include/linux/blkdev.h

   1 #ifndef _LINUX_BLKDEV_H
   2 #define _LINUX_BLKDEV_H
   3
   4 #include <linux/sched.h>
   5
   6 #ifdef CONFIG_BLOCK
   7
   8 #include <linux/major.h>
   9 #include <linux/genhd.h>
  10 #include <linux/list.h>
  11 #include <linux/timer.h>
  12 #include <linux/workqueue.h>
  13 #include <linux/pagemap.h>
  14 #include <linux/backing-dev.h>
  15 #include <linux/wait.h>
  16 #include <linux/mempool.h>
  17 #include <linux/bio.h>
  18 #include <linux/stringify.h>
  19 #include <linux/gfp.h>
  20 #include <linux/bsg.h>
  21 #include <linux/smp.h>
  22
  23 #include <asm/scatterlist.h>
  24
  25 struct module;
  26 struct scsi_ioctl_command;
  27
  28 struct request_queue;
  29 struct elevator_queue;
  30 struct request_pm_state;
  31 struct blk_trace;
  32 struct request;
  33 struct sg_io_hdr;
  34 struct bsg_job;
  35 struct blkcg_gq;
  36
  37 #define BLKDEV_MIN_RQ   4
  38 #define BLKDEV_MAX_RQ   128     /* Default maximum */
  39
  40 /*
  41  * Maximum number of blkcg policies allowed to be registered concurrently.
  42  * Defined here to simplify include dependency.
  43  */
  44 #define BLKCG_MAX_POLS          2
  45
  46 struct request;
  47 typedef void (rq_end_io_fn)(struct request *, int);
  48
  49 #define BLK_RL_SYNCFULL         (1U << 0)
  50 #define BLK_RL_ASYNCFULL        (1U << 1)
  51
  52 struct request_list {
  53         struct request_queue    *q;     /* the queue this rl belongs to */
  54
  55         /*
  56          * count[], starved[], and wait[] are indexed by
  57          * BLK_RW_SYNC/BLK_RW_ASYNC
  58          */
  59         int                     count[2];
  60         int                     starved[2];
  61         mempool_t               *rq_pool;
  62         wait_queue_head_t       wait[2];
  63         unsigned int            flags;
  64 };
  65
  66 /*
  67  * request command types
  68  */
  69 enum rq_cmd_type_bits {
  70         REQ_TYPE_FS             = 1,    /* fs request */
  71         REQ_TYPE_BLOCK_PC,              /* scsi command */
  72         REQ_TYPE_SENSE,                 /* sense request */
  73         REQ_TYPE_PM_SUSPEND,            /* suspend request */
  74         REQ_TYPE_PM_RESUME,             /* resume request */
  75         REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
  76         REQ_TYPE_SPECIAL,               /* driver defined type */
  77         /*
  78          * for ATA/ATAPI devices. this really doesn't belong here, ide should
  79          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  80          * private REQ_LB opcodes to differentiate what type of request this is
  81          */
  82         REQ_TYPE_ATA_TASKFILE,
  83         REQ_TYPE_ATA_PC,
  84 };
  85
  86 #define BLK_MAX_CDB     16
  87
  88 /*
  89  * try to put the fields that are referenced together in the same cacheline.
  90  * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
  91  * as well!
  92  */
  93 struct request {
  94         struct list_head queuelist;
  95         struct call_single_data csd;
  96
  97         struct request_queue *q;
  98
  99         unsigned int cmd_flags;
 100         enum rq_cmd_type_bits cmd_type;
 101         unsigned long atomic_flags;
 102
 103         int cpu;
 104
 105         /* the following two fields are internal, NEVER access directly */
 106         unsigned int __data_len;        /* total data len */
 107         sector_t __sector;              /* sector cursor */
 108
 109         struct bio *bio;
 110         struct bio *biotail;
 111
 112         struct hlist_node hash; /* merge hash */
 113         /*
 114          * The rb_node is only used inside the io scheduler, requests
 115          * are pruned when moved to the dispatch queue. So let the
 116          * completion_data share space with the rb_node.
 117          */
 118         union {
 119                 struct rb_node rb_node; /* sort/lookup */
 120                 void *completion_data;
 121         };
 122
 123         /*
 124          * Three pointers are available for the IO schedulers, if they need
 125          * more they have to dynamically allocate it.  Flush requests are
 126          * never put on the IO scheduler. So let the flush fields share
 127          * space with the elevator data.
 128          */
 129         union {
 130                 struct {
 131                         struct io_cq            *icq;
 132                         void                    *priv[2];
 133                 } elv;
 134
 135                 struct {
 136                         unsigned int            seq;
 137                         struct list_head        list;
 138                         rq_end_io_fn            *saved_end_io;
 139                 } flush;
 140         };
 141
 142         struct gendisk *rq_disk;
 143         struct hd_struct *part;
 144         unsigned long start_time;
 145 #ifdef CONFIG_BLK_CGROUP
 146         unsigned long long start_time_ns;
 147         unsigned long long io_start_time_ns;    /* when passed to hardware */
 148 #endif
 149         /* Number of scatter-gather DMA addr+len pairs after
 150          * physical address coalescing is performed.
