include/linux/blkdev.h

   1 #ifndef _LINUX_BLKDEV_H
   2 #define _LINUX_BLKDEV_H
   3
   4 #ifdef CONFIG_BLOCK
   5
   6 #include <linux/sched.h>
   7 #include <linux/major.h>
   8 #include <linux/genhd.h>
   9 #include <linux/list.h>
  10 #include <linux/timer.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/backing-dev.h>
  14 #include <linux/wait.h>
  15 #include <linux/mempool.h>
  16 #include <linux/bio.h>
  17 #include <linux/module.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 scsi_ioctl_command;
  26
  27 struct request_queue;
  28 struct elevator_queue;
  29 struct request_pm_state;
  30 struct blk_trace;
  31 struct request;
  32 struct sg_io_hdr;
  33
  34 #define BLKDEV_MIN_RQ   4
  35 #define BLKDEV_MAX_RQ   128     /* Default maximum */
  36
  37 struct request;
  38 typedef void (rq_end_io_fn)(struct request *, int);
  39
  40 struct request_list {
  41         /*
  42          * count[], starved[], and wait[] are indexed by
  43          * BLK_RW_SYNC/BLK_RW_ASYNC
  44          */
  45         int count[2];
  46         int starved[2];
  47         int elvpriv;
  48         mempool_t *rq_pool;
  49         wait_queue_head_t wait[2];
  50 };
  51
  52 /*
  53  * request command types
  54  */
  55 enum rq_cmd_type_bits {
  56         REQ_TYPE_FS             = 1,    /* fs request */
  57         REQ_TYPE_BLOCK_PC,              /* scsi command */
  58         REQ_TYPE_SENSE,                 /* sense request */
  59         REQ_TYPE_PM_SUSPEND,            /* suspend request */
  60         REQ_TYPE_PM_RESUME,             /* resume request */
  61         REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
  62         REQ_TYPE_SPECIAL,               /* driver defined type */
  63         REQ_TYPE_LINUX_BLOCK,           /* generic block layer message */
  64         /*
  65          * for ATA/ATAPI devices. this really doesn't belong here, ide should
  66          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  67          * private REQ_LB opcodes to differentiate what type of request this is
  68          */
  69         REQ_TYPE_ATA_TASKFILE,
  70         REQ_TYPE_ATA_PC,
  71 };
  72
  73 /*
  74  * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
  75  * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
  76  * SCSI cdb.
  77  *
  78  * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
  79  * typically to differentiate REQ_TYPE_SPECIAL requests.
  80  *
  81  */
  82 enum {
  83         REQ_LB_OP_EJECT = 0x40,         /* eject request */
  84         REQ_LB_OP_FLUSH = 0x41,         /* flush request */
  85         REQ_LB_OP_DISCARD = 0x42,       /* discard sectors */
  86 };
  87
  88 /*
  89  * request type modified bits. first four bits match BIO_RW* bits, important
  90  */
  91 enum rq_flag_bits {
  92         __REQ_RW,               /* not set, read. set, write */
  93         __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
  94         __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
  95         __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
  96         /* above flags must match BIO_RW_* */
  97         __REQ_DISCARD,          /* request to discard sectors */
  98         __REQ_SORTED,           /* elevator knows about this request */
  99         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 100         __REQ_HARDBARRIER,      /* may not be passed by drive either */
 101         __REQ_FUA,              /* forced unit access */
 102         __REQ_NOMERGE,          /* don't touch this for merging */
 103         __REQ_STARTED,          /* drive already may have started this one */
 104         __REQ_DONTPREP,         /* don't call prep for this one */
 105         __REQ_QUEUED,           /* uses queueing */
 106         __REQ_ELVPRIV,          /* elevator private data attached */
 107         __REQ_FAILED,           /* set if the request failed */
 108         __REQ_QUIET,            /* don't worry about errors */
 109         __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 110         __REQ_ORDERED_COLOR,    /* is before or after barrier */
 111         __REQ_RW_SYNC,          /* request is sync (sync write or read) */
 112         __REQ_ALLOCED,          /* request came from our alloc pool */
 113         __REQ_RW_META,          /* metadata io request */
 114         __REQ_COPY_USER,        /* contains copies of user pages */
 115         __REQ_INTEGRITY,        /* integrity metadata has been remapped */
 116         __REQ_NOIDLE,           /* Don't anticipate more IO after this one */
 117         __REQ_IO_STAT,          /* account I/O stat */
 118         __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
 119         __REQ_NR_BITS,          /* stops here */
 120 };
 121
 122 #define REQ_RW          (1 << __REQ_RW)
 123 #define REQ_FAILFAST_DEV        (1 << __REQ_FAILFAST_DEV)
 124 #define REQ_FAILFAST_TRANSPORT  (1 << __REQ_FAILFAST_TRANSPORT)
 125 #define REQ_FAILFAST_DRIVER     (1 << __REQ_FAILFAST_DRIVER)
 126 #define REQ_DISCARD     (1 << __REQ_DISCARD)
 127 #define REQ_SORTED      (1 << __REQ_SORTED)
 128 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
 129 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
 130 #define REQ_FUA         (1 << __REQ_FUA)
 131 #define REQ_NOMERGE     (1 << __REQ_NOMERGE)
 132 #define REQ_STARTED     (1 << __REQ_STARTED)
 133 #define REQ_DONTPREP    (1 << __REQ_DONTPREP)
 134 #define REQ_QUEUED      (1 << __REQ_QUEUED)
 135 #define REQ_ELVPRIV     (1 << __REQ_ELVPRIV)
 136 #define REQ_FAILED      (1 << __REQ_FAILED)
 137 #define REQ_QUIET       (1 << __REQ_QUIET)
 138 #define REQ_PREEMPT     (1 << __REQ_PREEMPT)
 139 #define REQ_ORDERED_COLOR       (1 << __REQ_ORDERED_COLOR)
 140 #define REQ_RW_SYNC     (1 << __REQ_RW_SYNC)
 141 #define REQ_ALLOCED     (1 << __REQ_ALLOCED)
 142 #define REQ_RW_META     (1 << __REQ_RW_META)
 143 #define REQ_COPY_USER   (1 << __REQ_COPY_USER)
 144 #define REQ_INTEGRITY   (1 << __REQ_INTEGRITY)
 145 #define REQ_NOIDLE      (1 << __REQ_NOIDLE)
 146 #define REQ_IO_STAT     (1 << __REQ_IO_STAT)
 147 #define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE)
 148
 149 #define REQ_FAILFAST_MASK       (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | \
 150                                  REQ_FAILFAST_DRIVER)
 151
 152 #define BLK_MAX_CDB     16
 153
 154 /*
 155  * try to put the fields that are referenced together in the same cacheline.
