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 scsi_ioctl_command;
  21
  22 struct request_queue;
  23 typedef struct request_queue request_queue_t;
  24 struct elevator_queue;
  25 typedef struct elevator_queue elevator_t;
  26 struct request_pm_state;
  27 struct blk_trace;
  28
  29 #define BLKDEV_MIN_RQ   4
  30 #define BLKDEV_MAX_RQ   128     /* Default maximum */
  31
  32 /*
  33  * This is the per-process anticipatory I/O scheduler state.
  34  */
  35 struct as_io_context {
  36         spinlock_t lock;
  37
  38         void (*dtor)(struct as_io_context *aic); /* destructor */
  39         void (*exit)(struct as_io_context *aic); /* called on task exit */
  40
  41         unsigned long state;
  42         atomic_t nr_queued; /* queued reads & sync writes */
  43         atomic_t nr_dispatched; /* number of requests gone to the drivers */
  44
  45         /* IO History tracking */
  46         /* Thinktime */
  47         unsigned long last_end_request;
  48         unsigned long ttime_total;
  49         unsigned long ttime_samples;
  50         unsigned long ttime_mean;
  51         /* Layout pattern */
  52         unsigned int seek_samples;
  53         sector_t last_request_pos;
  54         u64 seek_total;
  55         sector_t seek_mean;
  56 };
  57
  58 struct cfq_queue;
  59 struct cfq_io_context {
  60         struct rb_node rb_node;
  61         void *key;
  62
  63         struct cfq_queue *cfqq[2];
  64
  65         struct io_context *ioc;
  66
  67         unsigned long last_end_request;
  68         sector_t last_request_pos;
  69         unsigned long last_queue;
  70
  71         unsigned long ttime_total;
  72         unsigned long ttime_samples;
  73         unsigned long ttime_mean;
  74
  75         unsigned int seek_samples;
  76         u64 seek_total;
  77         sector_t seek_mean;
  78
  79         struct list_head queue_list;
  80
  81         void (*dtor)(struct io_context *); /* destructor */
  82         void (*exit)(struct io_context *); /* called on task exit */
  83 };
  84
  85 /*
  86  * This is the per-process I/O subsystem state.  It is refcounted and
  87  * kmalloc'ed. Currently all fields are modified in process io context
  88  * (apart from the atomic refcount), so require no locking.
  89  */
  90 struct io_context {
  91         atomic_t refcount;
  92         struct task_struct *task;
  93
  94         int (*set_ioprio)(struct io_context *, unsigned int);
  95
  96         /*
  97          * For request batching
  98          */
  99         unsigned long last_waited; /* Time last woken after wait for request */
 100         int nr_batch_requests;     /* Number of requests left in the batch */
 101
 102         struct as_io_context *aic;
 103         struct rb_root cic_root;
 104 };
 105
 106 void put_io_context(struct io_context *ioc);
 107 void exit_io_context(void);
 108 struct io_context *current_io_context(gfp_t gfp_flags);
 109 struct io_context *get_io_context(gfp_t gfp_flags);
 110 void copy_io_context(struct io_context **pdst, struct io_context **psrc);
 111 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
 112
 113 struct request;
 114 typedef void (rq_end_io_fn)(struct request *, int);
 115
 116 struct request_list {
 117         int count[2];
 118         int starved[2];
 119         int elvpriv;
 120         mempool_t *rq_pool;
 121         wait_queue_head_t wait[2];
 122 };
 123
 124 #define BLK_MAX_CDB     16
 125
 126 /*
 127  * try to put the fields that are referenced together in the same cacheline
 128  */
 129 struct request {
 130         struct list_head queuelist;
 131         struct list_head donelist;
 132
 133         unsigned long flags;            /* see REQ_ bits below */
 134
 135         /* Maintain bio traversal state for part by part I/O submission.
 136          * hard_* are block layer internals, no driver should touch them!
 137          */
 138
 139         sector_t sector;                /* next sector to submit */
 140         unsigned long nr_sectors;       /* no. of sectors left to submit */
 141         /* no. of sectors left to submit in the current segment */
 142         unsigned int current_nr_sectors;
 143
 144         sector_t hard_sector;           /* next sector to complete */
 145         unsigned long hard_nr_sectors;  /* no. of sectors left to complete */
 146         /* no. of sectors left to complete in the current segment */
 147         unsigned int hard_cur_sectors;
 148
 149         struct bio *bio;
 150         struct bio *biotail;
 151
 152         void *elevator_private;
 153         void *completion_data;
 154
 155         unsigned short ioprio;
 156
 157         int rq_status;  /* should split this into a few status bits */
 158         struct gendisk *rq_disk;
 159         int errors;
 160         unsigned long start_time;
 161
 162         /* Number of scatter-gather DMA addr+len pairs after
 163          * physical address coalescing is performed.
