include/linux/blkdev.h

   1 #ifndef _LINUX_BLKDEV_H
   2 #define _LINUX_BLKDEV_H
   3
   4 #include <linux/sched.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 #ifdef CONFIG_LBD
  21 # include <asm/div64.h>
  22 # define sector_div(a, b) do_div(a, b)
  23 #else
  24 # define sector_div(n, b)( \
  25 { \
  26         int _res; \
  27         _res = (n) % (b); \
  28         (n) /= (b); \
  29         _res; \
  30 } \
  31 )
  32 #endif
  33
  34 #ifdef CONFIG_BLOCK
  35
  36 struct scsi_ioctl_command;
  37
  38 struct request_queue;
  39 typedef struct request_queue request_queue_t;
  40 struct elevator_queue;
  41 typedef struct elevator_queue elevator_t;
  42 struct request_pm_state;
  43 struct blk_trace;
  44 struct request;
  45 struct sg_io_hdr;
  46
  47 #define BLKDEV_MIN_RQ   4
  48 #define BLKDEV_MAX_RQ   128     /* Default maximum */
  49
  50 /*
  51  * This is the per-process anticipatory I/O scheduler state.
  52  */
  53 struct as_io_context {
  54         spinlock_t lock;
  55
  56         void (*dtor)(struct as_io_context *aic); /* destructor */
  57         void (*exit)(struct as_io_context *aic); /* called on task exit */
  58
  59         unsigned long state;
  60         atomic_t nr_queued; /* queued reads & sync writes */
  61         atomic_t nr_dispatched; /* number of requests gone to the drivers */
  62
  63         /* IO History tracking */
  64         /* Thinktime */
  65         unsigned long last_end_request;
  66         unsigned long ttime_total;
  67         unsigned long ttime_samples;
  68         unsigned long ttime_mean;
  69         /* Layout pattern */
  70         unsigned int seek_samples;
  71         sector_t last_request_pos;
  72         u64 seek_total;
  73         sector_t seek_mean;
  74 };
  75
  76 struct cfq_queue;
  77 struct cfq_io_context {
  78         struct rb_node rb_node;
  79         void *key;
  80
  81         struct cfq_queue *cfqq[2];
  82
  83         struct io_context *ioc;
  84
  85         unsigned long last_end_request;
  86         sector_t last_request_pos;
  87
  88         unsigned long ttime_total;
  89         unsigned long ttime_samples;
  90         unsigned long ttime_mean;
  91
  92         unsigned int seek_samples;
  93         u64 seek_total;
  94         sector_t seek_mean;
  95
  96         struct list_head queue_list;
  97
  98         void (*dtor)(struct io_context *); /* destructor */
  99         void (*exit)(struct io_context *); /* called on task exit */
 100 };
 101
 102 /*
 103  * This is the per-process I/O subsystem state.  It is refcounted and
 104  * kmalloc'ed. Currently all fields are modified in process io context
 105  * (apart from the atomic refcount), so require no locking.
