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 #ifdef CONFIG_BLK_CGROUP
  55         struct blkcg_gq         *blkg;  /* blkg this request pool belongs to */
  56 #endif
  57         /*
  58          * count[], starved[], and wait[] are indexed by
  59          * BLK_RW_SYNC/BLK_RW_ASYNC
  60          */
  61         int                     count[2];
  62         int                     starved[2];
  63         mempool_t               *rq_pool;
  64         wait_queue_head_t       wait[2];
  65         unsigned int            flags;
  66 };
  67
  68 /*
  69  * request command types
  70  */
  71 enum rq_cmd_type_bits {
  72         REQ_TYPE_FS             = 1,    /* fs request */
  73         REQ_TYPE_BLOCK_PC,              /* scsi command */
  74         REQ_TYPE_SENSE,                 /* sense request */
  75         REQ_TYPE_PM_SUSPEND,            /* suspend request */
  76         REQ_TYPE_PM_RESUME,             /* resume request */
  77         REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
  78         REQ_TYPE_SPECIAL,               /* driver defined type */
  79         /*
  80          * for ATA/ATAPI devices. this really doesn't belong here, ide should
  81          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  82          * private REQ_LB opcodes to differentiate what type of request this is
  83          */
  84         REQ_TYPE_ATA_TASKFILE,
  85         REQ_TYPE_ATA_PC,
  86 };
  87
  88 #define BLK_MAX_CDB     16
  89
  90 /*
  91  * try to put the fields that are referenced together in the same cacheline.
  92  * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
  93  * as well!
  94  */
  95 struct request {
  96         struct list_head queuelist;
  97         struct call_single_data csd;
  98
  99         struct request_queue *q;
 100
 101         unsigned int cmd_flags;
 102         enum rq_cmd_type_bits cmd_type;
 103         unsigned long atomic_flags;
 104
 105         int cpu;
 106
 107         /* the following two fields are internal, NEVER access directly */
 108         unsigned int __data_len;        /* total data len */
 109         sector_t __sector;              /* sector cursor */
 110
 111         struct bio *bio;
 112         struct bio *biotail;
 113
 114         struct hlist_node hash; /* merge hash */
 115         /*
 116          * The rb_node is only used inside the io scheduler, requests
 117          * are pruned when moved to the dispatch queue. So let the
 118          * completion_data share space with the rb_node.
 119          */
 120         union {
 121                 struct rb_node rb_node; /* sort/lookup */
 122                 void *completion_data;
 123         };
 124
 125         /*
 126          * Three pointers are available for the IO schedulers, if they need
 127          * more they have to dynamically allocate it.  Flush requests are
 128          * never put on the IO scheduler. So let the flush fields share
 129          * space with the elevator data.
 130          */
 131         union {
 132                 struct {
 133                         struct io_cq            *icq;
 134                         void                    *priv[2];
 135                 } elv;
 136
 137                 struct {
 138                         unsigned int            seq;
 139                         struct list_head        list;
 140                         rq_end_io_fn            *saved_end_io;
 141                 } flush;
 142         };
 143
 144         struct gendisk *rq_disk;
 145         struct hd_struct *part;
 146         unsigned long start_time;
 147 #ifdef CONFIG_BLK_CGROUP
 148         struct request_list *rl;                /* rl this rq is alloced from */
 149         unsigned long long start_time_ns;
 150         unsigned long long io_start_time_ns;    /* when passed to hardware */
 151 #endif
 152         /* Number of scatter-gather DMA addr+len pairs after
 153          * physical address coalescing is performed.
 154          */
 155         unsigned short nr_phys_segments;
 156 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 157         unsigned short nr_integrity_segments;
 158 #endif
 159
 160         unsigned short ioprio;
 161
 162         int ref_count;
 163
 164         void *special;          /* opaque pointer available for LLD use */
 165         char *buffer;           /* kaddr of the current segment if available */
 166
 167         int tag;
 168         int errors;
 169
 170         /*
 171          * when request is used as a packet command carrier
 172          */
 173         unsigned char __cmd[BLK_MAX_CDB];
 174         unsigned char *cmd;
 175         unsigned short cmd_len;
 176
 177         unsigned int extra_len; /* length of alignment and padding */
 178         unsigned int sense_len;
 179         unsigned int resid_len; /* residual count */
 180         void *sense;
 181
 182         unsigned long deadline;
 183         struct list_head timeout_list;
 184         unsigned int timeout;
 185         int retries;
 186
 187         /*
 188          * completion callback.
 189          */
 190         rq_end_io_fn *end_io;
 191         void *end_io_data;
 192
 193         /* for bidi */
 194         struct request *next_rq;
 195 };
 196
 197 static inline unsigned short req_get_ioprio(struct request *req)
 198 {
 199         return req->ioprio;
 200 }
 201
 202 /*
 203  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 204  * requests. Some step values could eventually be made generic.