 164          */
 165         unsigned short nr_phys_segments;
 166
 167         /* Number of scatter-gather addr+len pairs after
 168          * physical and DMA remapping hardware coalescing is performed.
 169          * This is the number of scatter-gather entries the driver
 170          * will actually have to deal with after DMA mapping is done.
 171          */
 172         unsigned short nr_hw_segments;
 173
 174         int tag;
 175         char *buffer;
 176
 177         int ref_count;
 178         request_queue_t *q;
 179         struct request_list *rl;
 180
 181         struct completion *waiting;
 182         void *special;
 183
 184         /*
 185          * when request is used as a packet command carrier
 186          */
 187         unsigned int cmd_len;
 188         unsigned char cmd[BLK_MAX_CDB];
 189
 190         unsigned int data_len;
 191         void *data;
 192
 193         unsigned int sense_len;
 194         void *sense;
 195
 196         unsigned int timeout;
 197         int retries;
 198
 199         /*
 200          * For Power Management requests
 201          */
 202         struct request_pm_state *pm;
 203
 204         /*
 205          * completion callback. end_io_data should be folded in with waiting
 206          */
 207         rq_end_io_fn *end_io;
 208         void *end_io_data;
 209 };
 210
 211 /*
 212  * first three bits match BIO_RW* bits, important
 213  */
 214 enum rq_flag_bits {
 215         __REQ_RW,               /* not set, read. set, write */
 216         __REQ_FAILFAST,         /* no low level driver retries */
 217         __REQ_SORTED,           /* elevator knows about this request */
 218         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 219         __REQ_HARDBARRIER,      /* may not be passed by drive either */
 220         __REQ_FUA,              /* forced unit access */
 221         __REQ_CMD,              /* is a regular fs rw request */
 222         __REQ_NOMERGE,          /* don't touch this for merging */
 223         __REQ_STARTED,          /* drive already may have started this one */
 224         __REQ_DONTPREP,         /* don't call prep for this one */
 225         __REQ_QUEUED,           /* uses queueing */
 226         __REQ_ELVPRIV,          /* elevator private data attached */
 227         /*
 228          * for ATA/ATAPI devices
 229          */
 230         __REQ_PC,               /* packet command (special) */
 231         __REQ_BLOCK_PC,         /* queued down pc from block layer */
 232         __REQ_SENSE,            /* sense retrival */
 233
 234         __REQ_FAILED,           /* set if the request failed */
 235         __REQ_QUIET,            /* don't worry about errors */
 236         __REQ_SPECIAL,          /* driver suplied command */
 237         __REQ_DRIVE_CMD,
 238         __REQ_DRIVE_TASK,
 239         __REQ_DRIVE_TASKFILE,
 240         __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 241         __REQ_PM_SUSPEND,       /* suspend request */
 242         __REQ_PM_RESUME,        /* resume request */
 243         __REQ_PM_SHUTDOWN,      /* shutdown request */
 244         __REQ_ORDERED_COLOR,    /* is before or after barrier */
 245         __REQ_NR_BITS,          /* stops here */
 246 };
 247
 248 #define REQ_RW          (1 << __REQ_RW)
 249 #define REQ_FAILFAST    (1 << __REQ_FAILFAST)
 250 #define REQ_SORTED      (1 << __REQ_SORTED)
 251 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
 252 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
 253 #define REQ_FUA         (1 << __REQ_FUA)
 254 #define REQ_CMD         (1 << __REQ_CMD)
 255 #define REQ_NOMERGE     (1 << __REQ_NOMERGE)
 256 #define REQ_STARTED     (1 << __REQ_STARTED)
 257 #define REQ_DONTPREP    (1 << __REQ_DONTPREP)
 258 #define REQ_QUEUED      (1 << __REQ_QUEUED)
 259 #define REQ_ELVPRIV     (1 << __REQ_ELVPRIV)
 260 #define REQ_PC          (1 << __REQ_PC)
 261 #define REQ_BLOCK_PC    (1 << __REQ_BLOCK_PC)
 262 #define REQ_SENSE       (1 << __REQ_SENSE)
 263 #define REQ_FAILED      (1 << __REQ_FAILED)
 264 #define REQ_QUIET       (1 << __REQ_QUIET)
 265 #define REQ_SPECIAL     (1 << __REQ_SPECIAL)
