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TOMOYO Linux Cross Reference
Linux/include/linux/blkdev.h

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  1 #ifndef _LINUX_BLKDEV_H
  2 #define _LINUX_BLKDEV_H
  3 
  4 #include <linux/sched.h>
  5 
  6 #ifdef CONFIG_BLOCK
  7 
  8 #include <linux/major.h>
  9 #include <linux/genhd.h>
 10 #include <linux/list.h>
 11 #include <linux/timer.h>
 12 #include <linux/workqueue.h>
 13 #include <linux/pagemap.h>
 14 #include <linux/backing-dev.h>
 15 #include <linux/wait.h>
 16 #include <linux/mempool.h>
 17 #include <linux/bio.h>
 18 #include <linux/stringify.h>
 19 #include <linux/gfp.h>
 20 #include <linux/bsg.h>
 21 #include <linux/smp.h>
 22 #include <linux/rcupdate.h>
 23 
 24 #include <asm/scatterlist.h>
 25 
 26 struct module;
 27 struct scsi_ioctl_command;
 28 
 29 struct request_queue;
 30 struct elevator_queue;
 31 struct request_pm_state;
 32 struct blk_trace;
 33 struct request;
 34 struct sg_io_hdr;
 35 struct bsg_job;
 36 struct blkcg_gq;
 37 
 38 #define BLKDEV_MIN_RQ   4
 39 #define BLKDEV_MAX_RQ   128     /* Default maximum */
 40 
 41 /*
 42  * Maximum number of blkcg policies allowed to be registered concurrently.
 43  * Defined here to simplify include dependency.
 44  */
 45 #define BLKCG_MAX_POLS          2
 46 
 47 struct request;
 48 typedef void (rq_end_io_fn)(struct request *, int);
 49 
 50 #define BLK_RL_SYNCFULL         (1U << 0)
 51 #define BLK_RL_ASYNCFULL        (1U << 1)
 52 
 53 struct request_list {
 54         struct request_queue    *q;     /* the queue this rl belongs to */
 55 #ifdef CONFIG_BLK_CGROUP
 56         struct blkcg_gq         *blkg;  /* blkg this request pool belongs to */
 57 #endif
 58         /*
 59          * count[], starved[], and wait[] are indexed by
 60          * BLK_RW_SYNC/BLK_RW_ASYNC
 61          */
 62         int                     count[2];
 63         int                     starved[2];
 64         mempool_t               *rq_pool;
 65         wait_queue_head_t       wait[2];
 66         unsigned int            flags;
 67 };
 68 
 69 /*
 70  * request command types
 71  */
 72 enum rq_cmd_type_bits {
 73         REQ_TYPE_FS             = 1,    /* fs request */
 74         REQ_TYPE_BLOCK_PC,              /* scsi command */
 75         REQ_TYPE_SENSE,                 /* sense request */
 76         REQ_TYPE_PM_SUSPEND,            /* suspend request */
 77         REQ_TYPE_PM_RESUME,             /* resume request */
 78         REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
 79         REQ_TYPE_SPECIAL,               /* driver defined type */
 80         /*
 81          * for ATA/ATAPI devices. this really doesn't belong here, ide should
 82          * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
 83          * private REQ_LB opcodes to differentiate what type of request this is
 84          */
 85         REQ_TYPE_ATA_TASKFILE,
 86         REQ_TYPE_ATA_PC,
 87 };
 88 
 89 #define BLK_MAX_CDB     16
 90 
 91 /*
 92  * try to put the fields that are referenced together in the same cacheline.
 93  * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
 94  * as well!
 95  */
 96 struct request {
 97         struct list_head queuelist;
 98         struct call_single_data csd;
 99 
100         struct request_queue *q;
101 
102         unsigned int cmd_flags;
103         enum rq_cmd_type_bits cmd_type;
104         unsigned long atomic_flags;
105 
106         int cpu;
107 
108         /* the following two fields are internal, NEVER access directly */
109         unsigned int __data_len;        /* total data len */
110         sector_t __sector;              /* sector cursor */
111 
112         struct bio *bio;
113         struct bio *biotail;
114 
115         struct hlist_node hash; /* merge hash */
116         /*
117          * The rb_node is only used inside the io scheduler, requests
118          * are pruned when moved to the dispatch queue. So let the
119          * completion_data share space with the rb_node.
120          */
121         union {
122                 struct rb_node rb_node; /* sort/lookup */
123                 void *completion_data;
124         };
125 
126         /*
127          * Three pointers are available for the IO schedulers, if they need
128          * more they have to dynamically allocate it.  Flush requests are
129          * never put on the IO scheduler. So let the flush fields share
130          * space with the elevator data.
131          */
132         union {
133                 struct {
134                         struct io_cq            *icq;
135                         void                    *priv[2];
136                 } elv;
137 
138                 struct {
139                         unsigned int            seq;
140                         struct list_head        list;
141                         rq_end_io_fn            *saved_end_io;
142                 } flush;
143         };
144 
145         struct gendisk *rq_disk;
146         struct hd_struct *part;
147         unsigned long start_time;
148 #ifdef CONFIG_BLK_CGROUP
149         struct request_list *rl;                /* rl this rq is alloced from */
150         unsigned long long start_time_ns;
151         unsigned long long io_start_time_ns;    /* when passed to hardware */
152 #endif
153         /* Number of scatter-gather DMA addr+len pairs after
154          * physical address coalescing is performed.