 106  */
 107 struct io_context {
 108         atomic_t refcount;
 109         struct task_struct *task;
 110
 111         unsigned int ioprio_changed;
 112
 113         /*
 114          * For request batching
 115          */
 116         unsigned long last_waited; /* Time last woken after wait for request */
 117         int nr_batch_requests;     /* Number of requests left in the batch */
 118
 119         struct as_io_context *aic;
 120         struct rb_root cic_root;
 121         void *ioc_data;
 122 };
 123
 124 void put_io_context(struct io_context *ioc);
 125 void exit_io_context(void);
 126 struct io_context *get_io_context(gfp_t gfp_flags, int node);
 127 void copy_io_context(struct io_context **pdst, struct io_context **psrc);
 128 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
 129
 130 struct request;
 131 typedef void (rq_end_io_fn)(struct request *, int);
 132
 133 struct request_list {
 134         int count[2];
 135         int starved[2];
 136         int elvpriv;
 137         mempool_t *rq_pool;
 138         wait_queue_head_t wait[2];
 139 };
 140
 141 /*
 142  * request command types
 143  */
 144 enum rq_cmd_type_bits {
 145         REQ_TYPE_FS             = 1,    /* fs request */
 146         REQ_TYPE_BLOCK_PC,              /* scsi command */
 147         REQ_TYPE_SENSE,                 /* sense request */
 148         REQ_TYPE_PM_SUSPEND,            /* suspend request */
 149         REQ_TYPE_PM_RESUME,             /* resume request */
 150         REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
 151         REQ_TYPE_FLUSH,                 /* flush request */
 152         REQ_TYPE_SPECIAL,               /* driver defined type */
 153         REQ_TYPE_LINUX_BLOCK,           /* generic block layer message */
 154         /*
 155          * for ATA/ATAPI devices. this really doesn't belong here, ide should
 156          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
 157          * private REQ_LB opcodes to differentiate what type of request this is
 158          */
 159         REQ_TYPE_ATA_CMD,
 160         REQ_TYPE_ATA_TASK,
 161         REQ_TYPE_ATA_TASKFILE,
 162         REQ_TYPE_ATA_PC,
 163 };
 164
 165 /*
 166  * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
 167  * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
 168  * SCSI cdb.
 169  *
 170  * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
 171  * typically to differentiate REQ_TYPE_SPECIAL requests.
 172  *
 173  */
 174 enum {
 175         /*
 176          * just examples for now
 177          */
 178         REQ_LB_OP_EJECT = 0x40,         /* eject request */
 179         REQ_LB_OP_FLUSH = 0x41,         /* flush device */
 180 };
 181
 182 /*
 183  * request type modified bits. first three bits match BIO_RW* bits, important
 184  */
 185 enum rq_flag_bits {
 186         __REQ_RW,               /* not set, read. set, write */
 187         __REQ_FAILFAST,         /* no low level driver retries */
 188         __REQ_SORTED,           /* elevator knows about this request */
 189         __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
 190         __REQ_HARDBARRIER,      /* may not be passed by drive either */
 191         __REQ_FUA,              /* forced unit access */
 192         __REQ_NOMERGE,          /* don't touch this for merging */
 193         __REQ_STARTED,          /* drive already may have started this one */
 194         __REQ_DONTPREP,         /* don't call prep for this one */
 195         __REQ_QUEUED,           /* uses queueing */
 196         __REQ_ELVPRIV,          /* elevator private data attached */
 197         __REQ_FAILED,           /* set if the request failed */
 198         __REQ_QUIET,            /* don't worry about errors */
 199         __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 200         __REQ_ORDERED_COLOR,    /* is before or after barrier */
 201         __REQ_RW_SYNC,          /* request is sync (O_DIRECT) */
 202         __REQ_ALLOCED,          /* request came from our alloc pool */
 203         __REQ_RW_META,          /* metadata io request */
 204         __REQ_NR_BITS,          /* stops here */
 205 };
 206
 207 #define REQ_RW          (1 << __REQ_RW)
 208 #define REQ_FAILFAST    (1 << __REQ_FAILFAST)
 209 #define REQ_SORTED      (1 << __REQ_SORTED)
 210 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
 211 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
 212 #define REQ_FUA         (1 << __REQ_FUA)
 213 #define REQ_NOMERGE     (1 << __REQ_NOMERGE)
 214 #define REQ_STARTED     (1 << __REQ_STARTED)
 215 #define REQ_DONTPREP    (1 << __REQ_DONTPREP)
 216 #define REQ_QUEUED      (1 << __REQ_QUEUED)
 217 #define REQ_ELVPRIV     (1 << __REQ_ELVPRIV)
 218 #define REQ_FAILED      (1 << __REQ_FAILED)
 219 #define REQ_QUIET       (1 << __REQ_QUIET)
 220 #define REQ_PREEMPT     (1 << __REQ_PREEMPT)
 221 #define REQ_ORDERED_COLOR       (1 << __REQ_ORDERED_COLOR)
 222 #define REQ_RW_SYNC     (1 << __REQ_RW_SYNC)
 223 #define REQ_ALLOCED     (1 << __REQ_ALLOCED)
 224 #define REQ_RW_META     (1 << __REQ_RW_META)
 225
 226 #define BLK_MAX_CDB     16
 227
 228 /*
 229  * try to put the fields that are referenced together in the same cacheline
 230  */
 231 struct request {
 232         struct list_head queuelist;
 233         struct list_head donelist;
 234
 235         request_queue_t *q;
 236
 237         unsigned int cmd_flags;
 238         enum rq_cmd_type_bits cmd_type;
 239
 240         /* Maintain bio traversal state for part by part I/O submission.
