include/linux/blkdev.h

   1 #ifndef _LINUX_BLKDEV_H
   2 #define _LINUX_BLKDEV_H
   3
   4 #include <linux/config.h>
   5 #include <linux/major.h>
   6 #include <linux/genhd.h>
   7 #include <linux/list.h>
   8 #include <linux/timer.h>
   9 #include <linux/workqueue.h>
  10 #include <linux/pagemap.h>
  11 #include <linux/backing-dev.h>
  12 #include <linux/wait.h>
  13 #include <linux/mempool.h>
  14 #include <linux/bio.h>
  15 #include <linux/module.h>
  16 #include <linux/stringify.h>
  17
  18 #include <asm/scatterlist.h>
  19
  20 struct request_queue;
  21 typedef struct request_queue request_queue_t;
  22 struct elevator_queue;
  23 typedef struct elevator_queue elevator_t;
  24 struct request_pm_state;
  25
  26 #define BLKDEV_MIN_RQ   4
  27 #define BLKDEV_MAX_RQ   128     /* Default maximum */
  28
  29 /*
  30  * This is the per-process anticipatory I/O scheduler state.
  31  */
  32 struct as_io_context {
  33         spinlock_t lock;
  34
  35         void (*dtor)(struct as_io_context *aic); /* destructor */
  36         void (*exit)(struct as_io_context *aic); /* called on task exit */
  37
  38         unsigned long state;
  39         atomic_t nr_queued; /* queued reads & sync writes */
  40         atomic_t nr_dispatched; /* number of requests gone to the drivers */
  41
  42         /* IO History tracking */
  43         /* Thinktime */
  44         unsigned long last_end_request;
  45         unsigned long ttime_total;
  46         unsigned long ttime_samples;
  47         unsigned long ttime_mean;
  48         /* Layout pattern */
  49         unsigned int seek_samples;
  50         sector_t last_request_pos;
  51         u64 seek_total;
  52         sector_t seek_mean;
  53 };
  54
  55 struct cfq_queue;
  56 struct cfq_io_context {
  57         /*
  58          * circular list of cfq_io_contexts belonging to a process io context
  59          */
  60         struct list_head list;
  61         struct cfq_queue *cfqq[2];
  62         void *key;
  63
  64         struct io_context *ioc;
  65
  66         unsigned long last_end_request;
  67         unsigned long last_queue;
  68         unsigned long ttime_total;
  69         unsigned long ttime_samples;
  70         unsigned long ttime_mean;
  71
  72         struct list_head queue_list;
  73
  74         void (*dtor)(struct cfq_io_context *);
  75         void (*exit)(struct cfq_io_context *);
  76 };
  77
  78 /*
  79  * This is the per-process I/O subsystem state.  It is refcounted and
  80  * kmalloc'ed. Currently all fields are modified in process io context
  81  * (apart from the atomic refcount), so require no locking.
  82  */
  83 struct io_context {
  84         atomic_t refcount;
  85         struct task_struct *task;
  86
  87         int (*set_ioprio)(struct io_context *, unsigned int);
  88
  89         /*
  90          * For request batching
  91          */
  92         unsigned long last_waited; /* Time last woken after wait for request */
  93         int nr_batch_requests;     /* Number of requests left in the batch */
  94
  95         struct as_io_context *aic;
  96         struct cfq_io_context *cic;
  97 };
  98
  99 void put_io_context(struct io_context *ioc);
 100 void exit_io_context(void);
 101 struct io_context *current_io_context(gfp_t gfp_flags);
 102 struct io_context *get_io_context(gfp_t gfp_flags);
 103 void copy_io_context(struct io_context **pdst, struct io_context **psrc);
 104 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
 105
 106 struct request;
 107 typedef void (rq_end_io_fn)(struct request *, int);
 108
 109 struct request_list {
 110         int count[2];
 111         int starved[2];
 112         int elvpriv;
 113         mempool_t *rq_pool;
 114         wait_queue_head_t wait[2];
 115 };
 116
 117 #define BLK_MAX_CDB     16
 118
 119 /*
 120  * try to put the fields that are referenced together in the same cacheline
 121  */
 122 struct request {
 123         struct list_head queuelist;
 124         struct list_head donelist;
 125
 126         unsigned long flags;            /* see REQ_ bits below */
 127
 128         /* Maintain bio traversal state for part by part I/O submission.