155          */
156         unsigned short nr_phys_segments;
157 #if defined(CONFIG_BLK_DEV_INTEGRITY)
158         unsigned short nr_integrity_segments;
159 #endif
160 
161         unsigned short ioprio;
162 
163         int ref_count;
164 
165         void *special;          /* opaque pointer available for LLD use */
166         char *buffer;           /* kaddr of the current segment if available */
167 
168         int tag;
169         int errors;
170 
171         /*
172          * when request is used as a packet command carrier
173          */
174         unsigned char __cmd[BLK_MAX_CDB];
175         unsigned char *cmd;
176         unsigned short cmd_len;
177 
178         unsigned int extra_len; /* length of alignment and padding */
179         unsigned int sense_len;
180         unsigned int resid_len; /* residual count */
181         void *sense;
182 
183         unsigned long deadline;
184         struct list_head timeout_list;
185         unsigned int timeout;
186         int retries;
187 
188         /*
189          * completion callback.
190          */
191         rq_end_io_fn *end_io;
192         void *end_io_data;
193 
194         /* for bidi */
195         struct request *next_rq;
196 };
197 
198 static inline unsigned short req_get_ioprio(struct request *req)
199 {
200         return req->ioprio;
201 }
202 
203 /*
204  * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
205  * requests. Some step values could eventually be made generic.
206  */
207 struct request_pm_state
208 {
209         /* PM state machine step value, currently driver specific */
210         int     pm_step;
211         /* requested PM state value (S1, S2, S3, S4, ...) */
212         u32     pm_state;
213         void*   data;           /* for driver use */
214 };
215 
216 #include <linux/elevator.h>
217 
218 typedef void (request_fn_proc) (struct request_queue *q);
219 typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
220 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
221 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
222 
223 struct bio_vec;
224 struct bvec_merge_data {
225         struct block_device *bi_bdev;
226         sector_t bi_sector;
227         unsigned bi_size;
228         unsigned long bi_rw;
229 };
230 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
231                              struct bio_vec *);
232 typedef void (softirq_done_fn)(struct request *);
233 typedef int (dma_drain_needed_fn)(struct request *);
234 typedef int (lld_busy_fn) (struct request_queue *q);
235 typedef int (bsg_job_fn) (struct bsg_job *);
236 
237 enum blk_eh_timer_return {
238         BLK_EH_NOT_HANDLED,
239         BLK_EH_HANDLED,
240         BLK_EH_RESET_TIMER,
241 };
242 
243 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
244 
245 enum blk_queue_state {
246         Queue_down,
247         Queue_up,
248 };
249 
250 struct blk_queue_tag {
251         struct request **tag_index;     /* map of busy tags */
252         unsigned long *tag_map;         /* bit map of free/busy tags */
253         int busy;                       /* current depth */
254         int max_depth;                  /* what we will send to device */
255         int real_max_depth;             /* what the array can hold */
256         atomic_t refcnt;                /* map can be shared */
257 };
258 
259 #define BLK_SCSI_MAX_CMDS       (256)
260 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
261 
262 struct queue_limits {
263         unsigned long           bounce_pfn;
264         unsigned long           seg_boundary_mask;
265 
266         unsigned int            max_hw_sectors;
267         unsigned int            max_sectors;
268         unsigned int            max_segment_size;
269         unsigned int            physical_block_size;
270         unsigned int            alignment_offset;
271         unsigned int            io_min;
272         unsigned int            io_opt;
273         unsigned int            max_discard_sectors;
274         unsigned int            max_write_same_sectors;
275         unsigned int            discard_granularity;
276         unsigned int            discard_alignment;
277 
278         unsigned short          logical_block_size;
279         unsigned short          max_segments;
280         unsigned short          max_integrity_segments;
281 
282         unsigned char           misaligned;
283         unsigned char           discard_misaligned;
284         unsigned char           cluster;
285         unsigned char           discard_zeroes_data;
286 };
287 
288 struct request_queue {
289         /*
290          * Together with queue_head for cacheline sharing
291          */
292         struct list_head        queue_head;
293         struct request          *last_merge;
294         struct elevator_queue   *elevator;
295         int                     nr_rqs[2];      /* # allocated [a]sync rqs */
296         int                     nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
297 
298         /*
299          * If blkcg is not used, @q->root_rl serves all requests.  If blkcg
300          * is used, root blkg allocates from @q->root_rl and all other
301          * blkgs from their own blkg->rl.  Which one to use should be
302          * determined using bio_request_list().
303          */
304         struct request_list     root_rl;
305 
306         request_fn_proc         *request_fn;
307         make_request_fn         *make_request_fn;
308         prep_rq_fn              *prep_rq_fn;
309         unprep_rq_fn            *unprep_rq_fn;
310         merge_bvec_fn           *merge_bvec_fn;
311         softirq_done_fn         *softirq_done_fn;
312         rq_timed_out_fn         *rq_timed_out_fn;
313         dma_drain_needed_fn     *dma_drain_needed;
314         lld_busy_fn             *lld_busy_fn;
315 
316         /*
317          * Dispatch queue sorting
318          */
319         sector_t                end_sector;
320         struct request          *boundary_rq;
321 
322         /*
323          * Delayed queue handling
324          */
325         struct delayed_work     delay_work;
326 
327         struct backing_dev_info backing_dev_info;
328 
329         /*
330          * The queue owner gets to use this for whatever they like.
331          * ll_rw_blk doesn't touch it.
332          */
333         void                    *queuedata;
334 
335         /*
336          * various queue flags, see QUEUE_* below
337          */
338         unsigned long           queue_flags;
339 
340         /*
341          * ida allocated id for this queue.  Used to index queues from
342          * ioctx.
343          */
344         int                     id;
345 
346         /*
347          * queue needs bounce pages for pages above this limit
348          */
349         gfp_t                   bounce_gfp;
350 
351         /*
352          * protects queue structures from reentrancy. ->__queue_lock should
353          * _never_ be used directly, it is queue private. always use
354          * ->queue_lock.