 205  */
 206 struct request_pm_state
 207 {
 208         /* PM state machine step value, currently driver specific */
 209         int     pm_step;
 210         /* requested PM state value (S1, S2, S3, S4, ...) */
 211         u32     pm_state;
 212         void*   data;           /* for driver use */
 213 };
 214
 215 #include <linux/elevator.h>
 216
 217 typedef void (request_fn_proc) (struct request_queue *q);
 218 typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
 219 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 220 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
 221
 222 struct bio_vec;
 223 struct bvec_merge_data {
 224         struct block_device *bi_bdev;
 225         sector_t bi_sector;
 226         unsigned bi_size;
 227         unsigned long bi_rw;
 228 };
 229 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
 230                              struct bio_vec *);
 231 typedef void (softirq_done_fn)(struct request *);
 232 typedef int (dma_drain_needed_fn)(struct request *);
 233 typedef int (lld_busy_fn) (struct request_queue *q);
 234 typedef int (bsg_job_fn) (struct bsg_job *);
 235
 236 enum blk_eh_timer_return {
 237         BLK_EH_NOT_HANDLED,
 238         BLK_EH_HANDLED,
 239         BLK_EH_RESET_TIMER,
 240 };
 241
 242 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
 243
 244 enum blk_queue_state {
 245         Queue_down,
 246         Queue_up,
 247 };
 248
 249 struct blk_queue_tag {
 250         struct request **tag_index;     /* map of busy tags */
 251         unsigned long *tag_map;         /* bit map of free/busy tags */
 252         int busy;                       /* current depth */
 253         int max_depth;                  /* what we will send to device */
 254         int real_max_depth;             /* what the array can hold */
 255         atomic_t refcnt;                /* map can be shared */
 256 };
 257
 258 #define BLK_SCSI_MAX_CMDS       (256)
 259 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 260
 261 struct queue_limits {
 262         unsigned long           bounce_pfn;
 263         unsigned long           seg_boundary_mask;
 264
 265         unsigned int            max_hw_sectors;
 266         unsigned int            max_sectors;
 267         unsigned int            max_segment_size;
 268         unsigned int            physical_block_size;
 269         unsigned int            alignment_offset;
 270         unsigned int            io_min;
 271         unsigned int            io_opt;
 272         unsigned int            max_discard_sectors;
 273         unsigned int            discard_granularity;
 274         unsigned int            discard_alignment;
 275
 276         unsigned short          logical_block_size;
 277         unsigned short          max_segments;
 278         unsigned short          max_integrity_segments;
 279
 280         unsigned char           misaligned;
 281         unsigned char           discard_misaligned;
 282         unsigned char           cluster;
 283         unsigned char           discard_zeroes_data;
 284 };
 285
 286 struct request_queue {
 287         /*
 288          * Together with queue_head for cacheline sharing
 289          */
 290         struct list_head        queue_head;
 291         struct request          *last_merge;
 292         struct elevator_queue   *elevator;
 293         int                     nr_rqs[2];      /* # allocated [a]sync rqs */
 294         int                     nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
 295
 296         /*
 297          * If blkcg is not used, @q->root_rl serves all requests.  If blkcg
 298          * is used, root blkg allocates from @q->root_rl and all other
 299          * blkgs from their own blkg->rl.  Which one to use should be
 300          * determined using bio_request_list().
 301          */
 302         struct request_list     root_rl;
 303
 304         request_fn_proc         *request_fn;
 305         make_request_fn         *make_request_fn;
 306         prep_rq_fn              *prep_rq_fn;
 307         unprep_rq_fn            *unprep_rq_fn;
 308         merge_bvec_fn           *merge_bvec_fn;
 309         softirq_done_fn         *softirq_done_fn;
 310         rq_timed_out_fn         *rq_timed_out_fn;
 311         dma_drain_needed_fn     *dma_drain_needed;
 312         lld_busy_fn             *lld_busy_fn;
 313
 314         /*
 315          * Dispatch queue sorting
 316          */
 317         sector_t                end_sector;
 318         struct request          *boundary_rq;
 319
 320         /*
 321          * Delayed queue handling
 322          */
 323         struct delayed_work     delay_work;
 324
 325         struct backing_dev_info backing_dev_info;
 326
 327         /*
 328          * The queue owner gets to use this for whatever they like.
 329          * ll_rw_blk doesn't touch it.
 330          */
 331         void                    *queuedata;
 332
 333         /*
 334          * various queue flags, see QUEUE_* below
 335          */
 336         unsigned long           queue_flags;
 337
 338         /*
 339          * ida allocated id for this queue.  Used to index queues from
 340          * ioctx.
 341          */
 342         int                     id;
 343
 344         /*
 345          * queue needs bounce pages for pages above this limit
 346          */
 347         gfp_t                   bounce_gfp;
 348
 349         /*
 350          * protects queue structures from reentrancy. ->__queue_lock should
 351          * _never_ be used directly, it is queue private. always use
 352          * ->queue_lock.
