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 #include <linux/bsg.h> 18 19 #include <asm/scatterlist.h> 20 21 #ifdef CONFIG_LBD 22 # include <asm/div64.h> 23 # define sector_div(a, b) do_div(a, b) 24 #else 25 # define sector_div(n, b)( \ 26 { \ 27 int _res; \ 28 _res = (n) % (b); \ 29 (n) /= (b); \ 30 _res; \ 31 } \ 32 ) 33 #endif 34 35 #ifdef CONFIG_BLOCK 36 37 struct scsi_ioctl_command; 38 39 struct request_queue; 40 typedef struct request_queue request_queue_t __deprecated; 41 struct elevator_queue; 42 typedef struct elevator_queue elevator_t; 43 struct request_pm_state; 44 struct blk_trace; 45 struct request; 46 struct sg_io_hdr; 47 48 #define BLKDEV_MIN_RQ 4 49 #define BLKDEV_MAX_RQ 128 /* Default maximum */ 50 51 /* 52 * This is the per-process anticipatory I/O scheduler state. 53 */ 54 struct as_io_context { 55 spinlock_t lock; 56 57 void (*dtor)(struct as_io_context *aic); /* destructor */ 58 void (*exit)(struct as_io_context *aic); /* called on task exit */ 59 60 unsigned long state; 61 atomic_t nr_queued; /* queued reads & sync writes */ 62 atomic_t nr_dispatched; /* number of requests gone to the drivers */ 63 64 /* IO History tracking */ 65 /* Thinktime */ 66 unsigned long last_end_request; 67 unsigned long ttime_total; 68 unsigned long ttime_samples; 69 unsigned long ttime_mean; 70 /* Layout pattern */ 71 unsigned int seek_samples; 72 sector_t last_request_pos; 73 u64 seek_total; 74 sector_t seek_mean; 75 }; 76 77 struct cfq_queue; 78 struct cfq_io_context { 79 struct rb_node rb_node; 80 void *key; 81 82 struct cfq_queue *cfqq[2]; 83 84 struct io_context *ioc; 85 86 unsigned long last_end_request; 87 sector_t last_request_pos; 88 89 unsigned long ttime_total; 90 unsigned long ttime_samples; 91 unsigned long ttime_mean; 92 93 unsigned int seek_samples; 94 u64 seek_total; 95 sector_t seek_mean; 96 97 struct list_head queue_list; 98 99 void (*dtor)(struct io_context *); /* destructor */ 100 void (*exit)(struct io_context *); /* called on task exit */ 101 }; 102 103 /* 104 * This is the per-process I/O subsystem state. It is refcounted and 105 * kmalloc'ed. Currently all fields are modified in process io context 106 * (apart from the atomic refcount), so require no locking. 107 */ 108 struct io_context { 109 atomic_t refcount; 110 struct task_struct *task; 111 112 unsigned int ioprio_changed; 113 114 /* 115 * For request batching 116 */ 117 unsigned long last_waited; /* Time last woken after wait for request */ 118 int nr_batch_requests; /* Number of requests left in the batch */ 119 120 struct as_io_context *aic; 121 struct rb_root cic_root; 122 void *ioc_data; 123 }; 124 125 void put_io_context(struct io_context *ioc); 126 void exit_io_context(void); 127 struct io_context *get_io_context(gfp_t gfp_flags, int node); 128 void copy_io_context(struct io_context **pdst, struct io_context **psrc); 129 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2); 130 131 struct request; 132 typedef void (rq_end_io_fn)(struct request *, int); 133 134 struct request_list { 135 int count[2]; 136 int starved[2]; 137 int elvpriv; 138 mempool_t *rq_pool; 139 wait_queue_head_t wait[2]; 140 }; 141 142 /* 143 * request command types 144 */ 145 enum rq_cmd_type_bits { 146 REQ_TYPE_FS = 1, /* fs request */ 147 REQ_TYPE_BLOCK_PC, /* scsi command */ 148 REQ_TYPE_SENSE, /* sense request */ 149 REQ_TYPE_PM_SUSPEND, /* suspend request */ 150 REQ_TYPE_PM_RESUME, /* resume request */ 151 REQ_TYPE_PM_SHUTDOWN, /* shutdown request */ 152 REQ_TYPE_FLUSH, /* flush request */ 153 REQ_TYPE_SPECIAL, /* driver defined type */ 154 REQ_TYPE_LINUX_BLOCK, /* generic block layer message */ 155 /* 156 * for ATA/ATAPI devices. this really doesn't belong here, ide should 157 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver 158 * private REQ_LB opcodes to differentiate what type of request this is 159 */ 160 REQ_TYPE_ATA_CMD, 161 REQ_TYPE_ATA_TASK, 162 REQ_TYPE_ATA_TASKFILE, 163 REQ_TYPE_ATA_PC, 164 }; 165 166 /* 167 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being 168 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a 169 * SCSI cdb. 170 * 171 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need, 172 * typically to differentiate REQ_TYPE_SPECIAL requests. 