355          */
356         spinlock_t              __queue_lock;
357         spinlock_t              *queue_lock;
358 
359         /*
360          * queue kobject
361          */
362         struct kobject kobj;
363 
364         /*
365          * queue settings
366          */
367         unsigned long           nr_requests;    /* Max # of requests */
368         unsigned int            nr_congestion_on;
369         unsigned int            nr_congestion_off;
370         unsigned int            nr_batching;
371 
372         unsigned int            dma_drain_size;
373         void                    *dma_drain_buffer;
374         unsigned int            dma_pad_mask;
375         unsigned int            dma_alignment;
376 
377         struct blk_queue_tag    *queue_tags;
378         struct list_head        tag_busy_list;
379 
380         unsigned int            nr_sorted;
381         unsigned int            in_flight[2];
382         /*
383          * Number of active block driver functions for which blk_drain_queue()
384          * must wait. Must be incremented around functions that unlock the
385          * queue_lock internally, e.g. scsi_request_fn().
386          */
387         unsigned int            request_fn_active;
388 
389         unsigned int            rq_timeout;
390         struct timer_list       timeout;
391         struct list_head        timeout_list;
392 
393         struct list_head        icq_list;
394 #ifdef CONFIG_BLK_CGROUP
395         DECLARE_BITMAP          (blkcg_pols, BLKCG_MAX_POLS);
396         struct blkcg_gq         *root_blkg;
397         struct list_head        blkg_list;
398 #endif
399 
400         struct queue_limits     limits;
401 
402         /*
403          * sg stuff
404          */
405         unsigned int            sg_timeout;
406         unsigned int            sg_reserved_size;
407         int                     node;
408 #ifdef CONFIG_BLK_DEV_IO_TRACE
409         struct blk_trace        *blk_trace;
410 #endif
411         /*
412          * for flush operations
413          */
414         unsigned int            flush_flags;
415         unsigned int            flush_not_queueable:1;
416         unsigned int            flush_queue_delayed:1;
417         unsigned int            flush_pending_idx:1;
418         unsigned int            flush_running_idx:1;
419         unsigned long           flush_pending_since;
420         struct list_head        flush_queue[2];
421         struct list_head        flush_data_in_flight;
422         struct request          flush_rq;
423 
424         struct mutex            sysfs_lock;
425 
426         int                     bypass_depth;
427 
428 #if defined(CONFIG_BLK_DEV_BSG)
429         bsg_job_fn              *bsg_job_fn;
430         int                     bsg_job_size;
431         struct bsg_class_device bsg_dev;
432 #endif
433 
434 #ifdef CONFIG_BLK_CGROUP
435         struct list_head        all_q_node;
436 #endif
437 #ifdef CONFIG_BLK_DEV_THROTTLING
438         /* Throttle data */
439         struct throtl_data *td;
440 #endif
441         struct rcu_head         rcu_head;
442 };
443 
444 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
445 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
446 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
447 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
448 #define QUEUE_FLAG_DYING        5       /* queue being torn down */
449 #define QUEUE_FLAG_BYPASS       6       /* act as dumb FIFO queue */
450 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
451 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
452 #define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
453 #define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
454 #define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
455 #define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
456 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
457 #define QUEUE_FLAG_IO_STAT     13       /* do IO stats */
458 #define QUEUE_FLAG_DISCARD     14       /* supports DISCARD */
459 #define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
460 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
461 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
462 #define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
463 #define QUEUE_FLAG_DEAD        19       /* queue tear-down finished */
464 
465 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
466                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
467                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
468                                  (1 << QUEUE_FLAG_ADD_RANDOM))
469 
470 static inline void queue_lockdep_assert_held(struct request_queue *q)
471 {
472         if (q->queue_lock)
473                 lockdep_assert_held(q->queue_lock);
474 }
475 
476 static inline void queue_flag_set_unlocked(unsigned int flag,
477                                            struct request_queue *q)
478 {
479         __set_bit(flag, &q->queue_flags);
480 }
481 
482 static inline int queue_flag_test_and_clear(unsigned int flag,
483                                             struct request_queue *q)
484 {
485         queue_lockdep_assert_held(q);
486 
487         if (test_bit(flag, &q->queue_flags)) {
488                 __clear_bit(flag, &q->queue_flags);
489                 return 1;
490         }
491 
492         return 0;
493 }
494 
495 static inline int queue_flag_test_and_set(unsigned int flag,
496                                           struct request_queue *q)
497 {
498         queue_lockdep_assert_held(q);
499 
500         if (!test_bit(flag, &q->queue_flags)) {
501                 __set_bit(flag, &q->queue_flags);
502                 return 0;
503         }
504 
505         return 1;
506 }
507 
508 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
509 {
510         queue_lockdep_assert_held(q);
511         __set_bit(flag, &q->queue_flags);
512 }
513 
514 static inline void queue_flag_clear_unlocked(unsigned int flag,
515                                              struct request_queue *q)
516 {
517         __clear_bit(flag, &q->queue_flags);
518 }
519 
520 static inline int queue_in_flight(struct request_queue *q)
521 {
522         return q->in_flight[0] + q->in_flight[1];
523 }
524 
525 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
526 {
527         queue_lockdep_assert_held(q);
528         __clear_bit(flag, &q->queue_flags);
529 }
530 
531 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
532 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
533 #define blk_queue_dying(q)      test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
534 #define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
535 #define blk_queue_bypass(q)     test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
536 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
537 #define blk_queue_noxmerges(q)  \
538         test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
539 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
540 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
541 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
542 #define blk_queue_stackable(q)  \
543         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
544 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
545 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
546         test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
547 
548 #define blk_noretry_request(rq) \
549         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