 353          */
 354         spinlock_t              __queue_lock;
 355         spinlock_t              *queue_lock;
 356
 357         /*
 358          * queue kobject
 359          */
 360         struct kobject kobj;
 361
 362         /*
 363          * queue settings
 364          */
 365         unsigned long           nr_requests;    /* Max # of requests */
 366         unsigned int            nr_congestion_on;
 367         unsigned int            nr_congestion_off;
 368         unsigned int            nr_batching;
 369
 370         unsigned int            dma_drain_size;
 371         void                    *dma_drain_buffer;
 372         unsigned int            dma_pad_mask;
 373         unsigned int            dma_alignment;
 374
 375         struct blk_queue_tag    *queue_tags;
 376         struct list_head        tag_busy_list;
 377
 378         unsigned int            nr_sorted;
 379         unsigned int            in_flight[2];
 380
 381         unsigned int            rq_timeout;
 382         struct timer_list       timeout;
 383         struct list_head        timeout_list;
 384
 385         struct list_head        icq_list;
 386 #ifdef CONFIG_BLK_CGROUP
 387         DECLARE_BITMAP          (blkcg_pols, BLKCG_MAX_POLS);
 388         struct blkcg_gq         *root_blkg;
 389         struct list_head        blkg_list;
 390 #endif
 391
 392         struct queue_limits     limits;
 393
 394         /*
 395          * sg stuff
 396          */
 397         unsigned int            sg_timeout;
 398         unsigned int            sg_reserved_size;
 399         int                     node;
 400 #ifdef CONFIG_BLK_DEV_IO_TRACE
 401         struct blk_trace        *blk_trace;
 402 #endif
 403         /*
 404          * for flush operations
 405          */
 406         unsigned int            flush_flags;
 407         unsigned int            flush_not_queueable:1;
 408         unsigned int            flush_queue_delayed:1;
 409         unsigned int            flush_pending_idx:1;
 410         unsigned int            flush_running_idx:1;
 411         unsigned long           flush_pending_since;
 412         struct list_head        flush_queue[2];
 413         struct list_head        flush_data_in_flight;
 414         struct request          flush_rq;
 415
 416         struct mutex            sysfs_lock;
 417
 418         int                     bypass_depth;
 419
 420 #if defined(CONFIG_BLK_DEV_BSG)
 421         bsg_job_fn              *bsg_job_fn;
 422         int                     bsg_job_size;
 423         struct bsg_class_device bsg_dev;
 424 #endif
 425
 426 #ifdef CONFIG_BLK_CGROUP
 427         struct list_head        all_q_node;
 428 #endif
 429 #ifdef CONFIG_BLK_DEV_THROTTLING
 430         /* Throttle data */
 431         struct throtl_data *td;
 432 #endif
 433 };
 434
 435 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 436 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 437 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 438 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 439 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 440 #define QUEUE_FLAG_BYPASS       6       /* act as dumb FIFO queue */
 441 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
 442 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
 443 #define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
 444 #define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
 445 #define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
 446 #define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
 447 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 448 #define QUEUE_FLAG_IO_STAT     13       /* do IO stats */
 449 #define QUEUE_FLAG_DISCARD     14       /* supports DISCARD */
 450 #define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
 451 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
 452 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
 453 #define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
 454
 455 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 456                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
 457                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
 458                                  (1 << QUEUE_FLAG_ADD_RANDOM))
 459
 460 static inline void queue_lockdep_assert_held(struct request_queue *q)
 461 {
 462         if (q->queue_lock)
 463                 lockdep_assert_held(q->queue_lock);
 464 }
 465
 466 static inline void queue_flag_set_unlocked(unsigned int flag,
 467                                            struct request_queue *q)
 468 {
 469         __set_bit(flag, &q->queue_flags);
 470 }
 471
 472 static inline int queue_flag_test_and_clear(unsigned int flag,
 473                                             struct request_queue *q)
 474 {
 475         queue_lockdep_assert_held(q);
 476
 477         if (test_bit(flag, &q->queue_flags)) {
 478                 __clear_bit(flag, &q->queue_flags);
 479                 return 1;
 480         }
 481
 482         return 0;
 483 }
 484
 485 static inline int queue_flag_test_and_set(unsigned int flag,
 486                                           struct request_queue *q)
 487 {
 488         queue_lockdep_assert_held(q);
 489
 490         if (!test_bit(flag, &q->queue_flags)) {
 491                 __set_bit(flag, &q->queue_flags);
 492                 return 0;
 493         }
 494
 495         return 1;
 496 }
 497
 498 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 499 {
 500         queue_lockdep_assert_held(q);
 501         __set_bit(flag, &q->queue_flags);
 502 }
 503
 504 static inline void queue_flag_clear_unlocked(unsigned int flag,
 505                                              struct request_queue *q)
 506 {
 507         __clear_bit(flag, &q->queue_flags);
 508 }
 509
 510 static inline int queue_in_flight(struct request_queue *q)
 511 {
 512         return q->in_flight[0] + q->in_flight[1];
 513 }
 514
 515 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 516 {
 517         queue_lockdep_assert_held(q);
 518         __clear_bit(flag, &q->queue_flags);
 519 }
 520
 521 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 522 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 523 #define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 524 #define blk_queue_bypass(q)     test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
 525 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 526 #define blk_queue_noxmerges(q)  \
 527         test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
 528 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 529 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 530 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
 531 #define blk_queue_stackable(q)  \
 532         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 533 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
 534 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
 535         test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
 536
 537 #define blk_noretry_request(rq) \
 538         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
 539                              REQ_FAILFAST_DRIVER))
 540
 541 #define blk_account_rq(rq) \
 542         (((rq)->cmd_flags & REQ_STARTED) && \
 543          ((rq)->cmd_type == REQ_TYPE_FS || \
 544           ((rq)->cmd_flags & REQ_DISCARD)))
 545
 546 #define blk_pm_request(rq)      \
 547         ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
 548          (rq)->cmd_type == REQ_TYPE_PM_RESUME)
 549
 550 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 551 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 552 /* rq->queuelist of dequeued request must be list_empty() */
 553 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 554
 555 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 556
 557 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 558
 559 static inline unsigned int blk_queue_cluster(struct request_queue *q)
 560 {
 561         return q->limits.cluster;
 562 }
 563
 564 /*
 565  * We regard a request as sync, if either a read or a sync write
 566  */
 567 static inline bool rw_is_sync(unsigned int rw_flags)
 568 {
 569         return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
 570 }
 571
 572 static inline bool rq_is_sync(struct request *rq)
 573 {
 574         return rw_is_sync(rq->cmd_flags);
 575 }
 576
 577 static inline bool blk_rl_full(struct request_list *rl, bool sync)
 578 {
 579         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
 580
 581         return rl->flags & flag;
 582 }
 583
 584 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
 585 {
 586         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
 587
 588         rl->flags |= flag;
 589 }
 590
 591 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
 592 {
 593         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
 594
 595         rl->flags &= ~flag;
 596 }
 597
 598
 599 /*
 600  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 601  * it already be started by driver.
