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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/llist.h>
 12 #include <linux/timer.h>
 13 #include <linux/workqueue.h>
 14 #include <linux/pagemap.h>
 15 #include <linux/backing-dev-defs.h>
 16 #include <linux/wait.h>
 17 #include <linux/mempool.h>
 18 #include <linux/pfn.h>
 19 #include <linux/bio.h>
 20 #include <linux/stringify.h>
 21 #include <linux/gfp.h>
 22 #include <linux/bsg.h>
 23 #include <linux/smp.h>
 24 #include <linux/rcupdate.h>
 25 #include <linux/percpu-refcount.h>
 26 #include <linux/scatterlist.h>
 27 
 28 struct module;
 29 struct scsi_ioctl_command;
 30 
 31 struct request_queue;
 32 struct elevator_queue;
 33 struct blk_trace;
 34 struct request;
 35 struct sg_io_hdr;
 36 struct bsg_job;
 37 struct blkcg_gq;
 38 struct blk_flush_queue;
 39 struct pr_ops;
 40 
 41 #define BLKDEV_MIN_RQ   4
 42 #define BLKDEV_MAX_RQ   128     /* Default maximum */
 43 
 44 /*
 45  * Maximum number of blkcg policies allowed to be registered concurrently.
 46  * Defined here to simplify include dependency.
 47  */
 48 #define BLKCG_MAX_POLS          2
 49 
 50 struct request;
 51 typedef void (rq_end_io_fn)(struct request *, int);
 52 
 53 #define BLK_RL_SYNCFULL         (1U << 0)
 54 #define BLK_RL_ASYNCFULL        (1U << 1)
 55 
 56 struct request_list {
 57         struct request_queue    *q;     /* the queue this rl belongs to */
 58 #ifdef CONFIG_BLK_CGROUP
 59         struct blkcg_gq         *blkg;  /* blkg this request pool belongs to */
 60 #endif
 61         /*
 62          * count[], starved[], and wait[] are indexed by
 63          * BLK_RW_SYNC/BLK_RW_ASYNC
 64          */
 65         int                     count[2];
 66         int                     starved[2];
 67         mempool_t               *rq_pool;
 68         wait_queue_head_t       wait[2];
 69         unsigned int            flags;
 70 };
 71 
 72 /*
 73  * request command types
 74  */
 75 enum rq_cmd_type_bits {
 76         REQ_TYPE_FS             = 1,    /* fs request */
 77         REQ_TYPE_BLOCK_PC,              /* scsi command */
 78         REQ_TYPE_DRV_PRIV,              /* driver defined types from here */
 79 };
 80 
 81 #define BLK_MAX_CDB     16
 82 
 83 /*
 84  * Try to put the fields that are referenced together in the same cacheline.
 85  *
 86  * If you modify this structure, make sure to update blk_rq_init() and
 87  * especially blk_mq_rq_ctx_init() to take care of the added fields.
 88  */
 89 struct request {
 90         struct list_head queuelist;
 91         union {
 92                 struct call_single_data csd;
 93                 unsigned long fifo_time;
 94         };
 95 
 96         struct request_queue *q;
 97         struct blk_mq_ctx *mq_ctx;
 98 
 99         u64 cmd_flags;
100         unsigned cmd_type;
101         unsigned long atomic_flags;
102 
103         int cpu;
104 
105         /* the following two fields are internal, NEVER access directly */
106         unsigned int __data_len;        /* total data len */
107         sector_t __sector;              /* sector cursor */
108 
109         struct bio *bio;
110         struct bio *biotail;
111 
112         /*
113          * The hash is used inside the scheduler, and killed once the
114          * request reaches the dispatch list. The ipi_list is only used
115          * to queue the request for softirq completion, which is long
116          * after the request has been unhashed (and even removed from
117          * the dispatch list).
118          */
119         union {
120                 struct hlist_node hash; /* merge hash */
121                 struct list_head ipi_list;
122         };
123 
124         /*
125          * The rb_node is only used inside the io scheduler, requests
126          * are pruned when moved to the dispatch queue. So let the
127          * completion_data share space with the rb_node.
128          */
129         union {
130                 struct rb_node rb_node; /* sort/lookup */
131                 void *completion_data;
132         };
133 
134         /*
135          * Three pointers are available for the IO schedulers, if they need
136          * more they have to dynamically allocate it.  Flush requests are
137          * never put on the IO scheduler. So let the flush fields share
138          * space with the elevator data.
139          */
140         union {
141                 struct {
142                         struct io_cq            *icq;
143                         void                    *priv[2];
144                 } elv;
145 
146                 struct {
147                         unsigned int            seq;
148                         struct list_head        list;
149                         rq_end_io_fn            *saved_end_io;
150                 } flush;
151         };
152 
153         struct gendisk *rq_disk;
154         struct hd_struct *part;
155         unsigned long start_time;
156 #ifdef CONFIG_BLK_CGROUP
157         struct request_list *rl;                /* rl this rq is alloced from */
158         unsigned long long start_time_ns;
159         unsigned long long io_start_time_ns;    /* when passed to hardware */
160 #endif
161         /* Number of scatter-gather DMA addr+len pairs after
162          * physical address coalescing is performed.
163          */
164         unsigned short nr_phys_segments;
165 #if defined(CONFIG_BLK_DEV_INTEGRITY)
166         unsigned short nr_integrity_segments;
167 #endif
168 
169         unsigned short ioprio;
170 
171         void *special;          /* opaque pointer available for LLD use */
172 
173         int tag;
174         int errors;
175 
176         /*
177          * when request is used as a packet command carrier
178          */
179         unsigned char __cmd[BLK_MAX_CDB];
180         unsigned char *cmd;
181         unsigned short cmd_len;
182 
183         unsigned int extra_len; /* length of alignment and padding */
184         unsigned int sense_len;
185         unsigned int resid_len; /* residual count */
186         void *sense;
187 
188         unsigned long deadline;
189         struct list_head timeout_list;
190         unsigned int timeout;
191         int retries;
192 
193         /*
194          * completion callback.
