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