include/linux/blkdev.h

   1 #ifndef _LINUX_BLKDEV_H
   2 #define _LINUX_BLKDEV_H
   3
   4 #include <linux/sched.h>
   5
   6 #ifdef CONFIG_BLOCK
   7
   8 #include <linux/major.h>
   9 #include <linux/genhd.h>
  10 #include <linux/list.h>
  11 #include <linux/timer.h>
  12 #include <linux/workqueue.h>
  13 #include <linux/pagemap.h>
  14 #include <linux/backing-dev.h>
  15 #include <linux/wait.h>
  16 #include <linux/mempool.h>
  17 #include <linux/bio.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 module;
  26 struct scsi_ioctl_command;
  27
  28 struct request_queue;
  29 struct elevator_queue;
  30 struct request_pm_state;
  31 struct blk_trace;
  32 struct request;
  33 struct sg_io_hdr;
  34 struct bsg_job;
  35
  36 #define BLKDEV_MIN_RQ   4
  37 #define BLKDEV_MAX_RQ   128     /* Default maximum */
  38
  39 struct request;
  40 typedef void (rq_end_io_fn)(struct request *, int);
  41
  42 struct request_list {
  43         /*
  44          * count[], starved[], and wait[] are indexed by
  45          * BLK_RW_SYNC/BLK_RW_ASYNC
  46          */
  47         int count[2];
  48         int starved[2];
  49         int elvpriv;
  50         mempool_t *rq_pool;
  51         wait_queue_head_t wait[2];
  52 };
  53
  54 /*
  55  * request command types
  56  */
  57 enum rq_cmd_type_bits {
  58         REQ_TYPE_FS             = 1,    /* fs request */
  59         REQ_TYPE_BLOCK_PC,              /* scsi command */
  60         REQ_TYPE_SENSE,                 /* sense request */
  61         REQ_TYPE_PM_SUSPEND,            /* suspend request */
  62         REQ_TYPE_PM_RESUME,             /* resume request */
  63         REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
  64         REQ_TYPE_SPECIAL,               /* driver defined type */
  65         /*
  66          * for ATA/ATAPI devices. this really doesn't belong here, ide should
  67          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  68          * private REQ_LB opcodes to differentiate what type of request this is
  69          */
  70         REQ_TYPE_ATA_TASKFILE,
  71         REQ_TYPE_ATA_PC,
  72 };
  73
  74 #define BLK_MAX_CDB     16
  75
  76 /*
  77  * try to put the fields that are referenced together in the same cacheline.
  78  * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
  79  * as well!
  80  */
  81 struct request {
  82         struct list_head queuelist;
  83         struct call_single_data csd;
  84
  85         struct request_queue *q;
  86
  87         unsigned int cmd_flags;
  88         enum rq_cmd_type_bits cmd_type;
  89         unsigned long atomic_flags;
  90
  91         int cpu;
  92
  93         /* the following two fields are internal, NEVER access directly */
  94         unsigned int __data_len;        /* total data len */
  95         sector_t __sector;              /* sector cursor */
  96
  97         struct bio *bio;
  98         struct bio *biotail;
  99
 100         struct hlist_node hash; /* merge hash */
 101         /*
 102          * The rb_node is only used inside the io scheduler, requests
 103          * are pruned when moved to the dispatch queue. So let the
 104          * completion_data share space with the rb_node.
 105          */
 106         union {
 107                 struct rb_node rb_node; /* sort/lookup */
 108                 void *completion_data;
 109         };
 110
 111         /*
 112          * Three pointers are available for the IO schedulers, if they need
 113          * more they have to dynamically allocate it.  Flush requests are
 114          * never put on the IO scheduler. So let the flush fields share
 115          * space with the elevator data.
 116          */
 117         union {
 118                 struct {
 119                         struct io_cq            *icq;
 120                         void                    *priv[2];
 121                 } elv;
 122
 123                 struct {
 124                         unsigned int            seq;
 125                         struct list_head        list;
 126                         rq_end_io_fn            *saved_end_io;
 127                 } flush;
 128         };
 129
 130         struct gendisk *rq_disk;
 131         struct hd_struct *part;
 132         unsigned long start_time;
 133 #ifdef CONFIG_BLK_CGROUP
 134         unsigned long long start_time_ns;
 135         unsigned long long io_start_time_ns;    /* when passed to hardware */
 136 #endif
 137         /* Number of scatter-gather DMA addr+len pairs after
 138          * physical address coalescing is performed.
 139          */
 140         unsigned short nr_phys_segments;
 141 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 142         unsigned short nr_integrity_segments;
 143 #endif
 144
 145         unsigned short ioprio;
 146
 147         int ref_count;
 148
 149         void *special;          /* opaque pointer available for LLD use */
 150         char *buffer;           /* kaddr of the current segment if available */
 151
 152         int tag;
 153         int errors;
 154
 155         /*
 156          * when request is used as a packet command carrier
 157          */
 158         unsigned char __cmd[BLK_MAX_CDB];
 159         unsigned char *cmd;
 160         unsigned short cmd_len;
 161
 162         unsigned int extra_len; /* length of alignment and padding */
 163         unsigned int sense_len;
 164         unsigned int resid_len; /* residual count */
 165         void *sense;
 166
 167         unsigned long deadline;
 168         struct list_head timeout_list;
 169         unsigned int timeout;
 170         int retries;
 171
 172         /*
 173          * completion callback.