195          */
196         rq_end_io_fn *end_io;
197         void *end_io_data;
198 
199         /* for bidi */
200         struct request *next_rq;
201 };
202 
203 static inline unsigned short req_get_ioprio(struct request *req)
204 {
205         return req->ioprio;
206 }
207 
208 #include <linux/elevator.h>
209 
210 struct blk_queue_ctx;
211 
212 typedef void (request_fn_proc) (struct request_queue *q);
213 typedef blk_qc_t (make_request_fn) (struct request_queue *q, struct bio *bio);
214 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
215 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
216 
217 struct bio_vec;
218 typedef void (softirq_done_fn)(struct request *);
219 typedef int (dma_drain_needed_fn)(struct request *);
220 typedef int (lld_busy_fn) (struct request_queue *q);
221 typedef int (bsg_job_fn) (struct bsg_job *);
222 
223 enum blk_eh_timer_return {
224         BLK_EH_NOT_HANDLED,
225         BLK_EH_HANDLED,
226         BLK_EH_RESET_TIMER,
227 };
228 
229 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
230 
231 enum blk_queue_state {
232         Queue_down,
233         Queue_up,
234 };
235 
236 struct blk_queue_tag {
237         struct request **tag_index;     /* map of busy tags */
238         unsigned long *tag_map;         /* bit map of free/busy tags */
239         int busy;                       /* current depth */
240         int max_depth;                  /* what we will send to device */
241         int real_max_depth;             /* what the array can hold */
242         atomic_t refcnt;                /* map can be shared */
243         int alloc_policy;               /* tag allocation policy */
244         int next_tag;                   /* next tag */
245 };
246 #define BLK_TAG_ALLOC_FIFO 0 /* allocate starting from 0 */
247 #define BLK_TAG_ALLOC_RR 1 /* allocate starting from last allocated tag */
248 
249 #define BLK_SCSI_MAX_CMDS       (256)
250 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
251 
252 struct queue_limits {
253         unsigned long           bounce_pfn;
254         unsigned long           seg_boundary_mask;
255         unsigned long           virt_boundary_mask;
256 
257         unsigned int            max_hw_sectors;
258         unsigned int            max_dev_sectors;
259         unsigned int            chunk_sectors;
260         unsigned int            max_sectors;
261         unsigned int            max_segment_size;
262         unsigned int            physical_block_size;
263         unsigned int            alignment_offset;
264         unsigned int            io_min;
265         unsigned int            io_opt;
266         unsigned int            max_discard_sectors;
267         unsigned int            max_hw_discard_sectors;
268         unsigned int            max_write_same_sectors;
269         unsigned int            discard_granularity;
270         unsigned int            discard_alignment;
271 
272         unsigned short          logical_block_size;
273         unsigned short          max_segments;
274         unsigned short          max_integrity_segments;
275 
276         unsigned char           misaligned;
277         unsigned char           discard_misaligned;
278         unsigned char           cluster;
279         unsigned char           discard_zeroes_data;
280         unsigned char           raid_partial_stripes_expensive;
281 };
282 
283 struct request_queue {
284         /*
285          * Together with queue_head for cacheline sharing
286          */
287         struct list_head        queue_head;
288         struct request          *last_merge;
289         struct elevator_queue   *elevator;
290         int                     nr_rqs[2];      /* # allocated [a]sync rqs */
291         int                     nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
292 
293         /*
294          * If blkcg is not used, @q->root_rl serves all requests.  If blkcg
295          * is used, root blkg allocates from @q->root_rl and all other
296          * blkgs from their own blkg->rl.  Which one to use should be
297          * determined using bio_request_list().
298          */
299         struct request_list     root_rl;
300 
301         request_fn_proc         *request_fn;
302         make_request_fn         *make_request_fn;
303         prep_rq_fn              *prep_rq_fn;
304         unprep_rq_fn            *unprep_rq_fn;
305         softirq_done_fn         *softirq_done_fn;
306         rq_timed_out_fn         *rq_timed_out_fn;
307         dma_drain_needed_fn     *dma_drain_needed;
308         lld_busy_fn             *lld_busy_fn;
309 
310         struct blk_mq_ops       *mq_ops;
311 
312         unsigned int            *mq_map;
313 
314         /* sw queues */
315         struct blk_mq_ctx __percpu      *queue_ctx;
316         unsigned int            nr_queues;
317 
318         /* hw dispatch queues */
319         struct blk_mq_hw_ctx    **queue_hw_ctx;
320         unsigned int            nr_hw_queues;
321 
322         /*
323          * Dispatch queue sorting
324          */
325         sector_t                end_sector;
326         struct request          *boundary_rq;
327 
328         /*
329          * Delayed queue handling
330          */
331         struct delayed_work     delay_work;
332 
333         struct backing_dev_info backing_dev_info;
334 
335         /*
336          * The queue owner gets to use this for whatever they like.
337          * ll_rw_blk doesn't touch it.
338          */
339         void                    *queuedata;
340 
341         /*
342          * various queue flags, see QUEUE_* below
343          */
344         unsigned long           queue_flags;
345 
346         /*
347          * ida allocated id for this queue.  Used to index queues from
348          * ioctx.
349          */
350         int                     id;
351 
352         /*
353          * queue needs bounce pages for pages above this limit
354          */
355         gfp_t                   bounce_gfp;
356 
357         /*
358          * protects queue structures from reentrancy. ->__queue_lock should
359          * _never_ be used directly, it is queue private. always use
360          * ->queue_lock.
361          */
362         spinlock_t              __queue_lock;
363         spinlock_t              *queue_lock;
364 
365         /*
366          * queue kobject
367          */
368         struct kobject kobj;
369 
370         /*
371          * mq queue kobject
372          */
373         struct kobject mq_kobj;
374 
375 #ifdef  CONFIG_BLK_DEV_INTEGRITY
376         struct blk_integrity integrity;
377 #endif  /* CONFIG_BLK_DEV_INTEGRITY */
378 
379 #ifdef CONFIG_PM
380         struct device           *dev;
381         int                     rpm_status;
382         unsigned int            nr_pending;
383 #endif
384 
385         /*
386          * queue settings
387          */
388         unsigned long           nr_requests;    /* Max # of requests */
389         unsigned int            nr_congestion_on;
390         unsigned int            nr_congestion_off;
391         unsigned int            nr_batching;
392 
393         unsigned int            dma_drain_size;
394         void                    *dma_drain_buffer;
395         unsigned int            dma_pad_mask;
396         unsigned int            dma_alignment;
397 
398         struct blk_queue_tag    *queue_tags;
399         struct list_head        tag_busy_list;
400 
401         unsigned int            nr_sorted;
402         unsigned int            in_flight[2];
403         /*
404          * Number of active block driver functions for which blk_drain_queue()
405          * must wait. Must be incremented around functions that unlock the
406          * queue_lock internally, e.g. scsi_request_fn().