 151          */
 152         unsigned short nr_phys_segments;
 153 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 154         unsigned short nr_integrity_segments;
 155 #endif
 156
 157         unsigned short ioprio;
 158
 159         int ref_count;
 160
 161         void *special;          /* opaque pointer available for LLD use */
 162         char *buffer;           /* kaddr of the current segment if available */
 163
 164         int tag;
 165         int errors;
 166
 167         /*
 168          * when request is used as a packet command carrier
 169          */
 170         unsigned char __cmd[BLK_MAX_CDB];
 171         unsigned char *cmd;
 172         unsigned short cmd_len;
 173
 174         unsigned int extra_len; /* length of alignment and padding */
 175         unsigned int sense_len;
 176         unsigned int resid_len; /* residual count */
 177         void *sense;
 178
 179         unsigned long deadline;
 180         struct list_head timeout_list;
 181         unsigned int timeout;
 182         int retries;
 183
 184         /*
 185          * completion callback.
 186          */
 187         rq_end_io_fn *end_io;
 188         void *end_io_data;
 189
 190         /* for bidi */
 191         struct request *next_rq;
 192 };
 193
 194 static inline unsigned short req_get_ioprio(struct request *req)
 195 {
 196         return req->ioprio;
 197 }
 198
 199 /*
 200  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 201  * requests. Some step values could eventually be made generic.
 202  */
 203 struct request_pm_state
 204 {
 205         /* PM state machine step value, currently driver specific */
 206         int     pm_step;
 207         /* requested PM state value (S1, S2, S3, S4, ...) */
 208         u32     pm_state;
 209         void*   data;           /* for driver use */
 210 };
 211
 212 #include <linux/elevator.h>
 213
 214 typedef void (request_fn_proc) (struct request_queue *q);
 215 typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
 216 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 217 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
 218
 219 struct bio_vec;
 220 struct bvec_merge_data {
 221         struct block_device *bi_bdev;
 222         sector_t bi_sector;
 223         unsigned bi_size;
 224         unsigned long bi_rw;
 225 };
 226 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
 227                              struct bio_vec *);
 228 typedef void (softirq_done_fn)(struct request *);
 229 typedef int (dma_drain_needed_fn)(struct request *);
 230 typedef int (lld_busy_fn) (struct request_queue *q);
 231 typedef int (bsg_job_fn) (struct bsg_job *);
 232
 233 enum blk_eh_timer_return {
 234         BLK_EH_NOT_HANDLED,
 235         BLK_EH_HANDLED,
 236         BLK_EH_RESET_TIMER,
 237 };
 238
 239 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
 240
 241 enum blk_queue_state {
 242         Queue_down,
 243         Queue_up,
 244 };
 245
 246 struct blk_queue_tag {
 247         struct request **tag_index;     /* map of busy tags */
 248         unsigned long *tag_map;         /* bit map of free/busy tags */
 249         int busy;                       /* current depth */
 250         int max_depth;                  /* what we will send to device */
 251         int real_max_depth;             /* what the array can hold */
 252         atomic_t refcnt;                /* map can be shared */
 253 };
 254
 255 #define BLK_SCSI_MAX_CMDS       (256)
 256 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 257
 258 struct queue_limits {
 259         unsigned long           bounce_pfn;
 260         unsigned long           seg_boundary_mask;
 261
 262         unsigned int            max_hw_sectors;
 263         unsigned int            max_sectors;
 264         unsigned int            max_segment_size;
 265         unsigned int            physical_block_size;
 266         unsigned int            alignment_offset;
 267         unsigned int            io_min;
 268         unsigned int            io_opt;
 269         unsigned int            max_discard_sectors;
 270         unsigned int            discard_granularity;
 271         unsigned int            discard_alignment;
 272
 273         unsigned short          logical_block_size;
 274         unsigned short          max_segments;
 275         unsigned short          max_integrity_segments;
 276
 277         unsigned char           misaligned;
 278         unsigned char           discard_misaligned;
 279         unsigned char           cluster;
 280         unsigned char           discard_zeroes_data;
 281 };
 282
 283 struct request_queue {
 284         /*
 285          * Together with queue_head for cacheline sharing
 286          */
 287         struct list_head        queue_head;
 288         struct request          *last_merge;
 289         struct elevator_queue   *elevator;
 290         int                     nr_rqs[2];      /* # allocated [a]sync rqs */
 291         int                     nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
 292
 293         /*
 294          * the queue request freelist, one for reads and one for writes
 295          */
 296         struct request_list     rq;
 297
 298         request_fn_proc         *request_fn;
 299         make_request_fn         *make_request_fn;
 300         prep_rq_fn              *prep_rq_fn;
 301         unprep_rq_fn            *unprep_rq_fn;
 302         merge_bvec_fn           *merge_bvec_fn;
 303         softirq_done_fn         *softirq_done_fn;
 304         rq_timed_out_fn         *rq_timed_out_fn;
 305         dma_drain_needed_fn     *dma_drain_needed;
 306         lld_busy_fn             *lld_busy_fn;
 307
 308         /*
 309          * Dispatch queue sorting
 310          */
 311         sector_t                end_sector;
 312         struct request          *boundary_rq;
 313
 314         /*
 315          * Delayed queue handling
 316          */
 317         struct delayed_work     delay_work;
 318
 319         struct backing_dev_info backing_dev_info;
 320
 321         /*
 322          * The queue owner gets to use this for whatever they like.
 323          * ll_rw_blk doesn't touch it.