 266 #define REQ_DRIVE_CMD   (1 << __REQ_DRIVE_CMD)
 267 #define REQ_DRIVE_TASK  (1 << __REQ_DRIVE_TASK)
 268 #define REQ_DRIVE_TASKFILE      (1 << __REQ_DRIVE_TASKFILE)
 269 #define REQ_PREEMPT     (1 << __REQ_PREEMPT)
 270 #define REQ_PM_SUSPEND  (1 << __REQ_PM_SUSPEND)
 271 #define REQ_PM_RESUME   (1 << __REQ_PM_RESUME)
 272 #define REQ_PM_SHUTDOWN (1 << __REQ_PM_SHUTDOWN)
 273 #define REQ_ORDERED_COLOR       (1 << __REQ_ORDERED_COLOR)
 274
 275 /*
 276  * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME
 277  * requests. Some step values could eventually be made generic.
 278  */
 279 struct request_pm_state
 280 {
 281         /* PM state machine step value, currently driver specific */
 282         int     pm_step;
 283         /* requested PM state value (S1, S2, S3, S4, ...) */
 284         u32     pm_state;
 285         void*   data;           /* for driver use */
 286 };
 287
 288 #include <linux/elevator.h>
 289
 290 typedef int (merge_request_fn) (request_queue_t *, struct request *,
 291                                 struct bio *);
 292 typedef int (merge_requests_fn) (request_queue_t *, struct request *,
 293                                  struct request *);
 294 typedef void (request_fn_proc) (request_queue_t *q);
 295 typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
 296 typedef int (prep_rq_fn) (request_queue_t *, struct request *);
 297 typedef void (unplug_fn) (request_queue_t *);
 298
 299 struct bio_vec;
 300 typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
 301 typedef void (activity_fn) (void *data, int rw);
 302 typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
 303 typedef void (prepare_flush_fn) (request_queue_t *, struct request *);
 304 typedef void (softirq_done_fn)(struct request *);
 305
 306 enum blk_queue_state {
 307         Queue_down,
 308         Queue_up,
 309 };
 310
 311 struct blk_queue_tag {
 312         struct request **tag_index;     /* map of busy tags */
 313         unsigned long *tag_map;         /* bit map of free/busy tags */
 314         struct list_head busy_list;     /* fifo list of busy tags */
 315         int busy;                       /* current depth */
 316         int max_depth;                  /* what we will send to device */
 317         int real_max_depth;             /* what the array can hold */
 318         atomic_t refcnt;                /* map can be shared */
 319 };
 320
 321 struct request_queue
 322 {
 323         /*
 324          * Together with queue_head for cacheline sharing
 325          */
 326         struct list_head        queue_head;
 327         struct request          *last_merge;
 328         elevator_t              *elevator;
 329
 330         /*
 331          * the queue request freelist, one for reads and one for writes
 332          */
 333         struct request_list     rq;
 334
 335         request_fn_proc         *request_fn;
 336         merge_request_fn        *back_merge_fn;
 337         merge_request_fn        *front_merge_fn;
 338         merge_requests_fn       *merge_requests_fn;
 339         make_request_fn         *make_request_fn;
 340         prep_rq_fn              *prep_rq_fn;
 341         unplug_fn               *unplug_fn;
 342         merge_bvec_fn           *merge_bvec_fn;
 343         activity_fn             *activity_fn;
 344         issue_flush_fn          *issue_flush_fn;
 345         prepare_flush_fn        *prepare_flush_fn;
 346         softirq_done_fn         *softirq_done_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         void                    *activity_data;
 371
 372         /*
 373          * queue needs bounce pages for pages above this limit
 374          */
 375         unsigned long           bounce_pfn;
 376         gfp_t                   bounce_gfp;
 377
 378         /*
 379          * various queue flags, see QUEUE_* below
 380          */
 381         unsigned long           queue_flags;
 382
 383         /*
 384          * protects queue structures from reentrancy. ->__queue_lock should
 385          * _never_ be used directly, it is queue private. always use
 386          * ->queue_lock.