407          */
408         unsigned int            request_fn_active;
409 
410         unsigned int            rq_timeout;
411         struct timer_list       timeout;
412         struct work_struct      timeout_work;
413         struct list_head        timeout_list;
414 
415         struct list_head        icq_list;
416 #ifdef CONFIG_BLK_CGROUP
417         DECLARE_BITMAP          (blkcg_pols, BLKCG_MAX_POLS);
418         struct blkcg_gq         *root_blkg;
419         struct list_head        blkg_list;
420 #endif
421 
422         struct queue_limits     limits;
423 
424         /*
425          * sg stuff
426          */
427         unsigned int            sg_timeout;
428         unsigned int            sg_reserved_size;
429         int                     node;
430 #ifdef CONFIG_BLK_DEV_IO_TRACE
431         struct blk_trace        *blk_trace;
432 #endif
433         /*
434          * for flush operations
435          */
436         unsigned int            flush_flags;
437         unsigned int            flush_not_queueable:1;
438         struct blk_flush_queue  *fq;
439 
440         struct list_head        requeue_list;
441         spinlock_t              requeue_lock;
442         struct work_struct      requeue_work;
443 
444         struct mutex            sysfs_lock;
445 
446         int                     bypass_depth;
447         atomic_t                mq_freeze_depth;
448 
449 #if defined(CONFIG_BLK_DEV_BSG)
450         bsg_job_fn              *bsg_job_fn;
451         int                     bsg_job_size;
452         struct bsg_class_device bsg_dev;
453 #endif
454 
455 #ifdef CONFIG_BLK_DEV_THROTTLING
456         /* Throttle data */
457         struct throtl_data *td;
458 #endif
459         struct rcu_head         rcu_head;
460         wait_queue_head_t       mq_freeze_wq;
461         struct percpu_ref       q_usage_counter;
462         struct list_head        all_q_node;
463 
464         struct blk_mq_tag_set   *tag_set;
465         struct list_head        tag_set_list;
466         struct bio_set          *bio_split;
467 
468         bool                    mq_sysfs_init_done;
469 };
470 
471 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
472 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
473 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
474 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
475 #define QUEUE_FLAG_DYING        5       /* queue being torn down */
476 #define QUEUE_FLAG_BYPASS       6       /* act as dumb FIFO queue */
477 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
478 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
479 #define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
480 #define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
481 #define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
482 #define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
483 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
484 #define QUEUE_FLAG_IO_STAT     13       /* do IO stats */
485 #define QUEUE_FLAG_DISCARD     14       /* supports DISCARD */
486 #define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
487 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
488 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
489 #define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
490 #define QUEUE_FLAG_DEAD        19       /* queue tear-down finished */
491 #define QUEUE_FLAG_INIT_DONE   20       /* queue is initialized */
492 #define QUEUE_FLAG_NO_SG_MERGE 21       /* don't attempt to merge SG segments*/
493 #define QUEUE_FLAG_POLL        22       /* IO polling enabled if set */
494 
495 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
496                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
497                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
498                                  (1 << QUEUE_FLAG_ADD_RANDOM))
499 
500 #define QUEUE_FLAG_MQ_DEFAULT   ((1 << QUEUE_FLAG_IO_STAT) |            \
501                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
502                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
503                                  (1 << QUEUE_FLAG_POLL))
504 
505 static inline void queue_lockdep_assert_held(struct request_queue *q)
506 {
507         if (q->queue_lock)
508                 lockdep_assert_held(q->queue_lock);
509 }
510 
511 static inline void queue_flag_set_unlocked(unsigned int flag,
512                                            struct request_queue *q)
513 {
514         __set_bit(flag, &q->queue_flags);
515 }
516 
517 static inline int queue_flag_test_and_clear(unsigned int flag,
518                                             struct request_queue *q)
519 {
520         queue_lockdep_assert_held(q);
521 
522         if (test_bit(flag, &q->queue_flags)) {
523                 __clear_bit(flag, &q->queue_flags);
524                 return 1;
525         }
526 
527         return 0;
528 }
529 
530 static inline int queue_flag_test_and_set(unsigned int flag,
531                                           struct request_queue *q)
532 {
533         queue_lockdep_assert_held(q);
534 
535         if (!test_bit(flag, &q->queue_flags)) {
536                 __set_bit(flag, &q->queue_flags);
537                 return 0;
538         }
539 
540         return 1;
541 }
542 
543 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
544 {
545         queue_lockdep_assert_held(q);
546         __set_bit(flag, &q->queue_flags);
547 }
548 
549 static inline void queue_flag_clear_unlocked(unsigned int flag,
550                                              struct request_queue *q)
551 {
552         __clear_bit(flag, &q->queue_flags);
553 }
554 
555 static inline int queue_in_flight(struct request_queue *q)
556 {
557         return q->in_flight[0] + q->in_flight[1];
558 }
559 
560 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
561 {
562         queue_lockdep_assert_held(q);
563         __clear_bit(flag, &q->queue_flags);
564 }
565 
566 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
567 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
568 #define blk_queue_dying(q)      test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
569 #define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
570 #define blk_queue_bypass(q)     test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
571 #define blk_queue_init_done(q)  test_bit(QUEUE_FLAG_INIT_DONE, &(q)->queue_flags)
572 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
573 #define blk_queue_noxmerges(q)  \
574         test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
575 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
576 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
577 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
578 #define blk_queue_stackable(q)  \
579         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
580 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
581 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
582         test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
583 
584 #define blk_noretry_request(rq) \
585         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
586                              REQ_FAILFAST_DRIVER))
587 
588 #define blk_account_rq(rq) \
589         (((rq)->cmd_flags & REQ_STARTED) && \
590          ((rq)->cmd_type == REQ_TYPE_FS))
591 
592 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
593 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
594 /* rq->queuelist of dequeued request must be list_empty() */
595 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
596 
597 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
598 
599 #define rq_data_dir(rq)         ((int)((rq)->cmd_flags & 1))
600 
601 /*
602  * Driver can handle struct request, if it either has an old style
603  * request_fn defined, or is blk-mq based.