173 * 174 */ 175 enum { 176 /* 177 * just examples for now 178 */ 179 REQ_LB_OP_EJECT = 0x40, /* eject request */ 180 REQ_LB_OP_FLUSH = 0x41, /* flush device */ 181 }; 182 183 /* 184 * request type modified bits. first three bits match BIO_RW* bits, important 185 */ 186 enum rq_flag_bits { 187 __REQ_RW, /* not set, read. set, write */ 188 __REQ_FAILFAST, /* no low level driver retries */ 189 __REQ_SORTED, /* elevator knows about this request */ 190 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */ 191 __REQ_HARDBARRIER, /* may not be passed by drive either */ 192 __REQ_FUA, /* forced unit access */ 193 __REQ_NOMERGE, /* don't touch this for merging */ 194 __REQ_STARTED, /* drive already may have started this one */ 195 __REQ_DONTPREP, /* don't call prep for this one */ 196 __REQ_QUEUED, /* uses queueing */ 197 __REQ_ELVPRIV, /* elevator private data attached */ 198 __REQ_FAILED, /* set if the request failed */ 199 __REQ_QUIET, /* don't worry about errors */ 200 __REQ_PREEMPT, /* set for "ide_preempt" requests */ 201 __REQ_ORDERED_COLOR, /* is before or after barrier */ 202 __REQ_RW_SYNC, /* request is sync (O_DIRECT) */ 203 __REQ_ALLOCED, /* request came from our alloc pool */ 204 __REQ_RW_META, /* metadata io request */ 205 __REQ_NR_BITS, /* stops here */ 206 }; 207 208 #define REQ_RW (1 << __REQ_RW) 209 #define REQ_FAILFAST (1 << __REQ_FAILFAST) 210 #define REQ_SORTED (1 << __REQ_SORTED) 211 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER) 212 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER) 213 #define REQ_FUA (1 << __REQ_FUA) 214 #define REQ_NOMERGE (1 << __REQ_NOMERGE) 215 #define REQ_STARTED (1 << __REQ_STARTED) 216 #define REQ_DONTPREP (1 << __REQ_DONTPREP) 217 #define REQ_QUEUED (1 << __REQ_QUEUED) 218 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV) 219 #define REQ_FAILED (1 << __REQ_FAILED) 220 #define REQ_QUIET (1 << __REQ_QUIET) 221 #define REQ_PREEMPT (1 << __REQ_PREEMPT) 222 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR) 223 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC) 224 #define REQ_ALLOCED (1 << __REQ_ALLOCED) 225 #define REQ_RW_META (1 << __REQ_RW_META) 226 227 #define BLK_MAX_CDB 16 228 229 /* 230 * try to put the fields that are referenced together in the same cacheline 231 */ 232 struct request { 233 struct list_head queuelist; 234 struct list_head donelist; 235 236 struct request_queue *q; 237 238 unsigned int cmd_flags; 239 enum rq_cmd_type_bits cmd_type; 240 241 /* Maintain bio traversal state for part by part I/O submission. 242 * hard_* are block layer internals, no driver should touch them! 243 */ 244 245 sector_t sector; /* next sector to submit */ 246 sector_t hard_sector; /* next sector to complete */ 247 unsigned long nr_sectors; /* no. of sectors left to submit */ 248 unsigned long hard_nr_sectors; /* no. of sectors left to complete */ 249 /* no. of sectors left to submit in the current segment */ 250 unsigned int current_nr_sectors; 251 252 /* no. of sectors left to complete in the current segment */ 253 unsigned int hard_cur_sectors; 254 255 struct bio *bio; 256 struct bio *biotail; 257 258 struct hlist_node hash; /* merge hash */ 259 /* 260 * The rb_node is only used inside the io scheduler, requests 261 * are pruned when moved to the dispatch queue. So let the 262 * completion_data share space with the rb_node. 263 */ 264 union { 265 struct rb_node rb_node; /* sort/lookup */ 266 void *completion_data; 267 }; 268 269 /* 270 * two pointers are available for the IO schedulers, if they need 271 * more they have to dynamically allocate it. 272 */ 273 void *elevator_private; 274 void *elevator_private2; 275 276 struct gendisk *rq_disk; 277 unsigned long start_time; 278 279 /* Number of scatter-gather DMA addr+len pairs after 280 * physical address coalescing is performed. 281 */ 282 unsigned short nr_phys_segments; 283 284 /* Number of scatter-gather addr+len pairs after 285 * physical and DMA remapping hardware coalescing is performed. 