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/stringify.h>
  18 #include <linux/gfp.h>
  19 #include <linux/bsg.h>
  20 #include <linux/smp.h>
  21
  22 #include <asm/scatterlist.h>
  23
  24 struct module;
  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 struct bsg_job;
  34
  35 #define BLKDEV_MIN_RQ   4
  36 #define BLKDEV_MAX_RQ   128     /* Default maximum */
  37
  38 struct request;
  39 typedef void (rq_end_io_fn)(struct request *, int);
  40
  41 struct request_list {
  42         /*
  43          * count[], starved[], and wait[] are indexed by
  44          * BLK_RW_SYNC/BLK_RW_ASYNC
  45          */
  46         int count[2];
  47         int starved[2];
  48         int elvpriv;
  49         mempool_t *rq_pool;
  50         wait_queue_head_t wait[2];
  51 };
  52
  53 /*
  54  * request command types
  55  */
  56 enum rq_cmd_type_bits {
  57         REQ_TYPE_FS             = 1,    /* fs request */
  58         REQ_TYPE_BLOCK_PC,              /* scsi command */
  59         REQ_TYPE_SENSE,                 /* sense request */
  60         REQ_TYPE_PM_SUSPEND,            /* suspend request */
  61         REQ_TYPE_PM_RESUME,             /* resume request */
  62         REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
  63         REQ_TYPE_SPECIAL,               /* driver defined type */
  64         /*
  65          * for ATA/ATAPI devices. this really doesn't belong here, ide should
  66          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  67          * private REQ_LB opcodes to differentiate what type of request this is
  68          */
  69         REQ_TYPE_ATA_TASKFILE,
  70         REQ_TYPE_ATA_PC,
  71 };
  72
  73 #define BLK_MAX_CDB     16
  74
  75 /*
  76  * try to put the fields that are referenced together in the same cacheline.
  77  * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
  78  * as well!
  79  */
  80 struct request {
  81         struct list_head queuelist;
  82         struct call_single_data csd;
  83
  84         struct request_queue *q;
  85
  86         unsigned int cmd_flags;
  87         enum rq_cmd_type_bits cmd_type;
  88         unsigned long atomic_flags;
  89
  90         int cpu;
  91
  92         /* the following two fields are internal, NEVER access directly */
  93         unsigned int __data_len;        /* total data len */
  94         sector_t __sector;              /* sector cursor */
  95
  96         struct bio *bio;
  97         struct bio *biotail;
  98
  99         struct hlist_node hash; /* merge hash */
 100         /*
 101          * The rb_node is only used inside the io scheduler, requests
 102          * are pruned when moved to the dispatch queue. So let the
 103          * completion_data share space with the rb_node.
 104          */
 105         union {
 106                 struct rb_node rb_node; /* sort/lookup */
 107                 void *completion_data;
 108         };
 109
 110         /*
 111          * Three pointers are available for the IO schedulers, if they need
 112          * more they have to dynamically allocate it.  Flush requests are
 113          * never put on the IO scheduler. So let the flush fields share
 114          * space with the elevator data.
 115          */
 116         union {
 117                 struct {
 118                         struct io_cq            *icq;
 119                         void                    *priv[2];
 120                 } elv;
 121
 122                 struct {
 123                         unsigned int            seq;
 124                         struct list_head        list;
 125                         rq_end_io_fn            *saved_end_io;
 126                 } flush;
 127         };
 128
 129         struct gendisk *rq_disk;
 130         struct hd_struct *part;
 131         unsigned long start_time;
 132 #ifdef CONFIG_BLK_CGROUP
 133         unsigned long long start_time_ns;
 134         unsigned long long io_start_time_ns;    /* when passed to hardware */
 135 #endif
 136         /* Number of scatter-gather DMA addr+len pairs after
 137          * physical address coalescing is performed.
 138          */
 139         unsigned short nr_phys_segments;
 140 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 141         unsigned short nr_integrity_segments;
 142 #endif
 143
 144         unsigned short ioprio;
 145
 146         int ref_count;
 147
 148         void *special;          /* opaque pointer available for LLD use */
 149         char *buffer;           /* kaddr of the current segment if available */
 150
 151         int tag;
 152         int errors;
 153
 154         /*
 155          * when request is used as a packet command carrier
 156          */
 157         unsigned char __cmd[BLK_MAX_CDB];
 158         unsigned char *cmd;
 159         unsigned short cmd_len;
 160
 161         unsigned int extra_len; /* length of alignment and padding */
 162         unsigned int sense_len;
 163         unsigned int resid_len; /* residual count */
 164         void *sense;
 165
 166         unsigned long deadline;
 167         struct list_head timeout_list;
 168         unsigned int timeout;
 169         int retries;
 170
 171         /*
 172          * completion callback.
 173          */
 174         rq_end_io_fn *end_io;
 175         void *end_io_data;
 176
 177         /* for bidi */
 178         struct request *next_rq;
 179 };
 180
 181 static inline unsigned short req_get_ioprio(struct request *req)
 182 {
 183         return req->ioprio;
 184 }
 185
 186 /*
 187  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 188  * requests. Some step values could eventually be made generic.
