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/bsg.h>
  20
  21 #include <asm/scatterlist.h>
  22
  23 struct scsi_ioctl_command;
  24
  25 struct request_queue;
  26 typedef struct request_queue request_queue_t __deprecated;
  27 struct elevator_queue;
  28 typedef struct elevator_queue elevator_t;
  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 void put_io_context(struct io_context *ioc);
  38 void exit_io_context(void);
  39 struct io_context *get_io_context(gfp_t gfp_flags, int node);
  40 struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
  41 void copy_io_context(struct io_context **pdst, struct io_context **psrc);
  42 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
  43
  44 struct request;
  45 typedef void (rq_end_io_fn)(struct request *, int);
  46
  47 struct request_list {
  48         int count[2];
  49         int starved[2];
  50         int elvpriv;
  51         mempool_t *rq_pool;
  52         wait_queue_head_t wait[2];
  53 };
  54
  55 /*
  56  * request command types
  57  */
  58 enum rq_cmd_type_bits {
  59         REQ_TYPE_FS             = 1,    /* fs request */
  60         REQ_TYPE_BLOCK_PC,              /* scsi command */
  61         REQ_TYPE_SENSE,                 /* sense request */
  62         REQ_TYPE_PM_SUSPEND,            /* suspend request */
  63         REQ_TYPE_PM_RESUME,             /* resume request */
  64         REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
  65         REQ_TYPE_FLUSH,                 /* flush request */
  66         REQ_TYPE_SPECIAL,               /* driver defined type */
  67         REQ_TYPE_LINUX_BLOCK,           /* generic block layer message */
  68         /*
  69          * for ATA/ATAPI devices. this really doesn't belong here, ide should
  70          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  71          * private REQ_LB opcodes to differentiate what type of request this is
  72          */
  73         REQ_TYPE_ATA_TASKFILE,
  74         REQ_TYPE_ATA_PC,
  75 };
  76
  77 /*
  78  * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
  79  * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
  80  * SCSI cdb.
  81  *
  82  * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
  83  * typically to differentiate REQ_TYPE_SPECIAL requests.
  84  *
  85  */
  86 enum {
  87         /*
  88          * just examples for now
  89          */
  90         REQ_LB_OP_EJECT = 0x40,         /* eject request */
  91         REQ_LB_OP_FLUSH = 0x41,         /* flush device */
  92 };
  93
  94 /*
  95  * request type modified bits. first three bits match BIO_RW* bits, important
  96  */
  97 enum rq_flag_bits {
  98         __REQ_RW,               /* not set, read. set, write */
  99         __REQ_FAILFAST,         /* no low level driver retries */
 100         __REQ_SORTED,           /* elevator knows about this request */
 101         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 102         __REQ_HARDBARRIER,      /* may not be passed by drive either */
 103         __REQ_FUA,              /* forced unit access */
 104         __REQ_NOMERGE,          /* don't touch this for merging */
 105         __REQ_STARTED,          /* drive already may have started this one */
 106         __REQ_DONTPREP,         /* don't call prep for this one */
 107         __REQ_QUEUED,           /* uses queueing */
 108         __REQ_ELVPRIV,          /* elevator private data attached */
 109         __REQ_FAILED,           /* set if the request failed */
 110         __REQ_QUIET,            /* don't worry about errors */
 111         __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 112         __REQ_ORDERED_COLOR,    /* is before or after barrier */
 113         __REQ_RW_SYNC,          /* request is sync (O_DIRECT) */
 114         __REQ_ALLOCED,          /* request came from our alloc pool */
 115         __REQ_RW_META,          /* metadata io request */
 116         __REQ_NR_BITS,          /* stops here */
 117 };
 118
 119 #define REQ_RW          (1 << __REQ_RW)
 120 #define REQ_FAILFAST    (1 << __REQ_FAILFAST)