604  */
605 static inline bool queue_is_rq_based(struct request_queue *q)
606 {
607         return q->request_fn || q->mq_ops;
608 }
609 
610 static inline unsigned int blk_queue_cluster(struct request_queue *q)
611 {
612         return q->limits.cluster;
613 }
614 
615 /*
616  * We regard a request as sync, if either a read or a sync write
617  */
618 static inline bool rw_is_sync(unsigned int rw_flags)
619 {
620         return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
621 }
622 
623 static inline bool rq_is_sync(struct request *rq)
624 {
625         return rw_is_sync(rq->cmd_flags);
626 }
627 
628 static inline bool blk_rl_full(struct request_list *rl, bool sync)
629 {
630         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
631 
632         return rl->flags & flag;
633 }
634 
635 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
636 {
637         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
638 
639         rl->flags |= flag;
640 }
641 
642 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
643 {
644         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
645 
646         rl->flags &= ~flag;
647 }
648 
649 static inline bool rq_mergeable(struct request *rq)
650 {
651         if (rq->cmd_type != REQ_TYPE_FS)
652                 return false;
653 
654         if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
655                 return false;
656 
657         return true;
658 }
659 
660 static inline bool blk_check_merge_flags(unsigned int flags1,
661                                          unsigned int flags2)
662 {
663         if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD))
664                 return false;
665 
666         if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
667                 return false;
668 
669         if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME))
670                 return false;
671 
672         return true;
673 }
674 
675 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
676 {
677         if (bio_data(a) == bio_data(b))
678                 return true;
679 
680         return false;
681 }
682 
683 /*
684  * q->prep_rq_fn return values
685  */
686 enum {
687         BLKPREP_OK,             /* serve it */
688         BLKPREP_KILL,           /* fatal error, kill, return -EIO */
689         BLKPREP_DEFER,          /* leave on queue */
690         BLKPREP_INVALID,        /* invalid command, kill, return -EREMOTEIO */
691 };
692 
693 extern unsigned long blk_max_low_pfn, blk_max_pfn;
694 
695 /*
696  * standard bounce addresses:
697  *
698  * BLK_BOUNCE_HIGH      : bounce all highmem pages
699  * BLK_BOUNCE_ANY       : don't bounce anything
700  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
701  */
702 
703 #if BITS_PER_LONG == 32
704 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
705 #else
706 #define BLK_BOUNCE_HIGH         -1ULL
707 #endif
708 #define BLK_BOUNCE_ANY          (-1ULL)
709 #define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
710 
711 /*
712  * default timeout for SG_IO if none specified
713  */
714 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
715 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
716 
717 #ifdef CONFIG_BOUNCE
718 extern int init_emergency_isa_pool(void);
719 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
720 #else
721 static inline int init_emergency_isa_pool(void)
722 {
723         return 0;
724 }
725 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
726 {
727 }
728 #endif /* CONFIG_MMU */
729 
730 struct rq_map_data {
731         struct page **pages;
732         int page_order;
733         int nr_entries;
734         unsigned long offset;
735         int null_mapped;
736         int from_user;
737 };
738 
739 struct req_iterator {
740         struct bvec_iter iter;
741         struct bio *bio;
742 };
743 
744 /* This should not be used directly - use rq_for_each_segment */
745 #define for_each_bio(_bio)              \
746         for (; _bio; _bio = _bio->bi_next)
747 #define __rq_for_each_bio(_bio, rq)     \
748         if ((rq->bio))                  \
749                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
750 
751 #define rq_for_each_segment(bvl, _rq, _iter)                    \
752         __rq_for_each_bio(_iter.bio, _rq)                       \
753                 bio_for_each_segment(bvl, _iter.bio, _iter.iter)
754 
755 #define rq_iter_last(bvec, _iter)                               \
756                 (_iter.bio->bi_next == NULL &&                  \
757                  bio_iter_last(bvec, _iter.iter))
758 
759 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
760 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
761 #endif
762 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
763 extern void rq_flush_dcache_pages(struct request *rq);
764 #else
765 static inline void rq_flush_dcache_pages(struct request *rq)
766 {
767 }
768 #endif
769 
770 extern int blk_register_queue(struct gendisk *disk);
771 extern void blk_unregister_queue(struct gendisk *disk);
772 extern blk_qc_t generic_make_request(struct bio *bio);
773 extern void blk_rq_init(struct request_queue *q, struct request *rq);
774 extern void blk_put_request(struct request *);
775 extern void __blk_put_request(struct request_queue *, struct request *);
776 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
777 extern struct request *blk_make_request(struct request_queue *, struct bio *,
778                                         gfp_t);
779 extern void blk_rq_set_block_pc(struct request *);
780 extern void blk_requeue_request(struct request_queue *, struct request *);
781 extern void blk_add_request_payload(struct request *rq, struct page *page,
782                 unsigned int len);
783 extern int blk_lld_busy(struct request_queue *q);
784 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
785                              struct bio_set *bs, gfp_t gfp_mask,
786                              int (*bio_ctr)(struct bio *, struct bio *, void *),
787                              void *data);
788 extern void blk_rq_unprep_clone(struct request *rq);
789 extern int blk_insert_cloned_request(struct request_queue *q,
790                                      struct request *rq);
791 extern void blk_delay_queue(struct request_queue *, unsigned long);
792 extern void blk_queue_split(struct request_queue *, struct bio **,
793                             struct bio_set *);
794 extern void blk_recount_segments(struct request_queue *, struct bio *);
795 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
796 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
797                               unsigned int, void __user *);
798 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
799                           unsigned int, void __user *);
800 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
801                          struct scsi_ioctl_command __user *);
802 
803 extern int blk_queue_enter(struct request_queue *q, bool nowait);
804 extern void blk_queue_exit(struct request_queue *q);
805 extern void blk_start_queue(struct request_queue *q);
806 extern void blk_start_queue_async(struct request_queue *q);
807 extern void blk_stop_queue(struct request_queue *q);
808 extern void blk_sync_queue(struct request_queue *q);
809 extern void __blk_stop_queue(struct request_queue *q);
810 extern void __blk_run_queue(struct request_queue *q);
811 extern void __blk_run_queue_uncond(struct request_queue *q);
812 extern void blk_run_queue(struct request_queue *);
813 extern void blk_run_queue_async(struct request_queue *q);
814 extern int blk_rq_map_user(struct request_queue *, struct request *,
815                            struct rq_map_data *, void __user *, unsigned long,
816                            gfp_t);
817 extern int blk_rq_unmap_user(struct bio *);
818 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
819 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
820                                struct rq_map_data *, const struct iov_iter *,
821                                gfp_t);
822 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
823                           struct request *, int);
824 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
825                                   struct request *, int, rq_end_io_fn *);
826 
827 bool blk_poll(struct request_queue *q, blk_qc_t cookie);
828 
829 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
830 {
831         return bdev->bd_disk->queue;    /* this is never NULL */
832 }
833 
834 /*
835  * blk_rq_pos()                 : the current sector
836  * blk_rq_bytes()               : bytes left in the entire request
837  * blk_rq_cur_bytes()           : bytes left in the current segment
838  * blk_rq_err_bytes()           : bytes left till the next error boundary
839  * blk_rq_sectors()             : sectors left in the entire request
840  * blk_rq_cur_sectors()         : sectors left in the current segment
841  */
842 static inline sector_t blk_rq_pos(const struct request *rq)
843 {
844         return rq->__sector;
845 }
846 
847 static inline unsigned int blk_rq_bytes(const struct request *rq)
848 {
849         return rq->__data_len;
850 }
851 
852 static inline int blk_rq_cur_bytes(const struct request *rq)
853 {
854         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
855 }
856 
857 extern unsigned int blk_rq_err_bytes(const struct request *rq);
858 
859 static inline unsigned int blk_rq_sectors(const struct request *rq)
860 {
861         return blk_rq_bytes(rq) >> 9;
862 }
863 
864 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
865 {
866         return blk_rq_cur_bytes(rq) >> 9;
867 }
868 
869 static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
870                                                      unsigned int cmd_flags)
871 {
872         if (unlikely(cmd_flags & REQ_DISCARD))
873                 return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
874 
875         if (unlikely(cmd_flags & REQ_WRITE_SAME))
876                 return q->limits.max_write_same_sectors;
877 
878         return q->limits.max_sectors;
879 }
880 
881 /*
882  * Return maximum size of a request at given offset. Only valid for
883  * file system requests.
