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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 #ifdef CONFIG_PM_RUNTIME
365         struct device           *dev;
366         int                     rpm_status;
367         unsigned int            nr_pending;
368 #endif
369 
370         /*
371          * queue settings
372          */
373         unsigned long           nr_requests;    /* Max # of requests */
374         unsigned int            nr_congestion_on;
375         unsigned int            nr_congestion_off;
376         unsigned int            nr_batching;
377 
378         unsigned int            dma_drain_size;
379         void                    *dma_drain_buffer;
380         unsigned int            dma_pad_mask;
381         unsigned int            dma_alignment;
382 
383         struct blk_queue_tag    *queue_tags;
384         struct list_head        tag_busy_list;
385 
386         unsigned int            nr_sorted;
387         unsigned int            in_flight[2];
388         /*
389          * Number of active block driver functions for which blk_drain_queue()
390          * must wait. Must be incremented around functions that unlock the
391          * queue_lock internally, e.g. scsi_request_fn().
392          */
393         unsigned int            request_fn_active;
394 
395         unsigned int            rq_timeout;
396         struct timer_list       timeout;
397         struct list_head        timeout_list;
398 
399         struct list_head        icq_list;
400 #ifdef CONFIG_BLK_CGROUP
401         DECLARE_BITMAP          (blkcg_pols, BLKCG_MAX_POLS);
402         struct blkcg_gq         *root_blkg;
403         struct list_head        blkg_list;
404 #endif
405 
406         struct queue_limits     limits;
407 
408         /*
409          * sg stuff
410          */
411         unsigned int            sg_timeout;
412         unsigned int            sg_reserved_size;
413         int                     node;
414 #ifdef CONFIG_BLK_DEV_IO_TRACE
415         struct blk_trace        *blk_trace;
416 #endif
417         /*
418          * for flush operations
419          */
420         unsigned int            flush_flags;
421         unsigned int            flush_not_queueable:1;
422         unsigned int            flush_queue_delayed:1;
423         unsigned int            flush_pending_idx:1;
424         unsigned int            flush_running_idx:1;
425         unsigned long           flush_pending_since;
426         struct list_head        flush_queue[2];
427         struct list_head        flush_data_in_flight;
428         struct request          flush_rq;
429 
430         struct mutex            sysfs_lock;
431 
432         int                     bypass_depth;
433 
434 #if defined(CONFIG_BLK_DEV_BSG)
435         bsg_job_fn              *bsg_job_fn;
436         int                     bsg_job_size;
437         struct bsg_class_device bsg_dev;
438 #endif
439 
440 #ifdef CONFIG_BLK_CGROUP
441         struct list_head        all_q_node;
442 #endif
443 #ifdef CONFIG_BLK_DEV_THROTTLING
444         /* Throttle data */
445         struct throtl_data *td;
446 #endif
447         struct rcu_head         rcu_head;
448 };
449 
450 #define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
451 #define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
452 #define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
453 #define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
454 #define QUEUE_FLAG_DYING        5       /* queue being torn down */
455 #define QUEUE_FLAG_BYPASS       6       /* act as dumb FIFO queue */
456 #define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
457 #define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
458 #define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
459 #define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
460 #define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
461 #define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
462 #define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
463 #define QUEUE_FLAG_IO_STAT     13       /* do IO stats */
464 #define QUEUE_FLAG_DISCARD     14       /* supports DISCARD */
465 #define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
466 #define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
467 #define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
468 #define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
469 #define QUEUE_FLAG_DEAD        19       /* queue tear-down finished */
470 
471 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
472                                  (1 << QUEUE_FLAG_STACKABLE)    |       \
473                                  (1 << QUEUE_FLAG_SAME_COMP)    |       \
474                                  (1 << QUEUE_FLAG_ADD_RANDOM))
475 
476 static inline void queue_lockdep_assert_held(struct request_queue *q)
477 {
478         if (q->queue_lock)
479                 lockdep_assert_held(q->queue_lock);
480 }
481 
482 static inline void queue_flag_set_unlocked(unsigned int flag,
483                                            struct request_queue *q)
484 {
485         __set_bit(flag, &q->queue_flags);
486 }
487 