286 * This is the number of scatter-gather entries the driver 287 * will actually have to deal with after DMA mapping is done. 288 */ 289 unsigned short nr_hw_segments; 290 291 unsigned short ioprio; 292 293 void *special; 294 char *buffer; 295 296 int tag; 297 int errors; 298 299 int ref_count; 300 301 /* 302 * when request is used as a packet command carrier 303 */ 304 unsigned int cmd_len; 305 unsigned char cmd[BLK_MAX_CDB]; 306 307 unsigned int data_len; 308 unsigned int sense_len; 309 void *data; 310 void *sense; 311 312 unsigned int timeout; 313 int retries; 314 315 /* 316 * completion callback. 317 */ 318 rq_end_io_fn *end_io; 319 void *end_io_data; 320 321 /* for bidi */ 322 struct request *next_rq; 323 }; 324 325 /* 326 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME 327 * requests. Some step values could eventually be made generic. 328 */ 329 struct request_pm_state 330 { 331 /* PM state machine step value, currently driver specific */ 332 int pm_step; 333 /* requested PM state value (S1, S2, S3, S4, ...) */ 334 u32 pm_state; 335 void* data; /* for driver use */ 336 }; 337 338 #include <linux/elevator.h> 339 340 typedef void (request_fn_proc) (struct request_queue *q); 341 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio); 342 typedef int (prep_rq_fn) (struct request_queue *, struct request *); 343 typedef void (unplug_fn) (struct request_queue *); 344 345 struct bio_vec; 346 typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *); 347 typedef int (issue_flush_fn) (struct request_queue *, struct gendisk *, sector_t *); 348 typedef void (prepare_flush_fn) (struct request_queue *, struct request *); 349 typedef void (softirq_done_fn)(struct request *); 350 351 enum blk_queue_state { 352 Queue_down, 353 Queue_up, 354 }; 355 356 struct blk_queue_tag { 357 struct request **tag_index; /* map of busy tags */ 358 unsigned long *tag_map; /* bit map of free/busy tags */ 359 struct list_head busy_list; /* fifo list of busy tags */ 360 int busy; /* current depth */ 361 int max_depth; /* what we will send to device */ 362 int real_max_depth; /* what the array can hold */ 363 atomic_t refcnt; /* map can be shared */ 364 }; 365 366 struct request_queue 367 { 368 /* 369 * Together with queue_head for cacheline sharing 370 */ 371 struct list_head queue_head; 372 struct request *last_merge; 373 elevator_t *elevator; 374 375 /* 376 * the queue request freelist, one for reads and one for writes 377 */ 378 struct request_list rq; 379 380 request_fn_proc *request_fn; 381 make_request_fn *make_request_fn; 382 prep_rq_fn *prep_rq_fn; 383 unplug_fn *unplug_fn; 384 merge_bvec_fn *merge_bvec_fn; 385 issue_flush_fn *issue_flush_fn; 386 prepare_flush_fn *prepare_flush_fn; 387 softirq_done_fn *softirq_done_fn; 388 389 /* 390 * Dispatch queue sorting 391 */ 392 sector_t end_sector; 393 struct request *boundary_rq; 394 395 /* 396 * Auto-unplugging state 397 */ 398 struct timer_list unplug_timer; 399 int unplug_thresh; /* After this many requests */ 400 unsigned long unplug_delay; /* After this many jiffies */ 401 struct work_struct unplug_work; 402 403 struct backing_dev_info backing_dev_info; 404 405 /* 406 * The queue owner gets to use this for whatever they like. 407 * ll_rw_blk doesn't touch it. 408 */ 409 void *queuedata; 410 411 /* 412 * queue needs bounce pages for pages above this limit 413 */ 414 unsigned long bounce_pfn; 415 gfp_t bounce_gfp; 416 417 /* 418 * various queue flags, see QUEUE_* below 419 */ 420 unsigned long queue_flags; 421 422 /* 423 * protects queue structures from reentrancy. ->__queue_lock should 424 * _never_ be used directly, it is queue private. always use 425 * ->queue_lock. 426 */ 427 spinlock_t __queue_lock; 428 spinlock_t *queue_lock; 429 430 /* 431 * queue kobject 432 */ 433 struct kobject kobj; 434 435 /* 436 * queue settings 437 */ 438 unsigned long nr_requests; /* Max # of requests */ 439 unsigned int nr_congestion_on; 440 unsigned int nr_congestion_off; 441 unsigned int nr_batching; 442 443 unsigned int max_sectors; 444 unsigned int max_hw_sectors; 445 unsigned short max_phys_segments; 446 unsigned short max_hw_segments; 447 unsigned short