 156  * if you modify this structure, be sure to check block/blk-core.c:rq_init()
 157  * as well!
 158  */
 159 struct request {
 160         struct list_head queuelist;
 161         struct call_single_data csd;
 162         int cpu;
 163
 164         struct request_queue *q;
 165
 166         unsigned int cmd_flags;
 167         enum rq_cmd_type_bits cmd_type;
 168         unsigned long atomic_flags;
 169
 170         /* the following two fields are internal, NEVER access directly */
 171         sector_t __sector;              /* sector cursor */
 172         unsigned int __data_len;        /* total data len */
 173
 174         struct bio *bio;
 175         struct bio *biotail;
 176
 177         struct hlist_node hash; /* merge hash */
 178         /*
 179          * The rb_node is only used inside the io scheduler, requests
 180          * are pruned when moved to the dispatch queue. So let the
 181          * completion_data share space with the rb_node.
 182          */
 183         union {
 184                 struct rb_node rb_node; /* sort/lookup */
 185                 void *completion_data;
 186         };
 187
 188         /*
 189          * two pointers are available for the IO schedulers, if they need
 190          * more they have to dynamically allocate it.
 191          */
 192         void *elevator_private;
 193         void *elevator_private2;
 194
 195         struct gendisk *rq_disk;
 196         unsigned long start_time;
 197
 198         /* Number of scatter-gather DMA addr+len pairs after
 199          * physical address coalescing is performed.
 200          */
 201         unsigned short nr_phys_segments;
 202
 203         unsigned short ioprio;
 204
 205         void *special;          /* opaque pointer available for LLD use */
 206         char *buffer;           /* kaddr of the current segment if available */
 207
 208         int tag;
 209         int errors;
 210
 211         int ref_count;
 212
 213         /*
 214          * when request is used as a packet command carrier
 215          */
 216         unsigned short cmd_len;
 217         unsigned char __cmd[BLK_MAX_CDB];
 218         unsigned char *cmd;
 219
 220         unsigned int extra_len; /* length of alignment and padding */
 221         unsigned int sense_len;
 222         unsigned int resid_len; /* residual count */
 223         void *sense;
 224
 225         unsigned long deadline;
 226         struct list_head timeout_list;
 227         unsigned int timeout;
 228         int retries;
 229
 230         /*
 231          * completion callback.
 232          */
 233         rq_end_io_fn *end_io;
 234         void *end_io_data;
 235
 236         /* for bidi */
 237         struct request *next_rq;
 238 };
 239
 240 static inline unsigned short req_get_ioprio(struct request *req)
 241 {
 242         return req->ioprio;
 243 }
 244
 245 /*
 246  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 247  * requests. Some step values could eventually be made generic.