488 static inline int queue_flag_test_and_clear(unsigned int flag,
489                                             struct request_queue *q)
490 {
491         queue_lockdep_assert_held(q);
492 
493         if (test_bit(flag, &q->queue_flags)) {
494                 __clear_bit(flag, &q->queue_flags);
495                 return 1;
496         }
497 
498         return 0;
499 }
500 
501 static inline int queue_flag_test_and_set(unsigned int flag,
502                                           struct request_queue *q)
503 {
504         queue_lockdep_assert_held(q);
505 
506         if (!test_bit(flag, &q->queue_flags)) {
507                 __set_bit(flag, &q->queue_flags);
508                 return 0;
509         }
510 
511         return 1;
512 }
513 
514 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
515 {
516         queue_lockdep_assert_held(q);
517         __set_bit(flag, &q->queue_flags);
518 }
519 
520 static inline void queue_flag_clear_unlocked(unsigned int flag,
521                                              struct request_queue *q)
522 {
523         __clear_bit(flag, &q->queue_flags);
524 }
525 
526 static inline int queue_in_flight(struct request_queue *q)
527 {
528         return q->in_flight[0] + q->in_flight[1];
529 }
530 
531 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
532 {
533         queue_lockdep_assert_held(q);
534         __clear_bit(flag, &q->queue_flags);
535 }
536 
537 #define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
538 #define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
539 #define blk_queue_dying(q)      test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
540 #define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
541 #define blk_queue_bypass(q)     test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
542 #define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
543 #define blk_queue_noxmerges(q)  \
544         test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
545 #define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
546 #define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
547 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
548 #define blk_queue_stackable(q)  \
549         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
550 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
551 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
552         test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
553 
554 #define blk_noretry_request(rq) \
555         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
556                              REQ_FAILFAST_DRIVER))
557 
558 #define blk_account_rq(rq) \
559         (((rq)->cmd_flags & REQ_STARTED) && \
560          ((rq)->cmd_type == REQ_TYPE_FS))
561 
562 #define blk_pm_request(rq)      \
563         ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
564          (rq)->cmd_type == REQ_TYPE_PM_RESUME)
565 
566 #define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
567 #define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
568 /* rq->queuelist of dequeued request must be list_empty() */
569 #define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
570 
571 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
572 
573 #define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
574 
575 static inline unsigned int blk_queue_cluster(struct request_queue *q)
576 {
577         return q->limits.cluster;
578 }
579 
580 /*
581  * We regard a request as sync, if either a read or a sync write
582  */
583 static inline bool rw_is_sync(unsigned int rw_flags)
584 {
585         return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
586 }
587 
588 static inline bool rq_is_sync(struct request *rq)
589 {
590         return rw_is_sync(rq->cmd_flags);
591 }
592 
593 static inline bool blk_rl_full(struct request_list *rl, bool sync)
594 {
595         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
596 
597         return rl->flags & flag;
598 }
599 
600 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
601 {
602         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
603 
604         rl->flags |= flag;
605 }
606 
607 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
608 {
609         unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
610 
611         rl->flags &= ~flag;
612 }
613 
614 static inline bool rq_mergeable(struct request *rq)
615 {
616         if (rq->cmd_type != REQ_TYPE_FS)
617                 return false;
618 
619         if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
620                 return false;
621 
622         return true;
623 }
624 
625 static inline bool blk_check_merge_flags(unsigned int flags1,
626                                          unsigned int flags2)
627 {
628         if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD))
629                 return false;
630 
631         if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
632                 return false;
633 
634         if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME))
635                 return false;
636 
637         return true;
638 }
639 
640 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
641 {