 174          */
 175         rq_end_io_fn *end_io;
 176         void *end_io_data;
 177
 178         /* for bidi */
 179         struct request *next_rq;
 180 };
 181
 182 static inline unsigned short req_get_ioprio(struct request *req)
 183 {
 184         return req->ioprio;
 185 }
 186
 187 /*
 188  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 189  * requests. Some step values could eventually be made generic.
 190  */
 191 struct request_pm_state
 192 {
 193         /* PM state machine step value, currently driver specific */
 194         int     pm_step;
 195         /* requested PM state value (S1, S2, S3, S4, ...) */
 196         u32     pm_state;
 197         void*   data;           /* for driver use */
 198 };
 199
 200 #include <linux/elevator.h>
 201
 202 typedef void (request_fn_proc) (struct request_queue *q);
 203 typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
 204 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 205 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
 206
 207 struct bio_vec;
 208 struct bvec_merge_data {
 209         struct block_device *bi_bdev;
 210         sector_t bi_sector;
 211         unsigned bi_size;
 212         unsigned long bi_rw;
 213 };
 214 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
 215                              struct bio_vec *);
 216 typedef void (softirq_done_fn)(struct request *);
 217 typedef int (dma_drain_needed_fn)(struct request *);
 218 typedef int (lld_busy_fn) (struct request_queue *q);
 219 typedef int (bsg_job_fn) (struct bsg_job *);
 220
 221 enum blk_eh_timer_return {
 222         BLK_EH_NOT_HANDLED,
 223         BLK_EH_HANDLED,
 224         BLK_EH_RESET_TIMER,
 225 };
 226
 227 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
 228
 229 enum blk_queue_state {
 230         Queue_down,
 231         Queue_up,
 232 };
 233
 234 struct blk_queue_tag {
 235         struct request **tag_index;     /* map of busy tags */
 236         unsigned long *tag_map;         /* bit map of free/busy tags */
 237         int busy;                       /* current depth */
 238         int max_depth;                  /* what we will send to device */
 239         int real_max_depth;             /* what the array can hold */
 240         atomic_t refcnt;                /* map can be shared */
 241 };
 242
 243 #define BLK_SCSI_MAX_CMDS       (256)
 244 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 245
 246 struct queue_limits {
 247         unsigned long           bounce_pfn;
 248         unsigned long           seg_boundary_mask;
 249
 250         unsigned int            max_hw_sectors;
 251         unsigned int            max_sectors;
 252         unsigned int            max_segment_size;
 253         unsigned int            physical_block_size;
 254         unsigned int            alignment_offset;
 255         unsigned int            io_min;
 256         unsigned int            io_opt;
 257         unsigned int            max_discard_sectors;
 258         unsigned int            discard_granularity;
 259         unsigned int            discard_alignment;
 260
 261         unsigned short          logical_block_size;
 262         unsigned short          max_segments;
 263         unsigned short          max_integrity_segments;
 264
 265         unsigned char           misaligned;
 266         unsigned char           discard_misaligned;
 267         unsigned char           cluster;
 268         unsigned char           discard_zeroes_data;
 269 };
 270
 271 struct request_queue {
 272         /*
 273          * Together with queue_head for cacheline sharing
 274          */
 275         struct list_head        queue_head;
 276         struct request          *last_merge;
 277         struct elevator_queue   *elevator;
 278
 279         /*
 280          * the queue request freelist, one for reads and one for writes
 281          */
 282         struct request_list     rq;
 283
 284         request_fn_proc         *request_fn;
 285         make_request_fn         *make_request_fn;
 286         prep_rq_fn              *prep_rq_fn;
 287         unprep_rq_fn            *unprep_rq_fn;
 288         merge_bvec_fn           *merge_bvec_fn;
 289         softirq_done_fn         *softirq_done_fn;
 290         rq_timed_out_fn         *rq_timed_out_fn;
 291         dma_drain_needed_fn     *dma_drain_needed;
 292         lld_busy_fn             *lld_busy_fn;
 293
 294         /*
 295          * Dispatch queue sorting
 296          */
 297         sector_t                end_sector;
 298         struct request          *boundary_rq;
 299
 300         /*
 301          * Delayed queue handling
 302          */
 303         struct delayed_work     delay_work;
 304
 305         struct backing_dev_info backing_dev_info;
 306
 307         /*
 308          * The queue owner gets to use this for whatever they like.
 309          * ll_rw_blk doesn't touch it.
 310          */
 311         void                    *queuedata;
 312
 313         /*
 314          * various queue flags, see QUEUE_* below
 315          */
 316         unsigned long           queue_flags;
 317
 318         /*
 319          * ida allocated id for this queue.  Used to index queues from
 320          * ioctx.
 321          */
 322         int                     id;
 323
 324         /*
 325          * queue needs bounce pages for pages above this limit
 326          */
 327         gfp_t                   bounce_gfp;
 328
 329         /*
 330          * protects queue structures from reentrancy. ->__queue_lock should
 331          * _never_ be used directly, it is queue private. always use
 332          * ->queue_lock.