 121 #define REQ_SORTED      (1 << __REQ_SORTED)
 122 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
 123 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
 124 #define REQ_FUA         (1 << __REQ_FUA)
 125 #define REQ_NOMERGE     (1 << __REQ_NOMERGE)
 126 #define REQ_STARTED     (1 << __REQ_STARTED)
 127 #define REQ_DONTPREP    (1 << __REQ_DONTPREP)
 128 #define REQ_QUEUED      (1 << __REQ_QUEUED)
 129 #define REQ_ELVPRIV     (1 << __REQ_ELVPRIV)
 130 #define REQ_FAILED      (1 << __REQ_FAILED)
 131 #define REQ_QUIET       (1 << __REQ_QUIET)
 132 #define REQ_PREEMPT     (1 << __REQ_PREEMPT)
 133 #define REQ_ORDERED_COLOR       (1 << __REQ_ORDERED_COLOR)
 134 #define REQ_RW_SYNC     (1 << __REQ_RW_SYNC)
 135 #define REQ_ALLOCED     (1 << __REQ_ALLOCED)
 136 #define REQ_RW_META     (1 << __REQ_RW_META)
 137
 138 #define BLK_MAX_CDB     16
 139
 140 /*
 141  * try to put the fields that are referenced together in the same cacheline
 142  */
 143 struct request {
 144         struct list_head queuelist;
 145         struct list_head donelist;
 146
 147         struct request_queue *q;
 148
 149         unsigned int cmd_flags;
 150         enum rq_cmd_type_bits cmd_type;
 151
 152         /* Maintain bio traversal state for part by part I/O submission.
 153          * hard_* are block layer internals, no driver should touch them!
 154          */
 155
 156         sector_t sector;                /* next sector to submit */
 157         sector_t hard_sector;           /* next sector to complete */
 158         unsigned long nr_sectors;       /* no. of sectors left to submit */
 159         unsigned long hard_nr_sectors;  /* no. of sectors left to complete */
 160         /* no. of sectors left to submit in the current segment */
 161         unsigned int current_nr_sectors;
 162
 163         /* no. of sectors left to complete in the current segment */
 164         unsigned int hard_cur_sectors;
 165
 166         struct bio *bio;
 167         struct bio *biotail;
 168
 169         struct hlist_node hash; /* merge hash */
 170         /*
 171          * The rb_node is only used inside the io scheduler, requests
 172          * are pruned when moved to the dispatch queue. So let the
 173          * completion_data share space with the rb_node.
 174          */
 175         union {
 176                 struct rb_node rb_node; /* sort/lookup */
 177                 void *completion_data;
 178         };
 179
 180         /*
 181          * two pointers are available for the IO schedulers, if they need
 182          * more they have to dynamically allocate it.
 183          */
 184         void *elevator_private;
 185         void *elevator_private2;
 186
 187         struct gendisk *rq_disk;
 188         unsigned long start_time;
 189
 190         /* Number of scatter-gather DMA addr+len pairs after
 191          * physical address coalescing is performed.
 192          */
 193         unsigned short nr_phys_segments;
 194
 195         /* Number of scatter-gather addr+len pairs after
 196          * physical and DMA remapping hardware coalescing is performed.
 197          * This is the number of scatter-gather entries the driver
 198          * will actually have to deal with after DMA mapping is done.
 199          */
 200         unsigned short nr_hw_segments;
 201
 202         unsigned short ioprio;
 203
 204         void *special;
 205         char *buffer;
 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 int cmd_len;
 216         unsigned char cmd[BLK_MAX_CDB];
 217
 218         unsigned int data_len;
 219         unsigned int sense_len;
 220         void *data;
 221         void *sense;
 222
 223         unsigned int timeout;
 224         int retries;
 225
 226         /*
 227          * completion callback.
 228          */
 229         rq_end_io_fn *end_io;
 230         void *end_io_data;
 231
 232         /* for bidi */
 233         struct request *next_rq;
 234 };
 235
 236 /*
 237  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 238  * requests. Some step values could eventually be made generic.