 129          * hard_* are block layer internals, no driver should touch them!
 130          */
 131
 132         sector_t sector;                /* next sector to submit */
 133         unsigned long nr_sectors;       /* no. of sectors left to submit */
 134         /* no. of sectors left to submit in the current segment */
 135         unsigned int current_nr_sectors;
 136
 137         sector_t hard_sector;           /* next sector to complete */
 138         unsigned long hard_nr_sectors;  /* no. of sectors left to complete */
 139         /* no. of sectors left to complete in the current segment */
 140         unsigned int hard_cur_sectors;
 141
 142         struct bio *bio;
 143         struct bio *biotail;
 144
 145         void *elevator_private;
 146         void *completion_data;
 147
 148         unsigned short ioprio;
 149
 150         int rq_status;  /* should split this into a few status bits */
 151         struct gendisk *rq_disk;
 152         int errors;
 153         unsigned long start_time;
 154
 155         /* Number of scatter-gather DMA addr+len pairs after
 156          * physical address coalescing is performed.
 157          */
 158         unsigned short nr_phys_segments;
 159
 160         /* Number of scatter-gather addr+len pairs after
 161          * physical and DMA remapping hardware coalescing is performed.
 162          * This is the number of scatter-gather entries the driver
 163          * will actually have to deal with after DMA mapping is done.
 164          */
 165         unsigned short nr_hw_segments;
 166
 167         int tag;
 168         char *buffer;
 169
 170         int ref_count;
 171         request_queue_t *q;
 172         struct request_list *rl;
 173
 174         struct completion *waiting;
 175         void *special;
 176
 177         /*
 178          * when request is used as a packet command carrier
 179          */
 180         unsigned int cmd_len;
 181         unsigned char cmd[BLK_MAX_CDB];
 182
 183         unsigned int data_len;
 184         void *data;
 185
 186         unsigned int sense_len;
 187         void *sense;
 188
 189         unsigned int timeout;
 190         int retries;
 191
 192         /*
 193          * For Power Management requests
 194          */
 195         struct request_pm_state *pm;
 196
 197         /*
 198          * completion callback. end_io_data should be folded in with waiting
 199          */
 200         rq_end_io_fn *end_io;
 201         void *end_io_data;
 202 };
 203
 204 /*
 205  * first three bits match BIO_RW* bits, important
 206  */
 207 enum rq_flag_bits {
 208         __REQ_RW,               /* not set, read. set, write */
 209         __REQ_FAILFAST,         /* no low level driver retries */
 210         __REQ_SORTED,           /* elevator knows about this request */
 211         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 212         __REQ_HARDBARRIER,      /* may not be passed by drive either */
 213         __REQ_FUA,              /* forced unit access */
 214         __REQ_CMD,              /* is a regular fs rw request */
 215         __REQ_NOMERGE,          /* don't touch this for merging */
 216         __REQ_STARTED,          /* drive already may have started this one */
 217         __REQ_DONTPREP,         /* don't call prep for this one */
 218         __REQ_QUEUED,           /* uses queueing */
 219         __REQ_ELVPRIV,          /* elevator private data attached */
 220         /*
 221          * for ATA/ATAPI devices
 222          */
 223         __REQ_PC,               /* packet command (special) */
 224         __REQ_BLOCK_PC,         /* queued down pc from block layer */
 225         __REQ_SENSE,            /* sense retrival */
 226
 227         __REQ_FAILED,           /* set if the request failed */
 228         __REQ_QUIET,            /* don't worry about errors */
 229         __REQ_SPECIAL,          /* driver suplied command */
 230         __REQ_DRIVE_CMD,
 231         __REQ_DRIVE_TASK,
 232         __REQ_DRIVE_TASKFILE,
 233         __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 234         __REQ_PM_SUSPEND,       /* suspend request */
 235         __REQ_PM_RESUME,        /* resume request */
 236         __REQ_PM_SHUTDOWN,      /* shutdown request */