550                              REQ_FAILFAST_DRIVER))
551 
552 #define blk_account_rq(rq) \
553         (((rq)->cmd_flags & REQ_STARTED) && \
554          ((rq)->cmd_type == REQ_TYPE_FS))
555 
556 #define blk_pm_request(rq)      \
557         ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
558          (rq)->cmd_type == REQ_TYPE_PM_RESUME)
559 
560 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
561 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
562 /* rq->queuelist of dequeued request must be list_empty() */
563 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
564 
565 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
566 
567 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
568 
569 static inline unsigned int blk_queue_cluster(struct request_queue *q)
570 {
571         return q->limits.cluster;
572 }
573 
574 /*
575  * We regard a request as sync, if either a read or a sync write
576  */
577 static inline bool rw_is_sync(unsigned int rw_flags)
578 {
579         return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
580 }
581 
582 static inline bool rq_is_sync(struct request *rq)
583 {
584         return rw_is_sync(rq->cmd_flags);
585 }
586 
587 static inline bool blk_rl_full(struct request_list *rl, bool sync)
588 {
589         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
590 
591         return rl->flags & flag;
592 }
593 
594 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
595 {
596         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
597 
598         rl->flags |= flag;
599 }
600 
601 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
602 {
603         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
604 
605         rl->flags &= ~flag;
606 }
607 
608 static inline bool rq_mergeable(struct request *rq)
609 {
610         if (rq->cmd_type != REQ_TYPE_FS)
611                 return false;
612 
613         if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
614                 return false;
615 
616         return true;
617 }
618 
619 static inline bool blk_check_merge_flags(unsigned int flags1,
620                                          unsigned int flags2)
621 {
622         if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD))
623                 return false;
624 
625         if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
626                 return false;
627 
628         if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME))
629                 return false;
630 
631         return true;
632 }
633 
634 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
635 {
636         if (bio_data(a) == bio_data(b))
637                 return true;
638 
639         return false;
640 }
641 
642 /*
643  * q->prep_rq_fn return values
644  */
645 #define BLKPREP_OK              0       /* serve it */
646 #define BLKPREP_KILL            1       /* fatal error, kill */
647 #define BLKPREP_DEFER           2       /* leave on queue */
648 
649 extern unsigned long blk_max_low_pfn, blk_max_pfn;
650 
651 /*
652  * standard bounce addresses:
653  *
654  * BLK_BOUNCE_HIGH      : bounce all highmem pages
655  * BLK_BOUNCE_ANY       : don't bounce anything
656  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
657  */
658 
659 #if BITS_PER_LONG == 32
660 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
661 #else
662 #define BLK_BOUNCE_HIGH         -1ULL
663 #endif
664 #define BLK_BOUNCE_ANY          (-1ULL)
665 #define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
666 
667 /*
668  * default timeout for SG_IO if none specified
669  */
670 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
671 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
672 
673 #ifdef CONFIG_BOUNCE
674 extern int init_emergency_isa_pool(void);
675 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
676 #else
677 static inline int init_emergency_isa_pool(void)
678 {
679         return 0;
680 }
681 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
682 {
683 }
684 #endif /* CONFIG_MMU */
685 
686 struct rq_map_data {
687         struct page **pages;
688         int page_order;
689         int nr_entries;
690         unsigned long offset;
691         int null_mapped;
692         int from_user;
693 };
694 
695 struct req_iterator {
696         int i;
697         struct bio *bio;
698 };
699 
700 /* This should not be used directly - use rq_for_each_segment */
701 #define for_each_bio(_bio)              \
702         for (; _bio; _bio = _bio->bi_next)
703 #define __rq_for_each_bio(_bio, rq)     \
704         if ((rq->bio))                  \
705                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
706 
707 #define rq_for_each_segment(bvl, _rq, _iter)                    \
708         __rq_for_each_bio(_iter.bio, _rq)                       \
709                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
710 
711 #define rq_iter_last(rq, _iter)                                 \
712                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
713 
714 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
715 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
716 #endif
717 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
718 extern void rq_flush_dcache_pages(struct request *rq);
719 #else
720 static inline void rq_flush_dcache_pages(struct request *rq)
721 {
722 }
723 #endif
724 
725 extern int blk_register_queue(struct gendisk *disk);
726 extern void blk_unregister_queue(struct gendisk *disk);
727 extern void generic_make_request(struct bio *bio);
728 extern void blk_rq_init(struct request_queue *q, struct request *rq);
729 extern void blk_put_request(struct request *);
730 extern void __blk_put_request(struct request_queue *, struct request *);
731 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
732 extern struct request *blk_make_request(struct request_queue *, struct bio *,
733                                         gfp_t);
734 extern void blk_requeue_request(struct request_queue *, struct request *);
735 extern void blk_add_request_payload(struct request *rq, struct page *page,
736                 unsigned int len);
737 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
738 extern int blk_lld_busy(struct request_queue *q);
739 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
740                              struct bio_set *bs, gfp_t gfp_mask,
741                              int (*bio_ctr)(struct bio *, struct bio *, void *),
742                              void *data);
743 extern void blk_rq_unprep_clone(struct request *rq);
744 extern int blk_insert_cloned_request(struct request_queue *q,
745                                      struct request *rq);
746 extern void blk_delay_queue(struct request_queue *, unsigned long);
747 extern void blk_recount_segments(struct request_queue *, struct bio *);
748 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
749 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
750                               unsigned int, void __user *);
751 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
752                           unsigned int, void __user *);
753 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
754                          struct scsi_ioctl_command __user *);
755 
756 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
757 
758 /*
759  * A queue has just exitted congestion.  Note this in the global counter of
760  * congested queues, and wake up anyone who was waiting for requests to be
761  * put back.