884  */
885 static inline unsigned int blk_max_size_offset(struct request_queue *q,
886                                                sector_t offset)
887 {
888         if (!q->limits.chunk_sectors)
889                 return q->limits.max_sectors;
890 
891         return q->limits.chunk_sectors -
892                         (offset & (q->limits.chunk_sectors - 1));
893 }
894 
895 static inline unsigned int blk_rq_get_max_sectors(struct request *rq)
896 {
897         struct request_queue *q = rq->q;
898 
899         if (unlikely(rq->cmd_type != REQ_TYPE_FS))
900                 return q->limits.max_hw_sectors;
901 
902         if (!q->limits.chunk_sectors || (rq->cmd_flags & REQ_DISCARD))
903                 return blk_queue_get_max_sectors(q, rq->cmd_flags);
904 
905         return min(blk_max_size_offset(q, blk_rq_pos(rq)),
906                         blk_queue_get_max_sectors(q, rq->cmd_flags));
907 }
908 
909 static inline unsigned int blk_rq_count_bios(struct request *rq)
910 {
911         unsigned int nr_bios = 0;
912         struct bio *bio;
913 
914         __rq_for_each_bio(bio, rq)
915                 nr_bios++;
916 
917         return nr_bios;
918 }
919 
920 /*
921  * Request issue related functions.
922  */
923 extern struct request *blk_peek_request(struct request_queue *q);
924 extern void blk_start_request(struct request *rq);
925 extern struct request *blk_fetch_request(struct request_queue *q);
926 
927 /*
928  * Request completion related functions.
929  *
930  * blk_update_request() completes given number of bytes and updates
931  * the request without completing it.
932  *
933  * blk_end_request() and friends.  __blk_end_request() must be called
934  * with the request queue spinlock acquired.
935  *
936  * Several drivers define their own end_request and call
937  * blk_end_request() for parts of the original function.
938  * This prevents code duplication in drivers.
939  */
940 extern bool blk_update_request(struct request *rq, int error,
941                                unsigned int nr_bytes);
942 extern void blk_finish_request(struct request *rq, int error);
943 extern bool blk_end_request(struct request *rq, int error,
944                             unsigned int nr_bytes);
945 extern void blk_end_request_all(struct request *rq, int error);
946 extern bool blk_end_request_cur(struct request *rq, int error);
947 extern bool blk_end_request_err(struct request *rq, int error);
948 extern bool __blk_end_request(struct request *rq, int error,
949                               unsigned int nr_bytes);
950 extern void __blk_end_request_all(struct request *rq, int error);
951 extern bool __blk_end_request_cur(struct request *rq, int error);
952 extern bool __blk_end_request_err(struct request *rq, int error);
953 
954 extern void blk_complete_request(struct request *);
955 extern void __blk_complete_request(struct request *);
956 extern void blk_abort_request(struct request *);
957 extern void blk_unprep_request(struct request *);
958 
959 /*
960  * Access functions for manipulating queue properties
961  */
962 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
963                                         spinlock_t *lock, int node_id);
964 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
965 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
966                                                       request_fn_proc *, spinlock_t *);
967 extern void blk_cleanup_queue(struct request_queue *);
968 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
969 extern void blk_queue_bounce_limit(struct request_queue *, u64);
970 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
971 extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
972 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
973 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
974 extern void blk_queue_max_discard_sectors(struct request_queue *q,
975                 unsigned int max_discard_sectors);
976 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
977                 unsigned int max_write_same_sectors);
978 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
979 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
980 extern void blk_queue_alignment_offset(struct request_queue *q,
981                                        unsigned int alignment);
982 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
983 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
984 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
985 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
986 extern void blk_set_default_limits(struct queue_limits *lim);
987 extern void blk_set_stacking_limits(struct queue_limits *lim);
988 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
989                             sector_t offset);
990 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
991                             sector_t offset);
992 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
993                               sector_t offset);
994 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
995 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
996 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
997 extern int blk_queue_dma_drain(struct request_queue *q,
998                                dma_drain_needed_fn *dma_drain_needed,
999                                void *buf, unsigned int size);
1000 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
1001 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
1002 extern void blk_queue_virt_boundary(struct request_queue *, unsigned long);
1003 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
1004 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
1005 extern void blk_queue_dma_alignment(struct request_queue *, int);
1006 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
1007 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
1008 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
1009 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
1010 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
1011 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
1012 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
1013 
1014 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
1015 extern void blk_dump_rq_flags(struct request *, char *);
1016 extern long nr_blockdev_pages(void);
1017 
1018 bool __must_check blk_get_queue(struct request_queue *);
1019 struct request_queue *blk_alloc_queue(gfp_t);
1020 struct request_queue *blk_alloc_queue_node(gfp_t, int);
1021 extern void blk_put_queue(struct request_queue *);
1022 extern void blk_set_queue_dying(struct request_queue *);
1023 
1024 /*
1025  * block layer runtime pm functions
1026  */
1027 #ifdef CONFIG_PM
1028 extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev);
1029 extern int blk_pre_runtime_suspend(struct request_queue *q);
1030 extern void blk_post_runtime_suspend(struct request_queue *q, int err);
1031 extern void blk_pre_runtime_resume(struct request_queue *q);
1032 extern void blk_post_runtime_resume(struct request_queue *q, int err);
1033 extern void blk_set_runtime_active(struct request_queue *q);
1034 #else
1035 static inline void blk_pm_runtime_init(struct request_queue *q,
1036         struct device *dev) {}
1037 static inline int blk_pre_runtime_suspend(struct request_queue *q)
1038 {
1039         return -ENOSYS;
1040 }
1041 static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {}
1042 static inline void blk_pre_runtime_resume(struct request_queue *q) {}
1043 static inline void blk_post_runtime_resume(struct request_queue *q, int err) {}
1044 extern inline void blk_set_runtime_active(struct request_queue *q) {}
1045 #endif
1046 
1047 /*
1048  * blk_plug permits building a queue of related requests by holding the I/O
1049  * fragments for a short period. This allows merging of sequential requests
1050  * into single larger request. As the requests are moved from a per-task list to
1051  * the device's request_queue in a batch, this results in improved scalability
1052  * as the lock contention for request_queue lock is reduced.