 189  */
 190 struct request_pm_state
 191 {
 192         /* PM state machine step value, currently driver specific */
 193         int     pm_step;
 194         /* requested PM state value (S1, S2, S3, S4, ...) */
 195         u32     pm_state;
 196         void*   data;           /* for driver use */
 197 };
 198
 199 #include <linux/elevator.h>
 200
 201 typedef void (request_fn_proc) (struct request_queue *q);
 202 typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
 203 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 204 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
 205
 206 struct bio_vec;
 207 struct bvec_merge_data {
 208         struct block_device *bi_bdev;
 209         sector_t bi_sector;
 210         unsigned bi_size;
 211         unsigned long bi_rw;
 212 };
 213 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
 214                              struct bio_vec *);
 215 typedef void (softirq_done_fn)(struct request *);
 216 typedef int (dma_drain_needed_fn)(struct request *);
 217 typedef int (lld_busy_fn) (struct request_queue *q);
 218 typedef int (bsg_job_fn) (struct bsg_job *);
 219
 220 enum blk_eh_timer_return {
 221         BLK_EH_NOT_HANDLED,
 222         BLK_EH_HANDLED,
 223         BLK_EH_RESET_TIMER,
 224 };
 225
 226 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
 227
 228 enum blk_queue_state {
 229         Queue_down,
 230         Queue_up,
 231 };
 232
 233 struct blk_queue_tag {
 234         struct request **tag_index;     /* map of busy tags */
 235         unsigned long *tag_map;         /* bit map of free/busy tags */
 236         int busy;                       /* current depth */
 237         int max_depth;                  /* what we will send to device */
 238         int real_max_depth;             /* what the array can hold */
 239         atomic_t refcnt;                /* map can be shared */
 240 };
 241
 242 #define BLK_SCSI_MAX_CMDS       (256)
 243 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 244
 245 struct queue_limits {
 246         unsigned long           bounce_pfn;
 247         unsigned long           seg_boundary_mask;
 248
 249         unsigned int            max_hw_sectors;
 250         unsigned int            max_sectors;
 251         unsigned int            max_segment_size;
 252         unsigned int            physical_block_size;
 253         unsigned int            alignment_offset;
 254         unsigned int            io_min;
 255         unsigned int            io_opt;
 256         unsigned int            max_discard_sectors;
 257         unsigned int            discard_granularity;
 258         unsigned int            discard_alignment;
 259
 260         unsigned short          logical_block_size;
 261         unsigned short          max_segments;
 262         unsigned short          max_integrity_segments;
 263
 264         unsigned char           misaligned;
 265         unsigned char           discard_misaligned;
 266         unsigned char           cluster;
 267         unsigned char           discard_zeroes_data;
 268 };
 269
 270 struct request_queue {
 271         /*
 272          * Together with queue_head for cacheline sharing
 273          */
 274         struct list_head        queue_head;
 275         struct request          *last_merge;
 276         struct elevator_queue   *elevator;
 277
 278         /*
 279          * the queue request freelist, one for reads and one for writes
 280          */
 281         struct request_list     rq;
 282
 283         request_fn_proc         *request_fn;
 284         make_request_fn         *make_request_fn;
 285         prep_rq_fn              *prep_rq_fn;
 286         unprep_rq_fn            *unprep_rq_fn;
 287         merge_bvec_fn           *merge_bvec_fn;
 288         softirq_done_fn         *softirq_done_fn;
 289         rq_timed_out_fn         *rq_timed_out_fn;
 290         dma_drain_needed_fn     *dma_drain_needed;
 291         lld_busy_fn             *lld_busy_fn;
 292
 293         /*
 294          * Dispatch queue sorting
 295          */
 296         sector_t                end_sector;
 297         struct request          *boundary_rq;
 298
 299         /*
 300          * Delayed queue handling
 301          */
 302         struct delayed_work     delay_work;
 303
 304         struct backing_dev_info backing_dev_info;
 305
 306         /*
 307          * The queue owner gets to use this for whatever they like.
 308          * ll_rw_blk doesn't touch it.
 309          */
 310         void                    *queuedata;
 311
 312         /*
 313          * various queue flags, see QUEUE_* below
 314          */
 315         unsigned long           queue_flags;
 316
 317         /*
 318          * ida allocated id for this queue.  Used to index queues from
 319          * ioctx.
 320          */
 321         int                     id;
 322
 323         /*
 324          * queue needs bounce pages for pages above this limit
 325          */
 326         gfp_t                   bounce_gfp;
 327
 328         /*
 329          * protects queue structures from reentrancy. ->__queue_lock should
 330          * _never_ be used directly, it is queue private. always use
 331          * ->queue_lock.