 324          */
 325         void                    *queuedata;
 326
 327         /*
 328          * various queue flags, see QUEUE_* below
 329          */
 330         unsigned long           queue_flags;
 331
 332         /*
 333          * ida allocated id for this queue.  Used to index queues from
 334          * ioctx.
 335          */
 336         int                     id;
 337
 338         /*
 339          * queue needs bounce pages for pages above this limit
 340          */
 341         gfp_t                   bounce_gfp;
 342
 343         /*
 344          * protects queue structures from reentrancy. ->__queue_lock should
 345          * _never_ be used directly, it is queue private. always use
 346          * ->queue_lock.
 347          */
 348         spinlock_t              __queue_lock;
 349         spinlock_t              *queue_lock;
 350
 351         /*
 352          * queue kobject
 353          */
 354         struct kobject kobj;
 355
 356         /*
 357          * queue settings
 358          */
 359         unsigned long           nr_requests;    /* Max # of requests */
 360         unsigned int            nr_congestion_on;
 361         unsigned int            nr_congestion_off;
 362         unsigned int            nr_batching;
 363
 364         unsigned int            dma_drain_size;
 365         void                    *dma_drain_buffer;
 366         unsigned int            dma_pad_mask;
 367         unsigned int            dma_alignment;
 368
 369         struct blk_queue_tag    *queue_tags;
 370         struct list_head        tag_busy_list;
 371
 372         unsigned int            nr_sorted;
 373         unsigned int            in_flight[2];
 374
 375         unsigned int            rq_timeout;
 376         struct timer_list       timeout;
 377         struct list_head        timeout_list;
 378
 379         struct list_head        icq_list;
 380 #ifdef CONFIG_BLK_CGROUP
 381         DECLARE_BITMAP          (blkcg_pols, BLKCG_MAX_POLS);
 382         struct blkcg_gq         *root_blkg;
 383         struct list_head        blkg_list;
 384 #endif
 385
 386         struct queue_limits     limits;
 387
 388         /*
 389          * sg stuff
 390          */
 391         unsigned int            sg_timeout;
 392         unsigned int            sg_reserved_size;
 393         int                     node;
 394 #ifdef CONFIG_BLK_DEV_IO_TRACE
 395         struct blk_trace        *blk_trace;
 396 #endif
 397         /*
 398          * for flush operations
 399          */
 400         unsigned int            flush_flags;
 401         unsigned int            flush_not_queueable:1;
 402         unsigned int            flush_queue_delayed:1;
 403         unsigned int            flush_pending_idx:1;
 404         unsigned int            flush_running_idx:1;
 405         unsigned long           flush_pending_since;
 406         struct list_head        flush_queue[2];
 407         struct list_head        flush_data_in_flight;
 408         struct request          flush_rq;
 409
 410         struct mutex            sysfs_lock;
 411
 412         int                     bypass_depth;
 413
 414 #if defined(CONFIG_BLK_DEV_BSG)
 415         bsg_job_fn              *bsg_job_fn;
 416         int                     bsg_job_size;
 417         struct bsg_class_device bsg_dev;
 418 #endif
 419
 420 #ifdef CONFIG_BLK_CGROUP
 421         struct list_head        all_q_node;
 422 #endif
 423 #ifdef CONFIG_BLK_DEV_THROTTLING
 424         /* Throttle data */
 425         struct throtl_data *td;
 426 #endif
 427 };
 428
 429 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 430 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 431 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 432 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 433 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 434 #define QUEUE_FLAG_BYPASS       6       /* act as dumb FIFO queue */
 435 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
 436 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
 437 #define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
 438 #define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
 439 #define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
 440 #define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
 441 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 442 #define QUEUE_FLAG_IO_STAT     13       /* do IO stats */
 443 #define QUEUE_FLAG_DISCARD     14       /* supports DISCARD */
 444 #define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
 445 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
 446 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
 447 #define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
 448
 449 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 450                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
 451                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
 452                                  (1 << QUEUE_FLAG_ADD_RANDOM))
 453
 454 static inline void queue_lockdep_assert_held(struct request_queue *q)
 455 {
 456         if (q->queue_lock)
 457                 lockdep_assert_held(q->queue_lock);
 458 }
 459
 460 static inline void queue_flag_set_unlocked(unsigned int flag,
 461                                            struct request_queue *q)
 462 {
 463         __set_bit(flag, &q->queue_flags);
 464 }
 465
 466 static inline int queue_flag_test_and_clear(unsigned int flag,
 467                                             struct request_queue *q)
 468 {
 469         queue_lockdep_assert_held(q);
 470
 471         if (test_bit(flag, &q->queue_flags)) {
 472                 __clear_bit(flag, &q->queue_flags);
 473                 return 1;
 474         }
 475
 476         return 0;
 477 }
 478
 479 static inline int queue_flag_test_and_set(unsigned int flag,
 480                                           struct request_queue *q)
 481 {
 482         queue_lockdep_assert_held(q);
 483
 484         if (!test_bit(flag, &q->queue_flags)) {
 485                 __set_bit(flag, &q->queue_flags);
 486                 return 0;
 487         }
 488
 489         return 1;
 490 }
 491
 492 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 493 {
 494         queue_lockdep_assert_held(q);
 495         __set_bit(flag, &q->queue_flags);
 496 }
 497
 498 static inline void queue_flag_clear_unlocked(unsigned int flag,
 499                                              struct request_queue *q)
 500 {
 501         __clear_bit(flag, &q->queue_flags);
 502 }
 503
 504 static inline int queue_in_flight(struct request_queue *q)
 505 {
 506         return q->in_flight[0] + q->in_flight[1];
 507 }
 508
 509 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 510 {
 511         queue_lockdep_assert_held(q);
 512         __clear_bit(flag, &q->queue_flags);
 513 }
 514
 515 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 516 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 517 #define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 518 #define blk_queue_bypass(q)     test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
 519 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 520 #define blk_queue_noxmerges(q)  \
 521         test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
 522 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 523 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 524 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