1053  *
1054  * It is ok not to disable preemption when adding the request to the plug list
1055  * or when attempting a merge, because blk_schedule_flush_list() will only flush
1056  * the plug list when the task sleeps by itself. For details, please see
1057  * schedule() where blk_schedule_flush_plug() is called.
1058  */
1059 struct blk_plug {
1060         struct list_head list; /* requests */
1061         struct list_head mq_list; /* blk-mq requests */
1062         struct list_head cb_list; /* md requires an unplug callback */
1063 };
1064 #define BLK_MAX_REQUEST_COUNT 16
1065 
1066 struct blk_plug_cb;
1067 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
1068 struct blk_plug_cb {
1069         struct list_head list;
1070         blk_plug_cb_fn callback;
1071         void *data;
1072 };
1073 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
1074                                              void *data, int size);
1075 extern void blk_start_plug(struct blk_plug *);
1076 extern void blk_finish_plug(struct blk_plug *);
1077 extern void blk_flush_plug_list(struct blk_plug *, bool);
1078 
1079 static inline void blk_flush_plug(struct task_struct *tsk)
1080 {
1081         struct blk_plug *plug = tsk->plug;
1082 
1083         if (plug)
1084                 blk_flush_plug_list(plug, false);
1085 }
1086 
1087 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
1088 {
1089         struct blk_plug *plug = tsk->plug;
1090 
1091         if (plug)
1092                 blk_flush_plug_list(plug, true);
1093 }
1094 
1095 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1096 {
1097         struct blk_plug *plug = tsk->plug;
1098 
1099         return plug &&
1100                 (!list_empty(&plug->list) ||
1101                  !list_empty(&plug->mq_list) ||
1102                  !list_empty(&plug->cb_list));
1103 }
1104 
1105 /*
1106  * tag stuff
1107  */
1108 extern int blk_queue_start_tag(struct request_queue *, struct request *);
1109 extern struct request *blk_queue_find_tag(struct request_queue *, int);
1110 extern void blk_queue_end_tag(struct request_queue *, struct request *);
1111 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int);
1112 extern void blk_queue_free_tags(struct request_queue *);
1113 extern int blk_queue_resize_tags(struct request_queue *, int);
1114 extern void blk_queue_invalidate_tags(struct request_queue *);
1115 extern struct blk_queue_tag *blk_init_tags(int, int);
1116 extern void blk_free_tags(struct blk_queue_tag *);
1117 
1118 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
1119                                                 int tag)
1120 {
1121         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
1122                 return NULL;
1123         return bqt->tag_index[tag];
1124 }
1125 
1126 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
1127 
1128 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
1129 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1130                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
1131 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
1132                 sector_t nr_sects, gfp_t gfp_mask, struct page *page);
1133 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1134                 sector_t nr_sects, gfp_t gfp_mask, bool discard);
1135 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
1136                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
1137 {
1138         return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
1139                                     nr_blocks << (sb->s_blocksize_bits - 9),
1140                                     gfp_mask, flags);
1141 }
1142 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1143                 sector_t nr_blocks, gfp_t gfp_mask)
1144 {
1145         return blkdev_issue_zeroout(sb->s_bdev,
1146                                     block << (sb->s_blocksize_bits - 9),
1147                                     nr_blocks << (sb->s_blocksize_bits - 9),
1148                                     gfp_mask, true);
1149 }
1150 
1151 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1152 
1153 enum blk_default_limits {
1154         BLK_MAX_SEGMENTS        = 128,
1155         BLK_SAFE_MAX_SECTORS    = 255,
1156         BLK_DEF_MAX_SECTORS     = 2560,
1157         BLK_MAX_SEGMENT_SIZE    = 65536,
1158         BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
1159 };
1160 
1161 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1162 
1163 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1164 {
1165         return q->limits.bounce_pfn;
1166 }
1167 
1168 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1169 {
1170         return q->limits.seg_boundary_mask;
1171 }
1172 
1173 static inline unsigned long queue_virt_boundary(struct request_queue *q)
1174 {
1175         return q->limits.virt_boundary_mask;
1176 }
1177 
1178 static inline unsigned int queue_max_sectors(struct request_queue *q)
1179 {
1180         return q->limits.max_sectors;
1181 }
1182 
1183 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1184 {
1185         return q->limits.max_hw_sectors;
1186 }
1187 
1188 static inline unsigned short queue_max_segments(struct request_queue *q)
1189 {
1190         return q->limits.max_segments;
1191 }
1192 
1193 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1194 {
1195         return q->limits.max_segment_size;
1196 }
1197 
1198 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1199 {
1200         int retval = 512;
1201 
1202         if (q && q->limits.logical_block_size)
1203                 retval = q->limits.logical_block_size;
1204 
1205         return retval;
1206 }
1207 
1208 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1209 {
1210         return queue_logical_block_size(bdev_get_queue(bdev));
1211 }
1212 
1213 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1214 {
1215         return q->limits.physical_block_size;
1216 }
1217 
1218 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1219 {
1220         return queue_physical_block_size(bdev_get_queue(bdev));
1221 }
1222 
1223 static inline unsigned int queue_io_min(struct request_queue *q)
1224 {
1225         return q->limits.io_min;
1226 }
1227 
1228 static inline int bdev_io_min(struct block_device *bdev)
1229 {
1230         return queue_io_min(bdev_get_queue(bdev));
1231 }
1232 
1233 static inline unsigned int queue_io_opt(struct request_queue *q)
1234 {
1235         return q->limits.io_opt;
1236 }
1237 
1238 static inline int bdev_io_opt(struct block_device *bdev)
1239 {
1240         return queue_io_opt(bdev_get_queue(bdev));
1241 }
1242 
1243 static inline int queue_alignment_offset(struct request_queue *q)
1244 {
1245         if (q->limits.misaligned)
1246                 return -1;
1247 
1248         return q->limits.alignment_offset;
1249 }
1250 
1251 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1252 {
1253         unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1254         unsigned int alignment = sector_div(sector, granularity >> 9) << 9;
1255 
1256         return (granularity + lim->alignment_offset - alignment) % granularity;
1257 }
1258 
1259 static inline int bdev_alignment_offset(struct block_device *bdev)
1260 {
1261         struct request_queue *q = bdev_get_queue(bdev);
1262 
1263         if (q->limits.misaligned)
1264                 return -1;
1265 
1266         if (bdev != bdev->bd_contains)
1267                 return bdev->bd_part->alignment_offset;
1268 
1269         return q->limits.alignment_offset;
1270 }
1271 
1272 static inline int queue_discard_alignment(struct request_queue *q)
1273 {
1274         if (q->limits.discard_misaligned)