 332          */
 333         spinlock_t              __queue_lock;
 334         spinlock_t              *queue_lock;
 335
 336         /*
 337          * queue kobject
 338          */
 339         struct kobject kobj;
 340
 341         /*
 342          * queue settings
 343          */
 344         unsigned long           nr_requests;    /* Max # of requests */
 345         unsigned int            nr_congestion_on;
 346         unsigned int            nr_congestion_off;
 347         unsigned int            nr_batching;
 348
 349         unsigned int            dma_drain_size;
 350         void                    *dma_drain_buffer;
 351         unsigned int            dma_pad_mask;
 352         unsigned int            dma_alignment;
 353
 354         struct blk_queue_tag    *queue_tags;
 355         struct list_head        tag_busy_list;
 356
 357         unsigned int            nr_sorted;
 358         unsigned int            in_flight[2];
 359
 360         unsigned int            rq_timeout;
 361         struct timer_list       timeout;
 362         struct list_head        timeout_list;
 363
 364         struct list_head        icq_list;
 365
 366         struct queue_limits     limits;
 367
 368         /*
 369          * sg stuff
 370          */
 371         unsigned int            sg_timeout;
 372         unsigned int            sg_reserved_size;
 373         int                     node;
 374 #ifdef CONFIG_BLK_DEV_IO_TRACE
 375         struct blk_trace        *blk_trace;
 376 #endif
 377         /*
 378          * for flush operations
 379          */
 380         unsigned int            flush_flags;
 381         unsigned int            flush_not_queueable:1;
 382         unsigned int            flush_queue_delayed:1;
 383         unsigned int            flush_pending_idx:1;
 384         unsigned int            flush_running_idx:1;
 385         unsigned long           flush_pending_since;
 386         struct list_head        flush_queue[2];
 387         struct list_head        flush_data_in_flight;
 388         struct request          flush_rq;
 389
 390         struct mutex            sysfs_lock;
 391
 392         int                     bypass_depth;
 393
 394 #if defined(CONFIG_BLK_DEV_BSG)
 395         bsg_job_fn              *bsg_job_fn;
 396         int                     bsg_job_size;
 397         struct bsg_class_device bsg_dev;
 398 #endif
 399
 400 #ifdef CONFIG_BLK_CGROUP
 401         struct list_head        all_q_node;
 402 #endif
 403 #ifdef CONFIG_BLK_DEV_THROTTLING
 404         /* Throttle data */
 405         struct throtl_data *td;
 406 #endif
 407 };
 408
 409 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 410 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 411 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 412 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 413 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 414 #define QUEUE_FLAG_BYPASS       6       /* act as dumb FIFO queue */
 415 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
 416 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
 417 #define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
 418 #define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
 419 #define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
 420 #define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
 421 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 422 #define QUEUE_FLAG_IO_STAT     13       /* do IO stats */
 423 #define QUEUE_FLAG_DISCARD     14       /* supports DISCARD */
 424 #define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
 425 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
 426 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
 427 #define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
 428
 429 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 430                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
 431                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
 432                                  (1 << QUEUE_FLAG_ADD_RANDOM))
 433
 434 static inline int queue_is_locked(struct request_queue *q)
 435 {
 436 #ifdef CONFIG_SMP
 437         spinlock_t *lock = q->queue_lock;
 438         return lock && spin_is_locked(lock);
 439 #else
 440         return 1;
 441 #endif
 442 }
 443
 444 static inline void queue_flag_set_unlocked(unsigned int flag,
 445                                            struct request_queue *q)
 446 {
 447         __set_bit(flag, &q->queue_flags);
 448 }
 449
 450 static inline int queue_flag_test_and_clear(unsigned int flag,
 451                                             struct request_queue *q)
 452 {
 453         WARN_ON_ONCE(!queue_is_locked(q));
 454
 455         if (test_bit(flag, &q->queue_flags)) {
 456                 __clear_bit(flag, &q->queue_flags);
 457                 return 1;
 458         }
 459
 460         return 0;
 461 }
 462
 463 static inline int queue_flag_test_and_set(unsigned int flag,
 464                                           struct request_queue *q)
 465 {
 466         WARN_ON_ONCE(!queue_is_locked(q));
 467
 468         if (!test_bit(flag, &q->queue_flags)) {
 469                 __set_bit(flag, &q->queue_flags);
 470                 return 0;
 471         }
 472
 473         return 1;
 474 }
 475
 476 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 477 {
 478         WARN_ON_ONCE(!queue_is_locked(q));
 479         __set_bit(flag, &q->queue_flags);
 480 }
 481
 482 static inline void queue_flag_clear_unlocked(unsigned int flag,
 483                                              struct request_queue *q)
 484 {
 485         __clear_bit(flag, &q->queue_flags);
 486 }
 487
 488 static inline int queue_in_flight(struct request_queue *q)
 489 {
 490         return q->in_flight[0] + q->in_flight[1];
 491 }
 492
 493 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 494 {
 495         WARN_ON_ONCE(!queue_is_locked(q));
 496         __clear_bit(flag, &q->queue_flags);
 497 }
 498
 499 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 500 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 501 #define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 502 #define blk_queue_bypass(q)     test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
 503 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 504 #define blk_queue_noxmerges(q)  \
 505         test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
 506 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 507 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 508 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
 509 #define blk_queue_stackable(q)  \
 510         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 511 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
 512 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
 513         test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
 514
 515 #define blk_noretry_request(rq) \
 516         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
 517                              REQ_FAILFAST_DRIVER))
 518
 519 #define blk_account_rq(rq) \
 520         (((rq)->cmd_flags & REQ_STARTED) && \
 521          ((rq)->cmd_type == REQ_TYPE_FS || \
 522           ((rq)->cmd_flags & REQ_DISCARD)))
 523
 524 #define blk_pm_request(rq)      \
 525         ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
 526          (rq)->cmd_type == REQ_TYPE_PM_RESUME)
 527
 528 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 529 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 530 /* rq->queuelist of dequeued request must be list_empty() */
 531 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 532
 533 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 534
 535 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 536
 537 static inline unsigned int blk_queue_cluster(struct request_queue *q)
 538 {
 539         return q->limits.cluster;
 540 }
 541
 542 /*
 543  * We regard a request as sync, if either a read or a sync write
 544  */
 545 static inline bool rw_is_sync(unsigned int rw_flags)
 546 {
 547         return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
 548 }
 549
 550 static inline bool rq_is_sync(struct request *rq)
 551 {
 552         return rw_is_sync(rq->cmd_flags);
 553 }
 554
 555 static inline int blk_queue_full(struct request_queue *q, int sync)
 556 {
 557         if (sync)
 558                 return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
 559         return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
 560 }
 561
 562 static inline void blk_set_queue_full(struct request_queue *q, int sync)
 563 {
 564         if (sync)
 565                 queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
 566         else
 567                 queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
 568 }
 569
 570 static inline void blk_clear_queue_full(struct request_queue *q, int sync)
 571 {
 572         if (sync)
 573                 queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
 574         else
 575                 queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
 576 }
 577
 578
 579 /*
 580  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 581  * it already be started by driver.
