
 952         return q->limits.max_segment_size;
 953 }
 954
 955 static inline unsigned short queue_logical_block_size(struct request_queue *q)
 956 {
 957         int retval = 512;
 958
 959         if (q && q->limits.logical_block_size)
 960                 retval = q->limits.logical_block_size;
 961
 962         return retval;
 963 }
 964
 965 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
 966 {
 967         return queue_logical_block_size(bdev_get_queue(bdev));
 968 }
 969
 970 static inline unsigned int queue_physical_block_size(struct request_queue *q)
 971 {
 972         return q->limits.physical_block_size;
 973 }
 974
 975 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
 976 {
 977         return queue_physical_block_size(bdev_get_queue(bdev));
 978 }
 979
 980 static inline unsigned int queue_io_min(struct request_queue *q)
 981 {
 982         return q->limits.io_min;
 983 }
 984
 985 static inline int bdev_io_min(struct block_device *bdev)
 986 {
 987         return queue_io_min(bdev_get_queue(bdev));
 988 }
 989
 990 static inline unsigned int queue_io_opt(struct request_queue *q)
 991 {
 992         return q->limits.io_opt;
 993 }
 994
 995 static inline int bdev_io_opt(struct block_device *bdev)
 996 {
 997         return queue_io_opt(bdev_get_queue(bdev));
 998 }
 999
1000 static inline int queue_alignment_offset(struct request_queue *q)
1001 {
1002         if (q->limits.misaligned)
1003                 return -1;
1004
1005         return q->limits.alignment_offset;
1006 }
1007
1008 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1009 {
1010         unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1011         unsigned int alignment = (sector << 9) & (granularity - 1);
1012
1013         return (granularity + lim->alignment_offset - alignment)
1014                 & (granularity - 1);
1015 }
1016
1017 static inline int bdev_alignment_offset(struct block_device *bdev)
1018 {
1019         struct request_queue *q = bdev_get_queue(bdev);
1020
1021         if (q->limits.misaligned)
1022                 return -1;
1023
1024         if (bdev != bdev->bd_contains)
1025                 return bdev->bd_part->alignment_offset;
1026
1027         return q->limits.alignment_offset;
1028 }
1029
1030 static inline int queue_discard_alignment(struct request_queue *q)
1031 {
1032         if (q->limits.discard_misaligned)
1033                 return -1;
1034
1035         return q->limits.discard_alignment;
1036 }
1037
1038 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1039 {
1040         unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1041
1042         return (lim->discard_granularity + lim->discard_alignment - alignment)
1043                 & (lim->discard_granularity - 1);
1044 }
1045
1046 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1047 {
1048         if (q->limits.discard_zeroes_data == 1)
1049                 return 1;
1050
1051         return 0;
1052 }
1053
1054 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1055 {
1056         return queue_discard_zeroes_data(bdev_get_queue(bdev));
1057 }
1058
1059 static inline int queue_dma_alignment(struct request_queue *q)
1060 {
1061         return q ? q->dma_alignment : 511;
1062 }
1063
1064 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1065                                  unsigned int len)
1066 {
1067         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1068         return !(addr & alignment) && !(len & alignment);
1069 }
1070
1071 /* assumes size > 256 */
1072 static inline unsigned int blksize_bits(unsigned int size)
1073 {
1074         unsigned int bits = 8;
1075         do {
1076                 bits++;
1077                 size >>= 1;
1078         } while (size > 256);
1079         return bits;
1080 }
1081
1082 static inline unsigned int block_size(struct block_device *bdev)
1083 {
1084         return bdev->bd_block_size;
1085 }
1086
1087 typedef struct {struct page *v;} Sector;
1088
1089 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1090
1091 static inline void put_dev_sector(Sector p)
1092 {
1093         page_cache_release(p.v);
1094 }
1095
1096 struct work_struct;
1097 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1098 int kblockd_schedule_delayed_work(struct request_queue *q, struct delayed_work *dwork, unsigned long delay);
1099
1100 #ifdef CONFIG_BLK_CGROUP
1101 /*
1102  * This should not be using sched_clock(). A real patch is in progress
1103  * to fix this up, until that is in place we need to disable preemption
1104  * around sched_clock() in this function and set_io_start_time_ns().