hardsect_size; 448 unsigned int max_segment_size; 449 450 unsigned long seg_boundary_mask; 451 unsigned int dma_alignment; 452 453 struct blk_queue_tag *queue_tags; 454 455 unsigned int nr_sorted; 456 unsigned int in_flight; 457 458 /* 459 * sg stuff 460 */ 461 unsigned int sg_timeout; 462 unsigned int sg_reserved_size; 463 int node; 464 #ifdef CONFIG_BLK_DEV_IO_TRACE 465 struct blk_trace *blk_trace; 466 #endif 467 /* 468 * reserved for flush operations 469 */ 470 unsigned int ordered, next_ordered, ordseq; 471 int orderr, ordcolor; 472 struct request pre_flush_rq, bar_rq, post_flush_rq; 473 struct request *orig_bar_rq; 474 unsigned int bi_size; 475 476 struct mutex sysfs_lock; 477 478 #if defined(CONFIG_BLK_DEV_BSG) 479 struct bsg_class_device bsg_dev; 480 #endif 481 }; 482 483 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */ 484 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */ 485 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */ 486 #define QUEUE_FLAG_READFULL 3 /* read queue has been filled */ 487 #define QUEUE_FLAG_WRITEFULL 4 /* write queue has been filled */ 488 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */ 489 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */ 490 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */ 491 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */ 492 #define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */ 493 494 enum { 495 /* 496 * Hardbarrier is supported with one of the following methods. 497 * 498 * NONE : hardbarrier unsupported 499 * DRAIN : ordering by draining is enough 500 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes 501 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write 502 * TAG : ordering by tag is enough 503 * TAG_FLUSH : ordering by tag w/ pre and post flushes 504 * TAG_FUA : ordering by tag w/ pre flush and FUA write 505 */ 506 QUEUE_ORDERED_NONE = 0x00, 507 QUEUE_ORDERED_DRAIN = 0x01, 508 QUEUE_ORDERED_TAG = 0x02, 509 510 QUEUE_ORDERED_PREFLUSH = 0x10, 511 QUEUE_ORDERED_POSTFLUSH = 0x20, 512 QUEUE_ORDERED_FUA = 0x40, 513 514 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN | 515 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH, 516 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN | 517 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA, 518 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG | 519 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH, 520 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG | 521 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA, 522 523 /* 524 * Ordered operation sequence 525 */ 526 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */ 527 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */ 528 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */ 529 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */ 530 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */ 531 QUEUE_ORDSEQ_DONE = 0x20, 532 }; 533 534 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags) 535 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags) 536 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags) 537 #define blk_queue_flushing(q) ((q)->ordseq) 538 539 #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS) 540 #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC) 541 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL) 542 #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE) 543 544 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST) 545 #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED) 546 547 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq)) 548 549 #define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND) 550 #define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME) 551 #define blk_pm_request(rq) \ 552 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq)) 553 554 #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED) 555 #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER) 556 #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA) 557 #define blk_bidi_rq(rq) ((rq)->next_rq != NULL) 558 559 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist) 560 561 #define rq_data_dir(rq) ((rq)->cmd_flags & 1) 562 563 /* 564 * We regard a request as sync, if it's a READ or a SYNC write. 