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 #if defined(CONFIG_BLK_DEV_BSG)
 393         bsg_job_fn              *bsg_job_fn;
 394         int                     bsg_job_size;
 395         struct bsg_class_device bsg_dev;
 396 #endif
 397
 398 #ifdef CONFIG_BLK_DEV_THROTTLING
 399         /* Throttle data */
 400         struct throtl_data *td;
 401 #endif
 402 };
 403
 404 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 405 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 406 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 407 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 408 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 409 #define QUEUE_FLAG_ELVSWITCH    6       /* don't use elevator, just do FIFO */
 410 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
 411 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
 412 #define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
 413 #define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
 414 #define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
 415 #define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
 416 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 417 #define QUEUE_FLAG_IO_STAT     13       /* do IO stats */
 418 #define QUEUE_FLAG_DISCARD     14       /* supports DISCARD */
 419 #define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
 420 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
 421 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
 422 #define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
 423
 424 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 425                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
 426                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
 427                                  (1 << QUEUE_FLAG_ADD_RANDOM))
 428
 429 static inline int queue_is_locked(struct request_queue *q)
 430 {
 431 #ifdef CONFIG_SMP
 432         spinlock_t *lock = q->queue_lock;
 433         return lock && spin_is_locked(lock);
 434 #else
 435         return 1;
 436 #endif
 437 }
 438
 439 static inline void queue_flag_set_unlocked(unsigned int flag,
 440                                            struct request_queue *q)
 441 {
 442         __set_bit(flag, &q->queue_flags);
 443 }
 444
 445 static inline int queue_flag_test_and_clear(unsigned int flag,
 446                                             struct request_queue *q)
 447 {
 448         WARN_ON_ONCE(!queue_is_locked(q));
 449
 450         if (test_bit(flag, &q->queue_flags)) {
 451                 __clear_bit(flag, &q->queue_flags);
 452                 return 1;
 453         }
 454
 455         return 0;
 456 }
 457
 458 static inline int queue_flag_test_and_set(unsigned int flag,
 459                                           struct request_queue *q)
 460 {
 461         WARN_ON_ONCE(!queue_is_locked(q));
 462
 463         if (!test_bit(flag, &q->queue_flags)) {
 464                 __set_bit(flag, &q->queue_flags);
 465                 return 0;
 466         }
 467
 468         return 1;
 469 }
 470
 471 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 472 {
 473         WARN_ON_ONCE(!queue_is_locked(q));
 474         __set_bit(flag, &q->queue_flags);
 475 }
 476
 477 static inline void queue_flag_clear_unlocked(unsigned int flag,
 478                                              struct request_queue *q)
 479 {
 480         __clear_bit(flag, &q->queue_flags);
 481 }
 482
 483 static inline int queue_in_flight(struct request_queue *q)
 484 {
 485         return q->in_flight[0] + q->in_flight[1];
 486 }
 487
 488 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 489 {
 490         WARN_ON_ONCE(!queue_is_locked(q));
 491         __clear_bit(flag, &q->queue_flags);
 492 }
 493
 494 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 495 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 496 #define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 497 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 498 #define blk_queue_noxmerges(q)  \
 499         test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
 500 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 501 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 502 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
 503 #define blk_queue_stackable(q)  \
 504         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 505 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
 506 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
 507         test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
 508
 509 #define blk_noretry_request(rq) \
 510         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
 511                              REQ_FAILFAST_DRIVER))
 512
 513 #define blk_account_rq(rq) \
 514         (((rq)->cmd_flags & REQ_STARTED) && \
 515          ((rq)->cmd_type == REQ_TYPE_FS || \
 516           ((rq)->cmd_flags & REQ_DISCARD)))
 517
 518 #define blk_pm_request(rq)      \
 519         ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
 520          (rq)->cmd_type == REQ_TYPE_PM_RESUME)
 521
 522 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 523 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 524 /* rq->queuelist of dequeued request must be list_empty() */
 525 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 526
 527 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 528
 529 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 530
 531 static inline unsigned int blk_queue_cluster(struct request_queue *q)
 532 {
 533         return q->limits.cluster;
 534 }
 535
 536 /*
 537  * We regard a request as sync, if either a read or a sync write
 538  */
 539 static inline bool rw_is_sync(unsigned int rw_flags)
 540 {
 541         return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
 542 }
 543
 544 static inline bool rq_is_sync(struct request *rq)
 545 {
 546         return rw_is_sync(rq->cmd_flags);
 547 }
 548
 549 static inline int blk_queue_full(struct request_queue *q, int sync)
 550 {
 551         if (sync)
 552                 return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
 553         return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
 554 }
 555
 556 static inline void blk_set_queue_full(struct request_queue *q, int sync)
 557 {
 558         if (sync)
 559                 queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
 560         else
 561                 queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
 562 }
 563
 564 static inline void blk_clear_queue_full(struct request_queue *q, int sync)
 565 {
 566         if (sync)
 567                 queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
 568         else
 569                 queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
 570 }
 571
 572
 573 /*
 574  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 575  * it already be started by driver.