1105  */
1106 static inline void set_start_time_ns(struct request *req)
1107 {
1108         preempt_disable();
1109         req->start_time_ns = sched_clock();
1110         preempt_enable();
1111 }
1112
1113 static inline void set_io_start_time_ns(struct request *req)
1114 {
1115         preempt_disable();
1116         req->io_start_time_ns = sched_clock();
1117         preempt_enable();
1118 }
1119
1120 static inline uint64_t rq_start_time_ns(struct request *req)
1121 {
1122         return req->start_time_ns;
1123 }
1124
1125 static inline uint64_t rq_io_start_time_ns(struct request *req)
1126 {
1127         return req->io_start_time_ns;
1128 }
1129 #else
1130 static inline void set_start_time_ns(struct request *req) {}
1131 static inline void set_io_start_time_ns(struct request *req) {}
1132 static inline uint64_t rq_start_time_ns(struct request *req)
1133 {
1134         return 0;
1135 }
1136 static inline uint64_t rq_io_start_time_ns(struct request *req)
1137 {
1138         return 0;
1139 }
1140 #endif
1141
1142 #ifdef CONFIG_BLK_DEV_THROTTLING
1143 extern int blk_throtl_init(struct request_queue *q);
1144 extern void blk_throtl_exit(struct request_queue *q);
1145 extern int blk_throtl_bio(struct request_queue *q, struct bio **bio);
1146 extern void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay);
1147 extern void throtl_shutdown_timer_wq(struct request_queue *q);
1148 #else /* CONFIG_BLK_DEV_THROTTLING */
1149 static inline int blk_throtl_bio(struct request_queue *q, struct bio **bio)
1150 {
1151         return 0;
1152 }
1153
1154 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
1155 static inline int blk_throtl_exit(struct request_queue *q) { return 0; }
1156 static inline void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay) {}
1157 static inline void throtl_shutdown_timer_wq(struct request_queue *q) {}
1158 #endif /* CONFIG_BLK_DEV_THROTTLING */
1159
1160 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1161         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1162 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1163         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1164
1165 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1166
1167 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1168 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1169
1170 struct blk_integrity_exchg {
1171         void                    *prot_buf;
1172         void                    *data_buf;
1173         sector_t                sector;
1174         unsigned int            data_size;
1175         unsigned short          sector_size;
1176         const char              *disk_name;
1177 };
1178
1179 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1180 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1181 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1182 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1183
1184 struct blk_integrity {
1185         integrity_gen_fn        *generate_fn;
1186         integrity_vrfy_fn       *verify_fn;
1187         integrity_set_tag_fn    *set_tag_fn;
1188         integrity_get_tag_fn    *get_tag_fn;
1189
1190         unsigned short          flags;
1191         unsigned short          tuple_size;
1192         unsigned short          sector_size;
1193         unsigned short          tag_size;
1194
1195         const char              *name;
1196
1197         struct kobject          kobj;
1198 };
1199
1200 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1201 extern void blk_integrity_unregister(struct gendisk *);
1202 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1203 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1204                                    struct scatterlist *);
1205 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1206 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1207                                   struct request *);
1208 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1209                                    struct bio *);
1210
1211 static inline
1212 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1213 {
1214         return bdev->bd_disk->integrity;
1215 }
1216
1217 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1218 {
1219         return disk->integrity;
1220 }
1221
1222 static inline int blk_integrity_rq(struct request *rq)
1223 {
1224         if (rq->bio == NULL)
1225                 return 0;
1226
1227         return bio_integrity(rq->bio);
1228 }
1229
1230 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1231                                                     unsigned int segs)
1232 {
1233         q->limits.max_integrity_segments = segs;
1234 }
1235
1236 static inline unsigned short
1237 queue_max_integrity_segments(struct request_queue *q)
1238 {
1239         return q->limits.max_integrity_segments;
1240 }
1241
1242 #else /* CONFIG_BLK_DEV_INTEGRITY */
1243
1244 #define blk_integrity_rq(rq)                    (0)
1245 #define blk_rq_count_integrity_sg(a, b)         (0)
1246 #define blk_rq_map_integrity_sg(a, b, c)        (0)
1247 #define bdev_get_integrity(a)                   (0)
1248 #define blk_get_integrity(a)                    (0)
1249 #define blk_integrity_compare(a, b)             (0)
1250 #define blk_integrity_register(a, b)            (0)
1251 #define blk_integrity_unregister(a)             do { } while (0);
1252 #define blk_queue_max_integrity_segments(a, b)  do { } while (0);
1253 #define queue_max_integrity_segments(a)         (0)
1254 #define blk_integrity_merge_rq(a, b, c)         (0)
1255 #define blk_integrity_merge_bio(a, b, c)        (0)
1256
1257 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1258
1259 struct block_device_operations {
1260         int (*open) (struct block_device *, fmode_t);
1261         int (*release) (struct gendisk *, fmode_t);
1262         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1263         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1264         int (*direct_access) (struct block_device *, sector_t,
1265                                                 void **, unsigned long *);
1266         int (*media_changed) (struct gendisk *);
1267         void (*unlock_native_capacity) (struct gendisk *);
1268         int (*revalidate_disk) (struct gendisk *);
1269         int (*getgeo)(struct block_device *, struct hd_geometry *);
1270         /* this callback is with swap_lock and sometimes page table lock held */
1271         void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1272         struct module *owner;
1273 };
1274
1275 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1276                                  unsigned long);
1277 #else /* CONFIG_BLOCK */
1278 /*
1279  * stubs for when the block layer is configured out
1280  */
1281 #define buffer_heads_over_limit 0
1282
1283 static inline long nr_blockdev_pages(void)
1284 {
1285         return 0;
1286 }
1287
1288 #endif /* CONFIG_BLOCK */
1289
1290 #endif