565 */ 566 #define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC) 567 #define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META) 568 569 static inline int blk_queue_full(struct request_queue *q, int rw) 570 { 571 if (rw == READ) 572 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags); 573 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags); 574 } 575 576 static inline void blk_set_queue_full(struct request_queue *q, int rw) 577 { 578 if (rw == READ) 579 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags); 580 else 581 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags); 582 } 583 584 static inline void blk_clear_queue_full(struct request_queue *q, int rw) 585 { 586 if (rw == READ) 587 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags); 588 else 589 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags); 590 } 591 592 593 /* 594 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may 595 * it already be started by driver. 596 */ 597 #define RQ_NOMERGE_FLAGS \ 598 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER) 599 #define rq_mergeable(rq) \ 600 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq))) 601 602 /* 603 * q->prep_rq_fn return values 604 */ 605 #define BLKPREP_OK 0 /* serve it */ 606 #define BLKPREP_KILL 1 /* fatal error, kill */ 607 #define BLKPREP_DEFER 2 /* leave on queue */ 608 609 extern unsigned long blk_max_low_pfn, blk_max_pfn; 610 611 /* 612 * standard bounce addresses: 613 * 614 * BLK_BOUNCE_HIGH : bounce all highmem pages 615 * BLK_BOUNCE_ANY : don't bounce anything 616 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary 617 */ 618 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT) 619 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT) 620 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD) 621 622 /* 623 * default timeout for SG_IO if none specified 624 */ 625 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ) 626 627 #ifdef CONFIG_BOUNCE 628 extern int init_emergency_isa_pool(void); 629 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio); 630 #else 631 static inline int init_emergency_isa_pool(void) 632 { 633 return 0; 634 } 635 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio) 636 { 637 } 638 #endif /* CONFIG_MMU */ 639 640 #define rq_for_each_bio(_bio, rq) \ 641 if ((rq->bio)) \ 642 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next) 643 644 extern int blk_register_queue(struct gendisk *disk); 645 extern void blk_unregister_queue(struct gendisk *disk); 646 extern void register_disk(struct gendisk *dev); 647 extern void generic_make_request(struct bio *bio); 648 extern void blk_put_request(struct request *); 649 extern void __blk_put_request(struct request_queue *, struct request *); 650 extern void blk_end_sync_rq(struct request *rq, int error); 651 extern struct request *blk_get_request(struct request_queue *, int, gfp_t); 652 extern void blk_insert_request(struct request_queue *, struct request *, int, void *); 653 extern void blk_requeue_request(struct request_queue *, struct request *); 654 extern void blk_plug_device(struct request_queue *); 655 extern int blk_remove_plug(struct request_queue *); 656 extern void blk_recount_segments(struct request_queue *, struct bio *); 657 extern int scsi_cmd_ioctl(struct file *, struct request_queue *, 658 struct gendisk *, unsigned int, void __user *); 659 extern int sg_scsi_ioctl(struct file *, struct request_queue *, 660 struct gendisk *, struct scsi_ioctl_command __user *); 661 662 /* 663 * Temporary export, until SCSI gets fixed up. 664 */ 665 extern int ll_back_merge_fn(struct request_queue *, struct request *, 666 struct bio *); 667 668 /* 669 * A queue has just exitted congestion. Note this in the global counter of 670 * congested queues, and wake up anyone who was waiting for requests to be 671 * put back. 672 */ 673 static inline void blk_clear_queue_congested(struct request_queue *q, int rw) 674 { 675 clear_bdi_congested(&q->backing_dev_info, rw); 676 } 677 678 /* 679 * A queue has just entered congestion. Flag that in the queue's VM-visible 680 * state flags and increment the global gounter of congested queues. 