 248  */
 249 struct request_pm_state
 250 {
 251         /* PM state machine step value, currently driver specific */
 252         int     pm_step;
 253         /* requested PM state value (S1, S2, S3, S4, ...) */
 254         u32     pm_state;
 255         void*   data;           /* for driver use */
 256 };
 257
 258 #include <linux/elevator.h>
 259
 260 typedef void (request_fn_proc) (struct request_queue *q);
 261 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
 262 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 263 typedef void (unplug_fn) (struct request_queue *);
 264 typedef int (prepare_discard_fn) (struct request_queue *, struct request *);
 265
 266 struct bio_vec;
 267 struct bvec_merge_data {
 268         struct block_device *bi_bdev;
 269         sector_t bi_sector;
 270         unsigned bi_size;
 271         unsigned long bi_rw;
 272 };
 273 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
 274                              struct bio_vec *);
 275 typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
 276 typedef void (softirq_done_fn)(struct request *);
 277 typedef int (dma_drain_needed_fn)(struct request *);
 278 typedef int (lld_busy_fn) (struct request_queue *q);
 279
 280 enum blk_eh_timer_return {
 281         BLK_EH_NOT_HANDLED,
 282         BLK_EH_HANDLED,
 283         BLK_EH_RESET_TIMER,
 284 };
 285
 286 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
 287
 288 enum blk_queue_state {
 289         Queue_down,
 290         Queue_up,
 291 };
 292
 293 struct blk_queue_tag {
 294         struct request **tag_index;     /* map of busy tags */
 295         unsigned long *tag_map;         /* bit map of free/busy tags */
 296         int busy;                       /* current depth */
 297         int max_depth;                  /* what we will send to device */
 298         int real_max_depth;             /* what the array can hold */
 299         atomic_t refcnt;                /* map can be shared */
 300 };
 301
 302 #define BLK_SCSI_MAX_CMDS       (256)
 303 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 304
 305 struct queue_limits {
 306         unsigned long           bounce_pfn;
 307         unsigned long           seg_boundary_mask;
 308
 309         unsigned int            max_hw_sectors;
 310         unsigned int            max_sectors;
 311         unsigned int            max_segment_size;
 312         unsigned int            physical_block_size;
 313         unsigned int            alignment_offset;
 314         unsigned int            io_min;
 315         unsigned int            io_opt;
 316
 317         unsigned short          logical_block_size;
 318         unsigned short          max_hw_segments;
 319         unsigned short          max_phys_segments;
 320
 321         unsigned char           misaligned;
 322         unsigned char           no_cluster;
 323 };
 324
 325 struct request_queue
 326 {
 327         /*
 328          * Together with queue_head for cacheline sharing
 329          */
 330         struct list_head        queue_head;
 331         struct request          *last_merge;
 332         struct elevator_queue   *elevator;
 333
 334         /*
 335          * the queue request freelist, one for reads and one for writes
 336          */
 337         struct request_list     rq;
 338
 339         request_fn_proc         *request_fn;
 340         make_request_fn         *make_request_fn;
 341         prep_rq_fn              *prep_rq_fn;
 342         unplug_fn               *unplug_fn;
 343         prepare_discard_fn      *prepare_discard_fn;
 344         merge_bvec_fn           *merge_bvec_fn;
 345         prepare_flush_fn        *prepare_flush_fn;
 346         softirq_done_fn         *softirq_done_fn;
 347         rq_timed_out_fn         *rq_timed_out_fn;
 348         dma_drain_needed_fn     *dma_drain_needed;
 349         lld_busy_fn             *lld_busy_fn;
 350
 351         /*
 352          * Dispatch queue sorting
 353          */
 354         sector_t                end_sector;
 355         struct request          *boundary_rq;
 356
 357         /*
 358          * Auto-unplugging state
 359          */
 360         struct timer_list       unplug_timer;
 361         int                     unplug_thresh;  /* After this many requests */
 362         unsigned long           unplug_delay;   /* After this many jiffies */
 363         struct work_struct      unplug_work;
 364
 365         struct backing_dev_info backing_dev_info;
 366
 367         /*
 368          * The queue owner gets to use this for whatever they like.
 369          * ll_rw_blk doesn't touch it.
 370          */
 371         void                    *queuedata;
 372
 373         /*
 374          * queue needs bounce pages for pages above this limit
 375          */
 376         gfp_t                   bounce_gfp;
 377
 378         /*
 379          * various queue flags, see QUEUE_* below
 380          */
 381         unsigned long           queue_flags;
 382
 383         /*
 384          * protects queue structures from reentrancy. ->__queue_lock should
 385          * _never_ be used directly, it is queue private. always use
 386          * ->queue_lock.
 387          */
 388         spinlock_t              __queue_lock;
 389         spinlock_t              *queue_lock;
 390
 391         /*
 392          * queue kobject
 393          */
 394         struct kobject kobj;
 395
 396         /*
 397          * queue settings
 398          */
 399         unsigned long           nr_requests;    /* Max # of requests */
 400         unsigned int            nr_congestion_on;
 401         unsigned int            nr_congestion_off;
 402         unsigned int            nr_batching;
 403
 404         void                    *dma_drain_buffer;
 405         unsigned int            dma_drain_size;
 406         unsigned int            dma_pad_mask;
 407         unsigned int            dma_alignment;
 408
 409         struct blk_queue_tag    *queue_tags;
 410         struct list_head        tag_busy_list;
 411
 412         unsigned int            nr_sorted;
 413         unsigned int            in_flight[2];
 414
 415         unsigned int            rq_timeout;
 416         struct timer_list       timeout;
 417         struct list_head        timeout_list;
 418
 419         struct queue_limits     limits;
 420
 421         /*
 422          * sg stuff
 423          */
 424         unsigned int            sg_timeout;
 425         unsigned int            sg_reserved_size;
 426         int                     node;