 525 #define blk_queue_stackable(q)  \
 526         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 527 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
 528 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
 529         test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
 530
 531 #define blk_noretry_request(rq) \
 532         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
 533                              REQ_FAILFAST_DRIVER))
 534
 535 #define blk_account_rq(rq) \
 536         (((rq)->cmd_flags & REQ_STARTED) && \
 537          ((rq)->cmd_type == REQ_TYPE_FS || \
 538           ((rq)->cmd_flags & REQ_DISCARD)))
 539
 540 #define blk_pm_request(rq)      \
 541         ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
 542          (rq)->cmd_type == REQ_TYPE_PM_RESUME)
 543
 544 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 545 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 546 /* rq->queuelist of dequeued request must be list_empty() */
 547 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 548
 549 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 550
 551 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 552
 553 static inline unsigned int blk_queue_cluster(struct request_queue *q)
 554 {
 555         return q->limits.cluster;
 556 }
 557
 558 /*
 559  * We regard a request as sync, if either a read or a sync write
 560  */
 561 static inline bool rw_is_sync(unsigned int rw_flags)
 562 {
 563         return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
 564 }
 565
 566 static inline bool rq_is_sync(struct request *rq)
 567 {
 568         return rw_is_sync(rq->cmd_flags);
 569 }
 570
 571 static inline bool blk_rl_full(struct request_list *rl, bool sync)
 572 {
 573         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
 574
 575         return rl->flags & flag;
 576 }
 577
 578 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
 579 {
 580         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
 581
 582         rl->flags |= flag;
 583 }
 584
 585 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
 586 {
 587         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
 588
 589         rl->flags &= ~flag;
 590 }
 591
 592
 593 /*
 594  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 595  * it already be started by driver.
 596  */
 597 #define RQ_NOMERGE_FLAGS        \
 598         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
 599 #define rq_mergeable(rq)        \
 600         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 601          (((rq)->cmd_flags & REQ_DISCARD) || \
 602           (rq)->cmd_type == REQ_TYPE_FS))
 603
 604 /*
 605  * q->prep_rq_fn return values
 606  */
 607 #define BLKPREP_OK              0       /* serve it */
 608 #define BLKPREP_KILL            1       /* fatal error, kill */
 609 #define BLKPREP_DEFER           2       /* leave on queue */
 610
 611 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 612
 613 /*
 614  * standard bounce addresses:
 615  *
 616  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 617  * BLK_BOUNCE_ANY       : don't bounce anything
 618  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 619  */
 620
 621 #if BITS_PER_LONG == 32
 622 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 623 #else
 624 #define BLK_BOUNCE_HIGH         -1ULL
 625 #endif
 626 #define BLK_BOUNCE_ANY          (-1ULL)
 627 #define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
 628
 629 /*
 630  * default timeout for SG_IO if none specified
 631  */
 632 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 633 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 634
 635 #ifdef CONFIG_BOUNCE
 636 extern int init_emergency_isa_pool(void);
 637 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 638 #else
 639 static inline int init_emergency_isa_pool(void)
 640 {
 641         return 0;
 642 }
 643 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 644 {
 645 }
 646 #endif /* CONFIG_MMU */
 647
 648 struct rq_map_data {
 649         struct page **pages;
 650         int page_order;
 651         int nr_entries;
 652         unsigned long offset;
 653         int null_mapped;
 654         int from_user;
 655 };
 656
 657 struct req_iterator {
 658         int i;
 659         struct bio *bio;
 660 };
 661
 662 /* This should not be used directly - use rq_for_each_segment */
 663 #define for_each_bio(_bio)              \
 664         for (; _bio; _bio = _bio->bi_next)
 665 #define __rq_for_each_bio(_bio, rq)     \
 666         if ((rq->bio))                  \
 667                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 668
 669 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 670         __rq_for_each_bio(_iter.bio, _rq)                       \
 671                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 672
 673 #define rq_iter_last(rq, _iter)                                 \
 674                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 675
 676 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 677 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 678 #endif
 679 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 680 extern void rq_flush_dcache_pages(struct request *rq);
 681 #else
 682 static inline void rq_flush_dcache_pages(struct request *rq)
 683 {
 684 }
 685 #endif
 686
 687 extern int blk_register_queue(struct gendisk *disk);
 688 extern void blk_unregister_queue(struct gendisk *disk);
 689 extern void generic_make_request(struct bio *bio);
 690 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 691 extern void blk_put_request(struct request *);
 692 extern void __blk_put_request(struct request_queue *, struct request *);
 693 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 694 extern struct request *blk_make_request(struct request_queue *, struct bio *,
 695                                         gfp_t);
 696 extern void blk_requeue_request(struct request_queue *, struct request *);
 697 extern void blk_add_request_payload(struct request *rq, struct page *page,
 698                 unsigned int len);
 699 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 700 extern int blk_lld_busy(struct request_queue *q);
 701 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 702                              struct bio_set *bs, gfp_t gfp_mask,
 703                              int (*bio_ctr)(struct bio *, struct bio *, void *),
 704                              void *data);
 705 extern void blk_rq_unprep_clone(struct request *rq);
 706 extern int blk_insert_cloned_request(struct request_queue *q,
 707                                      struct request *rq);
 708 extern void blk_delay_queue(struct request_queue *, unsigned long);
 709 extern void blk_recount_segments(struct request_queue *, struct bio *);
 710 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
 711 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
 712                               unsigned int, void __user *);
 713 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 714                           unsigned int, void __user *);
 715 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 716                          struct scsi_ioctl_command __user *);
 717
 718 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
 719
 720 /*
 721  * A queue has just exitted congestion.  Note this in the global counter of
 722  * congested queues, and wake up anyone who was waiting for requests to be
 723  * put back.