 582  */
 583 #define RQ_NOMERGE_FLAGS        \
 584         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
 585 #define rq_mergeable(rq)        \
 586         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 587          (((rq)->cmd_flags & REQ_DISCARD) || \
 588           (rq)->cmd_type == REQ_TYPE_FS))
 589
 590 /*
 591  * q->prep_rq_fn return values
 592  */
 593 #define BLKPREP_OK              0       /* serve it */
 594 #define BLKPREP_KILL            1       /* fatal error, kill */
 595 #define BLKPREP_DEFER           2       /* leave on queue */
 596
 597 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 598
 599 /*
 600  * standard bounce addresses:
 601  *
 602  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 603  * BLK_BOUNCE_ANY       : don't bounce anything
 604  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 605  */
 606
 607 #if BITS_PER_LONG == 32
 608 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 609 #else
 610 #define BLK_BOUNCE_HIGH         -1ULL
 611 #endif
 612 #define BLK_BOUNCE_ANY          (-1ULL)
 613 #define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
 614
 615 /*
 616  * default timeout for SG_IO if none specified
 617  */
 618 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 619 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 620
 621 #ifdef CONFIG_BOUNCE
 622 extern int init_emergency_isa_pool(void);
 623 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 624 #else
 625 static inline int init_emergency_isa_pool(void)
 626 {
 627         return 0;
 628 }
 629 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 630 {
 631 }
 632 #endif /* CONFIG_MMU */
 633
 634 struct rq_map_data {
 635         struct page **pages;
 636         int page_order;
 637         int nr_entries;
 638         unsigned long offset;
 639         int null_mapped;
 640         int from_user;
 641 };
 642
 643 struct req_iterator {
 644         int i;
 645         struct bio *bio;
 646 };
 647
 648 /* This should not be used directly - use rq_for_each_segment */
 649 #define for_each_bio(_bio)              \
 650         for (; _bio; _bio = _bio->bi_next)
 651 #define __rq_for_each_bio(_bio, rq)     \
 652         if ((rq->bio))                  \
 653                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 654
 655 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 656         __rq_for_each_bio(_iter.bio, _rq)                       \
 657                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 658
 659 #define rq_iter_last(rq, _iter)                                 \
 660                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 661
 662 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 663 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 664 #endif
 665 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 666 extern void rq_flush_dcache_pages(struct request *rq);
 667 #else
 668 static inline void rq_flush_dcache_pages(struct request *rq)
 669 {
 670 }
 671 #endif
 672
 673 extern int blk_register_queue(struct gendisk *disk);
 674 extern void blk_unregister_queue(struct gendisk *disk);
 675 extern void generic_make_request(struct bio *bio);
 676 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 677 extern void blk_put_request(struct request *);
 678 extern void __blk_put_request(struct request_queue *, struct request *);
 679 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 680 extern struct request *blk_make_request(struct request_queue *, struct bio *,
 681                                         gfp_t);
 682 extern void blk_requeue_request(struct request_queue *, struct request *);
 683 extern void blk_add_request_payload(struct request *rq, struct page *page,
 684                 unsigned int len);
 685 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 686 extern int blk_lld_busy(struct request_queue *q);
 687 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 688                              struct bio_set *bs, gfp_t gfp_mask,
 689                              int (*bio_ctr)(struct bio *, struct bio *, void *),
 690                              void *data);
 691 extern void blk_rq_unprep_clone(struct request *rq);
 692 extern int blk_insert_cloned_request(struct request_queue *q,
 693                                      struct request *rq);
 694 extern void blk_delay_queue(struct request_queue *, unsigned long);
 695 extern void blk_recount_segments(struct request_queue *, struct bio *);
 696 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
 697 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
 698                               unsigned int, void __user *);
 699 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 700                           unsigned int, void __user *);
 701 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 702                          struct scsi_ioctl_command __user *);
 703
 704 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
 705
 706 /*
 707  * A queue has just exitted congestion.  Note this in the global counter of
 708  * congested queues, and wake up anyone who was waiting for requests to be
 709  * put back.