 427 #ifdef CONFIG_BLK_DEV_IO_TRACE
 428         struct blk_trace        *blk_trace;
 429 #endif
 430         /*
 431          * reserved for flush operations
 432          */
 433         unsigned int            ordered, next_ordered, ordseq;
 434         int                     orderr, ordcolor;
 435         struct request          pre_flush_rq, bar_rq, post_flush_rq;
 436         struct request          *orig_bar_rq;
 437
 438         struct mutex            sysfs_lock;
 439
 440 #if defined(CONFIG_BLK_DEV_BSG)
 441         struct bsg_class_device bsg_dev;
 442 #endif
 443 };
 444
 445 #define QUEUE_FLAG_CLUSTER      0       /* cluster several segments into 1 */
 446 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 447 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 448 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 449 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 450 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 451 #define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 452 #define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
 453 #define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 454 #define QUEUE_FLAG_BIDI         9       /* queue supports bidi requests */
 455 #define QUEUE_FLAG_NOMERGES    10       /* disable merge attempts */
 456 #define QUEUE_FLAG_SAME_COMP   11       /* force complete on same CPU */
 457 #define QUEUE_FLAG_FAIL_IO     12       /* fake timeout */
 458 #define QUEUE_FLAG_STACKABLE   13       /* supports request stacking */
 459 #define QUEUE_FLAG_NONROT      14       /* non-rotational device (SSD) */
 460 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 461 #define QUEUE_FLAG_IO_STAT     15       /* do IO stats */
 462 #define QUEUE_FLAG_CQ          16       /* hardware does queuing */
 463
 464 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 465                                  (1 << QUEUE_FLAG_CLUSTER) |            \
 466                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
 467                                  (1 << QUEUE_FLAG_SAME_COMP))
 468
 469 static inline int queue_is_locked(struct request_queue *q)
 470 {
 471 #ifdef CONFIG_SMP
 472         spinlock_t *lock = q->queue_lock;
 473         return lock && spin_is_locked(lock);
 474 #else
 475         return 1;
 476 #endif
 477 }
 478
 479 static inline void queue_flag_set_unlocked(unsigned int flag,
 480                                            struct request_queue *q)
 481 {
 482         __set_bit(flag, &q->queue_flags);
 483 }
 484
 485 static inline int queue_flag_test_and_clear(unsigned int flag,
 486                                             struct request_queue *q)
 487 {
 488         WARN_ON_ONCE(!queue_is_locked(q));
 489
 490         if (test_bit(flag, &q->queue_flags)) {
 491                 __clear_bit(flag, &q->queue_flags);
 492                 return 1;
 493         }
 494
 495         return 0;
 496 }
 497
 498 static inline int queue_flag_test_and_set(unsigned int flag,
 499                                           struct request_queue *q)
 500 {
 501         WARN_ON_ONCE(!queue_is_locked(q));
 502
 503         if (!test_bit(flag, &q->queue_flags)) {
 504                 __set_bit(flag, &q->queue_flags);
 505                 return 0;
 506         }
 507
 508         return 1;
 509 }
 510
 511 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 512 {
 513         WARN_ON_ONCE(!queue_is_locked(q));
 514         __set_bit(flag, &q->queue_flags);
 515 }
 516
 517 static inline void queue_flag_clear_unlocked(unsigned int flag,
 518                                              struct request_queue *q)
 519 {
 520         __clear_bit(flag, &q->queue_flags);
 521 }
 522
 523 static inline int queue_in_flight(struct request_queue *q)
 524 {
 525         return q->in_flight[0] + q->in_flight[1];
 526 }
 527
 528 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 529 {
 530         WARN_ON_ONCE(!queue_is_locked(q));
 531         __clear_bit(flag, &q->queue_flags);
 532 }
 533
 534 enum {
 535         /*
 536          * Hardbarrier is supported with one of the following methods.
 537          *
 538          * NONE         : hardbarrier unsupported
 539          * DRAIN        : ordering by draining is enough
 540          * DRAIN_FLUSH  : ordering by draining w/ pre and post flushes
 541          * DRAIN_FUA    : ordering by draining w/ pre flush and FUA write
 542          * TAG          : ordering by tag is enough
 543          * TAG_FLUSH    : ordering by tag w/ pre and post flushes
 544          * TAG_FUA      : ordering by tag w/ pre flush and FUA write
 545          */
 546         QUEUE_ORDERED_BY_DRAIN          = 0x01,
 547         QUEUE_ORDERED_BY_TAG            = 0x02,
 548         QUEUE_ORDERED_DO_PREFLUSH       = 0x10,
 549         QUEUE_ORDERED_DO_BAR            = 0x20,
 550         QUEUE_ORDERED_DO_POSTFLUSH      = 0x40,
 551         QUEUE_ORDERED_DO_FUA            = 0x80,
 552
 553         QUEUE_ORDERED_NONE              = 0x00,
 554
 555         QUEUE_ORDERED_DRAIN             = QUEUE_ORDERED_BY_DRAIN |
 556                                           QUEUE_ORDERED_DO_BAR,
 557         QUEUE_ORDERED_DRAIN_FLUSH       = QUEUE_ORDERED_DRAIN |
 558                                           QUEUE_ORDERED_DO_PREFLUSH |
 559                                           QUEUE_ORDERED_DO_POSTFLUSH,
 560         QUEUE_ORDERED_DRAIN_FUA         = QUEUE_ORDERED_DRAIN |
 561                                           QUEUE_ORDERED_DO_PREFLUSH |
 562                                           QUEUE_ORDERED_DO_FUA,
 563
 564         QUEUE_ORDERED_TAG               = QUEUE_ORDERED_BY_TAG |
 565                                           QUEUE_ORDERED_DO_BAR,
 566         QUEUE_ORDERED_TAG_FLUSH         = QUEUE_ORDERED_TAG |
 567                                           QUEUE_ORDERED_DO_PREFLUSH |
 568                                           QUEUE_ORDERED_DO_POSTFLUSH,
 569         QUEUE_ORDERED_TAG_FUA           = QUEUE_ORDERED_TAG |
 570                                           QUEUE_ORDERED_DO_PREFLUSH |
 571                                           QUEUE_ORDERED_DO_FUA,
 572
 573         /*
 574          * Ordered operation sequence
 575          */
 576         QUEUE_ORDSEQ_STARTED    = 0x01, /* flushing in progress */
 577         QUEUE_ORDSEQ_DRAIN      = 0x02, /* waiting for the queue to be drained */
 578         QUEUE_ORDSEQ_PREFLUSH   = 0x04, /* pre-flushing in progress */
 579         QUEUE_ORDSEQ_BAR        = 0x08, /* original barrier req in progress */