 387          */
 388         spinlock_t              __queue_lock;
 389         spinlock_t              *queue_lock;
 390
 391         /*
 392          * queue kobject
 393          */
 394         struct kobject kobj;
 395
 396         /*
 397          * queue settings
 398          */
 399         unsigned long           nr_requests;    /* Max # of requests */
 400         unsigned int            nr_congestion_on;
 401         unsigned int            nr_congestion_off;
 402         unsigned int            nr_batching;
 403
 404         unsigned int            max_sectors;
 405         unsigned int            max_hw_sectors;
 406         unsigned short          max_phys_segments;
 407         unsigned short          max_hw_segments;
 408         unsigned short          hardsect_size;
 409         unsigned int            max_segment_size;
 410
 411         unsigned long           seg_boundary_mask;
 412         unsigned int            dma_alignment;
 413
 414         struct blk_queue_tag    *queue_tags;
 415
 416         unsigned int            nr_sorted;
 417         unsigned int            in_flight;
 418
 419         /*
 420          * sg stuff
 421          */
 422         unsigned int            sg_timeout;
 423         unsigned int            sg_reserved_size;
 424         int                     node;
 425
 426         struct blk_trace        *blk_trace;
 427
 428         /*
 429          * reserved for flush operations
 430          */
 431         unsigned int            ordered, next_ordered, ordseq;
 432         int                     orderr, ordcolor;
 433         struct request          pre_flush_rq, bar_rq, post_flush_rq;
 434         struct request          *orig_bar_rq;
 435         unsigned int            bi_size;
 436
 437         struct mutex            sysfs_lock;
 438 };
 439
 440 #define RQ_INACTIVE             (-1)
 441 #define RQ_ACTIVE               1
 442 #define RQ_SCSI_BUSY            0xffff
 443 #define RQ_SCSI_DONE            0xfffe
 444 #define RQ_SCSI_DISCONNECTING   0xffe0
 445
 446 #define QUEUE_FLAG_CLUSTER      0       /* cluster several segments into 1 */
 447 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 448 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 449 #define QUEUE_FLAG_READFULL     3       /* write queue has been filled */
 450 #define QUEUE_FLAG_WRITEFULL    4       /* read queue has been filled */
 451 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 452 #define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 453 #define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
 454 #define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 455
 456 enum {
 457         /*
 458          * Hardbarrier is supported with one of the following methods.
 459          *
 460          * NONE         : hardbarrier unsupported
 461          * DRAIN        : ordering by draining is enough
 462          * DRAIN_FLUSH  : ordering by draining w/ pre and post flushes
 463          * DRAIN_FUA    : ordering by draining w/ pre flush and FUA write
 464          * TAG          : ordering by tag is enough
 465          * TAG_FLUSH    : ordering by tag w/ pre and post flushes
 466          * TAG_FUA      : ordering by tag w/ pre flush and FUA write
 467          */
 468         QUEUE_ORDERED_NONE      = 0x00,
 469         QUEUE_ORDERED_DRAIN     = 0x01,
 470         QUEUE_ORDERED_TAG       = 0x02,
 471
 472         QUEUE_ORDERED_PREFLUSH  = 0x10,
 473         QUEUE_ORDERED_POSTFLUSH = 0x20,
 474         QUEUE_ORDERED_FUA       = 0x40,
 475
 476         QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
 477                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 478         QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
 479                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 480         QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
 481                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 482         QUEUE_ORDERED_TAG_FUA   = QUEUE_ORDERED_TAG |
 483                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 484
 485         /*
 486          * Ordered operation sequence
 487          */
 488         QUEUE_ORDSEQ_STARTED    = 0x01, /* flushing in progress */
 489         QUEUE_ORDSEQ_DRAIN      = 0x02, /* waiting for the queue to be drained */
 490         QUEUE_ORDSEQ_PREFLUSH   = 0x04, /* pre-flushing in progress */
 491         QUEUE_ORDSEQ_BAR        = 0x08, /* original barrier req in progress */
 492         QUEUE_ORDSEQ_POSTFLUSH  = 0x10, /* post-flushing in progress */
 493         QUEUE_ORDSEQ_DONE       = 0x20,
 494 };
 495