 724  */
 725 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 726 {
 727         clear_bdi_congested(&q->backing_dev_info, sync);
 728 }
 729
 730 /*
 731  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 732  * state flags and increment the global gounter of congested queues.
 733  */
 734 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 735 {
 736         set_bdi_congested(&q->backing_dev_info, sync);
 737 }
 738
 739 extern void blk_start_queue(struct request_queue *q);
 740 extern void blk_stop_queue(struct request_queue *q);
 741 extern void blk_sync_queue(struct request_queue *q);
 742 extern void __blk_stop_queue(struct request_queue *q);
 743 extern void __blk_run_queue(struct request_queue *q);
 744 extern void blk_run_queue(struct request_queue *);
 745 extern void blk_run_queue_async(struct request_queue *q);
 746 extern int blk_rq_map_user(struct request_queue *, struct request *,
 747                            struct rq_map_data *, void __user *, unsigned long,
 748                            gfp_t);
 749 extern int blk_rq_unmap_user(struct bio *);
 750 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 751 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 752                                struct rq_map_data *, struct sg_iovec *, int,
 753                                unsigned int, gfp_t);
 754 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 755                           struct request *, int);
 756 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 757                                   struct request *, int, rq_end_io_fn *);
 758
 759 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 760 {
 761         return bdev->bd_disk->queue;
 762 }
 763
 764 /*
 765  * blk_rq_pos()                 : the current sector
 766  * blk_rq_bytes()               : bytes left in the entire request
 767  * blk_rq_cur_bytes()           : bytes left in the current segment
 768  * blk_rq_err_bytes()           : bytes left till the next error boundary
 769  * blk_rq_sectors()             : sectors left in the entire request
 770  * blk_rq_cur_sectors()         : sectors left in the current segment
 771  */
 772 static inline sector_t blk_rq_pos(const struct request *rq)
 773 {
 774         return rq->__sector;
 775 }
 776
 777 static inline unsigned int blk_rq_bytes(const struct request *rq)
 778 {
 779         return rq->__data_len;
 780 }
 781
 782 static inline int blk_rq_cur_bytes(const struct request *rq)
 783 {
 784         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 785 }
 786
 787 extern unsigned int blk_rq_err_bytes(const struct request *rq);
 788
 789 static inline unsigned int blk_rq_sectors(const struct request *rq)
 790 {
 791         return blk_rq_bytes(rq) >> 9;
 792 }
 793
 794 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 795 {
 796         return blk_rq_cur_bytes(rq) >> 9;
 797 }
 798
 799 /*
 800  * Request issue related functions.
 801  */
 802 extern struct request *blk_peek_request(struct request_queue *q);
 803 extern void blk_start_request(struct request *rq);
 804 extern struct request *blk_fetch_request(struct request_queue *q);
 805
 806 /*
 807  * Request completion related functions.
 808  *
 809  * blk_update_request() completes given number of bytes and updates
 810  * the request without completing it.
 811  *
 812  * blk_end_request() and friends.  __blk_end_request() must be called
 813  * with the request queue spinlock acquired.
 814  *
 815  * Several drivers define their own end_request and call
 816  * blk_end_request() for parts of the original function.
 817  * This prevents code duplication in drivers.