681 */ 682 static inline void blk_set_queue_congested(struct request_queue *q, int rw) 683 { 684 set_bdi_congested(&q->backing_dev_info, rw); 685 } 686 687 extern void blk_start_queue(struct request_queue *q); 688 extern void blk_stop_queue(struct request_queue *q); 689 extern void blk_sync_queue(struct request_queue *q); 690 extern void __blk_stop_queue(struct request_queue *q); 691 extern void blk_run_queue(struct request_queue *); 692 extern void blk_start_queueing(struct request_queue *); 693 extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long); 694 extern int blk_rq_unmap_user(struct bio *); 695 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t); 696 extern int blk_rq_map_user_iov(struct request_queue *, struct request *, 697 struct sg_iovec *, int, unsigned int); 698 extern int blk_execute_rq(struct request_queue *, struct gendisk *, 699 struct request *, int); 700 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *, 701 struct request *, int, rq_end_io_fn *); 702 extern int blk_verify_command(unsigned char *, int); 703 704 static inline struct request_queue *bdev_get_queue(struct block_device *bdev) 705 { 706 return bdev->bd_disk->queue; 707 } 708 709 static inline void blk_run_backing_dev(struct backing_dev_info *bdi, 710 struct page *page) 711 { 712 if (bdi && bdi->unplug_io_fn) 713 bdi->unplug_io_fn(bdi, page); 714 } 715 716 static inline void blk_run_address_space(struct address_space *mapping) 717 { 718 if (mapping) 719 blk_run_backing_dev(mapping->backing_dev_info, NULL); 720 } 721 722 /* 723 * end_request() and friends. Must be called with the request queue spinlock 724 * acquired. All functions called within end_request() _must_be_ atomic. 725 * 726 * Several drivers define their own end_request and call 727 * end_that_request_first() and end_that_request_last() 728 * for parts of the original function. This prevents 729 * code duplication in drivers. 730 */ 731 extern int end_that_request_first(struct request *, int, int); 732 extern int end_that_request_chunk(struct request *, int, int); 733 extern void end_that_request_last(struct request *, int); 734 extern void end_request(struct request *req, int uptodate); 735 extern void blk_complete_request(struct request *); 736 737 /* 738 * end_that_request_first/chunk() takes an uptodate argument. we account 739 * any value <= as an io error. 0 means -EIO for compatability reasons, 740 * any other < 0 value is the direct error type. An uptodate value of 741 * 1 indicates successful io completion 742 */ 743 #define end_io_error(uptodate) (unlikely((uptodate) <= 0)) 744 745 static inline void blkdev_dequeue_request(struct request *req) 746 { 747 elv_dequeue_request(req->q, req); 748 } 749 750 /* 751 * Access functions for manipulating queue properties 752 */ 753 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn, 754 spinlock_t *lock, int node_id); 755 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *); 756 extern void blk_cleanup_queue(struct request_queue *); 757 extern void blk_queue_make_request(struct request_queue *, make_request_fn *); 758 extern void blk_queue_bounce_limit(struct request_queue *, u64); 759 extern void blk_queue_max_sectors(struct request_queue *, unsigned int); 760 extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short); 761 extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short); 762 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int); 763 extern void blk_queue_hardsect_size(struct request_queue *, unsigned short); 764 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b); 765 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long); 766 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn); 767 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *); 768 extern void blk_queue_dma_alignment(struct request_queue *, int); 769 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *); 770 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); 