 602  */
 603 #define RQ_NOMERGE_FLAGS        \
 604         (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA | REQ_DISCARD)
 605 #define rq_mergeable(rq)        \
 606         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 607          (((rq)->cmd_flags & REQ_DISCARD) || \
 608           (rq)->cmd_type == REQ_TYPE_FS))
 609
 610 /*
 611  * q->prep_rq_fn return values
 612  */
 613 #define BLKPREP_OK              0       /* serve it */
 614 #define BLKPREP_KILL            1       /* fatal error, kill */
 615 #define BLKPREP_DEFER           2       /* leave on queue */
 616
 617 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 618
 619 /*
 620  * standard bounce addresses:
 621  *
 622  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 623  * BLK_BOUNCE_ANY       : don't bounce anything
 624  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 625  */
 626
 627 #if BITS_PER_LONG == 32
 628 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 629 #else
 630 #define BLK_BOUNCE_HIGH         -1ULL
 631 #endif
 632 #define BLK_BOUNCE_ANY          (-1ULL)
 633 #define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
 634
 635 /*
 636  * default timeout for SG_IO if none specified
 637  */
 638 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 639 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 640
 641 #ifdef CONFIG_BOUNCE
 642 extern int init_emergency_isa_pool(void);
 643 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 644 #else
 645 static inline int init_emergency_isa_pool(void)
 646 {
 647         return 0;
 648 }
 649 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 650 {
 651 }
 652 #endif /* CONFIG_MMU */
 653
 654 struct rq_map_data {
 655         struct page **pages;
 656         int page_order;
 657         int nr_entries;
 658         unsigned long offset;
 659         int null_mapped;
 660         int from_user;
 661 };
 662
 663 struct req_iterator {
 664         int i;
 665         struct bio *bio;
 666 };
 667
 668 /* This should not be used directly - use rq_for_each_segment */
 669 #define for_each_bio(_bio)              \
 670         for (; _bio; _bio = _bio->bi_next)
 671 #define __rq_for_each_bio(_bio, rq)     \
 672         if ((rq->bio))                  \
 673                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 674
 675 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 676         __rq_for_each_bio(_iter.bio, _rq)                       \
 677                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 678
 679 #define rq_iter_last(rq, _iter)                                 \
 680                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 681
 682 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 683 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 684 #endif
 685 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 686 extern void rq_flush_dcache_pages(struct request *rq);
 687 #else
 688 static inline void rq_flush_dcache_pages(struct request *rq)
 689 {
 690 }
 691 #endif
 692
 693 extern int blk_register_queue(struct gendisk *disk);
 694 extern void blk_unregister_queue(struct gendisk *disk);
 695 extern void generic_make_request(struct bio *bio);
 696 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 697 extern void blk_put_request(struct request *);
 698 extern void __blk_put_request(struct request_queue *, struct request *);
 699 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 700 extern struct request *blk_make_request(struct request_queue *, struct bio *,
 701                                         gfp_t);
 702 extern void blk_requeue_request(struct request_queue *, struct request *);
 703 extern void blk_add_request_payload(struct request *rq, struct page *page,
 704                 unsigned int len);
 705 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 706 extern int blk_lld_busy(struct request_queue *q);
 707 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 708                              struct bio_set *bs, gfp_t gfp_mask,
 709                              int (*bio_ctr)(struct bio *, struct bio *, void *),
 710                              void *data);
 711 extern void blk_rq_unprep_clone(struct request *rq);
 712 extern int blk_insert_cloned_request(struct request_queue *q,
 713                                      struct request *rq);
 714 extern void blk_delay_queue(struct request_queue *, unsigned long);
 715 extern void blk_recount_segments(struct request_queue *, struct bio *);
 716 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
 717 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
 718                               unsigned int, void __user *);
 719 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 720                           unsigned int, void __user *);
 721 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 722                          struct scsi_ioctl_command __user *);
 723
 724 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
 725
 726 /*
 727  * A queue has just exitted congestion.  Note this in the global counter of
 728  * congested queues, and wake up anyone who was waiting for requests to be
 729  * put back.