642         if (bio_data(a) == bio_data(b))
643                 return true;
644 
645         return false;
646 }
647 
648 /*
649  * q->prep_rq_fn return values
650  */
651 #define BLKPREP_OK              0       /* serve it */
652 #define BLKPREP_KILL            1       /* fatal error, kill */
653 #define BLKPREP_DEFER           2       /* leave on queue */
654 
655 extern unsigned long blk_max_low_pfn, blk_max_pfn;
656 
657 /*
658  * standard bounce addresses:
659  *
660  * BLK_BOUNCE_HIGH      : bounce all highmem pages
661  * BLK_BOUNCE_ANY       : don't bounce anything
662  * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
663  */
664 
665 #if BITS_PER_LONG == 32
666 #define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
667 #else
668 #define BLK_BOUNCE_HIGH         -1ULL
669 #endif
670 #define BLK_BOUNCE_ANY          (-1ULL)
671 #define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
672 
673 /*
674  * default timeout for SG_IO if none specified
675  */
676 #define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
677 #define BLK_MIN_SG_TIMEOUT      (7 * HZ)
678 
679 #ifdef CONFIG_BOUNCE
680 extern int init_emergency_isa_pool(void);
681 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
682 #else
683 static inline int init_emergency_isa_pool(void)
684 {
685         return 0;
686 }
687 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
688 {
689 }
690 #endif /* CONFIG_MMU */
691 
692 struct rq_map_data {
693         struct page **pages;
694         int page_order;
695         int nr_entries;
696         unsigned long offset;
697         int null_mapped;
698         int from_user;
699 };
700 
701 struct req_iterator {
702         int i;
703         struct bio *bio;
704 };
705 
706 /* This should not be used directly - use rq_for_each_segment */
707 #define for_each_bio(_bio)              \
708         for (; _bio; _bio = _bio->bi_next)
709 #define __rq_for_each_bio(_bio, rq)     \
710         if ((rq->bio))                  \
711                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
712 
713 #define rq_for_each_segment(bvl, _rq, _iter)                    \
714         __rq_for_each_bio(_iter.bio, _rq)                       \
715                 bio_for_each_segment(bvl, _iter.bio, _iter.i)
716 
717 #define rq_iter_last(rq, _iter)                                 \
718                 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
719 
720 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
721 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
722 #endif
723 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
724 extern void rq_flush_dcache_pages(struct request *rq);
725 #else
726 static inline void rq_flush_dcache_pages(struct request *rq)
727 {
728 }
729 #endif
730 
731 extern int blk_register_queue(struct gendisk *disk);
732 extern void blk_unregister_queue(struct gendisk *disk);
733 extern void generic_make_request(struct bio *bio);
734 extern void blk_rq_init(struct request_queue *q, struct request *rq);
735 extern void blk_put_request(struct request *);
736 extern void __blk_put_request(struct request_queue *, struct request *);
737 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
738 extern struct request *blk_make_request(struct request_queue *, struct bio *,
739                                         gfp_t);
740 extern void blk_requeue_request(struct request_queue *, struct request *);
741 extern void blk_add_request_payload(struct request *rq, struct page *page,
742                 unsigned int len);
743 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
744 extern int blk_lld_busy(struct request_queue *q);
745 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
746                              struct bio_set *bs, gfp_t gfp_mask,
747                              int (*bio_ctr)(struct bio *, struct bio *, void *),
748                              void *data);
749 extern void blk_rq_unprep_clone(struct request *rq);
750 extern int blk_insert_cloned_request(struct request_queue *q,
751                                      struct request *rq);
752 extern void blk_delay_queue(struct request_queue *, unsigned long);
753 extern void blk_recount_segments(struct request_queue *, struct bio *);
754 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
755 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
756                               unsigned int, void __user *);
757 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
758                           unsigned int, void __user *);
759 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
760                          struct scsi_ioctl_command __user *);
761 
762 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
763 
764 /*
765  * A queue has just exitted congestion.  Note this in the global counter of
766  * congested queues, and wake up anyone who was waiting for requests to be
767  * put back.
768  */
769 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
770 {
771         clear_bdi_congested(&q->backing_dev_info, sync);
772 }
773 
774 /*
775  * A queue has just entered congestion.  Flag that in the queue's VM-visible
776  * state flags and increment the global gounter of congested queues.