 239  */
 240 struct request_pm_state
 241 {
 242         /* PM state machine step value, currently driver specific */
 243         int     pm_step;
 244         /* requested PM state value (S1, S2, S3, S4, ...) */
 245         u32     pm_state;
 246         void*   data;           /* for driver use */
 247 };
 248
 249 #include <linux/elevator.h>
 250
 251 typedef void (request_fn_proc) (struct request_queue *q);
 252 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
 253 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 254 typedef void (unplug_fn) (struct request_queue *);
 255
 256 struct bio_vec;
 257 typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *);
 258 typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
 259 typedef void (softirq_done_fn)(struct request *);
 260
 261 enum blk_queue_state {
 262         Queue_down,
 263         Queue_up,
 264 };
 265
 266 struct blk_queue_tag {
 267         struct request **tag_index;     /* map of busy tags */
 268         unsigned long *tag_map;         /* bit map of free/busy tags */
 269         int busy;                       /* current depth */
 270         int max_depth;                  /* what we will send to device */
 271         int real_max_depth;             /* what the array can hold */
 272         atomic_t refcnt;                /* map can be shared */
 273 };
 274
 275 struct request_queue
 276 {
 277         /*
 278          * Together with queue_head for cacheline sharing
 279          */
 280         struct list_head        queue_head;
 281         struct request          *last_merge;
 282         elevator_t              *elevator;
 283
 284         /*
 285          * the queue request freelist, one for reads and one for writes
 286          */
 287         struct request_list     rq;
 288
 289         request_fn_proc         *request_fn;
 290         make_request_fn         *make_request_fn;
 291         prep_rq_fn              *prep_rq_fn;
 292         unplug_fn               *unplug_fn;
 293         merge_bvec_fn           *merge_bvec_fn;
 294         prepare_flush_fn        *prepare_flush_fn;
 295         softirq_done_fn         *softirq_done_fn;
 296
 297         /*
 298          * Dispatch queue sorting
 299          */
 300         sector_t                end_sector;
 301         struct request          *boundary_rq;
 302
 303         /*
 304          * Auto-unplugging state
 305          */
 306         struct timer_list       unplug_timer;
 307         int                     unplug_thresh;  /* After this many requests */
 308         unsigned long           unplug_delay;   /* After this many jiffies */
 309         struct work_struct      unplug_work;
 310
 311         struct backing_dev_info backing_dev_info;
 312
 313         /*
 314          * The queue owner gets to use this for whatever they like.
 315          * ll_rw_blk doesn't touch it.
 316          */
 317         void                    *queuedata;
 318
 319         /*
 320          * queue needs bounce pages for pages above this limit
 321          */
 322         unsigned long           bounce_pfn;
 323         gfp_t                   bounce_gfp;
 324
 325         /*
 326          * various queue flags, see QUEUE_* below
 327          */
 328         unsigned long           queue_flags;
 329
 330         /*
 331          * protects queue structures from reentrancy. ->__queue_lock should
 332          * _never_ be used directly, it is queue private. always use
 333          * ->queue_lock.