 333          */
 334         spinlock_t              __queue_lock;
 335         spinlock_t              *queue_lock;
 336
 337         /*
 338          * queue kobject
 339          */
 340         struct kobject kobj;
 341
 342         /*
 343          * queue settings
 344          */
 345         unsigned long           nr_requests;    /* Max # of requests */
 346         unsigned int            nr_congestion_on;
 347         unsigned int            nr_congestion_off;
 348         unsigned int            nr_batching;
 349
 350         unsigned int            dma_drain_size;
 351         void                    *dma_drain_buffer;
 352         unsigned int            dma_pad_mask;
 353         unsigned int            dma_alignment;
 354
 355         struct blk_queue_tag    *queue_tags;
 356         struct list_head        tag_busy_list;
 357
 358         unsigned int            nr_sorted;
 359         unsigned int            in_flight[2];
 360
 361         unsigned int            rq_timeout;
 362         struct timer_list       timeout;
 363         struct list_head        timeout_list;
 364
 365         struct list_head        icq_list;
 366
 367         struct queue_limits     limits;
 368
 369         /*
 370          * sg stuff
 371          */
 372         unsigned int            sg_timeout;
 373         unsigned int            sg_reserved_size;
 374         int                     node;
 375 #ifdef CONFIG_BLK_DEV_IO_TRACE
 376         struct blk_trace        *blk_trace;
 377 #endif
 378         /*
 379          * for flush operations
 380          */
 381         unsigned int            flush_flags;
 382         unsigned int            flush_not_queueable:1;
 383         unsigned int            flush_queue_delayed:1;
 384         unsigned int            flush_pending_idx:1;
 385         unsigned int            flush_running_idx:1;
 386         unsigned long           flush_pending_since;
 387         struct list_head        flush_queue[2];
 388         struct list_head        flush_data_in_flight;
 389         struct request          flush_rq;
 390
 391         struct mutex            sysfs_lock;
 392
 393 #if defined(CONFIG_BLK_DEV_BSG)
 394         bsg_job_fn              *bsg_job_fn;
 395         int                     bsg_job_size;
 396         struct bsg_class_device bsg_dev;
 397 #endif
 398
 399 #ifdef CONFIG_BLK_DEV_THROTTLING
 400         /* Throttle data */
 401         struct throtl_data *td;
 402 #endif
 403 };
 404
 405 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 406 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 407 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 408 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 409 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 410 #define QUEUE_FLAG_ELVSWITCH    6       /* don't use elevator, just do FIFO */
 411 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
 412 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
 413 #define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
 414 #define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
 415 #define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
 416 #define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
 417 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 418 #define QUEUE_FLAG_IO_STAT     13       /* do IO stats */
 419 #define QUEUE_FLAG_DISCARD     14       /* supports DISCARD */
 420 #define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
 421 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
 422 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
 423 #define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
 424
 425 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 426                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
 427                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
 428                                  (1 << QUEUE_FLAG_ADD_RANDOM))
 429
 430 static inline void queue_lockdep_assert_held(struct request_queue *q)
 431 {
 432         if (q->queue_lock)
 433                 lockdep_assert_held(q->queue_lock);
 434 }
 435
 436 static inline void queue_flag_set_unlocked(unsigned int flag,
 437                                            struct request_queue *q)
 438 {
 439         __set_bit(flag, &q->queue_flags);
 440 }
 441
 442 static inline int queue_flag_test_and_clear(unsigned int flag,
 443                                             struct request_queue *q)
 444 {
 445         queue_lockdep_assert_held(q);
 446
 447         if (test_bit(flag, &q->queue_flags)) {
 448                 __clear_bit(flag, &q->queue_flags);
 449                 return 1;
 450         }
 451
 452         return 0;
 453 }
 454
 455 static inline int queue_flag_test_and_set(unsigned int flag,
 456                                           struct request_queue *q)
 457 {
 458         queue_lockdep_assert_held(q);
 459
 460         if (!test_bit(flag, &q->queue_flags)) {
 461                 __set_bit(flag, &q->queue_flags);
 462                 return 0;
 463         }
 464
 465         return 1;
 466 }
 467
 468 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 469 {
 470         queue_lockdep_assert_held(q);
 471         __set_bit(flag, &q->queue_flags);
 472 }
 473
 474 static inline void queue_flag_clear_unlocked(unsigned int flag,
 475                                              struct request_queue *q)
 476 {
 477         __clear_bit(flag, &q->queue_flags);
 478 }
 479
 480 static inline int queue_in_flight(struct request_queue *q)
 481 {
 482         return q->in_flight[0] + q->in_flight[1];
 483 }
 484
 485 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 486 {
 487         queue_lockdep_assert_held(q);
 488         __clear_bit(flag, &q->queue_flags);
 489 }
 490
 491 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 492 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 493 #define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 494 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 495 #define blk_queue_noxmerges(q)  \
 496         test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
 497 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 498 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 499 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
 500 #define blk_queue_stackable(q)  \
 501         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 502 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
 503 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
 504         test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
 505
 506 #define blk_noretry_request(rq) \
 507         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
 508                              REQ_FAILFAST_DRIVER))
 509
 510 #define blk_account_rq(rq) \
 511         (((rq)->cmd_flags & REQ_STARTED) && \
 512          ((rq)->cmd_type == REQ_TYPE_FS || \
 513           ((rq)->cmd_flags & REQ_DISCARD)))
 514
 515 #define blk_pm_request(rq)      \
 516         ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