777  */
778 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
779 {
780         set_bdi_congested(&q->backing_dev_info, sync);
781 }
782 
783 extern void blk_start_queue(struct request_queue *q);
784 extern void blk_stop_queue(struct request_queue *q);
785 extern void blk_sync_queue(struct request_queue *q);
786 extern void __blk_stop_queue(struct request_queue *q);
787 extern void __blk_run_queue(struct request_queue *q);
788 extern void blk_run_queue(struct request_queue *);
789 extern void blk_run_queue_async(struct request_queue *q);
790 extern int blk_rq_map_user(struct request_queue *, struct request *,
791                            struct rq_map_data *, void __user *, unsigned long,
792                            gfp_t);
793 extern int blk_rq_unmap_user(struct bio *);
794 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
795 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
796                                struct rq_map_data *, struct sg_iovec *, int,
797                                unsigned int, gfp_t);
798 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
799                           struct request *, int);
800 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
801                                   struct request *, int, rq_end_io_fn *);
802 
803 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
804 {
805         return bdev->bd_disk->queue;
806 }
807 
808 /*
809  * blk_rq_pos()                 : the current sector
810  * blk_rq_bytes()               : bytes left in the entire request
811  * blk_rq_cur_bytes()           : bytes left in the current segment
812  * blk_rq_err_bytes()           : bytes left till the next error boundary
813  * blk_rq_sectors()             : sectors left in the entire request
814  * blk_rq_cur_sectors()         : sectors left in the current segment
815  */
816 static inline sector_t blk_rq_pos(const struct request *rq)
817 {
818         return rq->__sector;
819 }
820 
821 static inline unsigned int blk_rq_bytes(const struct request *rq)
822 {
823         return rq->__data_len;
824 }
825 
826 static inline int blk_rq_cur_bytes(const struct request *rq)
827 {
828         return rq->bio ? bio_cur_bytes(rq->bio) : 0;
829 }
830 
831 extern unsigned int blk_rq_err_bytes(const struct request *rq);
832 
833 static inline unsigned int blk_rq_sectors(const struct request *rq)
834 {
835         return blk_rq_bytes(rq) >> 9;
836 }
837 
838 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
839 {
840         return blk_rq_cur_bytes(rq) >> 9;
841 }
842 
843 static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
844                                                      unsigned int cmd_flags)
845 {
846         if (unlikely(cmd_flags & REQ_DISCARD))
847                 return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
848 
849         if (unlikely(cmd_flags & REQ_WRITE_SAME))
850                 return q->limits.max_write_same_sectors;
851 
852         return q->limits.max_sectors;
853 }
854 
855 static inline unsigned int blk_rq_get_max_sectors(struct request *rq)
856 {
857         struct request_queue *q = rq->q;
858 
859         if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC))
860                 return q->limits.max_hw_sectors;
861 
862         return blk_queue_get_max_sectors(q, rq->cmd_flags);
863 }
864 
865 /*
866  * Request issue related functions.
867  */
868 extern struct request *blk_peek_request(struct request_queue *q);
869 extern void blk_start_request(struct request *rq);
870 extern struct request *blk_fetch_request(struct request_queue *q);
871 
872 /*
873  * Request completion related functions.
874  *
875  * blk_update_request() completes given number of bytes and updates
876  * the request without completing it.
877  *
878  * blk_end_request() and friends.  __blk_end_request() must be called
879  * with the request queue spinlock acquired.
880  *
881  * Several drivers define their own end_request and call
882  * blk_end_request() for parts of the original function.
883  * This prevents code duplication in drivers.
884  */
885 extern bool blk_update_request(struct request *rq, int error,
886                                unsigned int nr_bytes);
887 extern bool blk_end_request(struct request *rq, int error,
888                             unsigned int nr_bytes);
889 extern void blk_end_request_all(struct request *rq, int error);
890 extern bool blk_end_request_cur(struct request *rq, int error);
891 extern bool blk_end_request_err(struct request *rq, int error);
892 extern bool __blk_end_request(struct request *rq, int error,
893                               unsigned int nr_bytes);
894 extern void __blk_end_request_all(struct request *rq, int error);
895 extern bool __blk_end_request_cur(struct request *rq, int error);
896 extern bool __blk_end_request_err(struct request *rq, int error);
897 
898 extern void blk_complete_request(struct request *);
899 extern void __blk_complete_request(struct request *);
900 extern void blk_abort_request(struct request *);
901 extern void blk_unprep_request(struct request *);
902 
903 /*
904  * Access functions for manipulating queue properties
905  */
906 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
907                                         spinlock_t *lock, int node_id);
908 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
909 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
910                                                       request_fn_proc *, spinlock_t *);
911 extern void blk_cleanup_queue(struct request_queue *);
912 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
913 extern void blk_queue_bounce_limit(struct request_queue *, u64);
914 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
915 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