 576  */
 577 #define RQ_NOMERGE_FLAGS        \
 578         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
 579 #define rq_mergeable(rq)        \
 580         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 581          (((rq)->cmd_flags & REQ_DISCARD) || \
 582           (rq)->cmd_type == REQ_TYPE_FS))
 583
 584 /*
 585  * q->prep_rq_fn return values
 586  */
 587 #define BLKPREP_OK              0       /* serve it */
 588 #define BLKPREP_KILL            1       /* fatal error, kill */
 589 #define BLKPREP_DEFER           2       /* leave on queue */
 590
 591 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 592
 593 /*
 594  * standard bounce addresses:
 595  *
 596  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 597  * BLK_BOUNCE_ANY       : don't bounce anything
 598  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 599  */
 600
 601 #if BITS_PER_LONG == 32
 602 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 603 #else
 604 #define BLK_BOUNCE_HIGH         -1ULL
 605 #endif
 606 #define BLK_BOUNCE_ANY          (-1ULL)
 607 #define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
 608
 609 /*
 610  * default timeout for SG_IO if none specified
 611  */
 612 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 613 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 614
 615 #ifdef CONFIG_BOUNCE
 616 extern int init_emergency_isa_pool(void);
 617 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 618 #else
 619 static inline int init_emergency_isa_pool(void)
 620 {
 621         return 0;
 622 }
 623 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 624 {
 625 }
 626 #endif /* CONFIG_MMU */
 627
 628 struct rq_map_data {
 629         struct page **pages;
 630         int page_order;
 631         int nr_entries;
 632         unsigned long offset;
 633         int null_mapped;
 634         int from_user;
 635 };
 636
 637 struct req_iterator {
 638         int i;
 639         struct bio *bio;
 640 };
 641
 642 /* This should not be used directly - use rq_for_each_segment */
 643 #define for_each_bio(_bio)              \
 644         for (; _bio; _bio = _bio->bi_next)
 645 #define __rq_for_each_bio(_bio, rq)     \
 646         if ((rq->bio))                  \
 647                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 648
 649 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 650         __rq_for_each_bio(_iter.bio, _rq)                       \
 651                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 652
 653 #define rq_iter_last(rq, _iter)                                 \
 654                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 655
 656 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 657 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 658 #endif
 659 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 660 extern void rq_flush_dcache_pages(struct request *rq);
 661 #else
 662 static inline void rq_flush_dcache_pages(struct request *rq)
 663 {
 664 }
 665 #endif
 666
 667 extern int blk_register_queue(struct gendisk *disk);
 668 extern void blk_unregister_queue(struct gendisk *disk);
 669 extern void generic_make_request(struct bio *bio);
 670 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 671 extern void blk_put_request(struct request *);
 672 extern void __blk_put_request(struct request_queue *, struct request *);
 673 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 674 extern struct request *blk_make_request(struct request_queue *, struct bio *,
 675                                         gfp_t);
 676 extern void blk_requeue_request(struct request_queue *, struct request *);
 677 extern void blk_add_request_payload(struct request *rq, struct page *page,
 678                 unsigned int len);
 679 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 680 extern int blk_lld_busy(struct request_queue *q);
 681 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 682                              struct bio_set *bs, gfp_t gfp_mask,
 683                              int (*bio_ctr)(struct bio *, struct bio *, void *),
 684                              void *data);
 685 extern void blk_rq_unprep_clone(struct request *rq);
 686 extern int blk_insert_cloned_request(struct request_queue *q,
 687                                      struct request *rq);
 688 extern void blk_delay_queue(struct request_queue *, unsigned long);
 689 extern void blk_recount_segments(struct request_queue *, struct bio *);
 690 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
 691 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
 692                               unsigned int, void __user *);
 693 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 694                           unsigned int, void __user *);
 695 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 696                          struct scsi_ioctl_command __user *);
 697
 698 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
 699
 700 /*
 701  * A queue has just exitted congestion.  Note this in the global counter of
 702  * congested queues, and wake up anyone who was waiting for requests to be
 703  * put back.