 730  */
 731 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 732 {
 733         clear_bdi_congested(&q->backing_dev_info, sync);
 734 }
 735
 736 /*
 737  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 738  * state flags and increment the global gounter of congested queues.
 739  */
 740 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 741 {
 742         set_bdi_congested(&q->backing_dev_info, sync);
 743 }
 744
 745 extern void blk_start_queue(struct request_queue *q);
 746 extern void blk_stop_queue(struct request_queue *q);
 747 extern void blk_sync_queue(struct request_queue *q);
 748 extern void __blk_stop_queue(struct request_queue *q);
 749 extern void __blk_run_queue(struct request_queue *q);
 750 extern void blk_run_queue(struct request_queue *);
 751 extern void blk_run_queue_async(struct request_queue *q);
 752 extern int blk_rq_map_user(struct request_queue *, struct request *,
 753                            struct rq_map_data *, void __user *, unsigned long,
 754                            gfp_t);
 755 extern int blk_rq_unmap_user(struct bio *);
 756 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 757 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 758                                struct rq_map_data *, struct sg_iovec *, int,
 759                                unsigned int, gfp_t);
 760 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 761                           struct request *, int);
 762 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 763                                   struct request *, int, rq_end_io_fn *);
 764
 765 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 766 {
 767         return bdev->bd_disk->queue;
 768 }
 769
 770 /*
 771  * blk_rq_pos()                 : the current sector
 772  * blk_rq_bytes()               : bytes left in the entire request
 773  * blk_rq_cur_bytes()           : bytes left in the current segment
 774  * blk_rq_err_bytes()           : bytes left till the next error boundary
 775  * blk_rq_sectors()             : sectors left in the entire request
 776  * blk_rq_cur_sectors()         : sectors left in the current segment
 777  */
 778 static inline sector_t blk_rq_pos(const struct request *rq)
 779 {
 780         return rq->__sector;
 781 }
 782
 783 static inline unsigned int blk_rq_bytes(const struct request *rq)
 784 {
 785         return rq->__data_len;
 786 }
 787
 788 static inline int blk_rq_cur_bytes(const struct request *rq)
 789 {
 790         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 791 }
 792
 793 extern unsigned int blk_rq_err_bytes(const struct request *rq);
 794
 795 static inline unsigned int blk_rq_sectors(const struct request *rq)
 796 {
 797         return blk_rq_bytes(rq) >> 9;
 798 }
 799
 800 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 801 {
 802         return blk_rq_cur_bytes(rq) >> 9;
 803 }
 804
 805 /*
 806  * Request issue related functions.
 807  */
 808 extern struct request *blk_peek_request(struct request_queue *q);
 809 extern void blk_start_request(struct request *rq);
 810 extern struct request *blk_fetch_request(struct request_queue *q);
 811
 812 /*
 813  * Request completion related functions.
 814  *
 815  * blk_update_request() completes given number of bytes and updates
 816  * the request without completing it.
 817  *
 818  * blk_end_request() and friends.  __blk_end_request() must be called
 819  * with the request queue spinlock acquired.
 820  *
 821  * Several drivers define their own end_request and call
 822  * blk_end_request() for parts of the original function.
 823  * This prevents code duplication in drivers.
 824  */
 825 extern bool blk_update_request(struct request *rq, int error,
 826                                unsigned int nr_bytes);
 827 extern bool blk_end_request(struct request *rq, int error,
 828                             unsigned int nr_bytes);
 829 extern void blk_end_request_all(struct request *rq, int error);
 830 extern bool blk_end_request_cur(struct request *rq, int error);
 831 extern bool blk_end_request_err(struct request *rq, int error);
 832 extern bool __blk_end_request(struct request *rq, int error,
 833                               unsigned int nr_bytes);
 834 extern void __blk_end_request_all(struct request *rq, int error);
 835 extern bool __blk_end_request_cur(struct request *rq, int error);
 836 extern bool __blk_end_request_err(struct request *rq, int error);
 837
 838 extern void blk_complete_request(struct request *);
 839 extern void __blk_complete_request(struct request *);
 840 extern void blk_abort_request(struct request *);
 841 extern void blk_unprep_request(struct request *);
 842
 843 /*
 844  * Access functions for manipulating queue properties
 845  */
 846 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 847                                         spinlock_t *lock, int node_id);
 848 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 849 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
 850                                                       request_fn_proc *, spinlock_t *);
 851 extern void blk_cleanup_queue(struct request_queue *);
 852 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 853 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 854 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
 855 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 856 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
 857 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 858 extern void blk_queue_max_discard_sectors(struct request_queue *q,
 859                 unsigned int max_discard_sectors);
 860 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 861 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
 862 extern void blk_queue_alignment_offset(struct request_queue *q,
 863                                        unsigned int alignment);
 864 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 865 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 866 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 867 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 868 extern void blk_set_default_limits(struct queue_limits *lim);
 869 extern void blk_set_stacking_limits(struct queue_limits *lim);
 870 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 871                             sector_t offset);
 872 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
 873                             sector_t offset);
 874 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 875                               sector_t offset);
 876 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 877 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 878 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 879 extern int blk_queue_dma_drain(struct request_queue *q,
 880                                dma_drain_needed_fn *dma_drain_needed,
 881                                void *buf, unsigned int size);
 882 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 883 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 884 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 885 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
 886 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 887 extern void blk_queue_dma_alignment(struct request_queue *, int);
 888 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 889 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 890 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 891 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 892 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
 893 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
 894 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 895
 896 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 897 extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
 898                           struct scatterlist *sglist);
 899 extern void blk_dump_rq_flags(struct request *, char *);
 900 extern long nr_blockdev_pages(void);
 901
 902 bool __must_check blk_get_queue(struct request_queue *);
 903 struct request_queue *blk_alloc_queue(gfp_t);
 904 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 905 extern void blk_put_queue(struct request_queue *);
 906
 907 /*
 908  * blk_plug permits building a queue of related requests by holding the I/O
 909  * fragments for a short period. This allows merging of sequential requests
 910  * into single larger request. As the requests are moved from a per-task list to
 911  * the device's request_queue in a batch, this results in improved scalability
 912  * as the lock contention for request_queue lock is reduced.