 237         __REQ_ORDERED_COLOR,    /* is before or after barrier */
 238         __REQ_NR_BITS,          /* stops here */
 239 };
 240
 241 #define REQ_RW          (1 << __REQ_RW)
 242 #define REQ_FAILFAST    (1 << __REQ_FAILFAST)
 243 #define REQ_SORTED      (1 << __REQ_SORTED)
 244 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
 245 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
 246 #define REQ_FUA         (1 << __REQ_FUA)
 247 #define REQ_CMD         (1 << __REQ_CMD)
 248 #define REQ_NOMERGE     (1 << __REQ_NOMERGE)
 249 #define REQ_STARTED     (1 << __REQ_STARTED)
 250 #define REQ_DONTPREP    (1 << __REQ_DONTPREP)
 251 #define REQ_QUEUED      (1 << __REQ_QUEUED)
 252 #define REQ_ELVPRIV     (1 << __REQ_ELVPRIV)
 253 #define REQ_PC          (1 << __REQ_PC)
 254 #define REQ_BLOCK_PC    (1 << __REQ_BLOCK_PC)
 255 #define REQ_SENSE       (1 << __REQ_SENSE)
 256 #define REQ_FAILED      (1 << __REQ_FAILED)
 257 #define REQ_QUIET       (1 << __REQ_QUIET)
 258 #define REQ_SPECIAL     (1 << __REQ_SPECIAL)
 259 #define REQ_DRIVE_CMD   (1 << __REQ_DRIVE_CMD)
 260 #define REQ_DRIVE_TASK  (1 << __REQ_DRIVE_TASK)
 261 #define REQ_DRIVE_TASKFILE      (1 << __REQ_DRIVE_TASKFILE)
 262 #define REQ_PREEMPT     (1 << __REQ_PREEMPT)
 263 #define REQ_PM_SUSPEND  (1 << __REQ_PM_SUSPEND)
 264 #define REQ_PM_RESUME   (1 << __REQ_PM_RESUME)
 265 #define REQ_PM_SHUTDOWN (1 << __REQ_PM_SHUTDOWN)
 266 #define REQ_ORDERED_COLOR       (1 << __REQ_ORDERED_COLOR)
 267
 268 /*
 269  * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME
 270  * requests. Some step values could eventually be made generic.
 271  */
 272 struct request_pm_state
 273 {
 274         /* PM state machine step value, currently driver specific */
 275         int     pm_step;
 276         /* requested PM state value (S1, S2, S3, S4, ...) */
 277         u32     pm_state;
 278         void*   data;           /* for driver use */
 279 };
 280
 281 #include <linux/elevator.h>
 282
 283 typedef int (merge_request_fn) (request_queue_t *, struct request *,
 284                                 struct bio *);
 285 typedef int (merge_requests_fn) (request_queue_t *, struct request *,
 286                                  struct request *);
 287 typedef void (request_fn_proc) (request_queue_t *q);
 288 typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
 289 typedef int (prep_rq_fn) (request_queue_t *, struct request *);
 290 typedef void (unplug_fn) (request_queue_t *);
 291
 292 struct bio_vec;
 293 typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
 294 typedef void (activity_fn) (void *data, int rw);
 295 typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
 296 typedef void (prepare_flush_fn) (request_queue_t *, struct request *);
 297 typedef void (softirq_done_fn)(struct request *);
 298
 299 enum blk_queue_state {
 300         Queue_down,
 301         Queue_up,
 302 };
 303
 304 struct blk_queue_tag {
 305         struct request **tag_index;     /* map of busy tags */
 306         unsigned long *tag_map;         /* bit map of free/busy tags */
 307         struct list_head busy_list;     /* fifo list of busy tags */
 308         int busy;                       /* current depth */
 309         int max_depth;                  /* what we will send to device */
 310         int real_max_depth;             /* what the array can hold */
 311         atomic_t refcnt;                /* map can be shared */
 312 };
 313
 314 struct request_queue
 315 {
 316         /*
 317          * Together with queue_head for cacheline sharing
 318          */
 319         struct list_head        queue_head;
 320         struct request          *last_merge;
 321         elevator_t              *elevator;
 322
 323         /*
 324          * the queue request freelist, one for reads and one for writes
 325          */
 326         struct request_list     rq;
 327
 328         request_fn_proc         *request_fn;
 329         merge_request_fn        *back_merge_fn;
 330         merge_request_fn        *front_merge_fn;
 331         merge_requests_fn       *merge_requests_fn;
 332         make_request_fn         *make_request_fn;
 333         prep_rq_fn              *prep_rq_fn;
 334         unplug_fn               *unplug_fn;
 335         merge_bvec_fn           *merge_bvec_fn;