 580         QUEUE_ORDSEQ_POSTFLUSH  = 0x10, /* post-flushing in progress */
 581         QUEUE_ORDSEQ_DONE       = 0x20,
 582 };
 583
 584 #define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 585 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 586 #define blk_queue_queuing(q)    test_bit(QUEUE_FLAG_CQ, &(q)->queue_flags)
 587 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 588 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 589 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 590 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 591 #define blk_queue_flushing(q)   ((q)->ordseq)
 592 #define blk_queue_stackable(q)  \
 593         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 594
 595 #define blk_fs_request(rq)      ((rq)->cmd_type == REQ_TYPE_FS)
 596 #define blk_pc_request(rq)      ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
 597 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
 598 #define blk_sense_request(rq)   ((rq)->cmd_type == REQ_TYPE_SENSE)
 599
 600 #define blk_failfast_dev(rq)    ((rq)->cmd_flags & REQ_FAILFAST_DEV)
 601 #define blk_failfast_transport(rq) ((rq)->cmd_flags & REQ_FAILFAST_TRANSPORT)
 602 #define blk_failfast_driver(rq) ((rq)->cmd_flags & REQ_FAILFAST_DRIVER)
 603 #define blk_noretry_request(rq) (blk_failfast_dev(rq) ||        \
 604                                  blk_failfast_transport(rq) ||  \
 605                                  blk_failfast_driver(rq))
 606 #define blk_rq_started(rq)      ((rq)->cmd_flags & REQ_STARTED)
 607 #define blk_rq_io_stat(rq)      ((rq)->cmd_flags & REQ_IO_STAT)
 608 #define blk_rq_quiet(rq)        ((rq)->cmd_flags & REQ_QUIET)
 609
 610 #define blk_account_rq(rq)      (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq)))
 611
 612 #define blk_pm_suspend_request(rq)      ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
 613 #define blk_pm_resume_request(rq)       ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
 614 #define blk_pm_request(rq)      \
 615         (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
 616
 617 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 618 #define blk_sorted_rq(rq)       ((rq)->cmd_flags & REQ_SORTED)
 619 #define blk_barrier_rq(rq)      ((rq)->cmd_flags & REQ_HARDBARRIER)
 620 #define blk_fua_rq(rq)          ((rq)->cmd_flags & REQ_FUA)
 621 #define blk_discard_rq(rq)      ((rq)->cmd_flags & REQ_DISCARD)
 622 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 623 /* rq->queuelist of dequeued request must be list_empty() */
 624 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 625
 626 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 627
 628 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 629
 630 /*
 631  * We regard a request as sync, if either a read or a sync write
 632  */
 633 static inline bool rw_is_sync(unsigned int rw_flags)
 634 {
 635         return !(rw_flags & REQ_RW) || (rw_flags & REQ_RW_SYNC);
 636 }
 637
 638 static inline bool rq_is_sync(struct request *rq)
 639 {
 640         return rw_is_sync(rq->cmd_flags);
 641 }
 642
 643 #define rq_is_meta(rq)          ((rq)->cmd_flags & REQ_RW_META)
 644 #define rq_noidle(rq)           ((rq)->cmd_flags & REQ_NOIDLE)
 645
 646 static inline int blk_queue_full(struct request_queue *q, int sync)
 647 {
 648         if (sync)
 649                 return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
 650         return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
 651 }
 652
 653 static inline void blk_set_queue_full(struct request_queue *q, int sync)
 654 {
 655         if (sync)
 656                 queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
 657         else
 658                 queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
 659 }
 660
 661 static inline void blk_clear_queue_full(struct request_queue *q, int sync)
 662 {
 663         if (sync)
 664                 queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
 665         else
 666                 queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
 667 }
 668
 669
 670 /*
 671  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 672  * it already be started by driver.
 673  */
 674 #define RQ_NOMERGE_FLAGS        \
 675         (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
 676 #define rq_mergeable(rq)        \
 677         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 678          (blk_discard_rq(rq) || blk_fs_request((rq))))
 679
 680 /*
 681  * q->prep_rq_fn return values
 682  */
 683 #define BLKPREP_OK              0       /* serve it */
 684 #define BLKPREP_KILL            1       /* fatal error, kill */
 685 #define BLKPREP_DEFER           2       /* leave on queue */
 686
 687 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 688
 689 /*
 690  * standard bounce addresses:
 691  *
 692  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 693  * BLK_BOUNCE_ANY       : don't bounce anything
 694  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 695  */
 696
 697 #if BITS_PER_LONG == 32
 698 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 699 #else
 700 #define BLK_BOUNCE_HIGH         -1ULL
 701 #endif
 702 #define BLK_BOUNCE_ANY          (-1ULL)
 703 #define BLK_BOUNCE_ISA          (ISA_DMA_THRESHOLD)
 704
 705 /*
 706  * default timeout for SG_IO if none specified
 707  */
 708 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 709 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 710
 711 #ifdef CONFIG_BOUNCE
 712 extern int init_emergency_isa_pool(void);
 713 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 714 #else
 715 static inline int init_emergency_isa_pool(void)
 716 {
 717         return 0;
 718 }
 719 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 720 {
 721 }
 722 #endif /* CONFIG_MMU */
 723
 724 struct rq_map_data {
 725         struct page **pages;
 726         int page_order;
 727         int nr_entries;
 728         unsigned long offset;
 729         int null_mapped;
 730         int from_user;
 731 };
 732
 733 struct req_iterator {
 734         int i;
 735         struct bio *bio;
 736 };
 737
 738 /* This should not be used directly - use rq_for_each_segment */
 739 #define for_each_bio(_bio)              \
 740         for (; _bio; _bio = _bio->bi_next)
 741 #define __rq_for_each_bio(_bio, rq)     \
 742         if ((rq->bio))                  \
 743                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 744