 334          */
 335         spinlock_t              __queue_lock;
 336         spinlock_t              *queue_lock;
 337
 338         /*
 339          * queue kobject
 340          */
 341         struct kobject kobj;
 342
 343         /*
 344          * queue settings
 345          */
 346         unsigned long           nr_requests;    /* Max # of requests */
 347         unsigned int            nr_congestion_on;
 348         unsigned int            nr_congestion_off;
 349         unsigned int            nr_batching;
 350
 351         unsigned int            max_sectors;
 352         unsigned int            max_hw_sectors;
 353         unsigned short          max_phys_segments;
 354         unsigned short          max_hw_segments;
 355         unsigned short          hardsect_size;
 356         unsigned int            max_segment_size;
 357
 358         unsigned long           seg_boundary_mask;
 359         unsigned int            dma_alignment;
 360
 361         struct blk_queue_tag    *queue_tags;
 362         struct list_head        tag_busy_list;
 363
 364         unsigned int            nr_sorted;
 365         unsigned int            in_flight;
 366
 367         /*
 368          * sg stuff
 369          */
 370         unsigned int            sg_timeout;
 371         unsigned int            sg_reserved_size;
 372         int                     node;
 373 #ifdef CONFIG_BLK_DEV_IO_TRACE
 374         struct blk_trace        *blk_trace;
 375 #endif
 376         /*
 377          * reserved for flush operations
 378          */
 379         unsigned int            ordered, next_ordered, ordseq;
 380         int                     orderr, ordcolor;
 381         struct request          pre_flush_rq, bar_rq, post_flush_rq;
 382         struct request          *orig_bar_rq;
 383
 384         struct mutex            sysfs_lock;
 385
 386 #if defined(CONFIG_BLK_DEV_BSG)
 387         struct bsg_class_device bsg_dev;
 388 #endif
 389 };
 390
 391 #define QUEUE_FLAG_CLUSTER      0       /* cluster several segments into 1 */
 392 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 393 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 394 #define QUEUE_FLAG_READFULL     3       /* read queue has been filled */
 395 #define QUEUE_FLAG_WRITEFULL    4       /* write queue has been filled */
 396 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 397 #define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 398 #define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
 399 #define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 400 #define QUEUE_FLAG_BIDI         9       /* queue supports bidi requests */
 401
 402 enum {
 403         /*
 404          * Hardbarrier is supported with one of the following methods.
 405          *
 406          * NONE         : hardbarrier unsupported
 407          * DRAIN        : ordering by draining is enough
 408          * DRAIN_FLUSH  : ordering by draining w/ pre and post flushes
 409          * DRAIN_FUA    : ordering by draining w/ pre flush and FUA write
 410          * TAG          : ordering by tag is enough
 411          * TAG_FLUSH    : ordering by tag w/ pre and post flushes
 412          * TAG_FUA      : ordering by tag w/ pre flush and FUA write
 413          */
 414         QUEUE_ORDERED_NONE      = 0x00,
 415         QUEUE_ORDERED_DRAIN     = 0x01,
 416         QUEUE_ORDERED_TAG       = 0x02,
 417
 418         QUEUE_ORDERED_PREFLUSH  = 0x10,
 419         QUEUE_ORDERED_POSTFLUSH = 0x20,
 420         QUEUE_ORDERED_FUA       = 0x40,
 421
 422         QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
 423                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 424         QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
 425                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 426         QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
 427                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 428         QUEUE_ORDERED_TAG_FUA   = QUEUE_ORDERED_TAG |
 429                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 430
 431         /*
 432          * Ordered operation sequence
 433          */
 434         QUEUE_ORDSEQ_STARTED    = 0x01, /* flushing in progress */
 435         QUEUE_ORDSEQ_DRAIN      = 0x02, /* waiting for the queue to be drained */
 436         QUEUE_ORDSEQ_PREFLUSH   = 0x04, /* pre-flushing in progress */
 437         QUEUE_ORDSEQ_BAR        = 0x08, /* original barrier req in progress */
 438         QUEUE_ORDSEQ_POSTFLUSH  = 0x10, /* post-flushing in progress */
 439         QUEUE_ORDSEQ_DONE       = 0x20,
 440 };
 441
 442 #define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 443 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 444 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 445 #define blk_queue_flushing(q)   ((q)->ordseq)
 446
 447 #define blk_fs_request(rq)      ((rq)->cmd_type == REQ_TYPE_FS)
 448 #define blk_pc_request(rq)      ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
 449 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
 450 #define blk_sense_request(rq)   ((rq)->cmd_type == REQ_TYPE_SENSE)
 451
 452 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
 453 #define blk_rq_started(rq)      ((rq)->cmd_flags & REQ_STARTED)
 454
 455 #define blk_account_rq(rq)      (blk_rq_started(rq) && blk_fs_request(rq))
 456
 457 #define blk_pm_suspend_request(rq)      ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
 458 #define blk_pm_resume_request(rq)       ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
 459 #define blk_pm_request(rq)      \
 460         (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
 461
 462 #define blk_sorted_rq(rq)       ((rq)->cmd_flags & REQ_SORTED)
 463 #define blk_barrier_rq(rq)      ((rq)->cmd_flags & REQ_HARDBARRIER)
 464 #define blk_fua_rq(rq)          ((rq)->cmd_flags & REQ_FUA)
 465 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 466 #define blk_empty_barrier(rq)   (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
 467
 468 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 469
 470 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 471
 472 /*
 473  * We regard a request as sync, if it's a READ or a SYNC write.