762  */
763 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
764 {
765         clear_bdi_congested(&q->backing_dev_info, sync);
766 }
767 
768 /*
769  * A queue has just entered congestion.  Flag that in the queue's VM-visible
770  * state flags and increment the global gounter of congested queues.
771  */
772 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
773 {
774         set_bdi_congested(&q->backing_dev_info, sync);
775 }
776 
777 extern void blk_start_queue(struct request_queue *q);
778 extern void blk_stop_queue(struct request_queue *q);
779 extern void blk_sync_queue(struct request_queue *q);
780 extern void __blk_stop_queue(struct request_queue *q);
781 extern void __blk_run_queue(struct request_queue *q);
782 extern void blk_run_queue(struct request_queue *);
783 extern void blk_run_queue_async(struct request_queue *q);
784 extern int blk_rq_map_user(struct request_queue *, struct request *,
785                            struct rq_map_data *, void __user *, unsigned long,
786                            gfp_t);
787 extern int blk_rq_unmap_user(struct bio *);
788 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
789 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
790                                struct rq_map_data *, struct sg_iovec *, int,
791                                unsigned int, gfp_t);
792 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
793                           struct request *, int);
794 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
795                                   struct request *, int, rq_end_io_fn *);
796 
797 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
798 {
799         return bdev->bd_disk->queue;
800 }
801 
802 /*
803  * blk_rq_pos()                 : the current sector
804  * blk_rq_bytes()               : bytes left in the entire request
805  * blk_rq_cur_bytes()           : bytes left in the current segment
806  * blk_rq_err_bytes()           : bytes left till the next error boundary
807  * blk_rq_sectors()             : sectors left in the entire request
808  * blk_rq_cur_sectors()         : sectors left in the current segment
809  */
810 static inline sector_t blk_rq_pos(const struct request *rq)
811 {
812         return rq->__sector;
813 }
814 
815 static inline unsigned int blk_rq_bytes(const struct request *rq)
816 {
817         return rq->__data_len;
818 }
819 
820 static inline int blk_rq_cur_bytes(const struct request *rq)
821 {
822         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
823 }
824 
825 extern unsigned int blk_rq_err_bytes(const struct request *rq);
826 
827 static inline unsigned int blk_rq_sectors(const struct request *rq)
828 {
829         return blk_rq_bytes(rq) >> 9;
830 }
831 
832 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
833 {
834         return blk_rq_cur_bytes(rq) >> 9;
835 }
836 
837 static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
838                                                      unsigned int cmd_flags)
839 {
840         if (unlikely(cmd_flags & REQ_DISCARD))
841                 return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
842 
843         if (unlikely(cmd_flags & REQ_WRITE_SAME))
844                 return q->limits.max_write_same_sectors;
845 
846         return q->limits.max_sectors;
847 }
848 
849 static inline unsigned int blk_rq_get_max_sectors(struct request *rq)
850 {
851         struct request_queue *q = rq->q;
852 
853         if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC))
854                 return q->limits.max_hw_sectors;
855 
856         return blk_queue_get_max_sectors(q, rq->cmd_flags);
857 }
858 
859 /*
860  * Request issue related functions.
861  */
862 extern struct request *blk_peek_request(struct request_queue *q);
863 extern void blk_start_request(struct request *rq);
864 extern struct request *blk_fetch_request(struct request_queue *q);
865 
866 /*
867  * Request completion related functions.
868  *
869  * blk_update_request() completes given number of bytes and updates
870  * the request without completing it.
871  *
872  * blk_end_request() and friends.  __blk_end_request() must be called
873  * with the request queue spinlock acquired.
874  *
875  * Several drivers define their own end_request and call
876  * blk_end_request() for parts of the original function.
877  * This prevents code duplication in drivers.
878  */
879 extern bool blk_update_request(struct request *rq, int error,
880                                unsigned int nr_bytes);
881 extern bool blk_end_request(struct request *rq, int error,
882                             unsigned int nr_bytes);
883 extern void blk_end_request_all(struct request *rq, int error);
884 extern bool blk_end_request_cur(struct request *rq, int error);
885 extern bool blk_end_request_err(struct request *rq, int error);
886 extern bool __blk_end_request(struct request *rq, int error,
887                               unsigned int nr_bytes);
888 extern void __blk_end_request_all(struct request *rq, int error);
889 extern bool __blk_end_request_cur(struct request *rq, int error);
890 extern bool __blk_end_request_err(struct request *rq, int error);
891 
892 extern void blk_complete_request(struct request *);
893 extern void __blk_complete_request(struct request *);
894 extern void blk_abort_request(struct request *);
895 extern void blk_unprep_request(struct request *);
896 
897 /*
898  * Access functions for manipulating queue properties
899  */
900 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
901                                         spinlock_t *lock, int node_id);
902 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
903 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
904                                                       request_fn_proc *, spinlock_t *);
905 extern void blk_cleanup_queue(struct request_queue *);
906 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
907 extern void blk_queue_bounce_limit(struct request_queue *, u64);
908 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
909 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
910 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
911 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
912 extern void blk_queue_max_discard_sectors(struct request_queue *q,
913                 unsigned int max_discard_sectors);
914 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
915                 unsigned int max_write_same_sectors);
916 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
917 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
918 extern void blk_queue_alignment_offset(struct request_queue *q,
919                                        unsigned int alignment);
920 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
921 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
922 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
923 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
924 extern void blk_set_default_limits(struct queue_limits *lim);
925 extern void blk_set_stacking_limits(struct queue_limits *lim);
926 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
927                             sector_t offset);
928 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
929                             sector_t offset);
930 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
931                               sector_t offset);
932 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
933 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
934 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
935 extern int blk_queue_dma_drain(struct request_queue *q,
936                                dma_drain_needed_fn *dma_drain_needed,
937                                void *buf, unsigned int size);
938 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
939 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
940 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
941 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
942 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
943 extern void blk_queue_dma_alignment(struct request_queue *, int);
944 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
945 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
946 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
947 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
948 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
949 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
950 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
951 
952 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
953 extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
954                           struct scatterlist *sglist);
955 extern void blk_dump_rq_flags(struct request *, char *);
956 extern long nr_blockdev_pages(void);
957 
958 bool __must_check blk_get_queue(struct request_queue *);
959 struct request_queue *blk_alloc_queue(gfp_t);
960 struct request_queue *blk_alloc_queue_node(gfp_t, int);
961 extern void blk_put_queue(struct request_queue *);
962 
963 /*
964  * blk_plug permits building a queue of related requests by holding the I/O
965  * fragments for a short period. This allows merging of sequential requests
966  * into single larger request. As the requests are moved from a per-task list to
967  * the device's request_queue in a batch, this results in improved scalability
968  * as the lock contention for request_queue lock is reduced.
