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