 818  */
 819 extern bool blk_update_request(struct request *rq, int error,
 820                                unsigned int nr_bytes);
 821 extern bool blk_end_request(struct request *rq, int error,
 822                             unsigned int nr_bytes);
 823 extern void blk_end_request_all(struct request *rq, int error);
 824 extern bool blk_end_request_cur(struct request *rq, int error);
 825 extern bool blk_end_request_err(struct request *rq, int error);
 826 extern bool __blk_end_request(struct request *rq, int error,
 827                               unsigned int nr_bytes);
 828 extern void __blk_end_request_all(struct request *rq, int error);
 829 extern bool __blk_end_request_cur(struct request *rq, int error);
 830 extern bool __blk_end_request_err(struct request *rq, int error);
 831
 832 extern void blk_complete_request(struct request *);
 833 extern void __blk_complete_request(struct request *);
 834 extern void blk_abort_request(struct request *);
 835 extern void blk_unprep_request(struct request *);
 836
 837 /*
 838  * Access functions for manipulating queue properties
 839  */
 840 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 841                                         spinlock_t *lock, int node_id);
 842 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 843 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
 844                                                       request_fn_proc *, spinlock_t *);
 845 extern void blk_cleanup_queue(struct request_queue *);
 846 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 847 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 848 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
 849 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 850 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
 851 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 852 extern void blk_queue_max_discard_sectors(struct request_queue *q,
 853                 unsigned int max_discard_sectors);
 854 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 855 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
 856 extern void blk_queue_alignment_offset(struct request_queue *q,
 857                                        unsigned int alignment);
 858 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 859 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 860 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 861 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 862 extern void blk_set_default_limits(struct queue_limits *lim);
 863 extern void blk_set_stacking_limits(struct queue_limits *lim);
 864 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 865                             sector_t offset);
 866 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
 867                             sector_t offset);
 868 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 869                               sector_t offset);
 870 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 871 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 872 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 873 extern int blk_queue_dma_drain(struct request_queue *q,
 874                                dma_drain_needed_fn *dma_drain_needed,
 875                                void *buf, unsigned int size);
 876 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 877 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 878 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 879 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
 880 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 881 extern void blk_queue_dma_alignment(struct request_queue *, int);
 882 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 883 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 884 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 885 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 886 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
 887 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
 888 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 889
 890 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 891 extern void blk_dump_rq_flags(struct request *, char *);
 892 extern long nr_blockdev_pages(void);
 893
 894 bool __must_check blk_get_queue(struct request_queue *);
 895 struct request_queue *blk_alloc_queue(gfp_t);
 896 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 897 extern void blk_put_queue(struct request_queue *);
 898
 899 /*
 900  * blk_plug permits building a queue of related requests by holding the I/O
 901  * fragments for a short period. This allows merging of sequential requests
 902  * into single larger request. As the requests are moved from a per-task list to
 903  * the device's request_queue in a batch, this results in improved scalability
 904  * as the lock contention for request_queue lock is reduced.
 905  *
 906  * It is ok not to disable preemption when adding the request to the plug list
 907  * or when attempting a merge, because blk_schedule_flush_list() will only flush
 908  * the plug list when the task sleeps by itself. For details, please see
 909  * schedule() where blk_schedule_flush_plug() is called.
 910  */
 911 struct blk_plug {
 912         unsigned long magic; /* detect uninitialized use-cases */
 913         struct list_head list; /* requests */
 914         struct list_head cb_list; /* md requires an unplug callback */
 915         unsigned int should_sort; /* list to be sorted before flushing? */
 916 };
 917 #define BLK_MAX_REQUEST_COUNT 16
 918
 919 struct blk_plug_cb {
 920         struct list_head list;
 921         void (*callback)(struct blk_plug_cb *);
 922 };
 923
 924 extern void blk_start_plug(struct blk_plug *);
 925 extern void blk_finish_plug(struct blk_plug *);
 926 extern void blk_flush_plug_list(struct blk_plug *, bool);
 927
 928 static inline void blk_flush_plug(struct task_struct *tsk)
 929 {
 930         struct blk_plug *plug = tsk->plug;
 931
 932         if (plug)
 933                 blk_flush_plug_list(plug, false);
 934 }
 935
 936 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
 937 {
 938         struct blk_plug *plug = tsk->plug;
 939
 940         if (plug)
 941                 blk_flush_plug_list(plug, true);
 942 }
 943
 944 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
 945 {
 946         struct blk_plug *plug = tsk->plug;
 947
 948         return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
 949 }
 950
 951 /*
 952  * tag stuff
 953  */
 954 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 955 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 956 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 957 extern void blk_queue_end_tag(struct request_queue *, struct request *);
 958 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 959 extern void blk_queue_free_tags(struct request_queue *);
 960 extern int blk_queue_resize_tags(struct request_queue *, int);
 961 extern void blk_queue_invalidate_tags(struct request_queue *);
 962 extern struct blk_queue_tag *blk_init_tags(int);
 963 extern void blk_free_tags(struct blk_queue_tag *);
 964