 241          * hard_* are block layer internals, no driver should touch them!
 242          */
 243
 244         sector_t sector;                /* next sector to submit */
 245         sector_t hard_sector;           /* next sector to complete */
 246         unsigned long nr_sectors;       /* no. of sectors left to submit */
 247         unsigned long hard_nr_sectors;  /* no. of sectors left to complete */
 248         /* no. of sectors left to submit in the current segment */
 249         unsigned int current_nr_sectors;
 250
 251         /* no. of sectors left to complete in the current segment */
 252         unsigned int hard_cur_sectors;
 253
 254         struct bio *bio;
 255         struct bio *biotail;
 256
 257         struct hlist_node hash; /* merge hash */
 258         /*
 259          * The rb_node is only used inside the io scheduler, requests
 260          * are pruned when moved to the dispatch queue. So let the
 261          * completion_data share space with the rb_node.
 262          */
 263         union {
 264                 struct rb_node rb_node; /* sort/lookup */
 265                 void *completion_data;
 266         };
 267
 268         /*
 269          * two pointers are available for the IO schedulers, if they need
 270          * more they have to dynamically allocate it.
 271          */
 272         void *elevator_private;
 273         void *elevator_private2;
 274
 275         struct gendisk *rq_disk;
 276         unsigned long start_time;
 277
 278         /* Number of scatter-gather DMA addr+len pairs after
 279          * physical address coalescing is performed.
 280          */
 281         unsigned short nr_phys_segments;
 282
 283         /* Number of scatter-gather addr+len pairs after
 284          * physical and DMA remapping hardware coalescing is performed.
 285          * This is the number of scatter-gather entries the driver
 286          * will actually have to deal with after DMA mapping is done.
 287          */
 288         unsigned short nr_hw_segments;
 289
 290         unsigned short ioprio;
 291
 292         void *special;
 293         char *buffer;
 294
 295         int tag;
 296         int errors;
 297
 298         int ref_count;
 299
 300         /*
 301          * when request is used as a packet command carrier
 302          */
 303         unsigned int cmd_len;
 304         unsigned char cmd[BLK_MAX_CDB];
 305
 306         unsigned int data_len;
 307         unsigned int sense_len;
 308         void *data;
 309         void *sense;
 310
 311         unsigned int timeout;
 312         int retries;
 313
 314         /*
 315          * completion callback.
 316          */
 317         rq_end_io_fn *end_io;
 318         void *end_io_data;
 319 };
 320
 321 /*
 322  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 323  * requests. Some step values could eventually be made generic.