 704  */
 705 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 706 {
 707         clear_bdi_congested(&q->backing_dev_info, sync);
 708 }
 709
 710 /*
 711  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 712  * state flags and increment the global gounter of congested queues.
 713  */
 714 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 715 {
 716         set_bdi_congested(&q->backing_dev_info, sync);
 717 }
 718
 719 extern void blk_start_queue(struct request_queue *q);
 720 extern void blk_stop_queue(struct request_queue *q);
 721 extern void blk_sync_queue(struct request_queue *q);
 722 extern void __blk_stop_queue(struct request_queue *q);
 723 extern void __blk_run_queue(struct request_queue *q);
 724 extern void blk_run_queue(struct request_queue *);
 725 extern void blk_run_queue_async(struct request_queue *q);
 726 extern int blk_rq_map_user(struct request_queue *, struct request *,
 727                            struct rq_map_data *, void __user *, unsigned long,
 728                            gfp_t);
 729 extern int blk_rq_unmap_user(struct bio *);
 730 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 731 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 732                                struct rq_map_data *, struct sg_iovec *, int,
 733                                unsigned int, gfp_t);
 734 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 735                           struct request *, int);
 736 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 737                                   struct request *, int, rq_end_io_fn *);
 738
 739 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 740 {
 741         return bdev->bd_disk->queue;
 742 }
 743
 744 /*
 745  * blk_rq_pos()                 : the current sector
 746  * blk_rq_bytes()               : bytes left in the entire request
 747  * blk_rq_cur_bytes()           : bytes left in the current segment
 748  * blk_rq_err_bytes()           : bytes left till the next error boundary
 749  * blk_rq_sectors()             : sectors left in the entire request
 750  * blk_rq_cur_sectors()         : sectors left in the current segment
 751  */
 752 static inline sector_t blk_rq_pos(const struct request *rq)
 753 {
 754         return rq->__sector;
 755 }
 756
 757 static inline unsigned int blk_rq_bytes(const struct request *rq)
 758 {
 759         return rq->__data_len;
 760 }
 761
 762 static inline int blk_rq_cur_bytes(const struct request *rq)
 763 {
 764         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 765 }
 766
 767 extern unsigned int blk_rq_err_bytes(const struct request *rq);
 768
 769 static inline unsigned int blk_rq_sectors(const struct request *rq)
 770 {
 771         return blk_rq_bytes(rq) >> 9;
 772 }
 773
 774 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 775 {
 776         return blk_rq_cur_bytes(rq) >> 9;
 777 }
 778
 779 /*
 780  * Request issue related functions.
 781  */
 782 extern struct request *blk_peek_request(struct request_queue *q);
 783 extern void blk_start_request(struct request *rq);
 784 extern struct request *blk_fetch_request(struct request_queue *q);
 785
 786 /*
 787  * Request completion related functions.
 788  *
 789  * blk_update_request() completes given number of bytes and updates
 790  * the request without completing it.
 791  *
 792  * blk_end_request() and friends.  __blk_end_request() must be called
 793  * with the request queue spinlock acquired.
 794  *
 795  * Several drivers define their own end_request and call
 796  * blk_end_request() for parts of the original function.
 797  * This prevents code duplication in drivers.