 965 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 966                                                 int tag)
 967 {
 968         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 969                 return NULL;
 970         return bqt->tag_index[tag];
 971 }
 972
 973 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
 974
 975 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
 976 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 977                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
 978 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 979                         sector_t nr_sects, gfp_t gfp_mask);
 980 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
 981                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
 982 {
 983         return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
 984                                     nr_blocks << (sb->s_blocksize_bits - 9),
 985                                     gfp_mask, flags);
 986 }
 987 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
 988                 sector_t nr_blocks, gfp_t gfp_mask)
 989 {
 990         return blkdev_issue_zeroout(sb->s_bdev,
 991                                     block << (sb->s_blocksize_bits - 9),
 992                                     nr_blocks << (sb->s_blocksize_bits - 9),
 993                                     gfp_mask);
 994 }
 995
 996 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
 997
 998 enum blk_default_limits {
 999         BLK_MAX_SEGMENTS        = 128,
1000         BLK_SAFE_MAX_SECTORS    = 255,
1001         BLK_DEF_MAX_SECTORS     = 1024,
1002         BLK_MAX_SEGMENT_SIZE    = 65536,
1003         BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
1004 };
1005
1006 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1007
1008 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1009 {
1010         return q->limits.bounce_pfn;
1011 }
1012
1013 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1014 {
1015         return q->limits.seg_boundary_mask;
1016 }
1017
1018 static inline unsigned int queue_max_sectors(struct request_queue *q)
1019 {
1020         return q->limits.max_sectors;
1021 }
1022
1023 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1024 {
1025         return q->limits.max_hw_sectors;
1026 }
1027
1028 static inline unsigned short queue_max_segments(struct request_queue *q)
1029 {
1030         return q->limits.max_segments;
1031 }
1032
1033 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1034 {
1035         return q->limits.max_segment_size;
1036 }
1037
1038 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1039 {
1040         int retval = 512;
1041
1042         if (q && q->limits.logical_block_size)
1043                 retval = q->limits.logical_block_size;
1044
1045         return retval;
1046 }
1047
1048 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1049 {
1050         return queue_logical_block_size(bdev_get_queue(bdev));
1051 }
1052
1053 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1054 {
1055         return q->limits.physical_block_size;
1056 }
1057
1058 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1059 {
1060         return queue_physical_block_size(bdev_get_queue(bdev));
1061 }
1062
1063 static inline unsigned int queue_io_min(struct request_queue *q)
1064 {
1065         return q->limits.io_min;
1066 }
1067
1068 static inline int bdev_io_min(struct block_device *bdev)
1069 {
1070         return queue_io_min(bdev_get_queue(bdev));
1071 }
1072
1073 static inline unsigned int queue_io_opt(struct request_queue *q)
1074 {
1075         return q->limits.io_opt;
1076 }
1077
1078 static inline int bdev_io_opt(struct block_device *bdev)
1079 {
1080         return queue_io_opt(bdev_get_queue(bdev));
1081 }
1082
1083 static inline int queue_alignment_offset(struct request_queue *q)
1084 {
1085         if (q->limits.misaligned)
1086                 return -1;
1087
1088         return q->limits.alignment_offset;
1089 }
1090
1091 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1092 {
1093         unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1094         unsigned int alignment = (sector << 9) & (granularity - 1);
1095
1096         return (granularity + lim->alignment_offset - alignment)
1097                 & (granularity - 1);
1098 }
1099
1100 static inline int bdev_alignment_offset(struct block_device *bdev)
1101 {
1102         struct request_queue *q = bdev_get_queue(bdev);
1103
1104         if (q->limits.misaligned)
1105                 return -1;
1106
1107         if (bdev != bdev->bd_contains)
1108                 return bdev->bd_part->alignment_offset;
1109
1110         return q->limits.alignment_offset;
1111 }
1112
1113 static inline int queue_discard_alignment(struct request_queue *q)
1114 {
1115         if (q->limits.discard_misaligned)
1116                 return -1;
1117
1118         return q->limits.discard_alignment;
1119 }
1120
1121 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1122 {
1123         unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1124
1125         if (!lim->max_discard_sectors)
1126                 return 0;
1127
1128         return (lim->discard_granularity + lim->discard_alignment - alignment)
1129                 & (lim->discard_granularity - 1);
1130 }
1131
1132 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1133 {
1134         if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1135                 return 1;
1136
1137         return 0;
1138 }
1139
1140 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1141 {
1142         return queue_discard_zeroes_data(bdev_get_queue(bdev));
1143 }
1144
1145 static inline int queue_dma_alignment(struct request_queue *q)
1146 {
1147         return q ? q->dma_alignment : 511;
1148 }
1149
1150 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1151                                  unsigned int len)
1152 {
1153         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1154         return !(addr & alignment) && !(len & alignment);
1155 }
1156
1157 /* assumes size > 256 */
1158 static inline unsigned int blksize_bits(unsigned int size)
1159 {
1160         unsigned int bits = 8;
1161         do {
1162                 bits++;
1163                 size >>= 1;
1164         } while (size > 256);
1165         return bits;
1166 }
1167
1168 static inline unsigned int block_size(struct block_device *bdev)
1169 {
1170         return bdev->bd_block_size;
1171 }
1172
1173 static inline bool queue_flush_queueable(struct request_queue *q)
1174 {
1175         return !q->flush_not_queueable;
1176 }
1177
1178 typedef struct {struct page *v;} Sector;
1179
1180 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1181
1182 static inline void put_dev_sector(Sector p)
1183 {
1184         page_cache_release(p.v);
1185 }
1186
1187 struct work_struct;
1188 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1189
1190 #ifdef CONFIG_BLK_CGROUP
1191 /*
1192  * This should not be using sched_clock(). A real patch is in progress
1193  * to fix this up, until that is in place we need to disable preemption
1194  * around sched_clock() in this function and set_io_start_time_ns().