 710  */
 711 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 712 {
 713         clear_bdi_congested(&q->backing_dev_info, sync);
 714 }
 715
 716 /*
 717  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 718  * state flags and increment the global gounter of congested queues.
 719  */
 720 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 721 {
 722         set_bdi_congested(&q->backing_dev_info, sync);
 723 }
 724
 725 extern void blk_start_queue(struct request_queue *q);
 726 extern void blk_stop_queue(struct request_queue *q);
 727 extern void blk_sync_queue(struct request_queue *q);
 728 extern void __blk_stop_queue(struct request_queue *q);
 729 extern void __blk_run_queue(struct request_queue *q);
 730 extern void blk_run_queue(struct request_queue *);
 731 extern void blk_run_queue_async(struct request_queue *q);
 732 extern int blk_rq_map_user(struct request_queue *, struct request *,
 733                            struct rq_map_data *, void __user *, unsigned long,
 734                            gfp_t);
 735 extern int blk_rq_unmap_user(struct bio *);
 736 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 737 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 738                                struct rq_map_data *, struct sg_iovec *, int,
 739                                unsigned int, gfp_t);
 740 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 741                           struct request *, int);
 742 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 743                                   struct request *, int, rq_end_io_fn *);
 744
 745 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 746 {
 747         return bdev->bd_disk->queue;
 748 }
 749
 750 /*
 751  * blk_rq_pos()                 : the current sector
 752  * blk_rq_bytes()               : bytes left in the entire request
 753  * blk_rq_cur_bytes()           : bytes left in the current segment
 754  * blk_rq_err_bytes()           : bytes left till the next error boundary
 755  * blk_rq_sectors()             : sectors left in the entire request
 756  * blk_rq_cur_sectors()         : sectors left in the current segment
 757  */
 758 static inline sector_t blk_rq_pos(const struct request *rq)
 759 {
 760         return rq->__sector;
 761 }
 762
 763 static inline unsigned int blk_rq_bytes(const struct request *rq)
 764 {
 765         return rq->__data_len;
 766 }
 767
 768 static inline int blk_rq_cur_bytes(const struct request *rq)
 769 {
 770         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 771 }
 772
 773 extern unsigned int blk_rq_err_bytes(const struct request *rq);
 774
 775 static inline unsigned int blk_rq_sectors(const struct request *rq)
 776 {
 777         return blk_rq_bytes(rq) >> 9;
 778 }
 779
 780 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 781 {
 782         return blk_rq_cur_bytes(rq) >> 9;
 783 }
 784
 785 /*
 786  * Request issue related functions.
 787  */
 788 extern struct request *blk_peek_request(struct request_queue *q);
 789 extern void blk_start_request(struct request *rq);
 790 extern struct request *blk_fetch_request(struct request_queue *q);
 791
 792 /*
 793  * Request completion related functions.
 794  *
 795  * blk_update_request() completes given number of bytes and updates
 796  * the request without completing it.
 797  *
 798  * blk_end_request() and friends.  __blk_end_request() must be called
 799  * with the request queue spinlock acquired.
 800  *
 801  * Several drivers define their own end_request and call
 802  * blk_end_request() for parts of the original function.
 803  * This prevents code duplication in drivers.
 804  */
 805 extern bool blk_update_request(struct request *rq, int error,
 806                                unsigned int nr_bytes);
 807 extern bool blk_end_request(struct request *rq, int error,
 808                             unsigned int nr_bytes);
 809 extern void blk_end_request_all(struct request *rq, int error);
 810 extern bool blk_end_request_cur(struct request *rq, int error);
 811 extern bool blk_end_request_err(struct request *rq, int error);
 812 extern bool __blk_end_request(struct request *rq, int error,
 813                               unsigned int nr_bytes);
 814 extern void __blk_end_request_all(struct request *rq, int error);
 815 extern bool __blk_end_request_cur(struct request *rq, int error);
 816 extern bool __blk_end_request_err(struct request *rq, int error);
 817
 818 extern void blk_complete_request(struct request *);
 819 extern void __blk_complete_request(struct request *);
 820 extern void blk_abort_request(struct request *);
 821 extern void blk_abort_queue(struct request_queue *);
 822 extern void blk_unprep_request(struct request *);
 823
 824 /*
 825  * Access functions for manipulating queue properties
 826  */
 827 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 828                                         spinlock_t *lock, int node_id);
 829 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 830 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
 831                                                       request_fn_proc *, spinlock_t *);
 832 extern void blk_cleanup_queue(struct request_queue *);
 833 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 834 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 835 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
 836 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 837 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
 838 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 839 extern void blk_queue_max_discard_sectors(struct request_queue *q,
 840                 unsigned int max_discard_sectors);
 841 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 842 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
 843 extern void blk_queue_alignment_offset(struct request_queue *q,
 844                                        unsigned int alignment);
 845 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 846 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 847 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 848 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 849 extern void blk_set_default_limits(struct queue_limits *lim);
 850 extern void blk_set_stacking_limits(struct queue_limits *lim);
 851 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 852                             sector_t offset);
 853 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
 854                             sector_t offset);
 855 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 856                               sector_t offset);
 857 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 858 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 859 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 860 extern int blk_queue_dma_drain(struct request_queue *q,
 861                                dma_drain_needed_fn *dma_drain_needed,
 862                                void *buf, unsigned int size);
 863 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 864 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 865 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 866 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
 867 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 868 extern void blk_queue_dma_alignment(struct request_queue *, int);
 869 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 870 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 871 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 872 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 873 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
 874 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
 875 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 876
 877 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 878 extern void blk_dump_rq_flags(struct request *, char *);
 879 extern long nr_blockdev_pages(void);
 880
 881 bool __must_check blk_get_queue(struct request_queue *);
 882 struct request_queue *blk_alloc_queue(gfp_t);
 883 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 884 extern void blk_put_queue(struct request_queue *);
 885
 886 /*
 887  * blk_plug permits building a queue of related requests by holding the I/O
 888  * fragments for a short period. This allows merging of sequential requests
 889  * into single larger request. As the requests are moved from a per-task list to
 890  * the device's request_queue in a batch, this results in improved scalability
 891  * as the lock contention for request_queue lock is reduced.