 798  */
 799 extern bool blk_update_request(struct request *rq, int error,
 800                                unsigned int nr_bytes);
 801 extern bool blk_end_request(struct request *rq, int error,
 802                             unsigned int nr_bytes);
 803 extern void blk_end_request_all(struct request *rq, int error);
 804 extern bool blk_end_request_cur(struct request *rq, int error);
 805 extern bool blk_end_request_err(struct request *rq, int error);
 806 extern bool __blk_end_request(struct request *rq, int error,
 807                               unsigned int nr_bytes);
 808 extern void __blk_end_request_all(struct request *rq, int error);
 809 extern bool __blk_end_request_cur(struct request *rq, int error);
 810 extern bool __blk_end_request_err(struct request *rq, int error);
 811
 812 extern void blk_complete_request(struct request *);
 813 extern void __blk_complete_request(struct request *);
 814 extern void blk_abort_request(struct request *);
 815 extern void blk_abort_queue(struct request_queue *);
 816 extern void blk_unprep_request(struct request *);
 817
 818 /*
 819  * Access functions for manipulating queue properties
 820  */
 821 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 822                                         spinlock_t *lock, int node_id);
 823 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 824 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
 825                                                       request_fn_proc *, spinlock_t *);
 826 extern void blk_cleanup_queue(struct request_queue *);
 827 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 828 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 829 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
 830 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 831 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
 832 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 833 extern void blk_queue_max_discard_sectors(struct request_queue *q,
 834                 unsigned int max_discard_sectors);
 835 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 836 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
 837 extern void blk_queue_alignment_offset(struct request_queue *q,
 838                                        unsigned int alignment);
 839 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 840 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 841 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 842 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 843 extern void blk_set_default_limits(struct queue_limits *lim);
 844 extern void blk_set_stacking_limits(struct queue_limits *lim);
 845 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 846                             sector_t offset);
 847 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
 848                             sector_t offset);
 849 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 850                               sector_t offset);
 851 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 852 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 853 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 854 extern int blk_queue_dma_drain(struct request_queue *q,
 855                                dma_drain_needed_fn *dma_drain_needed,
 856                                void *buf, unsigned int size);
 857 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 858 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 859 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 860 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
 861 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 862 extern void blk_queue_dma_alignment(struct request_queue *, int);
 863 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 864 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 865 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 866 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 867 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
 868 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
 869 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 870
 871 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 872 extern void blk_dump_rq_flags(struct request *, char *);
 873 extern long nr_blockdev_pages(void);
 874
 875 bool __must_check blk_get_queue(struct request_queue *);
 876 struct request_queue *blk_alloc_queue(gfp_t);
 877 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 878 extern void blk_put_queue(struct request_queue *);
 879
 880 /*
 881  * blk_plug permits building a queue of related requests by holding the I/O
 882  * fragments for a short period. This allows merging of sequential requests
 883  * into single larger request. As the requests are moved from a per-task list to
 884  * the device's request_queue in a batch, this results in improved scalability
 885  * as the lock contention for request_queue lock is reduced.
 886  *
 887  * It is ok not to disable preemption when adding the request to the plug list
 888  * or when attempting a merge, because blk_schedule_flush_list() will only flush
 889  * the plug list when the task sleeps by itself. For details, please see
 890  * schedule() where blk_schedule_flush_plug() is called.
 891  */
 892 struct blk_plug {
 893         unsigned long magic; /* detect uninitialized use-cases */
 894         struct list_head list; /* requests */
 895         struct list_head cb_list; /* md requires an unplug callback */
 896         unsigned int should_sort; /* list to be sorted before flushing? */
 897 };
 898 #define BLK_MAX_REQUEST_COUNT 16