 336         activity_fn             *activity_fn;
 337         issue_flush_fn          *issue_flush_fn;
 338         prepare_flush_fn        *prepare_flush_fn;
 339         softirq_done_fn         *softirq_done_fn;
 340
 341         /*
 342          * Dispatch queue sorting
 343          */
 344         sector_t                end_sector;
 345         struct request          *boundary_rq;
 346
 347         /*
 348          * Auto-unplugging state
 349          */
 350         struct timer_list       unplug_timer;
 351         int                     unplug_thresh;  /* After this many requests */
 352         unsigned long           unplug_delay;   /* After this many jiffies */
 353         struct work_struct      unplug_work;
 354
 355         struct backing_dev_info backing_dev_info;
 356
 357         /*
 358          * The queue owner gets to use this for whatever they like.
 359          * ll_rw_blk doesn't touch it.
 360          */
 361         void                    *queuedata;
 362
 363         void                    *activity_data;
 364
 365         /*
 366          * queue needs bounce pages for pages above this limit
 367          */
 368         unsigned long           bounce_pfn;
 369         gfp_t                   bounce_gfp;
 370
 371         /*
 372          * various queue flags, see QUEUE_* below
 373          */
 374         unsigned long           queue_flags;
 375
 376         /*
 377          * protects queue structures from reentrancy. ->__queue_lock should
 378          * _never_ be used directly, it is queue private. always use
 379          * ->queue_lock.
 380          */
 381         spinlock_t              __queue_lock;
 382         spinlock_t              *queue_lock;
 383
 384         /*
 385          * queue kobject
 386          */
 387         struct kobject kobj;
 388
 389         /*
 390          * queue settings
 391          */
 392         unsigned long           nr_requests;    /* Max # of requests */
 393         unsigned int            nr_congestion_on;
 394         unsigned int            nr_congestion_off;
 395         unsigned int            nr_batching;
 396
 397         unsigned int            max_sectors;
 398         unsigned int            max_hw_sectors;
 399         unsigned short          max_phys_segments;
 400         unsigned short          max_hw_segments;
 401         unsigned short          hardsect_size;
 402         unsigned int            max_segment_size;
 403
 404         unsigned long           seg_boundary_mask;
 405         unsigned int            dma_alignment;
 406
 407         struct blk_queue_tag    *queue_tags;
 408
 409         atomic_t                refcnt;
 410
 411         unsigned int            nr_sorted;
 412         unsigned int            in_flight;
 413
 414         /*
 415          * sg stuff
 416          */
 417         unsigned int            sg_timeout;
 418         unsigned int            sg_reserved_size;
 419         int                     node;
 420
 421         /*
 422          * reserved for flush operations
 423          */
 424         unsigned int            ordered, next_ordered, ordseq;
 425         int                     orderr, ordcolor;
 426         struct request          pre_flush_rq, bar_rq, post_flush_rq;
 427         struct request          *orig_bar_rq;
 428         unsigned int            bi_size;
 429 };
 430
 431 #define RQ_INACTIVE             (-1)
 432 #define RQ_ACTIVE               1
 433 #define RQ_SCSI_BUSY            0xffff
 434 #define RQ_SCSI_DONE            0xfffe
 435 #define RQ_SCSI_DISCONNECTING   0xffe0
 436
 437 #define QUEUE_FLAG_CLUSTER      0       /* cluster several segments into 1 */
 438 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 439 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 440 #define QUEUE_FLAG_READFULL     3       /* write queue has been filled */
 441 #define QUEUE_FLAG_WRITEFULL    4       /* read queue has been filled */
 442 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 443 #define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 444 #define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
 445 #define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 446
 447 enum {
 448         /*
 449          * Hardbarrier is supported with one of the following methods.