 496 #define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 497 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 498 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 499 #define blk_queue_flushing(q)   ((q)->ordseq)
 500
 501 #define blk_fs_request(rq)      ((rq)->flags & REQ_CMD)
 502 #define blk_pc_request(rq)      ((rq)->flags & REQ_BLOCK_PC)
 503 #define blk_noretry_request(rq) ((rq)->flags & REQ_FAILFAST)
 504 #define blk_rq_started(rq)      ((rq)->flags & REQ_STARTED)
 505
 506 #define blk_account_rq(rq)      (blk_rq_started(rq) && blk_fs_request(rq))
 507
 508 #define blk_pm_suspend_request(rq)      ((rq)->flags & REQ_PM_SUSPEND)
 509 #define blk_pm_resume_request(rq)       ((rq)->flags & REQ_PM_RESUME)
 510 #define blk_pm_request(rq)      \
 511         ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
 512
 513 #define blk_sorted_rq(rq)       ((rq)->flags & REQ_SORTED)
 514 #define blk_barrier_rq(rq)      ((rq)->flags & REQ_HARDBARRIER)
 515 #define blk_fua_rq(rq)          ((rq)->flags & REQ_FUA)
 516
 517 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 518
 519 #define rq_data_dir(rq)         ((rq)->flags & 1)
 520
 521 static inline int blk_queue_full(struct request_queue *q, int rw)
 522 {
 523         if (rw == READ)
 524                 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 525         return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 526 }
 527
 528 static inline void blk_set_queue_full(struct request_queue *q, int rw)
 529 {
 530         if (rw == READ)
 531                 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 532         else
 533                 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 534 }
 535
 536 static inline void blk_clear_queue_full(struct request_queue *q, int rw)
 537 {
 538         if (rw == READ)
 539                 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 540         else
 541                 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 542 }
 543
 544
 545 /*
 546  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 547  * it already be started by driver.
 548  */
 549 #define RQ_NOMERGE_FLAGS        \
 550         (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
 551 #define rq_mergeable(rq)        \
 552         (!((rq)->flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
 553
 554 /*
 555  * noop, requests are automagically marked as active/inactive by I/O
 556  * scheduler -- see elv_next_request
 557  */
 558 #define blk_queue_headactive(q, head_active)
 559
 560 /*
 561  * q->prep_rq_fn return values
 562  */
 563 #define BLKPREP_OK              0       /* serve it */
 564 #define BLKPREP_KILL            1       /* fatal error, kill */
 565 #define BLKPREP_DEFER           2       /* leave on queue */
 566
 567 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 568
 569 /*
 570  * standard bounce addresses:
 571  *
 572  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 573  * BLK_BOUNCE_ANY       : don't bounce anything
 574  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 575  */
 576 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 577 #define BLK_BOUNCE_ANY          ((u64)blk_max_pfn << PAGE_SHIFT)
 578 #define BLK_BOUNCE_ISA          (ISA_DMA_THRESHOLD)
 579
 580 #ifdef CONFIG_MMU
 581 extern int init_emergency_isa_pool(void);
 582 extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
 583 #else
 584 static inline int init_emergency_isa_pool(void)
 585 {
 586         return 0;
 587 }
 588 static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
 589 {
 590 }
 591 #endif /* CONFIG_MMU */
 592
 593 #define rq_for_each_bio(_bio, rq)       \
 594         if ((rq->bio))                  \
 595                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 596
 597 struct sec_size {
 598         unsigned block_size;
 599         unsigned block_size_bits;
 600 };
 601
 602 extern int blk_register_queue(struct gendisk *disk);
 603 extern void blk_unregister_queue(struct gendisk *disk);
 604 extern void register_disk(struct gendisk *dev);
 605 extern void generic_make_request(struct bio *bio);
 606 extern void blk_put_request(struct request *);
 607 extern void __blk_put_request(request_queue_t *, struct request *);
 608 extern void blk_end_sync_rq(struct request *rq, int error);
 609 extern struct request *blk_get_request(request_queue_t *, int, gfp_t);
 610 extern void blk_insert_request(request_queue_t *, struct request *, int, void *);
 611 extern void blk_requeue_request(request_queue_t *, struct request *);
 612 extern void blk_plug_device(request_queue_t *);
 613 extern int blk_remove_plug(request_queue_t *);