969  *
970  * It is ok not to disable preemption when adding the request to the plug list
971  * or when attempting a merge, because blk_schedule_flush_list() will only flush
972  * the plug list when the task sleeps by itself. For details, please see
973  * schedule() where blk_schedule_flush_plug() is called.
974  */
975 struct blk_plug {
976         unsigned long magic; /* detect uninitialized use-cases */
977         struct list_head list; /* requests */
978         struct list_head cb_list; /* md requires an unplug callback */
979 };
980 #define BLK_MAX_REQUEST_COUNT 16
981 
982 struct blk_plug_cb;
983 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
984 struct blk_plug_cb {
985         struct list_head list;
986         blk_plug_cb_fn callback;
987         void *data;
988 };
989 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
990                                              void *data, int size);
991 extern void blk_start_plug(struct blk_plug *);
992 extern void blk_finish_plug(struct blk_plug *);
993 extern void blk_flush_plug_list(struct blk_plug *, bool);
994 
995 static inline void blk_flush_plug(struct task_struct *tsk)
996 {
997         struct blk_plug *plug = tsk->plug;
998 
999         if (plug)
1000                 blk_flush_plug_list(plug, false);
1001 }
1002 
1003 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
1004 {
1005         struct blk_plug *plug = tsk->plug;
1006 
1007         if (plug)
1008                 blk_flush_plug_list(plug, true);
1009 }
1010 
1011 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1012 {
1013         struct blk_plug *plug = tsk->plug;
1014 
1015         return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
1016 }
1017 
1018 /*
1019  * tag stuff
1020  */
1021 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
1022 extern int blk_queue_start_tag(struct request_queue *, struct request *);
1023 extern struct request *blk_queue_find_tag(struct request_queue *, int);
1024 extern void blk_queue_end_tag(struct request_queue *, struct request *);
1025 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
1026 extern void blk_queue_free_tags(struct request_queue *);
1027 extern int blk_queue_resize_tags(struct request_queue *, int);
1028 extern void blk_queue_invalidate_tags(struct request_queue *);
1029 extern struct blk_queue_tag *blk_init_tags(int);
1030 extern void blk_free_tags(struct blk_queue_tag *);
1031 
1032 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
1033                                                 int tag)
1034 {
1035         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
1036                 return NULL;
1037         return bqt->tag_index[tag];
1038 }
1039 
1040 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
1041 
1042 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
1043 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1044                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
1045 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
1046                 sector_t nr_sects, gfp_t gfp_mask, struct page *page);
1047 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1048                         sector_t nr_sects, gfp_t gfp_mask);
1049 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
1050                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
1051 {
1052         return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
1053                                     nr_blocks << (sb->s_blocksize_bits - 9),
1054                                     gfp_mask, flags);
1055 }
1056 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1057                 sector_t nr_blocks, gfp_t gfp_mask)
1058 {
1059         return blkdev_issue_zeroout(sb->s_bdev,
1060                                     block << (sb->s_blocksize_bits - 9),
1061                                     nr_blocks << (sb->s_blocksize_bits - 9),
1062                                     gfp_mask);
1063 }
1064 
1065 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1066 
1067 enum blk_default_limits {
1068         BLK_MAX_SEGMENTS        = 128,
1069         BLK_SAFE_MAX_SECTORS    = 255,
1070         BLK_DEF_MAX_SECTORS     = 1024,
1071         BLK_MAX_SEGMENT_SIZE    = 65536,
1072         BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
1073 };
1074 
1075 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1076 
1077 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1078 {
1079         return q->limits.bounce_pfn;
1080 }
1081 
1082 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1083 {
1084         return q->limits.seg_boundary_mask;
1085 }
1086 
1087 static inline unsigned int queue_max_sectors(struct request_queue *q)
1088 {
1089         return q->limits.max_sectors;
1090 }
1091 
1092 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1093 {
1094         return q->limits.max_hw_sectors;
1095 }
1096 
1097 static inline unsigned short queue_max_segments(struct request_queue *q)
1098 {
1099         return q->limits.max_segments;
1100 }
1101 
1102 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1103 {
1104         return q->limits.max_segment_size;
1105 }
1106 
1107 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1108 {
1109         int retval = 512;
1110 
1111         if (q && q->limits.logical_block_size)
1112                 retval = q->limits.logical_block_size;
1113 
1114         return retval;
1115 }
1116 