 324  */
 325 struct request_pm_state
 326 {
 327         /* PM state machine step value, currently driver specific */
 328         int     pm_step;
 329         /* requested PM state value (S1, S2, S3, S4, ...) */
 330         u32     pm_state;
 331         void*   data;           /* for driver use */
 332 };
 333
 334 #include <linux/elevator.h>
 335
 336 typedef void (request_fn_proc) (request_queue_t *q);
 337 typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
 338 typedef int (prep_rq_fn) (request_queue_t *, struct request *);
 339 typedef void (unplug_fn) (request_queue_t *);
 340
 341 struct bio_vec;
 342 typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
 343 typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
 344 typedef void (prepare_flush_fn) (request_queue_t *, struct request *);
 345 typedef void (softirq_done_fn)(struct request *);
 346
 347 enum blk_queue_state {
 348         Queue_down,
 349         Queue_up,
 350 };
 351
 352 struct blk_queue_tag {
 353         struct request **tag_index;     /* map of busy tags */
 354         unsigned long *tag_map;         /* bit map of free/busy tags */
 355         struct list_head busy_list;     /* fifo list of busy tags */
 356         int busy;                       /* current depth */
 357         int max_depth;                  /* what we will send to device */
 358         int real_max_depth;             /* what the array can hold */
 359         atomic_t refcnt;                /* map can be shared */
 360 };
 361
 362 struct request_queue
 363 {
 364         /*
 365          * Together with queue_head for cacheline sharing
 366          */
 367         struct list_head        queue_head;
 368         struct request          *last_merge;
 369         elevator_t              *elevator;
 370
 371         /*
 372          * the queue request freelist, one for reads and one for writes
 373          */
 374         struct request_list     rq;
 375
 376         request_fn_proc         *request_fn;
 377         make_request_fn         *make_request_fn;
 378         prep_rq_fn              *prep_rq_fn;
 379         unplug_fn               *unplug_fn;
 380         merge_bvec_fn           *merge_bvec_fn;
 381         issue_flush_fn          *issue_flush_fn;
 382         prepare_flush_fn        *prepare_flush_fn;
 383         softirq_done_fn         *softirq_done_fn;
 384
 385         /*
 386          * Dispatch queue sorting
 387          */
 388         sector_t                end_sector;
 389         struct request          *boundary_rq;
 390
 391         /*
 392          * Auto-unplugging state
 393          */
 394         struct timer_list       unplug_timer;
 395         int                     unplug_thresh;  /* After this many requests */
 396         unsigned long           unplug_delay;   /* After this many jiffies */
 397         struct work_struct      unplug_work;
 398
 399         struct backing_dev_info backing_dev_info;
 400
 401         /*
 402          * The queue owner gets to use this for whatever they like.
 403          * ll_rw_blk doesn't touch it.
 404          */
 405         void                    *queuedata;
 406
 407         /*
 408          * queue needs bounce pages for pages above this limit
 409          */
 410         unsigned long           bounce_pfn;
 411         gfp_t                   bounce_gfp;
 412
 413         /*
 414          * various queue flags, see QUEUE_* below
 415          */
 416         unsigned long           queue_flags;
 417
 418         /*
 419          * protects queue structures from reentrancy. ->__queue_lock should
 420          * _never_ be used directly, it is queue private. always use
 421          * ->queue_lock.
 422          */
 423         spinlock_t              __queue_lock;
 424         spinlock_t              *queue_lock;
 425
 426         /*
 427          * queue kobject
 428          */
 429         struct kobject kobj;
 430
 431         /*
 432          * queue settings
 433          */
 434         unsigned long           nr_requests;    /* Max # of requests */
 435         unsigned int            nr_congestion_on;
 436         unsigned int            nr_congestion_off;
 437         unsigned int            nr_batching;
 438
 439         unsigned int            max_sectors;
 440         unsigned int            max_hw_sectors;
 441         unsigned short          max_phys_segments;
 442         unsigned short          max_hw_segments;
 443         unsigned short          hardsect_size;
 444         unsigned int            max_segment_size;
 445
 446         unsigned long           seg_boundary_mask;
 447         unsigned int            dma_alignment;
 448
 449         struct blk_queue_tag    *queue_tags;
 450
 451         unsigned int            nr_sorted;
 452         unsigned int            in_flight;
 453
 454         /*
 455          * sg stuff
 456          */
 457         unsigned int            sg_timeout;
 458         unsigned int            sg_reserved_size;
 459         int                     node;
 460 #ifdef CONFIG_BLK_DEV_IO_TRACE
 461         struct blk_trace        *blk_trace;
 462 #endif
 463         /*
 464          * reserved for flush operations
 465          */
 466         unsigned int            ordered, next_ordered, ordseq;
 467         int                     orderr, ordcolor;
 468         struct request          pre_flush_rq, bar_rq, post_flush_rq;
 469         struct request          *orig_bar_rq;
 470         unsigned int            bi_size;
 471
 472         struct mutex            sysfs_lock;
 473 };
 474
 475 #define QUEUE_FLAG_CLUSTER      0       /* cluster several segments into 1 */
 476 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 477 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 478 #define QUEUE_FLAG_READFULL     3       /* write queue has been filled */
 479 #define QUEUE_FLAG_WRITEFULL    4       /* read queue has been filled */
 480 #define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 481 #define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 482 #define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
 483 #define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 484
 485 enum {
 486         /*
 487          * Hardbarrier is supported with one of the following methods.