 474  */
 475 #define rq_is_sync(rq)          (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
 476 #define rq_is_meta(rq)          ((rq)->cmd_flags & REQ_RW_META)
 477
 478 static inline int blk_queue_full(struct request_queue *q, int rw)
 479 {
 480         if (rw == READ)
 481                 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 482         return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 483 }
 484
 485 static inline void blk_set_queue_full(struct request_queue *q, int rw)
 486 {
 487         if (rw == READ)
 488                 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 489         else
 490                 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 491 }
 492
 493 static inline void blk_clear_queue_full(struct request_queue *q, int rw)
 494 {
 495         if (rw == READ)
 496                 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 497         else
 498                 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 499 }
 500
 501
 502 /*
 503  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 504  * it already be started by driver.
 505  */
 506 #define RQ_NOMERGE_FLAGS        \
 507         (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
 508 #define rq_mergeable(rq)        \
 509         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
 510
 511 /*
 512  * q->prep_rq_fn return values
 513  */
 514 #define BLKPREP_OK              0       /* serve it */
 515 #define BLKPREP_KILL            1       /* fatal error, kill */
 516 #define BLKPREP_DEFER           2       /* leave on queue */
 517
 518 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 519
 520 /*
 521  * standard bounce addresses:
 522  *
 523  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 524  * BLK_BOUNCE_ANY       : don't bounce anything
 525  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 526  */
 527 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 528 #define BLK_BOUNCE_ANY          ((u64)blk_max_pfn << PAGE_SHIFT)
 529 #define BLK_BOUNCE_ISA          (ISA_DMA_THRESHOLD)
 530
 531 /*
 532  * default timeout for SG_IO if none specified
 533  */
 534 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 535
 536 #ifdef CONFIG_BOUNCE
 537 extern int init_emergency_isa_pool(void);
 538 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 539 #else
 540 static inline int init_emergency_isa_pool(void)
 541 {
 542         return 0;
 543 }
 544 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 545 {
 546 }
 547 #endif /* CONFIG_MMU */
 548
 549 struct req_iterator {
 550         int i;
 551         struct bio *bio;
 552 };
 553
 554 /* This should not be used directly - use rq_for_each_segment */
 555 #define __rq_for_each_bio(_bio, rq)     \
 556         if ((rq->bio))                  \
 557                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 558
 559 #define rq_for_each_segment(bvl, _rq, _iter)                    \
 560         __rq_for_each_bio(_iter.bio, _rq)                       \
 561                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
 562
 563 #define rq_iter_last(rq, _iter)                                 \
 564                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 565
 566 extern int blk_register_queue(struct gendisk *disk);
 567 extern void blk_unregister_queue(struct gendisk *disk);
 568 extern void register_disk(struct gendisk *dev);
 569 extern void generic_make_request(struct bio *bio);
 570 extern void blk_put_request(struct request *);
 571 extern void __blk_put_request(struct request_queue *, struct request *);
 572 extern void blk_end_sync_rq(struct request *rq, int error);
 573 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 574 extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
 575 extern void blk_requeue_request(struct request_queue *, struct request *);
 576 extern void blk_plug_device(struct request_queue *);
 577 extern int blk_remove_plug(struct request_queue *);
 578 extern void blk_recount_segments(struct request_queue *, struct bio *);
 579 extern int scsi_cmd_ioctl(struct file *, struct request_queue *,
 580                           struct gendisk *, unsigned int, void __user *);
 581 extern int sg_scsi_ioctl(struct file *, struct request_queue *,
 582                 struct gendisk *, struct scsi_ioctl_command __user *);
 583
 584 /*
 585  * Temporary export, until SCSI gets fixed up.