 517          (rq)->cmd_type == REQ_TYPE_PM_RESUME)
 518
 519 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 520 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 521 /* rq->queuelist of dequeued request must be list_empty() */
 522 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 523
 524 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 525
 526 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 527
 528 static inline unsigned int blk_queue_cluster(struct request_queue *q)
 529 {
 530         return q->limits.cluster;
 531 }
 532
 533 /*
 534  * We regard a request as sync, if either a read or a sync write
 535  */
 536 static inline bool rw_is_sync(unsigned int rw_flags)
 537 {
 538         return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
 539 }
 540
 541 static inline bool rq_is_sync(struct request *rq)
 542 {
 543         return rw_is_sync(rq->cmd_flags);
 544 }
 545
 546 static inline int blk_queue_full(struct request_queue *q, int sync)
 547 {
 548         if (sync)
 549                 return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
 550         return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
 551 }
 552
 553 static inline void blk_set_queue_full(struct request_queue *q, int sync)
 554 {
 555         if (sync)
 556                 queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
 557         else
 558                 queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
 559 }
 560
 561 static inline void blk_clear_queue_full(struct request_queue *q, int sync)
 562 {
 563         if (sync)
 564                 queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
 565         else
 566                 queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
 567 }
 568
 569
 570 /*
 571  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 572  * it already be started by driver.
 573  */
 574 #define RQ_NOMERGE_FLAGS        \
 575         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
 576 #define rq_mergeable(rq)        \
 577         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 578          (((rq)->cmd_flags & REQ_DISCARD) || \
 579           (rq)->cmd_type == REQ_TYPE_FS))
 580
 581 /*
 582  * q->prep_rq_fn return values
 583  */
 584 #define BLKPREP_OK              0       /* serve it */
 585 #define BLKPREP_KILL            1       /* fatal error, kill */
 586 #define BLKPREP_DEFER           2       /* leave on queue */
 587
 588 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 589
 590 /*
 591  * standard bounce addresses:
 592  *
 593  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 594  * BLK_BOUNCE_ANY       : don't bounce anything
 595  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 596  */
 597
 598 #if BITS_PER_LONG == 32
 599 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 600 #else
 601 #define BLK_BOUNCE_HIGH         -1ULL
 602 #endif
 603 #define BLK_BOUNCE_ANY          (-1ULL)
 604 #define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
 605
 606 /*
 607  * default timeout for SG_IO if none specified
 608  */
 609 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 610 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 611
 612 #ifdef CONFIG_BOUNCE
 613 extern int init_emergency_isa_pool(void);
 614 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 615 #else
 616 static inline int init_emergency_isa_pool(void)
 617 {
 618         return 0;
 619 }
 620 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 621 {
 622 }
 623 #endif /* CONFIG_MMU */
 624
 625 struct rq_map_data {
 626         struct page **pages;
 627         int page_order;
 628         int nr_entries;
 629         unsigned long offset;
 630         int null_mapped;
 631         int from_user;
 632 };
 633
 634 struct req_iterator {
 635         int i;
 636         struct bio *bio;
 637 };
 638
 639 /* This should not be used directly - use rq_for_each_segment */
 640 #define for_each_bio(_bio)              \
 641         for (; _bio; _bio = _bio->bi_next)
 642 #define __rq_for_each_bio(_bio, rq)     \
 643         if ((rq->bio))                  \
 644                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 645
 646 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 647         __rq_for_each_bio(_iter.bio, _rq)                       \
 648                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 649
 650 #define rq_iter_last(rq, _iter)                                 \
 651                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 652
 653 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 654 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 655 #endif
 656 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 657 extern void rq_flush_dcache_pages(struct request *rq);
 658 #else
 659 static inline void rq_flush_dcache_pages(struct request *rq)
 660 {
 661 }
 662 #endif
 663
 664 extern int blk_register_queue(struct gendisk *disk);
 665 extern void blk_unregister_queue(struct gendisk *disk);
 666 extern void generic_make_request(struct bio *bio);
 667 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 668 extern void blk_put_request(struct request *);
 669 extern void __blk_put_request(struct request_queue *, struct request *);
 670 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 671 extern struct request *blk_make_request(struct request_queue *, struct bio *,
 672                                         gfp_t);
 673 extern void blk_requeue_request(struct request_queue *, struct request *);
 674 extern void blk_add_request_payload(struct request *rq, struct page *page,
 675                 unsigned int len);
 676 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 677 extern int blk_lld_busy(struct request_queue *q);
 678 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 679                              struct bio_set *bs, gfp_t gfp_mask,
 680                              int (*bio_ctr)(struct bio *, struct bio *, void *),
 681                              void *data);
 682 extern void blk_rq_unprep_clone(struct request *rq);
 683 extern int blk_insert_cloned_request(struct request_queue *q,
 684                                      struct request *rq);
 685 extern void blk_delay_queue(struct request_queue *, unsigned long);
 686 extern void blk_recount_segments(struct request_queue *, struct bio *);
 687 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
 688 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
 689                               unsigned int, void __user *);
 690 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 691                           unsigned int, void __user *);
 692 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 693                          struct scsi_ioctl_command __user *);
 694
 695 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
 696
 697 /*
 698  * A queue has just exitted congestion.  Note this in the global counter of
 699  * congested queues, and wake up anyone who was waiting for requests to be
 700  * put back.