1117 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1118 {
1119         return queue_logical_block_size(bdev_get_queue(bdev));
1120 }
1121 
1122 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1123 {
1124         return q->limits.physical_block_size;
1125 }
1126 
1127 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1128 {
1129         return queue_physical_block_size(bdev_get_queue(bdev));
1130 }
1131 
1132 static inline unsigned int queue_io_min(struct request_queue *q)
1133 {
1134         return q->limits.io_min;
1135 }
1136 
1137 static inline int bdev_io_min(struct block_device *bdev)
1138 {
1139         return queue_io_min(bdev_get_queue(bdev));
1140 }
1141 
1142 static inline unsigned int queue_io_opt(struct request_queue *q)
1143 {
1144         return q->limits.io_opt;
1145 }
1146 
1147 static inline int bdev_io_opt(struct block_device *bdev)
1148 {
1149         return queue_io_opt(bdev_get_queue(bdev));
1150 }
1151 
1152 static inline int queue_alignment_offset(struct request_queue *q)
1153 {
1154         if (q->limits.misaligned)
1155                 return -1;
1156 
1157         return q->limits.alignment_offset;
1158 }
1159 
1160 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1161 {
1162         unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1163         unsigned int alignment = (sector << 9) & (granularity - 1);
1164 
1165         return (granularity + lim->alignment_offset - alignment)
1166                 & (granularity - 1);
1167 }
1168 
1169 static inline int bdev_alignment_offset(struct block_device *bdev)
1170 {
1171         struct request_queue *q = bdev_get_queue(bdev);
1172 
1173         if (q->limits.misaligned)
1174                 return -1;
1175 
1176         if (bdev != bdev->bd_contains)
1177                 return bdev->bd_part->alignment_offset;
1178 
1179         return q->limits.alignment_offset;
1180 }
1181 
1182 static inline int queue_discard_alignment(struct request_queue *q)
1183 {
1184         if (q->limits.discard_misaligned)
1185                 return -1;
1186 
1187         return q->limits.discard_alignment;
1188 }
1189 
1190 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1191 {
1192         unsigned int alignment, granularity, offset;
1193 
1194         if (!lim->max_discard_sectors)
1195                 return 0;
1196 
1197         /* Why are these in bytes, not sectors? */
1198         alignment = lim->discard_alignment >> 9;
1199         granularity = lim->discard_granularity >> 9;
1200         if (!granularity)
1201                 return 0;
1202 
1203         /* Offset of the partition start in 'granularity' sectors */
1204         offset = sector_div(sector, granularity);
1205 
1206         /* And why do we do this modulus *again* in blkdev_issue_discard()? */
1207         offset = (granularity + alignment - offset) % granularity;
1208 
1209         /* Turn it back into bytes, gaah */
1210         return offset << 9;
1211 }
1212 
1213 static inline int bdev_discard_alignment(struct block_device *bdev)
1214 {
1215         struct request_queue *q = bdev_get_queue(bdev);
1216 
1217         if (bdev != bdev->bd_contains)
1218                 return bdev->bd_part->discard_alignment;
1219 
1220         return q->limits.discard_alignment;
1221 }
1222 
1223 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1224 {
1225         if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1226                 return 1;
1227 
1228         return 0;
1229 }
1230 
1231 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1232 {
1233         return queue_discard_zeroes_data(bdev_get_queue(bdev));
1234 }
1235 
1236 static inline unsigned int bdev_write_same(struct block_device *bdev)
1237 {
1238         struct request_queue *q = bdev_get_queue(bdev);
1239 
1240         if (q)
1241                 return q->limits.max_write_same_sectors;
1242 
1243         return 0;
1244 }
1245 
1246 static inline int queue_dma_alignment(struct request_queue *q)
1247 {
1248         return q ? q->dma_alignment : 511;
1249 }
1250 
1251 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1252                                  unsigned int len)
1253 {
1254         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1255         return !(addr & alignment) && !(len & alignment);
1256 }
1257 
1258 /* assumes size > 256 */
1259 static inline unsigned int blksize_bits(unsigned int size)
1260 {
1261         unsigned int bits = 8;
1262         do {
1263                 bits++;
1264                 size >>= 1;
1265         } while (size > 256);
1266         return bits;
1267 }
1268 
1269 static inline unsigned int block_size(struct block_device *bdev)
1270 {
1271         return bdev->bd_block_size;
1272 }
1273 
1274 static inline bool queue_flush_queueable(struct request_queue *q)
1275 {
1276         return !q->flush_not_queueable;
1277 }
1278 
1279 typedef struct {struct page *v;} Sector;
1280 
1281 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1282 
1283 static inline void put_dev_sector(Sector p)
1284 {
1285         page_cache_release(p.v);
1286 }
1287 
1288 struct work_struct;
1289 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1290 
1291 #ifdef CONFIG_BLK_CGROUP
1292 /*
1293  * This should not be using sched_clock(). A real patch is in progress
1294  * to fix this up, until that is in place we need to disable preemption
1295  * around sched_clock() in this function and set_io_start_time_ns().