1195  */
1196 static inline void set_start_time_ns(struct request *req)
1197 {
1198         preempt_disable();
1199         req->start_time_ns = sched_clock();
1200         preempt_enable();
1201 }
1202
1203 static inline void set_io_start_time_ns(struct request *req)
1204 {
1205         preempt_disable();
1206         req->io_start_time_ns = sched_clock();
1207         preempt_enable();
1208 }
1209
1210 static inline uint64_t rq_start_time_ns(struct request *req)
1211 {
1212         return req->start_time_ns;
1213 }
1214
1215 static inline uint64_t rq_io_start_time_ns(struct request *req)
1216 {
1217         return req->io_start_time_ns;
1218 }
1219 #else
1220 static inline void set_start_time_ns(struct request *req) {}
1221 static inline void set_io_start_time_ns(struct request *req) {}
1222 static inline uint64_t rq_start_time_ns(struct request *req)
1223 {
1224         return 0;
1225 }
1226 static inline uint64_t rq_io_start_time_ns(struct request *req)
1227 {
1228         return 0;
1229 }
1230 #endif
1231
1232 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1233         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1234 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1235         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1236
1237 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1238
1239 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1240 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1241
1242 struct blk_integrity_exchg {
1243         void                    *prot_buf;
1244         void                    *data_buf;
1245         sector_t                sector;
1246         unsigned int            data_size;
1247         unsigned short          sector_size;
1248         const char              *disk_name;
1249 };
1250
1251 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1252 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1253 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1254 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1255
1256 struct blk_integrity {
1257         integrity_gen_fn        *generate_fn;
1258         integrity_vrfy_fn       *verify_fn;
1259         integrity_set_tag_fn    *set_tag_fn;
1260         integrity_get_tag_fn    *get_tag_fn;
1261
1262         unsigned short          flags;
1263         unsigned short          tuple_size;
1264         unsigned short          sector_size;
1265         unsigned short          tag_size;
1266
1267         const char              *name;
1268
1269         struct kobject          kobj;
1270 };
1271
1272 extern bool blk_integrity_is_initialized(struct gendisk *);
1273 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1274 extern void blk_integrity_unregister(struct gendisk *);
1275 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1276 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1277                                    struct scatterlist *);
1278 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1279 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1280                                   struct request *);
1281 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1282                                    struct bio *);
1283
1284 static inline
1285 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1286 {
1287         return bdev->bd_disk->integrity;
1288 }
1289
1290 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1291 {
1292         return disk->integrity;
1293 }
1294
1295 static inline int blk_integrity_rq(struct request *rq)
1296 {
1297         if (rq->bio == NULL)
1298                 return 0;
1299
1300         return bio_integrity(rq->bio);
1301 }
1302
1303 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1304                                                     unsigned int segs)
1305 {
1306         q->limits.max_integrity_segments = segs;
1307 }
1308
1309 static inline unsigned short
1310 queue_max_integrity_segments(struct request_queue *q)
1311 {
1312         return q->limits.max_integrity_segments;
1313 }
1314
1315 #else /* CONFIG_BLK_DEV_INTEGRITY */
1316
1317 struct bio;
1318 struct block_device;
1319 struct gendisk;
1320 struct blk_integrity;
1321
1322 static inline int blk_integrity_rq(struct request *rq)
1323 {
1324         return 0;
1325 }
1326 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1327                                             struct bio *b)
1328 {
1329         return 0;
1330 }
1331 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1332                                           struct bio *b,
1333                                           struct scatterlist *s)
1334 {
1335         return 0;
1336 }
1337 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1338 {
1339         return 0;
1340 }
1341 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1342 {
1343         return NULL;
1344 }
1345 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1346 {
1347         return 0;
1348 }
1349 static inline int blk_integrity_register(struct gendisk *d,
1350                                          struct blk_integrity *b)
1351 {
1352         return 0;
1353 }
1354 static inline void blk_integrity_unregister(struct gendisk *d)
1355 {
1356 }
1357 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1358                                                     unsigned int segs)
1359 {
1360 }
1361 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1362 {
1363         return 0;
1364 }
1365 static inline int blk_integrity_merge_rq(struct request_queue *rq,
1366                                          struct request *r1,
1367                                          struct request *r2)
1368 {
1369         return 0;
1370 }
1371 static inline int blk_integrity_merge_bio(struct request_queue *rq,
1372                                           struct request *r,
1373                                           struct bio *b)
1374 {
1375         return 0;
1376 }
1377 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1378 {
1379         return 0;
1380 }
1381
1382 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1383
1384 struct block_device_operations {
1385         int (*open) (struct block_device *, fmode_t);
1386         int (*release) (struct gendisk *, fmode_t);
1387         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1388         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1389         int (*direct_access) (struct block_device *, sector_t,
1390                                                 void **, unsigned long *);
1391         unsigned int (*check_events) (struct gendisk *disk,
1392                                       unsigned int clearing);
1393         /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1394         int (*media_changed) (struct gendisk *);
1395         void (*unlock_native_capacity) (struct gendisk *);
1396         int (*revalidate_disk) (struct gendisk *);
1397         int (*getgeo)(struct block_device *, struct hd_geometry *);
1398         /* this callback is with swap_lock and sometimes page table lock held */
1399         void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1400         struct module *owner;
1401 };
1402
1403 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1404                                  unsigned long);
1405 #else /* CONFIG_BLOCK */
1406 /*
1407  * stubs for when the block layer is configured out
1408  */
1409 #define buffer_heads_over_limit 0
1410
1411 static inline long nr_blockdev_pages(void)
1412 {
1413         return 0;
1414 }
1415
1416 struct blk_plug {
1417 };
1418
1419 static inline void blk_start_plug(struct blk_plug *plug)
1420 {
1421 }
1422
1423 static inline void blk_finish_plug(struct blk_plug *plug)
1424 {
1425 }
1426
1427 static inline void blk_flush_plug(struct task_struct *task)
1428 {
1429 }
1430
1431 static inline void blk_schedule_flush_plug(struct task_struct *task)
1432 {
1433 }
1434
1435
1436 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1437 {
1438         return false;
1439 }
1440
1441 #endif /* CONFIG_BLOCK */
1442
1443 #endif