 450          *
 451          * NONE         : hardbarrier unsupported
 452          * DRAIN        : ordering by draining is enough
 453          * DRAIN_FLUSH  : ordering by draining w/ pre and post flushes
 454          * DRAIN_FUA    : ordering by draining w/ pre flush and FUA write
 455          * TAG          : ordering by tag is enough
 456          * TAG_FLUSH    : ordering by tag w/ pre and post flushes
 457          * TAG_FUA      : ordering by tag w/ pre flush and FUA write
 458          */
 459         QUEUE_ORDERED_NONE      = 0x00,
 460         QUEUE_ORDERED_DRAIN     = 0x01,
 461         QUEUE_ORDERED_TAG       = 0x02,
 462
 463         QUEUE_ORDERED_PREFLUSH  = 0x10,
 464         QUEUE_ORDERED_POSTFLUSH = 0x20,
 465         QUEUE_ORDERED_FUA       = 0x40,
 466
 467         QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
 468                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 469         QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
 470                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 471         QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
 472                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 473         QUEUE_ORDERED_TAG_FUA   = QUEUE_ORDERED_TAG |
 474                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 475
 476         /*
 477          * Ordered operation sequence
 478          */
 479         QUEUE_ORDSEQ_STARTED    = 0x01, /* flushing in progress */
 480         QUEUE_ORDSEQ_DRAIN      = 0x02, /* waiting for the queue to be drained */
 481         QUEUE_ORDSEQ_PREFLUSH   = 0x04, /* pre-flushing in progress */
 482         QUEUE_ORDSEQ_BAR        = 0x08, /* original barrier req in progress */
 483         QUEUE_ORDSEQ_POSTFLUSH  = 0x10, /* post-flushing in progress */
 484         QUEUE_ORDSEQ_DONE       = 0x20,
 485 };
 486
 487 #define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 488 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 489 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 490 #define blk_queue_flushing(q)   ((q)->ordseq)
 491
 492 #define blk_fs_request(rq)      ((rq)->flags & REQ_CMD)
 493 #define blk_pc_request(rq)      ((rq)->flags & REQ_BLOCK_PC)
 494 #define blk_noretry_request(rq) ((rq)->flags & REQ_FAILFAST)
 495 #define blk_rq_started(rq)      ((rq)->flags & REQ_STARTED)
 496
 497 #define blk_account_rq(rq)      (blk_rq_started(rq) && blk_fs_request(rq))
 498
 499 #define blk_pm_suspend_request(rq)      ((rq)->flags & REQ_PM_SUSPEND)
 500 #define blk_pm_resume_request(rq)       ((rq)->flags & REQ_PM_RESUME)
 501 #define blk_pm_request(rq)      \
 502         ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
 503
 504 #define blk_sorted_rq(rq)       ((rq)->flags & REQ_SORTED)
 505 #define blk_barrier_rq(rq)      ((rq)->flags & REQ_HARDBARRIER)
 506 #define blk_fua_rq(rq)          ((rq)->flags & REQ_FUA)
 507
 508 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 509
 510 #define rq_data_dir(rq)         ((rq)->flags & 1)
 511
 512 static inline int blk_queue_full(struct request_queue *q, int rw)
 513 {
 514         if (rw == READ)
 515                 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 516         return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 517 }
 518
 519 static inline void blk_set_queue_full(struct request_queue *q, int rw)
 520 {
 521         if (rw == READ)
 522                 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 523         else
 524                 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 525 }
 526
 527 static inline void blk_clear_queue_full(struct request_queue *q, int rw)
 528 {
 529         if (rw == READ)
 530                 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 531         else
 532                 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 533 }
 534
 535
 536 /*
 537  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 538  * it already be started by driver.