 745 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 746         __rq_for_each_bio(_iter.bio, _rq)                       \
 747                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 748
 749 #define rq_iter_last(rq, _iter)                                 \
 750                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 751
 752 extern int blk_register_queue(struct gendisk *disk);
 753 extern void blk_unregister_queue(struct gendisk *disk);
 754 extern void register_disk(struct gendisk *dev);
 755 extern void generic_make_request(struct bio *bio);
 756 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 757 extern void blk_put_request(struct request *);
 758 extern void __blk_put_request(struct request_queue *, struct request *);
 759 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 760 extern struct request *blk_make_request(struct request_queue *, struct bio *,
 761                                         gfp_t);
 762 extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
 763 extern void blk_requeue_request(struct request_queue *, struct request *);
 764 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 765 extern int blk_lld_busy(struct request_queue *q);
 766 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 767                              struct bio_set *bs, gfp_t gfp_mask,
 768                              int (*bio_ctr)(struct bio *, struct bio *, void *),
 769                              void *data);
 770 extern void blk_rq_unprep_clone(struct request *rq);
 771 extern int blk_insert_cloned_request(struct request_queue *q,
 772                                      struct request *rq);
 773 extern void blk_plug_device(struct request_queue *);
 774 extern void blk_plug_device_unlocked(struct request_queue *);
 775 extern int blk_remove_plug(struct request_queue *);
 776 extern void blk_recount_segments(struct request_queue *, struct bio *);
 777 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 778                           unsigned int, void __user *);
 779 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 780                          struct scsi_ioctl_command __user *);
 781
 782 /*
 783  * A queue has just exitted congestion.  Note this in the global counter of
 784  * congested queues, and wake up anyone who was waiting for requests to be
 785  * put back.
 786  */
 787 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 788 {
 789         clear_bdi_congested(&q->backing_dev_info, sync);
 790 }
 791
 792 /*
 793  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 794  * state flags and increment the global gounter of congested queues.
 795  */
 796 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 797 {
 798         set_bdi_congested(&q->backing_dev_info, sync);
 799 }
 800
 801 extern void blk_start_queue(struct request_queue *q);
 802 extern void blk_stop_queue(struct request_queue *q);
 803 extern void blk_sync_queue(struct request_queue *q);
 804 extern void __blk_stop_queue(struct request_queue *q);
 805 extern void __blk_run_queue(struct request_queue *);
 806 extern void blk_run_queue(struct request_queue *);
 807 extern int blk_rq_map_user(struct request_queue *, struct request *,
 808                            struct rq_map_data *, void __user *, unsigned long,
 809                            gfp_t);
 810 extern int blk_rq_unmap_user(struct bio *);
 811 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 812 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 813                                struct rq_map_data *, struct sg_iovec *, int,
 814                                unsigned int, gfp_t);
 815 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 816                           struct request *, int);
 817 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 818                                   struct request *, int, rq_end_io_fn *);
 819 extern void blk_unplug(struct request_queue *q);
 820
 821 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 822 {
 823         return bdev->bd_disk->queue;
 824 }
 825
 826 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
 827                                        struct page *page)
 828 {
 829         if (bdi && bdi->unplug_io_fn)
 830                 bdi->unplug_io_fn(bdi, page);
 831 }
 832
 833 static inline void blk_run_address_space(struct address_space *mapping)
 834 {
 835         if (mapping)
 836                 blk_run_backing_dev(mapping->backing_dev_info, NULL);
 837 }
 838
 839 /*
 840  * blk_rq_pos()                 : the current sector
 841  * blk_rq_bytes()               : bytes left in the entire request
 842  * blk_rq_cur_bytes()           : bytes left in the current segment
 843  * blk_rq_err_bytes()           : bytes left till the next error boundary
 844  * blk_rq_sectors()             : sectors left in the entire request
 845  * blk_rq_cur_sectors()         : sectors left in the current segment
 846  * blk_rq_err_sectors()         : sectors left till the next error boundary
 847  */
 848 static inline sector_t blk_rq_pos(const struct request *rq)
 849 {
 850         return rq->__sector;
 851 }
 852
 853 static inline unsigned int blk_rq_bytes(const struct request *rq)
 854 {
 855         return rq->__data_len;
 856 }
 857
 858 static inline int blk_rq_cur_bytes(const struct request *rq)
 859 {
 860         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 861 }
 862
 863 extern unsigned int blk_rq_err_bytes(const struct request *rq);
 864
 865 static inline unsigned int blk_rq_sectors(const struct request *rq)
 866 {
 867         return blk_rq_bytes(rq) >> 9;
 868 }
 869
 870 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 871 {
 872         return blk_rq_cur_bytes(rq) >> 9;
 873 }
 874
 875 static inline unsigned int blk_rq_err_sectors(const struct request *rq)
 876 {
 877         return blk_rq_err_bytes(rq) >> 9;
 878 }
 879
 880 /*
 881  * Request issue related functions.
 882  */
 883 extern struct request *blk_peek_request(struct request_queue *q);
 884 extern void blk_start_request(struct request *rq);
 885 extern struct request *blk_fetch_request(struct request_queue *q);
 886
 887 /*
 888  * Request completion related functions.
 889  *
 890  * blk_update_request() completes given number of bytes and updates
 891  * the request without completing it.
 892  *
 893  * blk_end_request() and friends.  __blk_end_request() must be called
 894  * with the request queue spinlock acquired.
 895  *
 896  * Several drivers define their own end_request and call
 897  * blk_end_request() for parts of the original function.