916 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
917 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
918 extern void blk_queue_max_discard_sectors(struct request_queue *q,
919                 unsigned int max_discard_sectors);
920 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
921                 unsigned int max_write_same_sectors);
922 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
923 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
924 extern void blk_queue_alignment_offset(struct request_queue *q,
925                                        unsigned int alignment);
926 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
927 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
928 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
929 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
930 extern void blk_set_default_limits(struct queue_limits *lim);
931 extern void blk_set_stacking_limits(struct queue_limits *lim);
932 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
933                             sector_t offset);
934 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
935                             sector_t offset);
936 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
937                               sector_t offset);
938 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
939 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
940 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
941 extern int blk_queue_dma_drain(struct request_queue *q,
942                                dma_drain_needed_fn *dma_drain_needed,
943                                void *buf, unsigned int size);
944 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
945 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
946 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
947 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
948 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
949 extern void blk_queue_dma_alignment(struct request_queue *, int);
950 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
951 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
952 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
953 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
954 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
955 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
956 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
957 
958 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
959 extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
960                           struct scatterlist *sglist);
961 extern void blk_dump_rq_flags(struct request *, char *);
962 extern long nr_blockdev_pages(void);
963 
964 bool __must_check blk_get_queue(struct request_queue *);
965 struct request_queue *blk_alloc_queue(gfp_t);
966 struct request_queue *blk_alloc_queue_node(gfp_t, int);
967 extern void blk_put_queue(struct request_queue *);
968 
969 /*
970  * block layer runtime pm functions
971  */
972 #ifdef CONFIG_PM_RUNTIME
973 extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev);
974 extern int blk_pre_runtime_suspend(struct request_queue *q);
975 extern void blk_post_runtime_suspend(struct request_queue *q, int err);
976 extern void blk_pre_runtime_resume(struct request_queue *q);
977 extern void blk_post_runtime_resume(struct request_queue *q, int err);
978 #else
979 static inline void blk_pm_runtime_init(struct request_queue *q,
980         struct device *dev) {}
981 static inline int blk_pre_runtime_suspend(struct request_queue *q)
982 {
983         return -ENOSYS;
984 }
985 static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {}
986 static inline void blk_pre_runtime_resume(struct request_queue *q) {}
987 static inline void blk_post_runtime_resume(struct request_queue *q, int err) {}
988 #endif
989 
990 /*
991  * blk_plug permits building a queue of related requests by holding the I/O
992  * fragments for a short period. This allows merging of sequential requests
993  * into single larger request. As the requests are moved from a per-task list to
994  * the device's request_queue in a batch, this results in improved scalability
995  * as the lock contention for request_queue lock is reduced.
996  *
997  * It is ok not to disable preemption when adding the request to the plug list
998  * or when attempting a merge, because blk_schedule_flush_list() will only flush
999  * the plug list when the task sleeps by itself. For details, please see
1000  * schedule() where blk_schedule_flush_plug() is called.
1001  */
1002 struct blk_plug {
1003         unsigned long magic; /* detect uninitialized use-cases */
1004         struct list_head list; /* requests */
1005         struct list_head cb_list; /* md requires an unplug callback */
1006 };
1007 #define BLK_MAX_REQUEST_COUNT 16
1008 
1009 struct blk_plug_cb;
1010 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
1011 struct blk_plug_cb {
1012         struct list_head list;
1013         blk_plug_cb_fn callback;
1014         void *data;
1015 };
1016 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
1017                                              void *data, int size);
1018 extern void blk_start_plug(struct blk_plug *);
1019 extern void blk_finish_plug(struct blk_plug *);
1020 extern void blk_flush_plug_list(struct blk_plug *, bool);
1021 
1022 static inline void blk_flush_plug(struct task_struct *tsk)
1023 {
1024         struct blk_plug *plug = tsk->plug;
1025 
1026         if (plug)
1027                 blk_flush_plug_list(plug, false);
1028 }
1029 
1030 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
1031 {
1032         struct blk_plug *plug = tsk->plug;
1033 
1034         if (plug)
1035                 blk_flush_plug_list(plug, true);
1036 }
1037 
1038 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1039 {