 539  */
 540 #define RQ_NOMERGE_FLAGS        \
 541         (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
 542 #define rq_mergeable(rq)        \
 543         (!((rq)->flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
 544
 545 /*
 546  * noop, requests are automagically marked as active/inactive by I/O
 547  * scheduler -- see elv_next_request
 548  */
 549 #define blk_queue_headactive(q, head_active)
 550
 551 /*
 552  * q->prep_rq_fn return values
 553  */
 554 #define BLKPREP_OK              0       /* serve it */
 555 #define BLKPREP_KILL            1       /* fatal error, kill */
 556 #define BLKPREP_DEFER           2       /* leave on queue */
 557
 558 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 559
 560 /*
 561  * standard bounce addresses:
 562  *
 563  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 564  * BLK_BOUNCE_ANY       : don't bounce anything
 565  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 566  */
 567 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 568 #define BLK_BOUNCE_ANY          ((u64)blk_max_pfn << PAGE_SHIFT)
 569 #define BLK_BOUNCE_ISA          (ISA_DMA_THRESHOLD)
 570
 571 #ifdef CONFIG_MMU
 572 extern int init_emergency_isa_pool(void);
 573 extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
 574 #else
 575 static inline int init_emergency_isa_pool(void)
 576 {
 577         return 0;
 578 }
 579 static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
 580 {
 581 }
 582 #endif /* CONFIG_MMU */
 583
 584 #define rq_for_each_bio(_bio, rq)       \
 585         if ((rq->bio))                  \
 586                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 587
 588 struct sec_size {
 589         unsigned block_size;
 590         unsigned block_size_bits;
 591 };
 592
 593 extern int blk_register_queue(struct gendisk *disk);
 594 extern void blk_unregister_queue(struct gendisk *disk);
 595 extern void register_disk(struct gendisk *dev);
 596 extern void generic_make_request(struct bio *bio);
 597 extern void blk_put_request(struct request *);
 598 extern void __blk_put_request(request_queue_t *, struct request *);
 599 extern void blk_end_sync_rq(struct request *rq, int error);
 600 extern struct request *blk_get_request(request_queue_t *, int, gfp_t);
 601 extern void blk_insert_request(request_queue_t *, struct request *, int, void *);
 602 extern void blk_requeue_request(request_queue_t *, struct request *);
 603 extern void blk_plug_device(request_queue_t *);
 604 extern int blk_remove_plug(request_queue_t *);
 605 extern void blk_recount_segments(request_queue_t *, struct bio *);
 606 extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
 607 extern void blk_start_queue(request_queue_t *q);
 608 extern void blk_stop_queue(request_queue_t *q);
 609 extern void blk_sync_queue(struct request_queue *q);
 610 extern void __blk_stop_queue(request_queue_t *q);
 611 extern void blk_run_queue(request_queue_t *);
 612 extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
 613 extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
 614 extern int blk_rq_unmap_user(struct bio *, unsigned int);
 615 extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
 616 extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
 617 extern int blk_execute_rq(request_queue_t *, struct gendisk *,
 618                           struct request *, int);
 619 extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,
 620                                   struct request *, int, rq_end_io_fn *);
 621
 622 static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
 623 {
 624         return bdev->bd_disk->queue;
 625 }
 626
 627 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
 628                                        struct page *page)
 629 {
 630         if (bdi && bdi->unplug_io_fn)
 631                 bdi->unplug_io_fn(bdi, page);
 632 }
 633
 634 static inline void blk_run_address_space(struct address_space *mapping)
 635 {
 636         if (mapping)
 637                 blk_run_backing_dev(mapping->backing_dev_info, NULL);
 638 }
 639
 640 /*
 641  * end_request() and friends. Must be called with the request queue spinlock
 642  * acquired. All functions called within end_request() _must_be_ atomic.