 488          *
 489          * NONE         : hardbarrier unsupported
 490          * DRAIN        : ordering by draining is enough
 491          * DRAIN_FLUSH  : ordering by draining w/ pre and post flushes
 492          * DRAIN_FUA    : ordering by draining w/ pre flush and FUA write
 493          * TAG          : ordering by tag is enough
 494          * TAG_FLUSH    : ordering by tag w/ pre and post flushes
 495          * TAG_FUA      : ordering by tag w/ pre flush and FUA write
 496          */
 497         QUEUE_ORDERED_NONE      = 0x00,
 498         QUEUE_ORDERED_DRAIN     = 0x01,
 499         QUEUE_ORDERED_TAG       = 0x02,
 500
 501         QUEUE_ORDERED_PREFLUSH  = 0x10,
 502         QUEUE_ORDERED_POSTFLUSH = 0x20,
 503         QUEUE_ORDERED_FUA       = 0x40,
 504
 505         QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
 506                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 507         QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
 508                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 509         QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
 510                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 511         QUEUE_ORDERED_TAG_FUA   = QUEUE_ORDERED_TAG |
 512                         QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 513
 514         /*
 515          * Ordered operation sequence
 516          */
 517         QUEUE_ORDSEQ_STARTED    = 0x01, /* flushing in progress */
 518         QUEUE_ORDSEQ_DRAIN      = 0x02, /* waiting for the queue to be drained */
 519         QUEUE_ORDSEQ_PREFLUSH   = 0x04, /* pre-flushing in progress */
 520         QUEUE_ORDSEQ_BAR        = 0x08, /* original barrier req in progress */
 521         QUEUE_ORDSEQ_POSTFLUSH  = 0x10, /* post-flushing in progress */
 522         QUEUE_ORDSEQ_DONE       = 0x20,
 523 };
 524
 525 #define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 526 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 527 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 528 #define blk_queue_flushing(q)   ((q)->ordseq)
 529
 530 #define blk_fs_request(rq)      ((rq)->cmd_type == REQ_TYPE_FS)
 531 #define blk_pc_request(rq)      ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
 532 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
 533 #define blk_sense_request(rq)   ((rq)->cmd_type == REQ_TYPE_SENSE)
 534
 535 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
 536 #define blk_rq_started(rq)      ((rq)->cmd_flags & REQ_STARTED)
 537
 538 #define blk_account_rq(rq)      (blk_rq_started(rq) && blk_fs_request(rq))
 539
 540 #define blk_pm_suspend_request(rq)      ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
 541 #define blk_pm_resume_request(rq)       ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
 542 #define blk_pm_request(rq)      \
 543         (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
 544
 545 #define blk_sorted_rq(rq)       ((rq)->cmd_flags & REQ_SORTED)
 546 #define blk_barrier_rq(rq)      ((rq)->cmd_flags & REQ_HARDBARRIER)
 547 #define blk_fua_rq(rq)          ((rq)->cmd_flags & REQ_FUA)
 548
 549 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 550
 551 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 552
 553 /*
 554  * We regard a request as sync, if it's a READ or a SYNC write.