 898  * This prevents code duplication in drivers.
 899  */
 900 extern bool blk_update_request(struct request *rq, int error,
 901                                unsigned int nr_bytes);
 902 extern bool blk_end_request(struct request *rq, int error,
 903                             unsigned int nr_bytes);
 904 extern void blk_end_request_all(struct request *rq, int error);
 905 extern bool blk_end_request_cur(struct request *rq, int error);
 906 extern bool blk_end_request_err(struct request *rq, int error);
 907 extern bool __blk_end_request(struct request *rq, int error,
 908                               unsigned int nr_bytes);
 909 extern void __blk_end_request_all(struct request *rq, int error);
 910 extern bool __blk_end_request_cur(struct request *rq, int error);
 911 extern bool __blk_end_request_err(struct request *rq, int error);
 912
 913 extern void blk_complete_request(struct request *);
 914 extern void __blk_complete_request(struct request *);
 915 extern void blk_abort_request(struct request *);
 916 extern void blk_abort_queue(struct request_queue *);
 917
 918 /*
 919  * Access functions for manipulating queue properties
 920  */
 921 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 922                                         spinlock_t *lock, int node_id);
 923 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 924 extern void blk_cleanup_queue(struct request_queue *);
 925 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 926 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 927 extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
 928 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 929 extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
 930 extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
 931 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 932 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 933 extern void blk_queue_physical_block_size(struct request_queue *, unsigned short);
 934 extern void blk_queue_alignment_offset(struct request_queue *q,
 935                                        unsigned int alignment);
 936 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 937 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 938 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 939 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 940 extern void blk_set_default_limits(struct queue_limits *lim);
 941 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 942                             sector_t offset);
 943 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 944                               sector_t offset);
 945 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 946 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 947 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 948 extern int blk_queue_dma_drain(struct request_queue *q,
 949                                dma_drain_needed_fn *dma_drain_needed,
 950                                void *buf, unsigned int size);
 951 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 952 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 953 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 954 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 955 extern void blk_queue_dma_alignment(struct request_queue *, int);
 956 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 957 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 958 extern void blk_queue_set_discard(struct request_queue *, prepare_discard_fn *);
 959 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 960 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 961 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 962 extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
 963 extern bool blk_do_ordered(struct request_queue *, struct request **);
 964 extern unsigned blk_ordered_cur_seq(struct request_queue *);
 965 extern unsigned blk_ordered_req_seq(struct request *);
 966 extern bool blk_ordered_complete_seq(struct request_queue *, unsigned, int);
 967
 968 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 969 extern void blk_dump_rq_flags(struct request *, char *);
 970 extern void generic_unplug_device(struct request_queue *);
 971 extern long nr_blockdev_pages(void);
 972
 973 int blk_get_queue(struct request_queue *);
 974 struct request_queue *blk_alloc_queue(gfp_t);
 975 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 976 extern void blk_put_queue(struct request_queue *);
 977
 978 /*
 979  * tag stuff
 980  */
 981 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 982 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 983 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 984 extern void blk_queue_end_tag(struct request_queue *, struct request *);
 985 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 986 extern void blk_queue_free_tags(struct request_queue *);
 987 extern int blk_queue_resize_tags(struct request_queue *, int);
 988 extern void blk_queue_invalidate_tags(struct request_queue *);
 989 extern struct blk_queue_tag *blk_init_tags(int);
 990 extern void blk_free_tags(struct blk_queue_tag *);
 991
 992 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 993                                                 int tag)
 994 {
 995         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 996                 return NULL;
 997         return bqt->tag_index[tag];
 998 }
 999
1000 extern int blkdev_issue_flush(struct block_device *, sector_t *);
1001 #define DISCARD_FL_WAIT         0x01    /* wait for completion */
1002 #define DISCARD_FL_BARRIER      0x02    /* issue DISCARD_BARRIER request */
1003 extern int blkdev_issue_discard(struct block_device *, sector_t sector,
1004                 sector_t nr_sects, gfp_t, int flags);
1005
1006 static inline int sb_issue_discard(struct super_block *sb,
1007                                    sector_t block, sector_t nr_blocks)
1008 {
1009         block <<= (sb->s_blocksize_bits - 9);
1010         nr_blocks <<= (sb->s_blocksize_bits - 9);
1011         return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, GFP_KERNEL,
1012                                     DISCARD_FL_BARRIER);
1013 }
1014
1015 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1016
1017 #define MAX_PHYS_SEGMENTS 128
1018 #define MAX_HW_SEGMENTS 128
1019 #define SAFE_MAX_SECTORS 255
1020 #define BLK_DEF_MAX_SECTORS 1024
1021
1022 #define MAX_SEGMENT_SIZE        65536
1023
1024 #define BLK_SEG_BOUNDARY_MASK   0xFFFFFFFFUL
1025
1026 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1027
1028 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1029 {
1030         return q->limits.bounce_pfn;
1031 }
1032
1033 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1034 {
1035         return q->limits.seg_boundary_mask;
1036 }
1037
1038 static inline unsigned int queue_max_sectors(struct request_queue *q)
1039 {
1040         return q->limits.max_sectors;
1041 }
1042
1043 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1044 {
1045         return q->limits.max_hw_sectors;
1046 }
1047