1040         struct blk_plug *plug = tsk->plug;
1041 
1042         return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
1043 }
1044 
1045 /*
1046  * tag stuff
1047  */
1048 #define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
1049 extern int blk_queue_start_tag(struct request_queue *, struct request *);
1050 extern struct request *blk_queue_find_tag(struct request_queue *, int);
1051 extern void blk_queue_end_tag(struct request_queue *, struct request *);
1052 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
1053 extern void blk_queue_free_tags(struct request_queue *);
1054 extern int blk_queue_resize_tags(struct request_queue *, int);
1055 extern void blk_queue_invalidate_tags(struct request_queue *);
1056 extern struct blk_queue_tag *blk_init_tags(int);
1057 extern void blk_free_tags(struct blk_queue_tag *);
1058 
1059 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
1060                                                 int tag)
1061 {
1062         if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
1063                 return NULL;
1064         return bqt->tag_index[tag];
1065 }
1066 
1067 #define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
1068 
1069 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
1070 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1071                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
1072 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
1073                 sector_t nr_sects, gfp_t gfp_mask, struct page *page);
1074 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1075                         sector_t nr_sects, gfp_t gfp_mask);
1076 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
1077                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
1078 {
1079         return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
1080                                     nr_blocks << (sb->s_blocksize_bits - 9),
1081                                     gfp_mask, flags);
1082 }
1083 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1084                 sector_t nr_blocks, gfp_t gfp_mask)
1085 {
1086         return blkdev_issue_zeroout(sb->s_bdev,
1087                                     block << (sb->s_blocksize_bits - 9),
1088                                     nr_blocks << (sb->s_blocksize_bits - 9),
1089                                     gfp_mask);
1090 }
1091 
1092 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1093 
1094 enum blk_default_limits {
1095         BLK_MAX_SEGMENTS        = 128,
1096         BLK_SAFE_MAX_SECTORS    = 255,
1097         BLK_DEF_MAX_SECTORS     = 1024,
1098         BLK_MAX_SEGMENT_SIZE    = 65536,
1099         BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
1100 };
1101 
1102 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1103 
1104 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1105 {
1106         return q->limits.bounce_pfn;
1107 }
1108 
1109 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1110 {
1111         return q->limits.seg_boundary_mask;
1112 }
1113 
1114 static inline unsigned int queue_max_sectors(struct request_queue *q)
1115 {
1116         return q->limits.max_sectors;
1117 }
1118 
1119 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1120 {
1121         return q->limits.max_hw_sectors;
1122 }
1123 
1124 static inline unsigned short queue_max_segments(struct request_queue *q)
1125 {
1126         return q->limits.max_segments;
1127 }
1128 
1129 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1130 {
1131         return q->limits.max_segment_size;
1132 }
1133 
1134 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1135 {
1136         int retval = 512;
1137 
1138         if (q && q->limits.logical_block_size)
1139                 retval = q->limits.logical_block_size;
1140 
1141         return retval;
1142 }
1143 
1144 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1145 {
1146         return queue_logical_block_size(bdev_get_queue(bdev));
1147 }
1148 
1149 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1150 {
1151         return q->limits.physical_block_size;
1152 }
1153 
1154 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1155 {
1156         return queue_physical_block_size(bdev_get_queue(bdev));
1157 }
1158 
1159 static inline unsigned int queue_io_min(struct request_queue *q)
1160 {
1161         return q->limits.io_min;
1162 }
1163 
1164 static inline int bdev_io_min(struct block_device *bdev)
1165 {
1166         return queue_io_min(bdev_get_queue(bdev));
1167 }
1168 
1169 static inline unsigned int queue_io_opt(struct request_queue *q)
1170 {
1171         return q->limits.io_opt;
1172 }
1173 
1174 static inline int bdev_io_opt(struct block_device *bdev)
1175 {
1176         return queue_io_opt(bdev_get_queue(bdev));
1177 }
1178 
1179 static inline int queue_alignment_offset(struct request_queue *q)
1180 {
1181         if (q->limits.misaligned)
1182                 return -1;
1183 
1184         return q->limits.alignment_offset;
1185 }
1186 
1187 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1188 {
1189         unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1190         unsigned int alignment = sector_div(sector, granularity >> 9) << 9;
1191 
1192         return (granularity + lim->alignment_offset - alignment) % granularity;
1193 }
1194 
1195 static inline int bdev_alignment_offset(struct block_device *bdev)
1196 {
1197         struct request_queue *q = bdev_get_queue(bdev);
1198 
1199         if (q->limits.misaligned)
1200                 return -1;
1201 
1202         if (bdev != bdev->bd_contains)
1203                 return bdev->bd_part->alignment_offset;
1204 
1205         return q->limits.alignment_offset;
1206 }
1207 
1208 static inline int queue_discard_alignment(struct request_queue *q)