 555  */
 556 #define rq_is_sync(rq)          (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
 557 #define rq_is_meta(rq)          ((rq)->cmd_flags & REQ_RW_META)
 558
 559 static inline int blk_queue_full(struct request_queue *q, int rw)
 560 {
 561         if (rw == READ)
 562                 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 563         return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 564 }
 565
 566 static inline void blk_set_queue_full(struct request_queue *q, int rw)
 567 {
 568         if (rw == READ)
 569                 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 570         else
 571                 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 572 }
 573
 574 static inline void blk_clear_queue_full(struct request_queue *q, int rw)
 575 {
 576         if (rw == READ)
 577                 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 578         else
 579                 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 580 }
 581
 582
 583 /*
 584  * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 585  * it already be started by driver.
 586  */
 587 #define RQ_NOMERGE_FLAGS        \
 588         (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
 589 #define rq_mergeable(rq)        \
 590         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
 591
 592 /*
 593  * q->prep_rq_fn return values
 594  */
 595 #define BLKPREP_OK              0       /* serve it */
 596 #define BLKPREP_KILL            1       /* fatal error, kill */
 597 #define BLKPREP_DEFER           2       /* leave on queue */
 598
 599 extern unsigned long blk_max_low_pfn, blk_max_pfn;
 600
 601 /*
 602  * standard bounce addresses:
 603  *
 604  * BLK_BOUNCE_HIGH      : bounce all highmem pages
 605  * BLK_BOUNCE_ANY       : don't bounce anything
 606  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 607  */
 608 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 609 #define BLK_BOUNCE_ANY          ((u64)blk_max_pfn << PAGE_SHIFT)
 610 #define BLK_BOUNCE_ISA          (ISA_DMA_THRESHOLD)
 611
 612 /*
 613  * default timeout for SG_IO if none specified
 614  */
 615 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 616
 617 #ifdef CONFIG_MMU
 618 extern int init_emergency_isa_pool(void);
 619 extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
 620 #else
 621 static inline int init_emergency_isa_pool(void)
 622 {
 623         return 0;
 624 }
 625 static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
 626 {
 627 }
 628 #endif /* CONFIG_MMU */
 629
 630 #define rq_for_each_bio(_bio, rq)       \
 631         if ((rq->bio))                  \
 632                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 633
 634 extern int blk_register_queue(struct gendisk *disk);
 635 extern void blk_unregister_queue(struct gendisk *disk);
 636 extern void register_disk(struct gendisk *dev);
 637 extern void generic_make_request(struct bio *bio);
 638 extern void blk_put_request(struct request *);
 639 extern void __blk_put_request(request_queue_t *, struct request *);
 640 extern void blk_end_sync_rq(struct request *rq, int error);
 641 extern struct request *blk_get_request(request_queue_t *, int, gfp_t);
 642 extern void blk_insert_request(request_queue_t *, struct request *, int, void *);
 643 extern void blk_requeue_request(request_queue_t *, struct request *);
 644 extern void blk_plug_device(request_queue_t *);
 645 extern int blk_remove_plug(request_queue_t *);
 646 extern void blk_recount_segments(request_queue_t *, struct bio *);
 647 extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
 648 extern int sg_scsi_ioctl(struct file *, struct request_queue *,
 649                 struct gendisk *, struct scsi_ioctl_command __user *);
 650
 651 /*
 652  * Temporary export, until SCSI gets fixed up.
 653  */
 654 extern int ll_back_merge_fn(request_queue_t *, struct request *, struct bio *);
 655
 656 /*
 657  * A queue has just exitted congestion.  Note this in the global counter of
 658  * congested queues, and wake up anyone who was waiting for requests to be
 659  * put back.
 660  */
 661 static inline void blk_clear_queue_congested(request_queue_t *q, int rw)
 662 {
 663         clear_bdi_congested(&q->backing_dev_info, rw);
 664 }
 665
 666 /*
 667  * A queue has just entered congestion.  Flag that in the queue's VM-visible
 668  * state flags and increment the global gounter of congested queues.