1296  */
1297 static inline void set_start_time_ns(struct request *req)
1298 {
1299         preempt_disable();
1300         req->start_time_ns = sched_clock();
1301         preempt_enable();
1302 }
1303 
1304 static inline void set_io_start_time_ns(struct request *req)
1305 {
1306         preempt_disable();
1307         req->io_start_time_ns = sched_clock();
1308         preempt_enable();
1309 }
1310 
1311 static inline uint64_t rq_start_time_ns(struct request *req)
1312 {
1313         return req->start_time_ns;
1314 }
1315 
1316 static inline uint64_t rq_io_start_time_ns(struct request *req)
1317 {
1318         return req->io_start_time_ns;
1319 }
1320 #else
1321 static inline void set_start_time_ns(struct request *req) {}
1322 static inline void set_io_start_time_ns(struct request *req) {}
1323 static inline uint64_t rq_start_time_ns(struct request *req)
1324 {
1325         return 0;
1326 }
1327 static inline uint64_t rq_io_start_time_ns(struct request *req)
1328 {
1329         return 0;
1330 }
1331 #endif
1332 
1333 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1334         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1335 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1336         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1337 
1338 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1339 
1340 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1341 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1342 
1343 struct blk_integrity_exchg {
1344         void                    *prot_buf;
1345         void                    *data_buf;
1346         sector_t                sector;
1347         unsigned int            data_size;
1348         unsigned short          sector_size;
1349         const char              *disk_name;
1350 };
1351 
1352 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1353 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1354 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1355 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1356 
1357 struct blk_integrity {
1358         integrity_gen_fn        *generate_fn;
1359         integrity_vrfy_fn       *verify_fn;
1360         integrity_set_tag_fn    *set_tag_fn;
1361         integrity_get_tag_fn    *get_tag_fn;
1362 
1363         unsigned short          flags;
1364         unsigned short          tuple_size;
1365         unsigned short          sector_size;
1366         unsigned short          tag_size;
1367 
1368         const char              *name;
1369 
1370         struct kobject          kobj;
1371 };
1372 
1373 extern bool blk_integrity_is_initialized(struct gendisk *);
1374 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1375 extern void blk_integrity_unregister(struct gendisk *);
1376 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1377 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1378                                    struct scatterlist *);
1379 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1380 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1381                                   struct request *);
1382 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1383                                    struct bio *);
1384 
1385 static inline
1386 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1387 {
1388         return bdev->bd_disk->integrity;
1389 }
1390 
1391 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1392 {
1393         return disk->integrity;
1394 }
1395 
1396 static inline int blk_integrity_rq(struct request *rq)
1397 {
1398         if (rq->bio == NULL)
1399                 return 0;
1400 
1401         return bio_integrity(rq->bio);
1402 }
1403 
1404 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1405                                                     unsigned int segs)
1406 {
1407         q->limits.max_integrity_segments = segs;
1408 }
1409 
1410 static inline unsigned short
1411 queue_max_integrity_segments(struct request_queue *q)
1412 {
1413         return q->limits.max_integrity_segments;
1414 }
1415 
1416 #else /* CONFIG_BLK_DEV_INTEGRITY */
1417 
1418 struct bio;
1419 struct block_device;
1420 struct gendisk;
1421 struct blk_integrity;
1422 
1423 static inline int blk_integrity_rq(struct request *rq)
1424 {
1425         return 0;
1426 }
1427 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1428                                             struct bio *b)
1429 {
1430         return 0;
1431 }
1432 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1433                                           struct bio *b,
1434                                           struct scatterlist *s)
1435 {
1436         return 0;
1437 }
1438 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1439 {
1440         return 0;
1441 }
1442 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1443 {
1444         return NULL;
1445 }
1446 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1447 {
1448         return 0;
1449 }
1450 static inline int blk_integrity_register(struct gendisk *d,
1451                                          struct blk_integrity *b)
1452 {
1453         return 0;
1454 }
1455 static inline void blk_integrity_unregister(struct gendisk *d)
1456 {
1457 }
1458 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1459                                                     unsigned int segs)
1460 {
1461 }
1462 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1463 {
1464         return 0;
1465 }
1466 static inline int blk_integrity_merge_rq(struct request_queue *rq,
1467                                          struct request *r1,
1468                                          struct request *r2)
1469 {
1470         return 0;
1471 }
1472 static inline int blk_integrity_merge_bio(struct request_queue *rq,
1473                                           struct request *r,
1474                                           struct bio *b)
1475 {
1476         return 0;
1477 }
1478 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1479 {
1480         return 0;
1481 }
1482 
1483 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1484 
1485 struct block_device_operations {
1486         int (*open) (struct block_device *, fmode_t);
1487         int (*release) (struct gendisk *, fmode_t);
1488         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1489         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1490         int (*direct_access) (struct block_device *, sector_t,
1491                                                 void **, unsigned long *);
1492         unsigned int (*check_events) (struct gendisk *disk,
1493                                       unsigned int clearing);
1494         /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1495         int (*media_changed) (struct gendisk *);
1496         void (*unlock_native_capacity) (struct gendisk *);
1497         int (*revalidate_disk) (struct gendisk *);
1498         int (*getgeo)(struct block_device *, struct hd_geometry *);
1499         /* this callback is with swap_lock and sometimes page table lock held */
1500         void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1501         struct module *owner;
1502 };
1503 
1504 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1505                                  unsigned long);
1506 #else /* CONFIG_BLOCK */
1507 /*
1508  * stubs for when the block layer is configured out
1509  */
1510 #define buffer_heads_over_limit 0
1511 
1512 static inline long nr_blockdev_pages(void)
1513 {
1514         return 0;
1515 }
1516 
1517 struct blk_plug {
1518 };
1519 
1520 static inline void blk_start_plug(struct blk_plug *plug)
1521 {
1522 }
1523 
1524 static inline void blk_finish_plug(struct blk_plug *plug)
1525 {
1526 }
1527 
1528 static inline void blk_flush_plug(struct task_struct *task)
1529 {
1530 }
1531 
1532 static inline void blk_schedule_flush_plug(struct task_struct *task)
1533 {
1534 }
1535 
1536 
1537 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1538 {
1539         return false;
1540 }
1541 
1542 #endif /* CONFIG_BLOCK */
1543 
1544 #endif
1545 

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