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