 913  *
 914  * It is ok not to disable preemption when adding the request to the plug list
 915  * or when attempting a merge, because blk_schedule_flush_list() will only flush
 916  * the plug list when the task sleeps by itself. For details, please see
 917  * schedule() where blk_schedule_flush_plug() is called.
 918  */
 919 struct blk_plug {
 920         unsigned long magic; /* detect uninitialized use-cases */
 921         struct list_head list; /* requests */
 922         struct list_head cb_list; /* md requires an unplug callback */
 923         unsigned int should_sort; /* list to be sorted before flushing? */
 924 };
 925 #define BLK_MAX_REQUEST_COUNT 16
 926
 927 struct blk_plug_cb;
 928 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
 929 struct blk_plug_cb {
 930         struct list_head list;
 931         blk_plug_cb_fn callback;
 932         void *data;
 933 };
 934 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
 935                                              void *data, int size);
 936 extern void blk_start_plug(struct blk_plug *);
 937 extern void blk_finish_plug(struct blk_plug *);
 938 extern void blk_flush_plug_list(struct blk_plug *, bool);
 939
 940 static inline void blk_flush_plug(struct task_struct *tsk)
 941 {
 942         struct blk_plug *plug = tsk->plug;
 943
 944         if (plug)
 945                 blk_flush_plug_list(plug, false);
 946 }
 947
 948 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
 949 {
 950         struct blk_plug *plug = tsk->plug;
 951
 952         if (plug)
 953                 blk_flush_plug_list(plug, true);
 954 }
 955
 956 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
 957 {
 958         struct blk_plug *plug = tsk->plug;
 959
 960         return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
 961 }
 962
 963 /*
 964  * tag stuff
 965  */
 966 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 967 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 968 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 969 extern void blk_queue_end_tag(struct request_queue *, struct request *);
 970 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 971 extern void blk_queue_free_tags(struct request_queue *);
 972 extern int blk_queue_resize_tags(struct request_queue *, int);
 973 extern void blk_queue_invalidate_tags(struct request_queue *);
 974 extern struct blk_queue_tag *blk_init_tags(int);
 975 extern void blk_free_tags(struct blk_queue_tag *);
 976
 977 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 978                                                 int tag)
 979 {
 980         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 981                 return NULL;
 982         return bqt->tag_index[tag];
 983 }
 984
 985 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
 986
 987 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
 988 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 989                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
 990 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 991                         sector_t nr_sects, gfp_t gfp_mask);
 992 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
 993                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
 994 {
 995         return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
 996                                     nr_blocks << (sb->s_blocksize_bits - 9),
 997                                     gfp_mask, flags);
 998 }
 999 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1000                 sector_t nr_blocks, gfp_t gfp_mask)
1001 {
1002         return blkdev_issue_zeroout(sb->s_bdev,
1003                                     block << (sb->s_blocksize_bits - 9),
1004                                     nr_blocks << (sb->s_blocksize_bits - 9),
1005                                     gfp_mask);
1006 }
1007
1008 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1009
1010 enum blk_default_limits {
1011         BLK_MAX_SEGMENTS        = 128,
1012         BLK_SAFE_MAX_SECTORS    = 255,
1013         BLK_DEF_MAX_SECTORS     = 1024,
1014         BLK_MAX_SEGMENT_SIZE    = 65536,
1015         BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
1016 };
1017
1018 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1019
1020 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1021 {
1022         return q->limits.bounce_pfn;
1023 }
1024
1025 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1026 {
1027         return q->limits.seg_boundary_mask;
1028 }
1029
1030 static inline unsigned int queue_max_sectors(struct request_queue *q)
1031 {
1032         return q->limits.max_sectors;
1033 }
1034
1035 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1036 {
1037         return q->limits.max_hw_sectors;
1038 }
1039
1040 static inline unsigned short queue_max_segments(struct request_queue *q)
1041 {
1042         return q->limits.max_segments;
1043 }
1044
1045 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1046 {