 701  */
 702 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 703 {
 704         clear_bdi_congested(&q->backing_dev_info, sync);
 705 }
 706
 707 /*
 708  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 709  * state flags and increment the global gounter of congested queues.
 710  */
 711 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 712 {
 713         set_bdi_congested(&q->backing_dev_info, sync);
 714 }
 715
 716 extern void blk_start_queue(struct request_queue *q);
 717 extern void blk_stop_queue(struct request_queue *q);
 718 extern void blk_sync_queue(struct request_queue *q);
 719 extern void __blk_stop_queue(struct request_queue *q);
 720 extern void __blk_run_queue(struct request_queue *q);
 721 extern void blk_run_queue(struct request_queue *);
 722 extern void blk_run_queue_async(struct request_queue *q);
 723 extern int blk_rq_map_user(struct request_queue *, struct request *,
 724                            struct rq_map_data *, void __user *, unsigned long,
 725                            gfp_t);
 726 extern int blk_rq_unmap_user(struct bio *);
 727 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 728 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 729                                struct rq_map_data *, struct sg_iovec *, int,
 730                                unsigned int, gfp_t);
 731 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 732                           struct request *, int);
 733 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 734                                   struct request *, int, rq_end_io_fn *);
 735
 736 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 737 {
 738         return bdev->bd_disk->queue;
 739 }
 740
 741 /*
 742  * blk_rq_pos()                 : the current sector
 743  * blk_rq_bytes()               : bytes left in the entire request
 744  * blk_rq_cur_bytes()           : bytes left in the current segment
 745  * blk_rq_err_bytes()           : bytes left till the next error boundary
 746  * blk_rq_sectors()             : sectors left in the entire request
 747  * blk_rq_cur_sectors()         : sectors left in the current segment
 748  */
 749 static inline sector_t blk_rq_pos(const struct request *rq)
 750 {
 751         return rq->__sector;
 752 }
 753
 754 static inline unsigned int blk_rq_bytes(const struct request *rq)
 755 {
 756         return rq->__data_len;
 757 }
 758
 759 static inline int blk_rq_cur_bytes(const struct request *rq)
 760 {
 761         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 762 }
 763
 764 extern unsigned int blk_rq_err_bytes(const struct request *rq);
 765
 766 static inline unsigned int blk_rq_sectors(const struct request *rq)
 767 {
 768         return blk_rq_bytes(rq) >> 9;
 769 }
 770
 771 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 772 {
 773         return blk_rq_cur_bytes(rq) >> 9;
 774 }
 775
 776 /*
 777  * Request issue related functions.
 778  */
 779 extern struct request *blk_peek_request(struct request_queue *q);
 780 extern void blk_start_request(struct request *rq);
 781 extern struct request *blk_fetch_request(struct request_queue *q);
 782
 783 /*
 784  * Request completion related functions.
 785  *
 786  * blk_update_request() completes given number of bytes and updates
 787  * the request without completing it.
 788  *
 789  * blk_end_request() and friends.  __blk_end_request() must be called
 790  * with the request queue spinlock acquired.
 791  *
 792  * Several drivers define their own end_request and call
 793  * blk_end_request() for parts of the original function.
 794  * This prevents code duplication in drivers.
 795  */
 796 extern bool blk_update_request(struct request *rq, int error,
 797                                unsigned int nr_bytes);
 798 extern bool blk_end_request(struct request *rq, int error,
 799                             unsigned int nr_bytes);
 800 extern void blk_end_request_all(struct request *rq, int error);
 801 extern bool blk_end_request_cur(struct request *rq, int error);
 802 extern bool blk_end_request_err(struct request *rq, int error);
 803 extern bool __blk_end_request(struct request *rq, int error,
 804                               unsigned int nr_bytes);
 805 extern void __blk_end_request_all(struct request *rq, int error);
 806 extern bool __blk_end_request_cur(struct request *rq, int error);
 807 extern bool __blk_end_request_err(struct request *rq, int error);
 808
 809 extern void blk_complete_request(struct request *);
 810 extern void __blk_complete_request(struct request *);
 811 extern void blk_abort_request(struct request *);
 812 extern void blk_abort_queue(struct request_queue *);
 813 extern void blk_unprep_request(struct request *);
 814
 815 /*
 816  * Access functions for manipulating queue properties
 817  */
 818 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 819                                         spinlock_t *lock, int node_id);
 820 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 821 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
 822                                                       request_fn_proc *, spinlock_t *);
 823 extern void blk_cleanup_queue(struct request_queue *);
 824 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 825 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 826 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
 827 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 828 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
 829 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 830 extern void blk_queue_max_discard_sectors(struct request_queue *q,
 831                 unsigned int max_discard_sectors);
 832 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 833 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
 834 extern void blk_queue_alignment_offset(struct request_queue *q,
 835                                        unsigned int alignment);
 836 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 837 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 838 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 839 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 840 extern void blk_set_default_limits(struct queue_limits *lim);
 841 extern void blk_set_stacking_limits(struct queue_limits *lim);
 842 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 843                             sector_t offset);
 844 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
 845                             sector_t offset);
 846 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 847                               sector_t offset);
 848 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 849 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 850 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 851 extern int blk_queue_dma_drain(struct request_queue *q,
 852                                dma_drain_needed_fn *dma_drain_needed,
 853                                void *buf, unsigned int size);
 854 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 855 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 856 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 857 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
 858 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 859 extern void blk_queue_dma_alignment(struct request_queue *, int);
 860 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 861 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 862 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 863 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 864 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
 865 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
 866 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 867
 868 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 869 extern void blk_dump_rq_flags(struct request *, char *);
 870 extern long nr_blockdev_pages(void);
 871
 872 bool __must_check blk_get_queue(struct request_queue *);
 873 struct request_queue *blk_alloc_queue(gfp_t);
 874 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 875 extern void blk_put_queue(struct request_queue *);
 876
 877 /*
 878  * blk_plug permits building a queue of related requests by holding the I/O
 879  * fragments for a short period. This allows merging of sequential requests
 880  * into single larger request. As the requests are moved from a per-task list to
 881  * the device's request_queue in a batch, this results in improved scalability
 882  * as the lock contention for request_queue lock is reduced.