 899
 900 struct blk_plug_cb {
 901         struct list_head list;
 902         void (*callback)(struct blk_plug_cb *);
 903 };
 904
 905 extern void blk_start_plug(struct blk_plug *);
 906 extern void blk_finish_plug(struct blk_plug *);
 907 extern void blk_flush_plug_list(struct blk_plug *, bool);
 908
 909 static inline void blk_flush_plug(struct task_struct *tsk)
 910 {
 911         struct blk_plug *plug = tsk->plug;
 912
 913         if (plug)
 914                 blk_flush_plug_list(plug, false);
 915 }
 916
 917 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
 918 {
 919         struct blk_plug *plug = tsk->plug;
 920
 921         if (plug)
 922                 blk_flush_plug_list(plug, true);
 923 }
 924
 925 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
 926 {
 927         struct blk_plug *plug = tsk->plug;
 928
 929         return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
 930 }
 931
 932 /*
 933  * tag stuff
 934  */
 935 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 936 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 937 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 938 extern void blk_queue_end_tag(struct request_queue *, struct request *);
 939 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 940 extern void blk_queue_free_tags(struct request_queue *);
 941 extern int blk_queue_resize_tags(struct request_queue *, int);
 942 extern void blk_queue_invalidate_tags(struct request_queue *);
 943 extern struct blk_queue_tag *blk_init_tags(int);
 944 extern void blk_free_tags(struct blk_queue_tag *);
 945
 946 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 947                                                 int tag)
 948 {
 949         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 950                 return NULL;
 951         return bqt->tag_index[tag];
 952 }
 953
 954 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
 955
 956 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
 957 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 958                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
 959 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 960                         sector_t nr_sects, gfp_t gfp_mask);
 961 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
 962                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
 963 {
 964         return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
 965                                     nr_blocks << (sb->s_blocksize_bits - 9),
 966                                     gfp_mask, flags);
 967 }
 968 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
 969                 sector_t nr_blocks, gfp_t gfp_mask)
 970 {
 971         return blkdev_issue_zeroout(sb->s_bdev,
 972                                     block << (sb->s_blocksize_bits - 9),
 973                                     nr_blocks << (sb->s_blocksize_bits - 9),
 974                                     gfp_mask);
 975 }
 976
 977 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
 978
 979 enum blk_default_limits {
 980         BLK_MAX_SEGMENTS        = 128,
 981         BLK_SAFE_MAX_SECTORS    = 255,
 982         BLK_DEF_MAX_SECTORS     = 1024,
 983         BLK_MAX_SEGMENT_SIZE    = 65536,
 984         BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
 985 };
 986
 987 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
 988
 989 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
 990 {
 991         return q->limits.bounce_pfn;
 992 }
 993
 994 static inline unsigned long queue_segment_boundary(struct request_queue *q)
 995 {
 996         return q->limits.seg_boundary_mask;
 997 }
 998
 999 static inline unsigned int queue_max_sectors(struct request_queue *q)
1000 {
1001         return q->limits.max_sectors;
1002 }
1003
1004 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1005 {
1006         return q->limits.max_hw_sectors;
1007 }
1008
1009 static inline unsigned short queue_max_segments(struct request_queue *q)
1010 {
1011         return q->limits.max_segments;
1012 }
1013
1014 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1015 {
1016         return q->limits.max_segment_size;
1017 }
1018
1019 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1020 {
1021         int retval = 512;
1022
1023         if (q && q->limits.logical_block_size)
1024                 retval = q->limits.logical_block_size;
1025
1026         return retval;
1027 }
1028
1029 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1030 {
1031         return queue_logical_block_size(bdev_get_queue(bdev));
1032 }
1033
1034 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1035 {
1036         return q->limits.physical_block_size;
1037 }
1038
1039 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1040 {
1041         return queue_physical_block_size(bdev_get_queue(bdev));
1042 }
1043
1044 static inline unsigned int queue_io_min(struct request_queue *q)
1045 {
1046         return q->limits.io_min;
1047 }
1048
1049 static inline int bdev_io_min(struct block_device *bdev)
1050 {
1051         return queue_io_min(bdev_get_queue(bdev));
1052 }
1053
1054 static inline unsigned int queue_io_opt(struct request_queue *q)
1055 {
1056         return q->limits.io_opt;
1057 }
1058
1059 static inline int bdev_io_opt(struct block_device *bdev)
1060 {
1061         return queue_io_opt(bdev_get_queue(bdev));
1062 }
1063
1064 static inline int queue_alignment_offset(struct request_queue *q)
1065 {
1066         if (q->limits.misaligned)
1067                 return -1;
1068
1069         return q->limits.alignment_offset;