1209 {
1210         if (q->limits.discard_misaligned)
1211                 return -1;
1212 
1213         return q->limits.discard_alignment;
1214 }
1215 
1216 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1217 {
1218         unsigned int alignment, granularity, offset;
1219 
1220         if (!lim->max_discard_sectors)
1221                 return 0;
1222 
1223         /* Why are these in bytes, not sectors? */
1224         alignment = lim->discard_alignment >> 9;
1225         granularity = lim->discard_granularity >> 9;
1226         if (!granularity)
1227                 return 0;
1228 
1229         /* Offset of the partition start in 'granularity' sectors */
1230         offset = sector_div(sector, granularity);
1231 
1232         /* And why do we do this modulus *again* in blkdev_issue_discard()? */
1233         offset = (granularity + alignment - offset) % granularity;
1234 
1235         /* Turn it back into bytes, gaah */
1236         return offset << 9;
1237 }
1238 
1239 static inline int bdev_discard_alignment(struct block_device *bdev)
1240 {
1241         struct request_queue *q = bdev_get_queue(bdev);
1242 
1243         if (bdev != bdev->bd_contains)
1244                 return bdev->bd_part->discard_alignment;
1245 
1246         return q->limits.discard_alignment;
1247 }
1248 
1249 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1250 {
1251         if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1252                 return 1;
1253 
1254         return 0;
1255 }
1256 
1257 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1258 {
1259         return queue_discard_zeroes_data(bdev_get_queue(bdev));
1260 }
1261 
1262 static inline unsigned int bdev_write_same(struct block_device *bdev)
1263 {
1264         struct request_queue *q = bdev_get_queue(bdev);
1265 
1266         if (q)
1267                 return q->limits.max_write_same_sectors;
1268 
1269         return 0;
1270 }
1271 
1272 static inline int queue_dma_alignment(struct request_queue *q)
1273 {
1274         return q ? q->dma_alignment : 511;
1275 }
1276 
1277 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1278                                  unsigned int len)
1279 {
1280         unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1281         return !(addr & alignment) && !(len & alignment);
1282 }
1283 
1284 /* assumes size > 256 */
1285 static inline unsigned int blksize_bits(unsigned int size)
1286 {
1287         unsigned int bits = 8;
1288         do {
1289                 bits++;
1290                 size >>= 1;
1291         } while (size > 256);
1292         return bits;
1293 }
1294 
1295 static inline unsigned int block_size(struct block_device *bdev)
1296 {
1297         return bdev->bd_block_size;
1298 }
1299 
1300 static inline bool queue_flush_queueable(struct request_queue *q)
1301 {
1302         return !q->flush_not_queueable;
1303 }
1304 
1305 typedef struct {struct page *v;} Sector;
1306 
1307 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1308 
1309 static inline void put_dev_sector(Sector p)
1310 {
1311         page_cache_release(p.v);
1312 }
1313 
1314 struct work_struct;
1315 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1316 
1317 #ifdef CONFIG_BLK_CGROUP
1318 /*
1319  * This should not be using sched_clock(). A real patch is in progress
1320  * to fix this up, until that is in place we need to disable preemption
1321  * around sched_clock() in this function and set_io_start_time_ns().
1322  */
1323 static inline void set_start_time_ns(struct request *req)
1324 {
1325         preempt_disable();
1326         req->start_time_ns = sched_clock();
1327         preempt_enable();
1328 }
1329 
1330 static inline void set_io_start_time_ns(struct request *req)
1331 {
1332         preempt_disable();
1333         req->io_start_time_ns = sched_clock();
1334         preempt_enable();
1335 }
1336 
1337 static inline uint64_t rq_start_time_ns(struct request *req)
1338 {
1339         return req->start_time_ns;
1340 }
1341 
1342 static inline uint64_t rq_io_start_time_ns(struct request *req)
1343 {
1344         return req->io_start_time_ns;
1345 }
1346 #else
1347 static inline void set_start_time_ns(struct request *req) {}
1348 static inline void set_io_start_time_ns(struct request *req) {}
1349 static inline uint64_t rq_start_time_ns(struct request *req)
1350 {
1351         return 0;
1352 }
1353 static inline uint64_t rq_io_start_time_ns(struct request *req)
1354 {
1355         return 0;
1356 }
1357 #endif
1358 
1359 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1360         MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1361 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1362         MODULE_ALIAS("block-major-" __stringify(major) "-*")
1363 
1364 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1365 
1366 #define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1367 #define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1368 
1369 struct blk_integrity_exchg {
1370         void                    *prot_buf;
1371         void                    *data_buf;
1372         sector_t                sector;
1373         unsigned int            data_size;
1374         unsigned short          sector_size;
1375         const char              *disk_name;
1376 };
1377 
1378 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1379 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1380 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1381 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1382 
1383 struct blk_integrity {
1384         integrity_gen_fn        *generate_fn;
1385         integrity_vrfy_fn       *verify_fn;
1386         integrity_set_tag_fn    *set_tag_fn;
1387         integrity_get_tag_fn    *get_tag_fn;
1388 
1389         unsigned short          flags;