 883  *
 884  * It is ok not to disable preemption when adding the request to the plug list
 885  * or when attempting a merge, because blk_schedule_flush_list() will only flush
 886  * the plug list when the task sleeps by itself. For details, please see
 887  * schedule() where blk_schedule_flush_plug() is called.
 888  */
 889 struct blk_plug {
 890         unsigned long magic; /* detect uninitialized use-cases */
 891         struct list_head list; /* requests */
 892         struct list_head cb_list; /* md requires an unplug callback */
 893         unsigned int should_sort; /* list to be sorted before flushing? */
 894 };
 895 #define BLK_MAX_REQUEST_COUNT 16
 896
 897 struct blk_plug_cb {
 898         struct list_head list;
 899         void (*callback)(struct blk_plug_cb *);
 900 };
 901
 902 extern void blk_start_plug(struct blk_plug *);
 903 extern void blk_finish_plug(struct blk_plug *);
 904 extern void blk_flush_plug_list(struct blk_plug *, bool);
 905
 906 static inline void blk_flush_plug(struct task_struct *tsk)
 907 {
 908         struct blk_plug *plug = tsk->plug;
 909
 910         if (plug)
 911                 blk_flush_plug_list(plug, false);
 912 }
 913
 914 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
 915 {
 916         struct blk_plug *plug = tsk->plug;
 917
 918         if (plug)
 919                 blk_flush_plug_list(plug, true);
 920 }
 921
 922 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
 923 {
 924         struct blk_plug *plug = tsk->plug;
 925
 926         return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
 927 }
 928
 929 /*
 930  * tag stuff
 931  */
 932 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 933 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 934 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 935 extern void blk_queue_end_tag(struct request_queue *, struct request *);
 936 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 937 extern void blk_queue_free_tags(struct request_queue *);
 938 extern int blk_queue_resize_tags(struct request_queue *, int);
 939 extern void blk_queue_invalidate_tags(struct request_queue *);
 940 extern struct blk_queue_tag *blk_init_tags(int);
 941 extern void blk_free_tags(struct blk_queue_tag *);
 942
 943 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 944                                                 int tag)
 945 {
 946         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 947                 return NULL;
 948         return bqt->tag_index[tag];
 949 }
 950
 951 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
 952
 953 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
 954 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 955                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
 956 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 957                         sector_t nr_sects, gfp_t gfp_mask);
 958 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
 959                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
 960 {
 961         return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
 962                                     nr_blocks << (sb->s_blocksize_bits - 9),
 963                                     gfp_mask, flags);
 964 }
 965 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
 966                 sector_t nr_blocks, gfp_t gfp_mask)
 967 {
 968         return blkdev_issue_zeroout(sb->s_bdev,
 969                                     block << (sb->s_blocksize_bits - 9),
 970                                     nr_blocks << (sb->s_blocksize_bits - 9),
 971                                     gfp_mask);
 972 }
 973
 974 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
 975
 976 enum blk_default_limits {
 977         BLK_MAX_SEGMENTS        = 128,
 978         BLK_SAFE_MAX_SECTORS    = 255,
 979         BLK_DEF_MAX_SECTORS     = 1024,
 980         BLK_MAX_SEGMENT_SIZE    = 65536,
 981         BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
 982 };
 983
 984 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
 985
 986 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
 987 {
 988         return q->limits.bounce_pfn;
 989 }
 990
 991 static inline unsigned long queue_segment_boundary(struct request_queue *q)
 992 {
 993         return q->limits.seg_boundary_mask;
 994 }
 995
 996 static inline unsigned int queue_max_sectors(struct request_queue *q)
 997 {
 998         return q->limits.max_sectors;
 999 }
1000
1001 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1002 {
1003         return q->limits.max_hw_sectors;
1004 }
1005
1006 static inline unsigned short queue_max_segments(struct request_queue *q)
1007 {
1008         return q->limits.max_segments;