 643  *
 644  * Several drivers define their own end_request and call
 645  * end_that_request_first() and end_that_request_last()
 646  * for parts of the original function. This prevents
 647  * code duplication in drivers.
 648  */
 649 extern int end_that_request_first(struct request *, int, int);
 650 extern int end_that_request_chunk(struct request *, int, int);
 651 extern void end_that_request_last(struct request *, int);
 652 extern void end_request(struct request *req, int uptodate);
 653 extern void blk_complete_request(struct request *);
 654
 655 static inline int rq_all_done(struct request *rq, unsigned int nr_bytes)
 656 {
 657         if (blk_fs_request(rq))
 658                 return (nr_bytes >= (rq->hard_nr_sectors << 9));
 659         else if (blk_pc_request(rq))
 660                 return nr_bytes >= rq->data_len;
 661
 662         return 0;
 663 }
 664
 665 /*
 666  * end_that_request_first/chunk() takes an uptodate argument. we account
 667  * any value <= as an io error. 0 means -EIO for compatability reasons,
 668  * any other < 0 value is the direct error type. An uptodate value of
 669  * 1 indicates successful io completion
 670  */
 671 #define end_io_error(uptodate)  (unlikely((uptodate) <= 0))
 672
 673 static inline void blkdev_dequeue_request(struct request *req)
 674 {
 675         elv_dequeue_request(req->q, req);
 676 }
 677
 678 /*
 679  * This should be in elevator.h, but that requires pulling in rq and q
 680  */
 681 static inline void elv_dispatch_add_tail(struct request_queue *q,
 682                                          struct request *rq)
 683 {
 684         if (q->last_merge == rq)
 685                 q->last_merge = NULL;
 686         q->nr_sorted--;
 687
 688         q->end_sector = rq_end_sector(rq);
 689         q->boundary_rq = rq;
 690         list_add_tail(&rq->queuelist, &q->queue_head);
 691 }
 692
 693 /*
 694  * Access functions for manipulating queue properties
 695  */
 696 extern request_queue_t *blk_init_queue_node(request_fn_proc *rfn,
 697                                         spinlock_t *lock, int node_id);
 698 extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
 699 extern void blk_cleanup_queue(request_queue_t *);
 700 extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
 701 extern void blk_queue_bounce_limit(request_queue_t *, u64);
 702 extern void blk_queue_max_sectors(request_queue_t *, unsigned int);
 703 extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
 704 extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
 705 extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
 706 extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
 707 extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
 708 extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
 709 extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
 710 extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
 711 extern void blk_queue_dma_alignment(request_queue_t *, int);
 712 extern void blk_queue_softirq_done(request_queue_t *, softirq_done_fn *);
 713 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 714 extern int blk_queue_ordered(request_queue_t *, unsigned, prepare_flush_fn *);
 715 extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
 716 extern int blk_do_ordered(request_queue_t *, struct request **);
 717 extern unsigned blk_ordered_cur_seq(request_queue_t *);
 718 extern unsigned blk_ordered_req_seq(struct request *);
 719 extern void blk_ordered_complete_seq(request_queue_t *, unsigned, int);
 720
 721 extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
 722 extern void blk_dump_rq_flags(struct request *, char *);
 723 extern void generic_unplug_device(request_queue_t *);