 586  */
 587 extern int blk_rq_append_bio(struct request_queue *q, struct request *rq,
 588                              struct bio *bio);
 589
 590 /*
 591  * A queue has just exitted congestion.  Note this in the global counter of
 592  * congested queues, and wake up anyone who was waiting for requests to be
 593  * put back.
 594  */
 595 static inline void blk_clear_queue_congested(struct request_queue *q, int rw)
 596 {
 597         clear_bdi_congested(&q->backing_dev_info, rw);
 598 }
 599
 600 /*
 601  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 602  * state flags and increment the global gounter of congested queues.
 603  */
 604 static inline void blk_set_queue_congested(struct request_queue *q, int rw)
 605 {
 606         set_bdi_congested(&q->backing_dev_info, rw);
 607 }
 608
 609 extern void blk_start_queue(struct request_queue *q);
 610 extern void blk_stop_queue(struct request_queue *q);
 611 extern void blk_sync_queue(struct request_queue *q);
 612 extern void __blk_stop_queue(struct request_queue *q);
 613 extern void blk_run_queue(struct request_queue *);
 614 extern void blk_start_queueing(struct request_queue *);
 615 extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long);
 616 extern int blk_rq_unmap_user(struct bio *);
 617 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 618 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 619                                struct sg_iovec *, int, unsigned int);
 620 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 621                           struct request *, int);
 622 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 623                                   struct request *, int, rq_end_io_fn *);
 624 extern int blk_verify_command(unsigned char *, int);
 625 extern void blk_unplug(struct request_queue *q);
 626
 627 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 628 {
 629         return bdev->bd_disk->queue;
 630 }
 631
 632 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
 633                                        struct page *page)
 634 {
 635         if (bdi && bdi->unplug_io_fn)
 636                 bdi->unplug_io_fn(bdi, page);
 637 }
 638
 639 static inline void blk_run_address_space(struct address_space *mapping)
 640 {
 641         if (mapping)
 642                 blk_run_backing_dev(mapping->backing_dev_info, NULL);
 643 }
 644
 645 /*
 646  * end_request() and friends. Must be called with the request queue spinlock
 647  * acquired. All functions called within end_request() _must_be_ atomic.
 648  *
 649  * Several drivers define their own end_request and call
 650  * end_that_request_first() and end_that_request_last()
 651  * for parts of the original function. This prevents
 652  * code duplication in drivers.
 653  */
 654 extern int end_that_request_first(struct request *, int, int);
 655 extern int end_that_request_chunk(struct request *, int, int);
 656 extern void end_that_request_last(struct request *, int);
 657 extern void end_request(struct request *, int);
 658 extern void end_queued_request(struct request *, int);
 659 extern void end_dequeued_request(struct request *, int);
 660 extern void blk_complete_request(struct request *);
 661
 662 /*
 663  * end_that_request_first/chunk() takes an uptodate argument. we account
 664  * any value <= as an io error. 0 means -EIO for compatability reasons,
 665  * any other < 0 value is the direct error type. An uptodate value of
 666  * 1 indicates successful io completion
 667  */
 668 #define end_io_error(uptodate)  (unlikely((uptodate) <= 0))
 669
 670 static inline void blkdev_dequeue_request(struct request *req)
 671 {
 672         elv_dequeue_request(req->q, req);
 673 }
 674
 675 /*
 676  * Access functions for manipulating queue properties
 677  */
 678 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 679                                         spinlock_t *lock, int node_id);
 680 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 681 extern void blk_cleanup_queue(struct request_queue *);
 682 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 683 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 684 extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
 685 extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
 686 extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
 687 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 688 extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
 689 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 690 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 691 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 692 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 693 extern void blk_queue_dma_alignment(struct request_queue *, int);