 892  *
 893  * It is ok not to disable preemption when adding the request to the plug list
 894  * or when attempting a merge, because blk_schedule_flush_list() will only flush
 895  * the plug list when the task sleeps by itself. For details, please see
 896  * schedule() where blk_schedule_flush_plug() is called.
 897  */
 898 struct blk_plug {
 899         unsigned long magic; /* detect uninitialized use-cases */
 900         struct list_head list; /* requests */
 901         struct list_head cb_list; /* md requires an unplug callback */
 902         unsigned int should_sort; /* list to be sorted before flushing? */
 903 };
 904 #define BLK_MAX_REQUEST_COUNT 16
 905
 906 struct blk_plug_cb {
 907         struct list_head list;
 908         void (*callback)(struct blk_plug_cb *);
 909 };
 910
 911 extern void blk_start_plug(struct blk_plug *);
 912 extern void blk_finish_plug(struct blk_plug *);
 913 extern void blk_flush_plug_list(struct blk_plug *, bool);
 914
 915 static inline void blk_flush_plug(struct task_struct *tsk)
 916 {
 917         struct blk_plug *plug = tsk->plug;
 918
 919         if (plug)
 920                 blk_flush_plug_list(plug, false);
 921 }
 922
 923 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
 924 {
 925         struct blk_plug *plug = tsk->plug;
 926
 927         if (plug)
 928                 blk_flush_plug_list(plug, true);
 929 }
 930
 931 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
 932 {
 933         struct blk_plug *plug = tsk->plug;
 934
 935         return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
 936 }
 937
 938 /*
 939  * tag stuff
 940  */
 941 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 942 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 943 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 944 extern void blk_queue_end_tag(struct request_queue *, struct request *);
 945 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 946 extern void blk_queue_free_tags(struct request_queue *);
 947 extern int blk_queue_resize_tags(struct request_queue *, int);
 948 extern void blk_queue_invalidate_tags(struct request_queue *);
 949 extern struct blk_queue_tag *blk_init_tags(int);
 950 extern void blk_free_tags(struct blk_queue_tag *);
 951
 952 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 953                                                 int tag)
 954 {
 955         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 956                 return NULL;
 957         return bqt->tag_index[tag];
 958 }
 959
 960 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
 961
 962 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
 963 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 964                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
 965 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 966                         sector_t nr_sects, gfp_t gfp_mask);
 967 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
 968                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
 969 {
 970         return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
 971                                     nr_blocks << (sb->s_blocksize_bits - 9),
 972                                     gfp_mask, flags);
 973 }
 974 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
 975                 sector_t nr_blocks, gfp_t gfp_mask)
 976 {
 977         return blkdev_issue_zeroout(sb->s_bdev,
 978                                     block << (sb->s_blocksize_bits - 9),
 979                                     nr_blocks << (sb->s_blocksize_bits - 9),
 980                                     gfp_mask);
 981 }
 982
 983 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
 984
 985 enum blk_default_limits {
 986         BLK_MAX_SEGMENTS        = 128,
 987         BLK_SAFE_MAX_SECTORS    = 255,
 988         BLK_DEF_MAX_SECTORS     = 1024,
 989         BLK_MAX_SEGMENT_SIZE    = 65536,
 990         BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
 991 };
 992
 993 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
 994
 995 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
 996 {
 997         return q->limits.bounce_pfn;
 998 }
 999
1000 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1001 {
1002         return q->limits.seg_boundary_mask;
1003 }
1004
1005 static inline unsigned int queue_max_sectors(struct request_queue *q)
1006 {
1007         return q->limits.max_sectors;
1008 }
1009
1010 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1011 {
1012         return q->limits.max_hw_sectors;
1013 }
1014
1015 static inline unsigned short queue_max_segments(struct request_queue *q)
1016 {
1017         return q->limits.max_segments;
1018 }