1009 }
1010
1011 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1012 {
1013         return q->limits.max_segment_size;
1014 }
1015
1016 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1017 {
1018         int retval = 512;
1019
1020         if (q && q->limits.logical_block_size)
1021                 retval = q->limits.logical_block_size;
1022
1023         return retval;
1024 }
1025
1026 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1027 {
1028         return queue_logical_block_size(bdev_get_queue(bdev));
1029 }
1030
1031 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1032 {
1033         return q->limits.physical_block_size;
1034 }
1035
1036 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1037 {
1038         return queue_physical_block_size(bdev_get_queue(bdev));
1039 }
1040
1041 static inline unsigned int queue_io_min(struct request_queue *q)
1042 {
1043         return q->limits.io_min;
1044 }
1045
1046 static inline int bdev_io_min(struct block_device *bdev)
1047 {
1048         return queue_io_min(bdev_get_queue(bdev));
1049 }
1050
1051 static inline unsigned int queue_io_opt(struct request_queue *q)
1052 {
1053         return q->limits.io_opt;
1054 }
1055
1056 static inline int bdev_io_opt(struct block_device *bdev)
1057 {
1058         return queue_io_opt(bdev_get_queue(bdev));
1059 }
1060
1061 static inline int queue_alignment_offset(struct request_queue *q)
1062 {
1063         if (q->limits.misaligned)
1064                 return -1;
1065
1066         return q->limits.alignment_offset;
1067 }
1068
1069 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1070 {
1071         unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1072         unsigned int alignment = (sector << 9) & (granularity - 1);
1073
1074         return (granularity + lim->alignment_offset - alignment)
1075                 & (granularity - 1);
1076 }
1077
1078 static inline int bdev_alignment_offset(struct block_device *bdev)
1079 {
1080         struct request_queue *q = bdev_get_queue(bdev);
1081
1082         if (q->limits.misaligned)
1083                 return -1;
1084
1085         if (bdev != bdev->bd_contains)
1086                 return bdev->bd_part->alignment_offset;
1087
1088         return q->limits.alignment_offset;
1089 }
1090
1091 static inline int queue_discard_alignment(struct request_queue *q)
1092 {
1093         if (q->limits.discard_misaligned)
1094                 return -1;
1095
1096         return q->limits.discard_alignment;
1097 }
1098
1099 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1100 {
1101         unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1102
1103         if (!lim->max_discard_sectors)
1104                 return 0;
1105
1106         return (lim->discard_granularity + lim->discard_alignment - alignment)
1107                 & (lim->discard_granularity - 1);
1108 }
1109
1110 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1111 {
1112         if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1113                 return 1;
1114
1115         return 0;
1116 }
1117
1118 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1119 {
1120         return queue_discard_zeroes_data(bdev_get_queue(bdev));
1121 }
1122
1123 static inline int queue_dma_alignment(struct request_queue *q)
1124 {
1125         return q ? q->dma_alignment : 511;
1126 }
1127
1128 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1129                                  unsigned int len)
1130 {
1131         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1132         return !(addr & alignment) && !(len & alignment);
1133 }
1134
1135 /* assumes size > 256 */
1136 static inline unsigned int blksize_bits(unsigned int size)
1137 {
1138         unsigned int bits = 8;
1139         do {
1140                 bits++;
1141                 size >>= 1;
1142         } while (size > 256);
1143         return bits;
1144 }
1145
1146 static inline unsigned int block_size(struct block_device *bdev)
1147 {
1148         return bdev->bd_block_size;
1149 }
1150
1151 static inline bool queue_flush_queueable(struct request_queue *q)
1152 {
1153         return !q->flush_not_queueable;
1154 }
1155
1156 typedef struct {struct page *v;} Sector;
1157
1158 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1159
1160 static inline void put_dev_sector(Sector p)
1161 {
1162         page_cache_release(p.v);
1163 }
1164
1165 struct work_struct;
1166 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1167
1168 #ifdef CONFIG_BLK_CGROUP
1169 /*
1170  * This should not be using sched_clock(). A real patch is in progress
1171  * to fix this up, until that is in place we need to disable preemption
1172  * around sched_clock() in this function and set_io_start_time_ns().