 614 extern void blk_recount_segments(request_queue_t *, struct bio *);
 615 extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
 616 extern int sg_scsi_ioctl(struct file *, struct request_queue *,
 617                 struct gendisk *, struct scsi_ioctl_command __user *);
 618 extern void blk_start_queue(request_queue_t *q);
 619 extern void blk_stop_queue(request_queue_t *q);
 620 extern void blk_sync_queue(struct request_queue *q);
 621 extern void __blk_stop_queue(request_queue_t *q);
 622 extern void blk_run_queue(request_queue_t *);
 623 extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
 624 extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
 625 extern int blk_rq_unmap_user(struct bio *, unsigned int);
 626 extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
 627 extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
 628 extern int blk_execute_rq(request_queue_t *, struct gendisk *,
 629                           struct request *, int);
 630 extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,
 631                                   struct request *, int, rq_end_io_fn *);
 632
 633 static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
 634 {
 635         return bdev->bd_disk->queue;
 636 }
 637
 638 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
 639                                        struct page *page)
 640 {
 641         if (bdi && bdi->unplug_io_fn)
 642                 bdi->unplug_io_fn(bdi, page);
 643 }
 644
 645 static inline void blk_run_address_space(struct address_space *mapping)
 646 {
 647         if (mapping)
 648                 blk_run_backing_dev(mapping->backing_dev_info, NULL);
 649 }
 650
 651 /*
 652  * end_request() and friends. Must be called with the request queue spinlock
 653  * acquired. All functions called within end_request() _must_be_ atomic.
 654  *
 655  * Several drivers define their own end_request and call
 656  * end_that_request_first() and end_that_request_last()
 657  * for parts of the original function. This prevents
 658  * code duplication in drivers.
 659  */
 660 extern int end_that_request_first(struct request *, int, int);
 661 extern int end_that_request_chunk(struct request *, int, int);
 662 extern void end_that_request_last(struct request *, int);
 663 extern void end_request(struct request *req, int uptodate);
 664 extern void blk_complete_request(struct request *);
 665
 666 static inline int rq_all_done(struct request *rq, unsigned int nr_bytes)
 667 {
 668         if (blk_fs_request(rq))
 669                 return (nr_bytes >= (rq->hard_nr_sectors << 9));
 670         else if (blk_pc_request(rq))
 671                 return nr_bytes >= rq->data_len;
 672
 673         return 0;
 674 }
 675
 676 /*
 677  * end_that_request_first/chunk() takes an uptodate argument. we account
 678  * any value <= as an io error. 0 means -EIO for compatability reasons,
 679  * any other < 0 value is the direct error type. An uptodate value of
 680  * 1 indicates successful io completion
 681  */
 682 #define end_io_error(uptodate)  (unlikely((uptodate) <= 0))
 683
 684 static inline void blkdev_dequeue_request(struct request *req)
 685 {
 686         elv_dequeue_request(req->q, req);
 687 }
 688
 689 /*
 690  * This should be in elevator.h, but that requires pulling in rq and q
 691  */
 692 static inline void elv_dispatch_add_tail(struct request_queue *q,
 693                                          struct request *rq)
 694 {
 695         if (q->last_merge == rq)
 696                 q->last_merge = NULL;
 697         q->nr_sorted--;
 698
 699         q->end_sector = rq_end_sector(rq);
 700         q->boundary_rq = rq;
 701         list_add_tail(&rq->queuelist, &q->queue_head);
 702 }
 703
 704 /*
 705  * Access functions for manipulating queue properties
 706  */
 707 extern request_queue_t *blk_init_queue_node(request_fn_proc *rfn,
 708                                         spinlock_t *lock, int node_id);
 709 extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
 710 extern void blk_cleanup_queue(request_queue_t *);
 711 extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
 712 extern void blk_queue_bounce_limit(request_queue_t *, u64);
 713 extern void blk_queue_max_sectors(request_queue_t *, unsigned int);
 714 extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
 715 extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
 716 extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
 717 extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
 718 extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
 719 extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