 724 extern void __generic_unplug_device(request_queue_t *);
 725 extern long nr_blockdev_pages(void);
 726
 727 int blk_get_queue(request_queue_t *);
 728 request_queue_t *blk_alloc_queue(gfp_t);
 729 request_queue_t *blk_alloc_queue_node(gfp_t, int);
 730 #define blk_put_queue(q) blk_cleanup_queue((q))
 731
 732 /*
 733  * tag stuff
 734  */
 735 #define blk_queue_tag_depth(q)          ((q)->queue_tags->busy)
 736 #define blk_queue_tag_queue(q)          ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
 737 #define blk_rq_tagged(rq)               ((rq)->flags & REQ_QUEUED)
 738 extern int blk_queue_start_tag(request_queue_t *, struct request *);
 739 extern struct request *blk_queue_find_tag(request_queue_t *, int);
 740 extern void blk_queue_end_tag(request_queue_t *, struct request *);
 741 extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
 742 extern void blk_queue_free_tags(request_queue_t *);
 743 extern int blk_queue_resize_tags(request_queue_t *, int);
 744 extern void blk_queue_invalidate_tags(request_queue_t *);
 745 extern long blk_congestion_wait(int rw, long timeout);
 746
 747 extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
 748 extern int blkdev_issue_flush(struct block_device *, sector_t *);
 749
 750 #define MAX_PHYS_SEGMENTS 128
 751 #define MAX_HW_SEGMENTS 128
 752 #define SAFE_MAX_SECTORS 255
 753 #define BLK_DEF_MAX_SECTORS 1024
 754
 755 #define MAX_SEGMENT_SIZE        65536
 756
 757 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
 758
 759 static inline int queue_hardsect_size(request_queue_t *q)
 760 {
 761         int retval = 512;
 762
 763         if (q && q->hardsect_size)
 764                 retval = q->hardsect_size;
 765
 766         return retval;
 767 }
 768
 769 static inline int bdev_hardsect_size(struct block_device *bdev)
 770 {
 771         return queue_hardsect_size(bdev_get_queue(bdev));
 772 }
 773
 774 static inline int queue_dma_alignment(request_queue_t *q)
 775 {
 776         int retval = 511;
 777
 778         if (q && q->dma_alignment)
 779                 retval = q->dma_alignment;
 780
 781         return retval;
 782 }
 783
 784 static inline int bdev_dma_aligment(struct block_device *bdev)
 785 {
 786         return queue_dma_alignment(bdev_get_queue(bdev));
 787 }
 788
 789 #define blk_finished_io(nsects) do { } while (0)
 790 #define blk_started_io(nsects)  do { } while (0)
 791
 792 /* assumes size > 256 */
 793 static inline unsigned int blksize_bits(unsigned int size)
 794 {
 795         unsigned int bits = 8;
 796         do {
 797                 bits++;
 798                 size >>= 1;
 799         } while (size > 256);
 800         return bits;
 801 }
 802
 803 static inline unsigned int block_size(struct block_device *bdev)
 804 {
 805         return bdev->bd_block_size;
 806 }
 807
 808 typedef struct {struct page *v;} Sector;
 809
 810 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
 811
 812 static inline void put_dev_sector(Sector p)
 813 {
 814         page_cache_release(p.v);
 815 }
 816
 817 struct work_struct;
 818 int kblockd_schedule_work(struct work_struct *work);
 819 void kblockd_flush(void);
 820
 821 #ifdef CONFIG_LBD
 822 # include <asm/div64.h>
 823 # define sector_div(a, b) do_div(a, b)
 824 #else
 825 # define sector_div(n, b)( \
 826 { \
 827         int _res; \
 828         _res = (n) % (b); \
 829         (n) /= (b); \
 830         _res; \
 831 } \
 832 )
 833 #endif
 834
 835 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
 836         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
 837 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
 838         MODULE_ALIAS("block-major-" __stringify(major) "-*")
 839
 840
 841 #endif