1173  */
1174 static inline void set_start_time_ns(struct request *req)
1175 {
1176         preempt_disable();
1177         req->start_time_ns = sched_clock();
1178         preempt_enable();
1179 }
1180
1181 static inline void set_io_start_time_ns(struct request *req)
1182 {
1183         preempt_disable();
1184         req->io_start_time_ns = sched_clock();
1185         preempt_enable();
1186 }
1187
1188 static inline uint64_t rq_start_time_ns(struct request *req)
1189 {
1190         return req->start_time_ns;
1191 }
1192
1193 static inline uint64_t rq_io_start_time_ns(struct request *req)
1194 {
1195         return req->io_start_time_ns;
1196 }
1197 #else
1198 static inline void set_start_time_ns(struct request *req) {}
1199 static inline void set_io_start_time_ns(struct request *req) {}
1200 static inline uint64_t rq_start_time_ns(struct request *req)
1201 {
1202         return 0;
1203 }
1204 static inline uint64_t rq_io_start_time_ns(struct request *req)
1205 {
1206         return 0;
1207 }
1208 #endif
1209
1210 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1211         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1212 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1213         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1214
1215 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1216
1217 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1218 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1219
1220 struct blk_integrity_exchg {
1221         void                    *prot_buf;
1222         void                    *data_buf;
1223         sector_t                sector;
1224         unsigned int            data_size;
1225         unsigned short          sector_size;
1226         const char              *disk_name;
1227 };
1228
1229 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1230 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1231 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1232 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1233
1234 struct blk_integrity {
1235         integrity_gen_fn        *generate_fn;
1236         integrity_vrfy_fn       *verify_fn;
1237         integrity_set_tag_fn    *set_tag_fn;
1238         integrity_get_tag_fn    *get_tag_fn;
1239
1240         unsigned short          flags;
1241         unsigned short          tuple_size;
1242         unsigned short          sector_size;
1243         unsigned short          tag_size;
1244
1245         const char              *name;
1246
1247         struct kobject          kobj;
1248 };
1249
1250 extern bool blk_integrity_is_initialized(struct gendisk *);
1251 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1252 extern void blk_integrity_unregister(struct gendisk *);
1253 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1254 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1255                                    struct scatterlist *);
1256 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1257 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1258                                   struct request *);
1259 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1260                                    struct bio *);
1261
1262 static inline
1263 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1264 {
1265         return bdev->bd_disk->integrity;
1266 }
1267
1268 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1269 {
1270         return disk->integrity;
1271 }
1272
1273 static inline int blk_integrity_rq(struct request *rq)
1274 {
1275         if (rq->bio == NULL)
1276                 return 0;
1277
1278         return bio_integrity(rq->bio);
1279 }
1280
1281 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1282                                                     unsigned int segs)
1283 {
1284         q->limits.max_integrity_segments = segs;
1285 }
1286
1287 static inline unsigned short
1288 queue_max_integrity_segments(struct request_queue *q)
1289 {
1290         return q->limits.max_integrity_segments;
1291 }
1292
1293 #else /* CONFIG_BLK_DEV_INTEGRITY */
1294
1295 struct bio;
1296 struct block_device;
1297 struct gendisk;
1298 struct blk_integrity;
1299
1300 static inline int blk_integrity_rq(struct request *rq)
1301 {
1302         return 0;
1303 }
1304 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1305                                             struct bio *b)
1306 {
1307         return 0;
1308 }
1309 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1310                                           struct bio *b,
1311                                           struct scatterlist *s)
1312 {
1313         return 0;
1314 }
1315 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1316 {
1317         return 0;
1318 }
1319 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1320 {
1321         return NULL;
1322 }
1323 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1324 {
1325         return 0;
1326 }
1327 static inline int blk_integrity_register(struct gendisk *d,
1328                                          struct blk_integrity *b)
1329 {
1330         return 0;
1331 }
1332 static inline void blk_integrity_unregister(struct gendisk *d)
1333 {
1334 }
1335 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1336                                                     unsigned int segs)
1337 {
1338 }
1339 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1340 {
1341         return 0;
1342 }
1343 static inline int blk_integrity_merge_rq(struct request_queue *rq,
1344                                          struct request *r1,
1345                                          struct request *r2)
1346 {
1347         return 0;
1348 }
1349 static inline int blk_integrity_merge_bio(struct request_queue *rq,
1350                                           struct request *r,
1351                                           struct bio *b)
1352 {
1353         return 0;
1354 }
1355 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1356 {
1357         return 0;
1358 }
1359
1360 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1361
1362 struct block_device_operations {
1363         int (*open) (struct block_device *, fmode_t);
1364         int (*release) (struct gendisk *, fmode_t);
1365         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1366         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1367         int (*direct_access) (struct block_device *, sector_t,
1368                                                 void **, unsigned long *);
1369         unsigned int (*check_events) (struct gendisk *disk,
1370                                       unsigned int clearing);
1371         /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1372         int (*media_changed) (struct gendisk *);
1373         void (*unlock_native_capacity) (struct gendisk *);
1374         int (*revalidate_disk) (struct gendisk *);
1375         int (*getgeo)(struct block_device *, struct hd_geometry *);
1376         /* this callback is with swap_lock and sometimes page table lock held */
1377         void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1378         struct module *owner;
1379 };
1380
1381 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1382                                  unsigned long);
1383 #else /* CONFIG_BLOCK */
1384 /*
1385  * stubs for when the block layer is configured out
1386  */
1387 #define buffer_heads_over_limit 0
1388
1389 static inline long nr_blockdev_pages(void)
1390 {
1391         return 0;
1392 }
1393
1394 struct blk_plug {
1395 };
1396
1397 static inline void blk_start_plug(struct blk_plug *plug)
1398 {
1399 }
1400
1401 static inline void blk_finish_plug(struct blk_plug *plug)
1402 {
1403 }
1404
1405 static inline void blk_flush_plug(struct task_struct *task)
1406 {
1407 }
1408
1409 static inline void blk_schedule_flush_plug(struct task_struct *task)
1410 {
1411 }
1412
1413
1414 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1415 {
1416         return false;
1417 }
1418
1419 #endif /* CONFIG_BLOCK */
1420
1421 #endif