1390         unsigned short          tuple_size;
1391         unsigned short          sector_size;
1392         unsigned short          tag_size;
1393 
1394         const char              *name;
1395 
1396         struct kobject          kobj;
1397 };
1398 
1399 extern bool blk_integrity_is_initialized(struct gendisk *);
1400 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1401 extern void blk_integrity_unregister(struct gendisk *);
1402 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1403 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1404                                    struct scatterlist *);
1405 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1406 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1407                                   struct request *);
1408 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1409                                    struct bio *);
1410 
1411 static inline
1412 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1413 {
1414         return bdev->bd_disk->integrity;
1415 }
1416 
1417 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1418 {
1419         return disk->integrity;
1420 }
1421 
1422 static inline int blk_integrity_rq(struct request *rq)
1423 {
1424         if (rq->bio == NULL)
1425                 return 0;
1426 
1427         return bio_integrity(rq->bio);
1428 }
1429 
1430 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1431                                                     unsigned int segs)
1432 {
1433         q->limits.max_integrity_segments = segs;
1434 }
1435 
1436 static inline unsigned short
1437 queue_max_integrity_segments(struct request_queue *q)
1438 {
1439         return q->limits.max_integrity_segments;
1440 }
1441 
1442 #else /* CONFIG_BLK_DEV_INTEGRITY */
1443 
1444 struct bio;
1445 struct block_device;
1446 struct gendisk;
1447 struct blk_integrity;
1448 
1449 static inline int blk_integrity_rq(struct request *rq)
1450 {
1451         return 0;
1452 }
1453 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1454                                             struct bio *b)
1455 {
1456         return 0;
1457 }
1458 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1459                                           struct bio *b,
1460                                           struct scatterlist *s)
1461 {
1462         return 0;
1463 }
1464 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1465 {
1466         return 0;
1467 }
1468 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1469 {
1470         return NULL;
1471 }
1472 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1473 {
1474         return 0;
1475 }
1476 static inline int blk_integrity_register(struct gendisk *d,
1477                                          struct blk_integrity *b)
1478 {
1479         return 0;
1480 }
1481 static inline void blk_integrity_unregister(struct gendisk *d)
1482 {
1483 }
1484 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1485                                                     unsigned int segs)
1486 {
1487 }
1488 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1489 {
1490         return 0;
1491 }
1492 static inline int blk_integrity_merge_rq(struct request_queue *rq,
1493                                          struct request *r1,
1494                                          struct request *r2)
1495 {
1496         return 0;
1497 }
1498 static inline int blk_integrity_merge_bio(struct request_queue *rq,
1499                                           struct request *r,
1500                                           struct bio *b)
1501 {
1502         return 0;
1503 }
1504 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1505 {
1506         return 0;
1507 }
1508 
1509 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1510 
1511 struct block_device_operations {
1512         int (*open) (struct block_device *, fmode_t);
1513         void (*release) (struct gendisk *, fmode_t);
1514         int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1515         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1516         int (*direct_access) (struct block_device *, sector_t,
1517                                                 void **, unsigned long *);
1518         unsigned int (*check_events) (struct gendisk *disk,
1519                                       unsigned int clearing);
1520         /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1521         int (*media_changed) (struct gendisk *);
1522         void (*unlock_native_capacity) (struct gendisk *);
1523         int (*revalidate_disk) (struct gendisk *);
1524         int (*getgeo)(struct block_device *, struct hd_geometry *);
1525         /* this callback is with swap_lock and sometimes page table lock held */
1526         void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1527         struct module *owner;
1528 };
1529 
1530 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1531                                  unsigned long);
1532 #else /* CONFIG_BLOCK */
1533 /*
1534  * stubs for when the block layer is configured out
1535  */
1536 #define buffer_heads_over_limit 0
1537 
1538 static inline long nr_blockdev_pages(void)
1539 {
1540         return 0;
1541 }
1542 
1543 struct blk_plug {
1544 };
1545 
1546 static inline void blk_start_plug(struct blk_plug *plug)
1547 {
1548 }
1549 
1550 static inline void blk_finish_plug(struct blk_plug *plug)
1551 {
1552 }
1553 
1554 static inline void blk_flush_plug(struct task_struct *task)
1555 {
1556 }
1557 
1558 static inline void blk_schedule_flush_plug(struct task_struct *task)
1559 {
1560 }
1561 
1562 
1563 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1564 {
1565         return false;
1566 }
1567 
1568 #endif /* CONFIG_BLOCK */
1569 
1570 #endif
1571 

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