1047         return q->limits.max_segment_size;
1048 }
1049
1050 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1051 {
1052         int retval = 512;
1053
1054         if (q && q->limits.logical_block_size)
1055                 retval = q->limits.logical_block_size;
1056
1057         return retval;
1058 }
1059
1060 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1061 {
1062         return queue_logical_block_size(bdev_get_queue(bdev));
1063 }
1064
1065 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1066 {
1067         return q->limits.physical_block_size;
1068 }
1069
1070 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1071 {
1072         return queue_physical_block_size(bdev_get_queue(bdev));
1073 }
1074
1075 static inline unsigned int queue_io_min(struct request_queue *q)
1076 {
1077         return q->limits.io_min;
1078 }
1079
1080 static inline int bdev_io_min(struct block_device *bdev)
1081 {
1082         return queue_io_min(bdev_get_queue(bdev));
1083 }
1084
1085 static inline unsigned int queue_io_opt(struct request_queue *q)
1086 {
1087         return q->limits.io_opt;
1088 }
1089
1090 static inline int bdev_io_opt(struct block_device *bdev)
1091 {
1092         return queue_io_opt(bdev_get_queue(bdev));
1093 }
1094
1095 static inline int queue_alignment_offset(struct request_queue *q)
1096 {
1097         if (q->limits.misaligned)
1098                 return -1;
1099
1100         return q->limits.alignment_offset;
1101 }
1102
1103 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1104 {
1105         unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1106         unsigned int alignment = (sector << 9) & (granularity - 1);
1107
1108         return (granularity + lim->alignment_offset - alignment)
1109                 & (granularity - 1);
1110 }
1111
1112 static inline int bdev_alignment_offset(struct block_device *bdev)
1113 {
1114         struct request_queue *q = bdev_get_queue(bdev);
1115
1116         if (q->limits.misaligned)
1117                 return -1;
1118
1119         if (bdev != bdev->bd_contains)
1120                 return bdev->bd_part->alignment_offset;
1121
1122         return q->limits.alignment_offset;
1123 }
1124
1125 static inline int queue_discard_alignment(struct request_queue *q)
1126 {
1127         if (q->limits.discard_misaligned)
1128                 return -1;
1129
1130         return q->limits.discard_alignment;
1131 }
1132
1133 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1134 {
1135         unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1136
1137         if (!lim->max_discard_sectors)
1138                 return 0;
1139
1140         return (lim->discard_granularity + lim->discard_alignment - alignment)
1141                 & (lim->discard_granularity - 1);
1142 }
1143
1144 static inline int bdev_discard_alignment(struct block_device *bdev)
1145 {
1146         struct request_queue *q = bdev_get_queue(bdev);
1147
1148         if (bdev != bdev->bd_contains)
1149                 return bdev->bd_part->discard_alignment;
1150
1151         return q->limits.discard_alignment;
1152 }
1153
1154 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1155 {
1156         if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1157                 return 1;
1158
1159         return 0;
1160 }
1161
1162 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1163 {
1164         return queue_discard_zeroes_data(bdev_get_queue(bdev));
1165 }
1166
1167 static inline int queue_dma_alignment(struct request_queue *q)
1168 {
1169         return q ? q->dma_alignment : 511;
1170 }
1171
1172 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1173                                  unsigned int len)
1174 {
1175         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1176         return !(addr & alignment) && !(len & alignment);
1177 }
1178
1179 /* assumes size > 256 */
1180 static inline unsigned int blksize_bits(unsigned int size)
1181 {
1182         unsigned int bits = 8;
1183         do {
1184                 bits++;
1185                 size >>= 1;
1186         } while (size > 256);
1187         return bits;
1188 }
1189
1190 static inline unsigned int block_size(struct block_device *bdev)
1191 {
1192         return bdev->bd_block_size;
1193 }
1194
1195 static inline bool queue_flush_queueable(struct request_queue *q)
1196 {
1197         return !q->flush_not_queueable;
1198 }
1199
1200 typedef struct {struct page *v;} Sector;
1201
1202 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1203
1204 static inline void put_dev_sector(Sector p)
1205 {
1206         page_cache_release(p.v);
1207 }
1208
1209 struct work_struct;
1210 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1211
1212 #ifdef CONFIG_BLK_CGROUP
1213 /*
1214  * This should not be using sched_clock(). A real patch is in progress
1215  * to fix this up, until that is in place we need to disable preemption
1216  * around sched_clock() in this function and set_io_start_time_ns().