1019
1020 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1021 {
1022         return q->limits.max_segment_size;
1023 }
1024
1025 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1026 {
1027         int retval = 512;
1028
1029         if (q && q->limits.logical_block_size)
1030                 retval = q->limits.logical_block_size;
1031
1032         return retval;
1033 }
1034
1035 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1036 {
1037         return queue_logical_block_size(bdev_get_queue(bdev));
1038 }
1039
1040 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1041 {
1042         return q->limits.physical_block_size;
1043 }
1044
1045 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1046 {
1047         return queue_physical_block_size(bdev_get_queue(bdev));
1048 }
1049
1050 static inline unsigned int queue_io_min(struct request_queue *q)
1051 {
1052         return q->limits.io_min;
1053 }
1054
1055 static inline int bdev_io_min(struct block_device *bdev)
1056 {
1057         return queue_io_min(bdev_get_queue(bdev));
1058 }
1059
1060 static inline unsigned int queue_io_opt(struct request_queue *q)
1061 {
1062         return q->limits.io_opt;
1063 }
1064
1065 static inline int bdev_io_opt(struct block_device *bdev)
1066 {
1067         return queue_io_opt(bdev_get_queue(bdev));
1068 }
1069
1070 static inline int queue_alignment_offset(struct request_queue *q)
1071 {
1072         if (q->limits.misaligned)
1073                 return -1;
1074
1075         return q->limits.alignment_offset;
1076 }
1077
1078 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1079 {
1080         unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1081         unsigned int alignment = (sector << 9) & (granularity - 1);
1082
1083         return (granularity + lim->alignment_offset - alignment)
1084                 & (granularity - 1);
1085 }
1086
1087 static inline int bdev_alignment_offset(struct block_device *bdev)
1088 {
1089         struct request_queue *q = bdev_get_queue(bdev);
1090
1091         if (q->limits.misaligned)
1092                 return -1;
1093
1094         if (bdev != bdev->bd_contains)
1095                 return bdev->bd_part->alignment_offset;
1096
1097         return q->limits.alignment_offset;
1098 }
1099
1100 static inline int queue_discard_alignment(struct request_queue *q)
1101 {
1102         if (q->limits.discard_misaligned)
1103                 return -1;
1104
1105         return q->limits.discard_alignment;
1106 }
1107
1108 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1109 {
1110         unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1111
1112         if (!lim->max_discard_sectors)
1113                 return 0;
1114
1115         return (lim->discard_granularity + lim->discard_alignment - alignment)
1116                 & (lim->discard_granularity - 1);
1117 }
1118
1119 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1120 {
1121         if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1122                 return 1;
1123
1124         return 0;
1125 }
1126
1127 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1128 {
1129         return queue_discard_zeroes_data(bdev_get_queue(bdev));
1130 }
1131
1132 static inline int queue_dma_alignment(struct request_queue *q)
1133 {
1134         return q ? q->dma_alignment : 511;
1135 }
1136
1137 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1138                                  unsigned int len)
1139 {
1140         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1141         return !(addr & alignment) && !(len & alignment);
1142 }
1143
1144 /* assumes size > 256 */
1145 static inline unsigned int blksize_bits(unsigned int size)
1146 {
1147         unsigned int bits = 8;
1148         do {
1149                 bits++;
1150                 size >>= 1;
1151         } while (size > 256);
1152         return bits;
1153 }
1154
1155 static inline unsigned int block_size(struct block_device *bdev)
1156 {
1157         return bdev->bd_block_size;
1158 }
1159
1160 static inline bool queue_flush_queueable(struct request_queue *q)
1161 {
1162         return !q->flush_not_queueable;
1163 }
1164
1165 typedef struct {struct page *v;} Sector;
1166
1167 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1168
1169 static inline void put_dev_sector(Sector p)
1170 {
1171         page_cache_release(p.v);
1172 }
1173
1174 struct work_struct;
1175 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1176
1177 #ifdef CONFIG_BLK_CGROUP
1178 /*
1179  * This should not be using sched_clock(). A real patch is in progress
1180  * to fix this up, until that is in place we need to disable preemption
1181  * around sched_clock() in this function and set_io_start_time_ns().