 694 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 695 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 696 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 697 extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
 698 extern int blk_do_ordered(struct request_queue *, struct request **);
 699 extern unsigned blk_ordered_cur_seq(struct request_queue *);
 700 extern unsigned blk_ordered_req_seq(struct request *);
 701 extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int);
 702
 703 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 704 extern void blk_dump_rq_flags(struct request *, char *);
 705 extern void generic_unplug_device(struct request_queue *);
 706 extern void __generic_unplug_device(struct request_queue *);
 707 extern long nr_blockdev_pages(void);
 708
 709 int blk_get_queue(struct request_queue *);
 710 struct request_queue *blk_alloc_queue(gfp_t);
 711 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 712 extern void blk_put_queue(struct request_queue *);
 713
 714 /*
 715  * tag stuff
 716  */
 717 #define blk_queue_tag_depth(q)          ((q)->queue_tags->busy)
 718 #define blk_queue_tag_queue(q)          ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
 719 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 720 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 721 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 722 extern void blk_queue_end_tag(struct request_queue *, struct request *);
 723 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 724 extern void blk_queue_free_tags(struct request_queue *);
 725 extern int blk_queue_resize_tags(struct request_queue *, int);
 726 extern void blk_queue_invalidate_tags(struct request_queue *);
 727 extern struct blk_queue_tag *blk_init_tags(int);
 728 extern void blk_free_tags(struct blk_queue_tag *);
 729
 730 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 731                                                 int tag)
 732 {
 733         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 734                 return NULL;
 735         return bqt->tag_index[tag];
 736 }
 737
 738 extern int blkdev_issue_flush(struct block_device *, sector_t *);
 739
 740 #define MAX_PHYS_SEGMENTS 128
 741 #define MAX_HW_SEGMENTS 128
 742 #define SAFE_MAX_SECTORS 255
 743 #define BLK_DEF_MAX_SECTORS 1024
 744
 745 #define MAX_SEGMENT_SIZE        65536
 746
 747 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
 748
 749 static inline int queue_hardsect_size(struct request_queue *q)
 750 {
 751         int retval = 512;
 752
 753         if (q && q->hardsect_size)
 754                 retval = q->hardsect_size;
 755
 756         return retval;
 757 }
 758
 759 static inline int bdev_hardsect_size(struct block_device *bdev)
 760 {
 761         return queue_hardsect_size(bdev_get_queue(bdev));
 762 }
 763
 764 static inline int queue_dma_alignment(struct request_queue *q)
 765 {
 766         int retval = 511;
 767
 768         if (q && q->dma_alignment)
 769                 retval = q->dma_alignment;
 770
 771         return retval;
 772 }
 773
 774 /* assumes size > 256 */
 775 static inline unsigned int blksize_bits(unsigned int size)
 776 {
 777         unsigned int bits = 8;
 778         do {
 779                 bits++;
 780                 size >>= 1;
 781         } while (size > 256);
 782         return bits;
 783 }
 784
 785 static inline unsigned int block_size(struct block_device *bdev)
 786 {
 787         return bdev->bd_block_size;
 788 }
 789
 790 typedef struct {struct page *v;} Sector;
 791
 792 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
 793
 794 static inline void put_dev_sector(Sector p)
 795 {
 796         page_cache_release(p.v);
 797 }
 798
 799 struct work_struct;
 800 int kblockd_schedule_work(struct work_struct *work);
 801 void kblockd_flush_work(struct work_struct *work);
 802
 803 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
 804         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
 805 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
 806         MODULE_ALIAS("block-major-" __stringify(major) "-*")
 807
 808
 809 #else /* CONFIG_BLOCK */
 810 /*
 811  * stubs for when the block layer is configured out
 812  */
 813 #define buffer_heads_over_limit 0
 814
 815 static inline long nr_blockdev_pages(void)
 816 {
 817         return 0;
 818 }
 819
 820 static inline void exit_io_context(void)
 821 {
 822 }
 823
 824 static inline int put_io_context(struct io_context *ioc)
 825 {
 826         return 1;
 827 }
 828
 829
 830 #endif /* CONFIG_BLOCK */
 831
 832 #endif