1070 }
1071
1072 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1073 {
1074         unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1075         unsigned int alignment = (sector << 9) & (granularity - 1);
1076
1077         return (granularity + lim->alignment_offset - alignment)
1078                 & (granularity - 1);
1079 }
1080
1081 static inline int bdev_alignment_offset(struct block_device *bdev)
1082 {
1083         struct request_queue *q = bdev_get_queue(bdev);
1084
1085         if (q->limits.misaligned)
1086                 return -1;
1087
1088         if (bdev != bdev->bd_contains)
1089                 return bdev->bd_part->alignment_offset;
1090
1091         return q->limits.alignment_offset;
1092 }
1093
1094 static inline int queue_discard_alignment(struct request_queue *q)
1095 {
1096         if (q->limits.discard_misaligned)
1097                 return -1;
1098
1099         return q->limits.discard_alignment;
1100 }
1101
1102 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1103 {
1104         unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1105
1106         if (!lim->max_discard_sectors)
1107                 return 0;
1108
1109         return (lim->discard_granularity + lim->discard_alignment - alignment)
1110                 & (lim->discard_granularity - 1);
1111 }
1112
1113 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1114 {
1115         if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1116                 return 1;
1117
1118         return 0;
1119 }
1120
1121 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1122 {
1123         return queue_discard_zeroes_data(bdev_get_queue(bdev));
1124 }
1125
1126 static inline int queue_dma_alignment(struct request_queue *q)
1127 {
1128         return q ? q->dma_alignment : 511;
1129 }
1130
1131 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1132                                  unsigned int len)
1133 {
1134         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1135         return !(addr & alignment) && !(len & alignment);
1136 }
1137
1138 /* assumes size > 256 */
1139 static inline unsigned int blksize_bits(unsigned int size)
1140 {
1141         unsigned int bits = 8;
1142         do {
1143                 bits++;
1144                 size >>= 1;
1145         } while (size > 256);
1146         return bits;
1147 }
1148
1149 static inline unsigned int block_size(struct block_device *bdev)
1150 {
1151         return bdev->bd_block_size;
1152 }
1153
1154 static inline bool queue_flush_queueable(struct request_queue *q)
1155 {
1156         return !q->flush_not_queueable;
1157 }
1158
1159 typedef struct {struct page *v;} Sector;
1160
1161 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1162
1163 static inline void put_dev_sector(Sector p)
1164 {
1165         page_cache_release(p.v);
1166 }
1167
1168 struct work_struct;
1169 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1170
1171 #ifdef CONFIG_BLK_CGROUP
1172 /*
1173  * This should not be using sched_clock(). A real patch is in progress
1174  * to fix this up, until that is in place we need to disable preemption
1175  * around sched_clock() in this function and set_io_start_time_ns().
1176  */
1177 static inline void set_start_time_ns(struct request *req)
1178 {
1179         preempt_disable();
1180         req->start_time_ns = sched_clock();
1181         preempt_enable();
1182 }
1183
1184 static inline void set_io_start_time_ns(struct request *req)
1185 {
1186         preempt_disable();
1187         req->io_start_time_ns = sched_clock();
1188         preempt_enable();
1189 }
1190
1191 static inline uint64_t rq_start_time_ns(struct request *req)
1192 {
1193         return req->start_time_ns;
1194 }
1195
1196 static inline uint64_t rq_io_start_time_ns(struct request *req)
1197 {
1198         return req->io_start_time_ns;
1199 }
1200 #else
1201 static inline void set_start_time_ns(struct request *req) {}
1202 static inline void set_io_start_time_ns(struct request *req) {}
1203 static inline uint64_t rq_start_time_ns(struct request *req)
1204 {
1205         return 0;
1206 }
1207 static inline uint64_t rq_io_start_time_ns(struct request *req)
1208 {
1209         return 0;
1210 }
1211 #endif
1212
1213 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1214         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1215 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1216         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1217
1218 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1219
1220 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1221 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1222
1223 struct blk_integrity_exchg {
1224         void                    *prot_buf;
1225         void                    *data_buf;
1226         sector_t                sector;
1227         unsigned int            data_size;
1228         unsigned short          sector_size;
1229         const char              *disk_name;
1230 };
1231
1232 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1233 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1234 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1235 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1236
1237 struct blk_integrity {
1238         integrity_gen_fn        *generate_fn;
1239         integrity_vrfy_fn       *verify_fn;
1240         integrity_set_tag_fn    *set_tag_fn;
1241         integrity_get_tag_fn    *get_tag_fn;
1242
1243         unsigned short          flags;
1244         unsigned short          tuple_size;
1245         unsigned short          sector_size;