 720 extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
 721 extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
 722 extern void blk_queue_dma_alignment(request_queue_t *, int);
 723 extern void blk_queue_softirq_done(request_queue_t *, softirq_done_fn *);
 724 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 725 extern int blk_queue_ordered(request_queue_t *, unsigned, prepare_flush_fn *);
 726 extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
 727 extern int blk_do_ordered(request_queue_t *, struct request **);
 728 extern unsigned blk_ordered_cur_seq(request_queue_t *);
 729 extern unsigned blk_ordered_req_seq(struct request *);
 730 extern void blk_ordered_complete_seq(request_queue_t *, unsigned, int);
 731
 732 extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
 733 extern void blk_dump_rq_flags(struct request *, char *);
 734 extern void generic_unplug_device(request_queue_t *);
 735 extern void __generic_unplug_device(request_queue_t *);
 736 extern long nr_blockdev_pages(void);
 737
 738 int blk_get_queue(request_queue_t *);
 739 request_queue_t *blk_alloc_queue(gfp_t);
 740 request_queue_t *blk_alloc_queue_node(gfp_t, int);
 741 extern void blk_put_queue(request_queue_t *);
 742
 743 /*
 744  * tag stuff
 745  */
 746 #define blk_queue_tag_depth(q)          ((q)->queue_tags->busy)
 747 #define blk_queue_tag_queue(q)          ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
 748 #define blk_rq_tagged(rq)               ((rq)->flags & REQ_QUEUED)
 749 extern int blk_queue_start_tag(request_queue_t *, struct request *);
 750 extern struct request *blk_queue_find_tag(request_queue_t *, int);
 751 extern void blk_queue_end_tag(request_queue_t *, struct request *);
 752 extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
 753 extern void blk_queue_free_tags(request_queue_t *);
 754 extern int blk_queue_resize_tags(request_queue_t *, int);
 755 extern void blk_queue_invalidate_tags(request_queue_t *);
 756 extern long blk_congestion_wait(int rw, long timeout);
 757
 758 extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
 759 extern int blkdev_issue_flush(struct block_device *, sector_t *);
 760
 761 #define MAX_PHYS_SEGMENTS 128
 762 #define MAX_HW_SEGMENTS 128
 763 #define SAFE_MAX_SECTORS 255
 764 #define BLK_DEF_MAX_SECTORS 1024
 765
 766 #define MAX_SEGMENT_SIZE        65536
 767
 768 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
 769
 770 static inline int queue_hardsect_size(request_queue_t *q)
 771 {
 772         int retval = 512;
 773
 774         if (q && q->hardsect_size)
 775                 retval = q->hardsect_size;
 776
 777         return retval;
 778 }
 779
 780 static inline int bdev_hardsect_size(struct block_device *bdev)
 781 {
 782         return queue_hardsect_size(bdev_get_queue(bdev));
 783 }
 784
 785 static inline int queue_dma_alignment(request_queue_t *q)
 786 {
 787         int retval = 511;
 788
 789         if (q && q->dma_alignment)
 790                 retval = q->dma_alignment;
 791
 792         return retval;
 793 }
 794
 795 static inline int bdev_dma_aligment(struct block_device *bdev)
 796 {
 797         return queue_dma_alignment(bdev_get_queue(bdev));
 798 }
 799
 800 #define blk_finished_io(nsects) do { } while (0)
 801 #define blk_started_io(nsects)  do { } while (0)
 802
 803 /* assumes size > 256 */
 804 static inline unsigned int blksize_bits(unsigned int size)
 805 {
 806         unsigned int bits = 8;
 807         do {
 808                 bits++;
 809                 size >>= 1;
 810         } while (size > 256);
 811         return bits;
 812 }
 813
 814 static inline unsigned int block_size(struct block_device *bdev)
 815 {
 816         return bdev->bd_block_size;
 817 }
 818
 819 typedef struct {struct page *v;} Sector;
 820
 821 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
 822
 823 static inline void put_dev_sector(Sector p)
 824 {
 825         page_cache_release(p.v);
 826 }
 827
 828 struct work_struct;
 829 int kblockd_schedule_work(struct work_struct *work);
 830 void kblockd_flush(void);
 831
 832 #ifdef CONFIG_LBD
 833 # include <asm/div64.h>
 834 # define sector_div(a, b) do_div(a, b)
 835 #else
 836 # define sector_div(n, b)( \
 837 { \
 838         int _res; \
 839         _res = (n) % (b); \
 840         (n) /= (b); \
 841         _res; \
 842 } \
 843 )
 844 #endif
 845
 846 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
 847         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
 848 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
 849         MODULE_ALIAS("block-major-" __stringify(major) "-*")
 850
 851
 852 #endif