1275                 return -1;
1276 
1277         return q->limits.discard_alignment;
1278 }
1279 
1280 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1281 {
1282         unsigned int alignment, granularity, offset;
1283 
1284         if (!lim->max_discard_sectors)
1285                 return 0;
1286 
1287         /* Why are these in bytes, not sectors? */
1288         alignment = lim->discard_alignment >> 9;
1289         granularity = lim->discard_granularity >> 9;
1290         if (!granularity)
1291                 return 0;
1292 
1293         /* Offset of the partition start in 'granularity' sectors */
1294         offset = sector_div(sector, granularity);
1295 
1296         /* And why do we do this modulus *again* in blkdev_issue_discard()? */
1297         offset = (granularity + alignment - offset) % granularity;
1298 
1299         /* Turn it back into bytes, gaah */
1300         return offset << 9;
1301 }
1302 
1303 static inline int bdev_discard_alignment(struct block_device *bdev)
1304 {
1305         struct request_queue *q = bdev_get_queue(bdev);
1306 
1307         if (bdev != bdev->bd_contains)
1308                 return bdev->bd_part->discard_alignment;
1309 
1310         return q->limits.discard_alignment;
1311 }
1312 
1313 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1314 {
1315         if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1316                 return 1;
1317 
1318         return 0;
1319 }
1320 
1321 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1322 {
1323         return queue_discard_zeroes_data(bdev_get_queue(bdev));
1324 }
1325 
1326 static inline unsigned int bdev_write_same(struct block_device *bdev)
1327 {
1328         struct request_queue *q = bdev_get_queue(bdev);
1329 
1330         if (q)
1331                 return q->limits.max_write_same_sectors;
1332 
1333         return 0;
1334 }
1335 
1336 static inline int queue_dma_alignment(struct request_queue *q)
1337 {
1338         return q ? q->dma_alignment : 511;
1339 }
1340 
1341 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1342                                  unsigned int len)
1343 {
1344         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1345         return !(addr & alignment) && !(len & alignment);
1346 }
1347 
1348 /* assumes size > 256 */
1349 static inline unsigned int blksize_bits(unsigned int size)
1350 {
1351         unsigned int bits = 8;
1352         do {
1353                 bits++;
1354                 size >>= 1;
1355         } while (size > 256);
1356         return bits;
1357 }
1358 
1359 static inline unsigned int block_size(struct block_device *bdev)
1360 {
1361         return bdev->bd_block_size;
1362 }
1363 
1364 static inline bool queue_flush_queueable(struct request_queue *q)
1365 {
1366         return !q->flush_not_queueable;
1367 }
1368 
1369 typedef struct {struct page *v;} Sector;
1370 
1371 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1372 
1373 static inline void put_dev_sector(Sector p)
1374 {
1375         put_page(p.v);
1376 }
1377 
1378 static inline bool __bvec_gap_to_prev(struct request_queue *q,
1379                                 struct bio_vec *bprv, unsigned int offset)
1380 {
1381         return offset ||
1382                 ((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q));
1383 }
1384 
1385 /*
1386  * Check if adding a bio_vec after bprv with offset would create a gap in
1387  * the SG list. Most drivers don't care about this, but some do.
1388  */
1389 static inline bool bvec_gap_to_prev(struct request_queue *q,
1390                                 struct bio_vec *bprv, unsigned int offset)
1391 {
1392         if (!queue_virt_boundary(q))
1393                 return false;
1394         return __bvec_gap_to_prev(q, bprv, offset);
1395 }
1396 
1397 static inline bool bio_will_gap(struct request_queue *q, struct bio *prev,
1398                          struct bio *next)
1399 {
1400         if (bio_has_data(prev) && queue_virt_boundary(q)) {
1401                 struct bio_vec pb, nb;
1402 
1403                 bio_get_last_bvec(prev, &pb);
1404                 bio_get_first_bvec(next, &nb);
1405 
1406                 return __bvec_gap_to_prev(q, &pb, nb.bv_offset);
1407         }
1408 
1409         return false;
1410 }
1411 
1412 static inline bool req_gap_back_merge(struct request *req, struct bio *bio)
1413 {
1414         return bio_will_gap(req->q, req->biotail, bio);
1415 }
1416 
1417 static inline bool req_gap_front_merge(struct request *req, struct bio *bio)
1418 {
1419         return bio_will_gap(req->q, bio, req->bio);
1420 }
1421 
1422 struct work_struct;
1423 int kblockd_schedule_work(struct work_struct *work);
1424 int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);
1425 int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);
1426 
1427 #ifdef CONFIG_BLK_CGROUP
1428 /*
1429  * This should not be using sched_clock(). A real patch is in progress
1430  * to fix this up, until that is in place we need to disable preemption
1431  * around sched_clock() in this function and set_io_start_time_ns().
1432  */
1433 static inline void set_start_time_ns(struct request *req)
1434 {
1435         preempt_disable();
1436         req->start_time_ns = sched_clock();
1437         preempt_enable();
1438 }
1439 
1440 static inline void set_io_start_time_ns(struct request *req)
1441 {
1442         preempt_disable();
1443         req->io_start_time_ns = sched_clock();
1444         preempt_enable();
1445 }
1446 
1447 static inline uint64_t rq_start_time_ns(struct request *req)
1448 {
1449         return req->start_time_ns;
1450 }
1451 
1452 static inline uint64_t rq_io_start_time_ns(struct request *req)
1453 {
1454         return req->io_start_time_ns;
1455 }
1456 #else
1457 static inline void set_start_time_ns(struct request *req) {}
1458 static inline void set_io_start_time_ns(struct request *req) {}
1459 static inline uint64_t rq_start_time_ns(struct request *req)
1460 {
1461         return 0;
1462 }
1463 static inline uint64_t rq_io_start_time_ns(struct request *req)
1464 {
1465         return 0;
1466 }
1467 #endif
1468 
1469 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1470         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1471 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1472         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1473 
1474 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1475 
1476 enum blk_integrity_flags {
1477         BLK_INTEGRITY_VERIFY            = 1 << 0,
1478         BLK_INTEGRITY_GENERATE          = 1 << 1,
1479         BLK_INTEGRITY_DEVICE_CAPABLE    = 1 << 2,
1480         BLK_INTEGRITY_IP_CHECKSUM       = 1 << 3,
1481 };
1482 
1483 struct blk_integrity_iter {
1484         void                    *prot_buf;
1485         void                    *data_buf;
1486         sector_t                seed;
1487         unsigned int            data_size;
1488         unsigned short          interval;
1489         const char              *disk_name;
1490 };
1491 
1492 typedef int (integrity_processing_fn) (struct blk_integrity_iter *);
1493 
1494 struct blk_integrity_profile {
1495         integrity_processing_fn         *generate_fn;
1496         integrity_processing_fn         *verify_fn;
1497         const char                      *name;
1498 };
1499 
1500 extern void blk_integrity_register(struct gendisk *, struct blk_integrity *);
1501 extern void blk_integrity_unregister(struct gendisk *);
1502 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1503 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1504                                    struct scatterlist *);