1217  */
1218 static inline void set_start_time_ns(struct request *req)
1219 {
1220         preempt_disable();
1221         req->start_time_ns = sched_clock();
1222         preempt_enable();
1223 }
1224
1225 static inline void set_io_start_time_ns(struct request *req)
1226 {
1227         preempt_disable();
1228         req->io_start_time_ns = sched_clock();
1229         preempt_enable();
1230 }
1231
1232 static inline uint64_t rq_start_time_ns(struct request *req)
1233 {
1234         return req->start_time_ns;
1235 }
1236
1237 static inline uint64_t rq_io_start_time_ns(struct request *req)
1238 {
1239         return req->io_start_time_ns;
1240 }
1241 #else
1242 static inline void set_start_time_ns(struct request *req) {}
1243 static inline void set_io_start_time_ns(struct request *req) {}
1244 static inline uint64_t rq_start_time_ns(struct request *req)
1245 {
1246         return 0;
1247 }
1248 static inline uint64_t rq_io_start_time_ns(struct request *req)
1249 {
1250         return 0;
1251 }
1252 #endif
1253
1254 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1255         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1256 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1257         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1258
1259 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1260
1261 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1262 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1263
1264 struct blk_integrity_exchg {
1265         void                    *prot_buf;
1266         void                    *data_buf;
1267         sector_t                sector;
1268         unsigned int            data_size;
1269         unsigned short          sector_size;
1270         const char              *disk_name;
1271 };
1272
1273 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1274 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1275 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1276 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1277
1278 struct blk_integrity {
1279         integrity_gen_fn        *generate_fn;
1280         integrity_vrfy_fn       *verify_fn;
1281         integrity_set_tag_fn    *set_tag_fn;
1282         integrity_get_tag_fn    *get_tag_fn;
1283
1284         unsigned short          flags;
1285         unsigned short          tuple_size;
1286         unsigned short          sector_size;
1287         unsigned short          tag_size;
1288
1289         const char              *name;
1290
1291         struct kobject          kobj;
1292 };
1293
1294 extern bool blk_integrity_is_initialized(struct gendisk *);
1295 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1296 extern void blk_integrity_unregister(struct gendisk *);
1297 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1298 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1299                                    struct scatterlist *);
1300 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1301 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1302                                   struct request *);
1303 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1304                                    struct bio *);
1305
1306 static inline
1307 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1308 {
1309         return bdev->bd_disk->integrity;
1310 }
1311
1312 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1313 {
1314         return disk->integrity;
1315 }
1316
1317 static inline int blk_integrity_rq(struct request *rq)
1318 {
1319         if (rq->bio == NULL)
1320                 return 0;
1321
1322         return bio_integrity(rq->bio);
1323 }
1324
1325 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1326                                                     unsigned int segs)
1327 {
1328         q->limits.max_integrity_segments = segs;
1329 }
1330
1331 static inline unsigned short
1332 queue_max_integrity_segments(struct request_queue *q)
1333 {
1334         return q->limits.max_integrity_segments;
1335 }
1336
1337 #else /* CONFIG_BLK_DEV_INTEGRITY */
1338
1339 struct bio;
1340 struct block_device;
1341 struct gendisk;
1342 struct blk_integrity;
1343
1344 static inline int blk_integrity_rq(struct request *rq)
1345 {
1346         return 0;
1347 }
1348 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1349                                             struct bio *b)
1350 {
1351         return 0;
1352 }
1353 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1354                                           struct bio *b,
1355                                           struct scatterlist *s)
1356 {
1357         return 0;
1358 }
1359 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1360 {
1361         return 0;
1362 }
1363 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1364 {
1365         return NULL;
1366 }
1367 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1368 {
1369         return 0;
1370 }
1371 static inline int blk_integrity_register(struct gendisk *d,
1372                                          struct blk_integrity *b)
1373 {
1374         return 0;
1375 }
1376 static inline void blk_integrity_unregister(struct gendisk *d)
1377 {
1378 }
1379 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1380                                                     unsigned int segs)
1381 {
1382 }
1383 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1384 {
1385         return 0;
1386 }
1387 static inline int blk_integrity_merge_rq(struct request_queue *rq,
1388                                          struct request *r1,
1389                                          struct request *r2)
1390 {
1391         return 0;
1392 }
1393 static inline int blk_integrity_merge_bio(struct request_queue *rq,
1394                                           struct request *r,
1395                                           struct bio *b)
1396 {
1397         return 0;
1398 }
1399 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1400 {
1401         return 0;
1402 }
1403
1404 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1405
1406 struct block_device_operations {
1407         int (*open) (struct block_device *, fmode_t);
1408         int (*release) (struct gendisk *, fmode_t);
1409         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1410         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1411         int (*direct_access) (struct block_device *, sector_t,
1412                                                 void **, unsigned long *);
1413         unsigned int (*check_events) (struct gendisk *disk,
1414                                       unsigned int clearing);
1415         /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1416         int (*media_changed) (struct gendisk *);
1417         void (*unlock_native_capacity) (struct gendisk *);
1418         int (*revalidate_disk) (struct gendisk *);
1419         int (*getgeo)(struct block_device *, struct hd_geometry *);
1420         /* this callback is with swap_lock and sometimes page table lock held */
1421         void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1422         struct module *owner;
1423 };
1424
1425 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1426                                  unsigned long);
1427 #else /* CONFIG_BLOCK */
1428 /*
1429  * stubs for when the block layer is configured out
1430  */
1431 #define buffer_heads_over_limit 0
1432
1433 static inline long nr_blockdev_pages(void)
1434 {
1435         return 0;
1436 }
1437
1438 struct blk_plug {
1439 };
1440
1441 static inline void blk_start_plug(struct blk_plug *plug)
1442 {
1443 }
1444
1445 static inline void blk_finish_plug(struct blk_plug *plug)
1446 {
1447 }
1448
1449 static inline void blk_flush_plug(struct task_struct *task)
1450 {
1451 }
1452
1453 static inline void blk_schedule_flush_plug(struct task_struct *task)
1454 {
1455 }
1456
1457
1458 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1459 {
1460         return false;
1461 }
1462
1463 #endif /* CONFIG_BLOCK */
1464
1465 #endif