771 extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *); 772 extern void blk_queue_issue_flush_fn(struct request_queue *, issue_flush_fn *); 773 extern int blk_do_ordered(struct request_queue *, struct request **); 774 extern unsigned blk_ordered_cur_seq(struct request_queue *); 775 extern unsigned blk_ordered_req_seq(struct request *); 776 extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int); 777 778 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); 779 extern void blk_dump_rq_flags(struct request *, char *); 780 extern void generic_unplug_device(struct request_queue *); 781 extern void __generic_unplug_device(struct request_queue *); 782 extern long nr_blockdev_pages(void); 783 784 int blk_get_queue(struct request_queue *); 785 struct request_queue *blk_alloc_queue(gfp_t); 786 struct request_queue *blk_alloc_queue_node(gfp_t, int); 787 extern void blk_put_queue(struct request_queue *); 788 789 /* 790 * tag stuff 791 */ 792 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy) 793 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth) 794 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED) 795 extern int blk_queue_start_tag(struct request_queue *, struct request *); 796 extern struct request *blk_queue_find_tag(struct request_queue *, int); 797 extern void blk_queue_end_tag(struct request_queue *, struct request *); 798 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *); 799 extern void blk_queue_free_tags(struct request_queue *); 800 extern int blk_queue_resize_tags(struct request_queue *, int); 801 extern void blk_queue_invalidate_tags(struct request_queue *); 802 extern struct blk_queue_tag *blk_init_tags(int); 803 extern void blk_free_tags(struct blk_queue_tag *); 804 805 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt, 806 int tag) 807 { 808 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth)) 809 return NULL; 810 return bqt->tag_index[tag]; 811 } 812 813 extern void blk_rq_bio_prep(struct request_queue *, struct request *, struct bio *); 814 extern int blkdev_issue_flush(struct block_device *, sector_t *); 815 816 #define MAX_PHYS_SEGMENTS 128 817 #define MAX_HW_SEGMENTS 128 818 #define SAFE_MAX_SECTORS 255 819 #define BLK_DEF_MAX_SECTORS 1024 820 821 #define MAX_SEGMENT_SIZE 65536 822 823 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist) 824 825 static inline int queue_hardsect_size(struct request_queue *q) 826 { 827 int retval = 512; 828 829 if (q && q->hardsect_size) 830 retval = q->hardsect_size; 831 832 return retval; 833 } 834 835 static inline int bdev_hardsect_size(struct block_device *bdev) 836 { 837 return queue_hardsect_size(bdev_get_queue(bdev)); 838 } 839 840 static inline int queue_dma_alignment(struct request_queue *q) 841 { 842 int retval = 511; 843 844 if (q && q->dma_alignment) 845 retval = q->dma_alignment; 846 847 return retval; 848 } 849 850 /* assumes size > 256 */ 851 static inline unsigned int blksize_bits(unsigned int size) 852 { 853 unsigned int bits = 8; 854 do { 855 bits++; 856 size >>= 1; 857 } while (size > 256); 858 return bits; 859 } 860 861 static inline unsigned int block_size(struct block_device *bdev) 862 { 863 return bdev->bd_block_size; 864 } 865 866 typedef struct {struct page *v;} Sector; 867 868 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *); 869 870 static inline void put_dev_sector(Sector p) 871 { 872 page_cache_release(p.v); 873 } 874 875 struct work_struct; 876 int kblockd_schedule_work(struct work_struct *work); 877 void kblockd_flush_work(struct work_struct *work); 878 879 #define MODULE_ALIAS_BLOCKDEV(major,minor) \ 880 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor)) 881 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \ 882 MODULE_ALIAS("block-major-" __stringify(major) "-*") 883 884 885 #else /* CONFIG_BLOCK */ 886 /* 887 * stubs for when the block layer is configured out 888 */ 889 #define buffer_heads_over_limit 0 890 891 static inline long nr_blockdev_pages(void) 892 { 893 return 0; 894 } 895 896 static inline void exit_io_context(void) 897 { 898 } 899 900 #endif /* CONFIG_BLOCK */ 901 902 #endif 903