1505 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1506 extern bool blk_integrity_merge_rq(struct request_queue *, struct request *,
1507                                    struct request *);
1508 extern bool blk_integrity_merge_bio(struct request_queue *, struct request *,
1509                                     struct bio *);
1510 
1511 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1512 {
1513         struct blk_integrity *bi = &disk->queue->integrity;
1514 
1515         if (!bi->profile)
1516                 return NULL;
1517 
1518         return bi;
1519 }
1520 
1521 static inline
1522 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1523 {
1524         return blk_get_integrity(bdev->bd_disk);
1525 }
1526 
1527 static inline bool blk_integrity_rq(struct request *rq)
1528 {
1529         return rq->cmd_flags & REQ_INTEGRITY;
1530 }
1531 
1532 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1533                                                     unsigned int segs)
1534 {
1535         q->limits.max_integrity_segments = segs;
1536 }
1537 
1538 static inline unsigned short
1539 queue_max_integrity_segments(struct request_queue *q)
1540 {
1541         return q->limits.max_integrity_segments;
1542 }
1543 
1544 static inline bool integrity_req_gap_back_merge(struct request *req,
1545                                                 struct bio *next)
1546 {
1547         struct bio_integrity_payload *bip = bio_integrity(req->bio);
1548         struct bio_integrity_payload *bip_next = bio_integrity(next);
1549 
1550         return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
1551                                 bip_next->bip_vec[0].bv_offset);
1552 }
1553 
1554 static inline bool integrity_req_gap_front_merge(struct request *req,
1555                                                  struct bio *bio)
1556 {
1557         struct bio_integrity_payload *bip = bio_integrity(bio);
1558         struct bio_integrity_payload *bip_next = bio_integrity(req->bio);
1559 
1560         return bvec_gap_to_prev(req->q, &bip->bip_vec[bip->bip_vcnt - 1],
1561                                 bip_next->bip_vec[0].bv_offset);
1562 }
1563 
1564 #else /* CONFIG_BLK_DEV_INTEGRITY */
1565 
1566 struct bio;
1567 struct block_device;
1568 struct gendisk;
1569 struct blk_integrity;
1570 
1571 static inline int blk_integrity_rq(struct request *rq)
1572 {
1573         return 0;
1574 }
1575 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1576                                             struct bio *b)
1577 {
1578         return 0;
1579 }
1580 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1581                                           struct bio *b,
1582                                           struct scatterlist *s)
1583 {
1584         return 0;
1585 }
1586 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1587 {
1588         return NULL;
1589 }
1590 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1591 {
1592         return NULL;
1593 }
1594 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1595 {
1596         return 0;
1597 }
1598 static inline void blk_integrity_register(struct gendisk *d,
1599                                          struct blk_integrity *b)
1600 {
1601 }
1602 static inline void blk_integrity_unregister(struct gendisk *d)
1603 {
1604 }
1605 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1606                                                     unsigned int segs)
1607 {
1608 }
1609 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1610 {
1611         return 0;
1612 }
1613 static inline bool blk_integrity_merge_rq(struct request_queue *rq,
1614                                           struct request *r1,
1615                                           struct request *r2)
1616 {
1617         return true;
1618 }
1619 static inline bool blk_integrity_merge_bio(struct request_queue *rq,
1620                                            struct request *r,
1621                                            struct bio *b)
1622 {
1623         return true;
1624 }
1625 
1626 static inline bool integrity_req_gap_back_merge(struct request *req,
1627                                                 struct bio *next)
1628 {
1629         return false;
1630 }
1631 static inline bool integrity_req_gap_front_merge(struct request *req,
1632                                                  struct bio *bio)
1633 {
1634         return false;
1635 }
1636 
1637 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1638 
1639 /**
1640  * struct blk_dax_ctl - control and output parameters for ->direct_access
1641  * @sector: (input) offset relative to a block_device
1642  * @addr: (output) kernel virtual address for @sector populated by driver
1643  * @pfn: (output) page frame number for @addr populated by driver
1644  * @size: (input) number of bytes requested
1645  */
1646 struct blk_dax_ctl {
1647         sector_t sector;
1648         void __pmem *addr;
1649         long size;
1650         pfn_t pfn;
1651 };
1652 
1653 struct block_device_operations {
1654         int (*open) (struct block_device *, fmode_t);
1655         void (*release) (struct gendisk *, fmode_t);
1656         int (*rw_page)(struct block_device *, sector_t, struct page *, int rw);
1657         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1658         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1659         long (*direct_access)(struct block_device *, sector_t, void __pmem **,
1660                         pfn_t *);
1661         unsigned int (*check_events) (struct gendisk *disk,
1662                                       unsigned int clearing);
1663         /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1664         int (*media_changed) (struct gendisk *);
1665         void (*unlock_native_capacity) (struct gendisk *);
1666         int (*revalidate_disk) (struct gendisk *);
1667         int (*getgeo)(struct block_device *, struct hd_geometry *);
1668         /* this callback is with swap_lock and sometimes page table lock held */
1669         void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1670         struct module *owner;
1671         const struct pr_ops *pr_ops;
1672 };
1673 
1674 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1675                                  unsigned long);
1676 extern int bdev_read_page(struct block_device *, sector_t, struct page *);
1677 extern int bdev_write_page(struct block_device *, sector_t, struct page *,
1678                                                 struct writeback_control *);
1679 extern long bdev_direct_access(struct block_device *, struct blk_dax_ctl *);
1680 #else /* CONFIG_BLOCK */
1681 
1682 struct block_device;
1683 
1684 /*
1685  * stubs for when the block layer is configured out
1686  */
1687 #define buffer_heads_over_limit 0
1688 
1689 static inline long nr_blockdev_pages(void)
1690 {
1691         return 0;
1692 }
1693 
1694 struct blk_plug {
1695 };
1696 
1697 static inline void blk_start_plug(struct blk_plug *plug)
1698 {
1699 }
1700 
1701 static inline void blk_finish_plug(struct blk_plug *plug)
1702 {
1703 }
1704 
1705 static inline void blk_flush_plug(struct task_struct *task)
1706 {
1707 }
1708 
1709 static inline void blk_schedule_flush_plug(struct task_struct *task)
1710 {
1711 }
1712 
1713 
1714 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1715 {
1716         return false;
1717 }
1718 
1719 static inline int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
1720                                      sector_t *error_sector)
1721 {
1722         return 0;
1723 }
1724 
1725 #endif /* CONFIG_BLOCK */
1726 
1727 #endif
1728 

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