1048 static inline unsigned short queue_max_hw_segments(struct request_queue *q)
1049 {
1050         return q->limits.max_hw_segments;
1051 }
1052
1053 static inline unsigned short queue_max_phys_segments(struct request_queue *q)
1054 {
1055         return q->limits.max_phys_segments;
1056 }
1057
1058 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1059 {
1060         return q->limits.max_segment_size;
1061 }
1062
1063 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1064 {
1065         int retval = 512;
1066
1067         if (q && q->limits.logical_block_size)
1068                 retval = q->limits.logical_block_size;
1069
1070         return retval;
1071 }
1072
1073 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1074 {
1075         return queue_logical_block_size(bdev_get_queue(bdev));
1076 }
1077
1078 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1079 {
1080         return q->limits.physical_block_size;
1081 }
1082
1083 static inline unsigned int queue_io_min(struct request_queue *q)
1084 {
1085         return q->limits.io_min;
1086 }
1087
1088 static inline unsigned int queue_io_opt(struct request_queue *q)
1089 {
1090         return q->limits.io_opt;
1091 }
1092
1093 static inline int queue_alignment_offset(struct request_queue *q)
1094 {
1095         if (q && q->limits.misaligned)
1096                 return -1;
1097
1098         if (q && q->limits.alignment_offset)
1099                 return q->limits.alignment_offset;
1100
1101         return 0;
1102 }
1103
1104 static inline int queue_sector_alignment_offset(struct request_queue *q,
1105                                                 sector_t sector)
1106 {
1107         return ((sector << 9) - q->limits.alignment_offset)
1108                 & (q->limits.io_min - 1);
1109 }
1110
1111 static inline int queue_dma_alignment(struct request_queue *q)
1112 {
1113         return q ? q->dma_alignment : 511;
1114 }
1115
1116 static inline int blk_rq_aligned(struct request_queue *q, void *addr,
1117                                  unsigned int len)
1118 {
1119         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1120         return !((unsigned long)addr & alignment) && !(len & alignment);
1121 }
1122
1123 /* assumes size > 256 */
1124 static inline unsigned int blksize_bits(unsigned int size)
1125 {
1126         unsigned int bits = 8;
1127         do {
1128                 bits++;
1129                 size >>= 1;
1130         } while (size > 256);
1131         return bits;
1132 }
1133
1134 static inline unsigned int block_size(struct block_device *bdev)
1135 {
1136         return bdev->bd_block_size;
1137 }
1138
1139 typedef struct {struct page *v;} Sector;
1140
1141 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1142
1143 static inline void put_dev_sector(Sector p)
1144 {
1145         page_cache_release(p.v);
1146 }
1147
1148 struct work_struct;
1149 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1150
1151 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1152         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1153 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1154         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1155
1156 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1157
1158 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1159 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1160
1161 struct blk_integrity_exchg {
1162         void                    *prot_buf;
1163         void                    *data_buf;
1164         sector_t                sector;
1165         unsigned int            data_size;
1166         unsigned short          sector_size;
1167         const char              *disk_name;
1168 };
1169
1170 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1171 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1172 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1173 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1174
1175 struct blk_integrity {
1176         integrity_gen_fn        *generate_fn;
1177         integrity_vrfy_fn       *verify_fn;
1178         integrity_set_tag_fn    *set_tag_fn;
1179         integrity_get_tag_fn    *get_tag_fn;
1180
1181         unsigned short          flags;
1182         unsigned short          tuple_size;
1183         unsigned short          sector_size;
1184         unsigned short          tag_size;
1185
1186         const char              *name;
1187
1188         struct kobject          kobj;
1189 };
1190
1191 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1192 extern void blk_integrity_unregister(struct gendisk *);
1193 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1194 extern int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
1195 extern int blk_rq_count_integrity_sg(struct request *);
1196
1197 static inline
1198 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1199 {
1200         return bdev->bd_disk->integrity;
1201 }
1202
1203 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1204 {
1205         return disk->integrity;
1206 }
1207
1208 static inline int blk_integrity_rq(struct request *rq)
1209 {
1210         if (rq->bio == NULL)
1211                 return 0;
1212
1213         return bio_integrity(rq->bio);
1214 }
1215
1216 #else /* CONFIG_BLK_DEV_INTEGRITY */
1217
1218 #define blk_integrity_rq(rq)                    (0)
1219 #define blk_rq_count_integrity_sg(a)            (0)
1220 #define blk_rq_map_integrity_sg(a, b)           (0)
1221 #define bdev_get_integrity(a)                   (0)
1222 #define blk_get_integrity(a)                    (0)
1223 #define blk_integrity_compare(a, b)             (0)
1224 #define blk_integrity_register(a, b)            (0)
1225 #define blk_integrity_unregister(a)             do { } while (0);
1226
1227 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1228
1229 struct block_device_operations {
1230         int (*open) (struct block_device *, fmode_t);
1231         int (*release) (struct gendisk *, fmode_t);
1232         int (*locked_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1233         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1234         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1235         int (*direct_access) (struct block_device *, sector_t,
1236                                                 void **, unsigned long *);
1237         int (*media_changed) (struct gendisk *);
1238         unsigned long long (*set_capacity) (struct gendisk *,
1239                                                 unsigned long long);
1240         int (*revalidate_disk) (struct gendisk *);
1241         int (*getgeo)(struct block_device *, struct hd_geometry *);
1242         struct module *owner;
1243 };
1244
1245 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1246                                  unsigned long);
1247 #else /* CONFIG_BLOCK */
1248 /*
1249  * stubs for when the block layer is configured out
1250  */
1251 #define buffer_heads_over_limit 0
1252
1253 static inline long nr_blockdev_pages(void)
1254 {
1255         return 0;
1256 }
1257
1258 #endif /* CONFIG_BLOCK */
1259
1260 #endif