1246         unsigned short          tag_size;
1247
1248         const char              *name;
1249
1250         struct kobject          kobj;
1251 };
1252
1253 extern bool blk_integrity_is_initialized(struct gendisk *);
1254 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1255 extern void blk_integrity_unregister(struct gendisk *);
1256 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1257 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1258                                    struct scatterlist *);
1259 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1260 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1261                                   struct request *);
1262 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1263                                    struct bio *);
1264
1265 static inline
1266 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1267 {
1268         return bdev->bd_disk->integrity;
1269 }
1270
1271 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1272 {
1273         return disk->integrity;
1274 }
1275
1276 static inline int blk_integrity_rq(struct request *rq)
1277 {
1278         if (rq->bio == NULL)
1279                 return 0;
1280
1281         return bio_integrity(rq->bio);
1282 }
1283
1284 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1285                                                     unsigned int segs)
1286 {
1287         q->limits.max_integrity_segments = segs;
1288 }
1289
1290 static inline unsigned short
1291 queue_max_integrity_segments(struct request_queue *q)
1292 {
1293         return q->limits.max_integrity_segments;
1294 }
1295
1296 #else /* CONFIG_BLK_DEV_INTEGRITY */
1297
1298 struct bio;
1299 struct block_device;
1300 struct gendisk;
1301 struct blk_integrity;
1302
1303 static inline int blk_integrity_rq(struct request *rq)
1304 {
1305         return 0;
1306 }
1307 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1308                                             struct bio *b)
1309 {
1310         return 0;
1311 }
1312 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1313                                           struct bio *b,
1314                                           struct scatterlist *s)
1315 {
1316         return 0;
1317 }
1318 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1319 {
1320         return 0;
1321 }
1322 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1323 {
1324         return NULL;
1325 }
1326 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1327 {
1328         return 0;
1329 }
1330 static inline int blk_integrity_register(struct gendisk *d,
1331                                          struct blk_integrity *b)
1332 {
1333         return 0;
1334 }
1335 static inline void blk_integrity_unregister(struct gendisk *d)
1336 {
1337 }
1338 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1339                                                     unsigned int segs)
1340 {
1341 }
1342 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1343 {
1344         return 0;
1345 }
1346 static inline int blk_integrity_merge_rq(struct request_queue *rq,
1347                                          struct request *r1,
1348                                          struct request *r2)
1349 {
1350         return 0;
1351 }
1352 static inline int blk_integrity_merge_bio(struct request_queue *rq,
1353                                           struct request *r,
1354                                           struct bio *b)
1355 {
1356         return 0;
1357 }
1358 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1359 {
1360         return 0;
1361 }
1362
1363 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1364
1365 struct block_device_operations {
1366         int (*open) (struct block_device *, fmode_t);
1367         int (*release) (struct gendisk *, fmode_t);
1368         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1369         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1370         int (*direct_access) (struct block_device *, sector_t,
1371                                                 void **, unsigned long *);
1372         unsigned int (*check_events) (struct gendisk *disk,
1373                                       unsigned int clearing);
1374         /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1375         int (*media_changed) (struct gendisk *);
1376         void (*unlock_native_capacity) (struct gendisk *);
1377         int (*revalidate_disk) (struct gendisk *);
1378         int (*getgeo)(struct block_device *, struct hd_geometry *);
1379         /* this callback is with swap_lock and sometimes page table lock held */
1380         void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1381         struct module *owner;
1382 };
1383
1384 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1385                                  unsigned long);
1386 #else /* CONFIG_BLOCK */
1387 /*
1388  * stubs for when the block layer is configured out
1389  */
1390 #define buffer_heads_over_limit 0
1391
1392 static inline long nr_blockdev_pages(void)
1393 {
1394         return 0;
1395 }
1396
1397 struct blk_plug {
1398 };
1399
1400 static inline void blk_start_plug(struct blk_plug *plug)
1401 {
1402 }
1403
1404 static inline void blk_finish_plug(struct blk_plug *plug)
1405 {
1406 }
1407
1408 static inline void blk_flush_plug(struct task_struct *task)
1409 {
1410 }
1411
1412 static inline void blk_schedule_flush_plug(struct task_struct *task)
1413 {
1414 }
1415
1416
1417 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1418 {
1419         return false;
1420 }
1421
1422 #endif /* CONFIG_BLOCK */
1423
1424 #endif