 669  */
 670 static inline void blk_set_queue_congested(request_queue_t *q, int rw)
 671 {
 672         set_bdi_congested(&q->backing_dev_info, rw);
 673 }
 674
 675 extern void blk_start_queue(request_queue_t *q);
 676 extern void blk_stop_queue(request_queue_t *q);
 677 extern void blk_sync_queue(struct request_queue *q);
 678 extern void __blk_stop_queue(request_queue_t *q);
 679 extern void blk_run_queue(request_queue_t *);
 680 extern void blk_start_queueing(request_queue_t *);
 681 extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned long);
 682 extern int blk_rq_unmap_user(struct bio *);
 683 extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
 684 extern int blk_rq_map_user_iov(request_queue_t *, struct request *,
 685                                struct sg_iovec *, int, unsigned int);
 686 extern int blk_execute_rq(request_queue_t *, struct gendisk *,
 687                           struct request *, int);
 688 extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,
 689                                   struct request *, int, rq_end_io_fn *);
 690 extern int blk_fill_sghdr_rq(request_queue_t *, struct request *,
 691                       struct sg_io_hdr *, int);
 692 extern int blk_unmap_sghdr_rq(struct request *, struct sg_io_hdr *);
 693 extern int blk_complete_sghdr_rq(struct request *, struct sg_io_hdr *,
 694                           struct bio *);
 695 extern int blk_verify_command(unsigned char *, int);
 696
 697 static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
 698 {
 699         return bdev->bd_disk->queue;
 700 }
 701
 702 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
 703                                        struct page *page)
 704 {
 705         if (bdi && bdi->unplug_io_fn)
 706                 bdi->unplug_io_fn(bdi, page);
 707 }
 708
 709 static inline void blk_run_address_space(struct address_space *mapping)
 710 {
 711         if (mapping)
 712                 blk_run_backing_dev(mapping->backing_dev_info, NULL);
 713 }
 714
 715 /*
 716  * end_request() and friends. Must be called with the request queue spinlock
 717  * acquired. All functions called within end_request() _must_be_ atomic.
 718  *
 719  * Several drivers define their own end_request and call
 720  * end_that_request_first() and end_that_request_last()
 721  * for parts of the original function. This prevents
 722  * code duplication in drivers.
 723  */
 724 extern int end_that_request_first(struct request *, int, int);
 725 extern int end_that_request_chunk(struct request *, int, int);
 726 extern void end_that_request_last(struct request *, int);
 727 extern void end_request(struct request *req, int uptodate);
 728 extern void blk_complete_request(struct request *);
 729
 730 /*
 731  * end_that_request_first/chunk() takes an uptodate argument. we account
 732  * any value <= as an io error. 0 means -EIO for compatability reasons,
 733  * any other < 0 value is the direct error type. An uptodate value of
 734  * 1 indicates successful io completion
 735  */
 736 #define end_io_error(uptodate)  (unlikely((uptodate) <= 0))
 737
 738 static inline void blkdev_dequeue_request(struct request *req)
 739 {
 740         elv_dequeue_request(req->q, req);
 741 }
 742
 743 /*
 744  * Access functions for manipulating queue properties
 745  */
 746 extern request_queue_t *blk_init_queue_node(request_fn_proc *rfn,
 747                                         spinlock_t *lock, int node_id);
 748 extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
 749 extern void blk_cleanup_queue(request_queue_t *);
 750 extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
 751 extern void blk_queue_bounce_limit(request_queue_t *, u64);
 752 extern void blk_queue_max_sectors(request_queue_t *, unsigned int);
 753 extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
 754 extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
 755 extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
 756 extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
 757 extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
 758 extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
 759 extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
 760 extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
 761 extern void blk_queue_dma_alignment(request_queue_t *, int);
 762 extern void blk_queue_softirq_done(request_queue_t *, softirq_done_fn *);