1182  */
1183 static inline void set_start_time_ns(struct request *req)
1184 {
1185         preempt_disable();
1186         req->start_time_ns = sched_clock();
1187         preempt_enable();
1188 }
1189
1190 static inline void set_io_start_time_ns(struct request *req)
1191 {
1192         preempt_disable();
1193         req->io_start_time_ns = sched_clock();
1194         preempt_enable();
1195 }
1196
1197 static inline uint64_t rq_start_time_ns(struct request *req)
1198 {
1199         return req->start_time_ns;
1200 }
1201
1202 static inline uint64_t rq_io_start_time_ns(struct request *req)
1203 {
1204         return req->io_start_time_ns;
1205 }
1206 #else
1207 static inline void set_start_time_ns(struct request *req) {}
1208 static inline void set_io_start_time_ns(struct request *req) {}
1209 static inline uint64_t rq_start_time_ns(struct request *req)
1210 {
1211         return 0;
1212 }
1213 static inline uint64_t rq_io_start_time_ns(struct request *req)
1214 {
1215         return 0;
1216 }
1217 #endif
1218
1219 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1220         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1221 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1222         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1223
1224 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1225
1226 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1227 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1228
1229 struct blk_integrity_exchg {
1230         void                    *prot_buf;
1231         void                    *data_buf;
1232         sector_t                sector;
1233         unsigned int            data_size;
1234         unsigned short          sector_size;
1235         const char              *disk_name;
1236 };
1237
1238 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1239 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1240 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1241 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1242
1243 struct blk_integrity {
1244         integrity_gen_fn        *generate_fn;
1245         integrity_vrfy_fn       *verify_fn;
1246         integrity_set_tag_fn    *set_tag_fn;
1247         integrity_get_tag_fn    *get_tag_fn;
1248
1249         unsigned short          flags;
1250         unsigned short          tuple_size;
1251         unsigned short          sector_size;
1252         unsigned short          tag_size;
1253
1254         const char              *name;
1255
1256         struct kobject          kobj;
1257 };
1258
1259 extern bool blk_integrity_is_initialized(struct gendisk *);
1260 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1261 extern void blk_integrity_unregister(struct gendisk *);
1262 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1263 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1264                                    struct scatterlist *);
1265 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1266 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1267                                   struct request *);
1268 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1269                                    struct bio *);
1270
1271 static inline
1272 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1273 {
1274         return bdev->bd_disk->integrity;
1275 }
1276
1277 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1278 {
1279         return disk->integrity;
1280 }
1281
1282 static inline int blk_integrity_rq(struct request *rq)
1283 {
1284         if (rq->bio == NULL)
1285                 return 0;
1286
1287         return bio_integrity(rq->bio);
1288 }
1289
1290 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1291                                                     unsigned int segs)
1292 {
1293         q->limits.max_integrity_segments = segs;
1294 }
1295
1296 static inline unsigned short
1297 queue_max_integrity_segments(struct request_queue *q)
1298 {
1299         return q->limits.max_integrity_segments;
1300 }
1301
1302 #else /* CONFIG_BLK_DEV_INTEGRITY */
1303
1304 struct bio;
1305 struct block_device;
1306 struct gendisk;
1307 struct blk_integrity;
1308
1309 static inline int blk_integrity_rq(struct request *rq)
1310 {
1311         return 0;
1312 }
1313 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1314                                             struct bio *b)
1315 {
1316         return 0;
1317 }
1318 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1319                                           struct bio *b,
1320                                           struct scatterlist *s)
1321 {
1322         return 0;
1323 }
1324 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1325 {
1326         return 0;
1327 }
1328 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1329 {
1330         return NULL;
1331 }
1332 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1333 {
1334         return 0;
1335 }
1336 static inline int blk_integrity_register(struct gendisk *d,
1337                                          struct blk_integrity *b)
1338 {
1339         return 0;
1340 }
1341 static inline void blk_integrity_unregister(struct gendisk *d)
1342 {
1343 }
1344 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1345                                                     unsigned int segs)
1346 {
1347 }
1348 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1349 {
1350         return 0;
1351 }
1352 static inline int blk_integrity_merge_rq(struct request_queue *rq,
1353                                          struct request *r1,
1354                                          struct request *r2)
1355 {
1356         return 0;
1357 }
1358 static inline int blk_integrity_merge_bio(struct request_queue *rq,
1359                                           struct request *r,
1360                                           struct bio *b)
1361 {
1362         return 0;
1363 }
1364 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1365 {
1366         return 0;
1367 }
1368
1369 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1370
1371 struct block_device_operations {
1372         int (*open) (struct block_device *, fmode_t);
1373         int (*release) (struct gendisk *, fmode_t);
1374         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1375         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1376         int (*direct_access) (struct block_device *, sector_t,
1377                                                 void **, unsigned long *);
1378         unsigned int (*check_events) (struct gendisk *disk,
1379                                       unsigned int clearing);
1380         /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1381         int (*media_changed) (struct gendisk *);
1382         void (*unlock_native_capacity) (struct gendisk *);
1383         int (*revalidate_disk) (struct gendisk *);
1384         int (*getgeo)(struct block_device *, struct hd_geometry *);
1385         /* this callback is with swap_lock and sometimes page table lock held */
1386         void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1387         struct module *owner;
1388 };
1389
1390 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1391                                  unsigned long);
1392 #else /* CONFIG_BLOCK */
1393 /*
1394  * stubs for when the block layer is configured out
1395  */
1396 #define buffer_heads_over_limit 0
1397
1398 static inline long nr_blockdev_pages(void)
1399 {
1400         return 0;
1401 }
1402
1403 struct blk_plug {
1404 };
1405
1406 static inline void blk_start_plug(struct blk_plug *plug)
1407 {
1408 }
1409
1410 static inline void blk_finish_plug(struct blk_plug *plug)
1411 {
1412 }
1413
1414 static inline void blk_flush_plug(struct task_struct *task)
1415 {
1416 }
1417
1418 static inline void blk_schedule_flush_plug(struct task_struct *task)
1419 {
1420 }
1421
1422
1423 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1424 {
1425         return false;
1426 }
1427
1428 #endif /* CONFIG_BLOCK */
1429
1430 #endif