 763 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 764 extern int blk_queue_ordered(request_queue_t *, unsigned, prepare_flush_fn *);
 765 extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
 766 extern int blk_do_ordered(request_queue_t *, struct request **);
 767 extern unsigned blk_ordered_cur_seq(request_queue_t *);
 768 extern unsigned blk_ordered_req_seq(struct request *);
 769 extern void blk_ordered_complete_seq(request_queue_t *, unsigned, int);
 770
 771 extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
 772 extern void blk_dump_rq_flags(struct request *, char *);
 773 extern void generic_unplug_device(request_queue_t *);
 774 extern void __generic_unplug_device(request_queue_t *);
 775 extern long nr_blockdev_pages(void);
 776
 777 int blk_get_queue(request_queue_t *);
 778 request_queue_t *blk_alloc_queue(gfp_t);
 779 request_queue_t *blk_alloc_queue_node(gfp_t, int);
 780 extern void blk_put_queue(request_queue_t *);
 781
 782 /*
 783  * tag stuff
 784  */
 785 #define blk_queue_tag_depth(q)          ((q)->queue_tags->busy)
 786 #define blk_queue_tag_queue(q)          ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
 787 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 788 extern int blk_queue_start_tag(request_queue_t *, struct request *);
 789 extern struct request *blk_queue_find_tag(request_queue_t *, int);
 790 extern void blk_queue_end_tag(request_queue_t *, struct request *);
 791 extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
 792 extern void blk_queue_free_tags(request_queue_t *);
 793 extern int blk_queue_resize_tags(request_queue_t *, int);
 794 extern void blk_queue_invalidate_tags(request_queue_t *);
 795 extern struct blk_queue_tag *blk_init_tags(int);
 796 extern void blk_free_tags(struct blk_queue_tag *);
 797
 798 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 799                                                 int tag)
 800 {
 801         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 802                 return NULL;
 803         return bqt->tag_index[tag];
 804 }
 805
 806 extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
 807 extern int blkdev_issue_flush(struct block_device *, sector_t *);
 808
 809 #define MAX_PHYS_SEGMENTS 128
 810 #define MAX_HW_SEGMENTS 128
 811 #define SAFE_MAX_SECTORS 255
 812 #define BLK_DEF_MAX_SECTORS 1024
 813
 814 #define MAX_SEGMENT_SIZE        65536
 815
 816 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
 817
 818 static inline int queue_hardsect_size(request_queue_t *q)
 819 {
 820         int retval = 512;
 821
 822         if (q && q->hardsect_size)
 823                 retval = q->hardsect_size;
 824
 825         return retval;
 826 }
 827
 828 static inline int bdev_hardsect_size(struct block_device *bdev)
 829 {
 830         return queue_hardsect_size(bdev_get_queue(bdev));
 831 }
 832
 833 static inline int queue_dma_alignment(request_queue_t *q)
 834 {
 835         int retval = 511;
 836
 837         if (q && q->dma_alignment)
 838                 retval = q->dma_alignment;
 839
 840         return retval;
 841 }
 842
 843 /* assumes size > 256 */
 844 static inline unsigned int blksize_bits(unsigned int size)
 845 {
 846         unsigned int bits = 8;
 847         do {
 848                 bits++;
 849                 size >>= 1;
 850         } while (size > 256);
 851         return bits;
 852 }
 853
 854 static inline unsigned int block_size(struct block_device *bdev)
 855 {
 856         return bdev->bd_block_size;
 857 }
 858
 859 typedef struct {struct page *v;} Sector;
 860
 861 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
 862
 863 static inline void put_dev_sector(Sector p)
 864 {
 865         page_cache_release(p.v);
 866 }
 867
 868 struct work_struct;
 869 int kblockd_schedule_work(struct work_struct *work);
 870 void kblockd_flush_work(struct work_struct *work);
 871
 872 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
 873         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
 874 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
 875         MODULE_ALIAS("block-major-" __stringify(major) "-*")
 876
 877
 878 #else /* CONFIG_BLOCK */
 879 /*
 880  * stubs for when the block layer is configured out
 881  */
 882 #define buffer_heads_over_limit 0
 883
 884 static inline long nr_blockdev_pages(void)
 885 {
 886         return 0;
 887 }
 888
 889 static inline void exit_io_context(void)
 890 {
 891 }
 892
 893 #endif /* CONFIG_BLOCK */
 894
 895 #endif