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            discard_granularity;
 274        unsigned int            discard_alignment;
 275
 276        unsigned short          logical_block_size;
 277        unsigned short          max_segments;
 278        unsigned short          max_integrity_segments;
 279
 280        unsigned char           misaligned;
 281        unsigned char           discard_misaligned;
 282        unsigned char           cluster;
 283        unsigned char           discard_zeroes_data;
 284};
 285
 286struct request_queue {
 287        /*
 288         * Together with queue_head for cacheline sharing
 289         */
 290        struct list_head        queue_head;
 291        struct request          *last_merge;
 292        struct elevator_queue   *elevator;
 293        int                     nr_rqs[2];      /* # allocated [a]sync rqs */
 294        int                     nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
 295
 296        /*
 297         * If blkcg is not used, @q->root_rl serves all requests.  If blkcg
 298         * is used, root blkg allocates from @q->root_rl and all other
 299         * blkgs from their own blkg->rl.  Which one to use should be
 300         * determined using bio_request_list().
 301         */
 302        struct request_list     root_rl;
 303
 304        request_fn_proc         *request_fn;
 305        make_request_fn         *make_request_fn;
 306        prep_rq_fn              *prep_rq_fn;
 307        unprep_rq_fn            *unprep_rq_fn;
 308        merge_bvec_fn           *merge_bvec_fn;
 309        softirq_done_fn         *softirq_done_fn;
 310        rq_timed_out_fn         *rq_timed_out_fn;
 311        dma_drain_needed_fn     *dma_drain_needed;
 312        lld_busy_fn             *lld_busy_fn;
 313
 314        /*
 315         * Dispatch queue sorting
 316         */
 317        sector_t                end_sector;
 318        struct request          *boundary_rq;
 319
 320        /*
 321         * Delayed queue handling
 322         */
 323        struct delayed_work     delay_work;
 324
 325        struct backing_dev_info backing_dev_info;
 326
 327        /*
 328         * The queue owner gets to use this for whatever they like.
 329         * ll_rw_blk doesn't touch it.
 330         */
 331        void                    *queuedata;
 332
 333        /*
 334         * various queue flags, see QUEUE_* below
 335         */
 336        unsigned long           queue_flags;
 337
 338        /*
 339         * ida allocated id for this queue.  Used to index queues from
 340         * ioctx.
 341         */
 342        int                     id;
 343
 344        /*
 345         * queue needs bounce pages for pages above this limit
 346         */
 347        gfp_t                   bounce_gfp;
 348
 349        /*
 350         * protects queue structures from reentrancy. ->__queue_lock should
 351         * _never_ be used directly, it is queue private. always use
 352         * ->queue_lock.
 353         */
 354        spinlock_t              __queue_lock;
 355        spinlock_t              *queue_lock;
 356
 357        /*
 358         * queue kobject
 359         */
 360        struct kobject kobj;
 361
 362        /*
 363         * queue settings
 364         */
 365        unsigned long           nr_requests;    /* Max # of requests */
 366        unsigned int            nr_congestion_on;
 367        unsigned int            nr_congestion_off;
 368        unsigned int            nr_batching;
 369
 370        unsigned int            dma_drain_size;
 371        void                    *dma_drain_buffer;
 372        unsigned int            dma_pad_mask;
 373        unsigned int            dma_alignment;
 374
 375        struct blk_queue_tag    *queue_tags;
 376        struct list_head        tag_busy_list;
 377
 378        unsigned int            nr_sorted;
 379        unsigned int            in_flight[2];
 380
 381        unsigned int            rq_timeout;
 382        struct timer_list       timeout;
 383        struct list_head        timeout_list;
 384
 385        struct list_head        icq_list;
 386#ifdef CONFIG_BLK_CGROUP
 387        DECLARE_BITMAP          (blkcg_pols, BLKCG_MAX_POLS);
 388        struct blkcg_gq         *root_blkg;
 389        struct list_head        blkg_list;
 390#endif
 391
 392        struct queue_limits     limits;
 393
 394        /*
 395         * sg stuff
 396         */
 397        unsigned int            sg_timeout;
 398        unsigned int            sg_reserved_size;
 399        int                     node;
 400#ifdef CONFIG_BLK_DEV_IO_TRACE
 401        struct blk_trace        *blk_trace;
 402#endif
 403        /*
 404         * for flush operations
 405         */
 406        unsigned int            flush_flags;
 407        unsigned int            flush_not_queueable:1;
 408        unsigned int            flush_queue_delayed:1;
 409        unsigned int            flush_pending_idx:1;
 410        unsigned int            flush_running_idx:1;
 411        unsigned long           flush_pending_since;
 412        struct list_head        flush_queue[2];
 413        struct list_head        flush_data_in_flight;
 414        struct request          flush_rq;
 415
 416        struct mutex            sysfs_lock;
 417
 418        int                     bypass_depth;
 419
 420#if defined(CONFIG_BLK_DEV_BSG)
 421        bsg_job_fn              *bsg_job_fn;
 422        int                     bsg_job_size;
 423        struct bsg_class_device bsg_dev;
 424#endif
 425
 426#ifdef CONFIG_BLK_CGROUP
 427        struct list_head        all_q_node;
 428#endif
 429#ifdef CONFIG_BLK_DEV_THROTTLING
 430        /* Throttle data */
 431        struct throtl_data *td;
 432#endif
 433};
 434
 435#define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 436#define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 437#define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 438#define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 439#define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 440#define QUEUE_FLAG_BYPASS       6       /* act as dumb FIFO queue */
 441#define QUEUE_FLAG_BIDI         7       /* queue supports bidi requests */
 442#define QUEUE_FLAG_NOMERGES     8       /* disable merge attempts */
 443#define QUEUE_FLAG_SAME_COMP    9       /* complete on same CPU-group */
 444#define QUEUE_FLAG_FAIL_IO     10       /* fake timeout */
 445#define QUEUE_FLAG_STACKABLE   11       /* supports request stacking */
 446#define QUEUE_FLAG_NONROT      12       /* non-rotational device (SSD) */
 447#define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 448#define QUEUE_FLAG_IO_STAT     13       /* do IO stats */
 449#define QUEUE_FLAG_DISCARD     14       /* supports DISCARD */
 450#define QUEUE_FLAG_NOXMERGES   15       /* No extended merges */
 451#define QUEUE_FLAG_ADD_RANDOM  16       /* Contributes to random pool */
 452#define QUEUE_FLAG_SECDISCARD  17       /* supports SECDISCARD */
 453#define QUEUE_FLAG_SAME_FORCE  18       /* force complete on same CPU */
 454
 455#define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 456                                 (1 << QUEUE_FLAG_STACKABLE)    |       \
 457                                 (1 << QUEUE_FLAG_SAME_COMP)    |       \
 458                                 (1 << QUEUE_FLAG_ADD_RANDOM))
 459
 460static inline void queue_lockdep_assert_held(struct request_queue *q)
 461{
 462        if (q->queue_lock)
 463                lockdep_assert_held(q->queue_lock);
 464}
 465
 466static inline void queue_flag_set_unlocked(unsigned int flag,
 467                                           struct request_queue *q)
 468{
 469        __set_bit(flag, &q->queue_flags);
 470}
 471
 472static inline int queue_flag_test_and_clear(unsigned int flag,
 473                                            struct request_queue *q)
 474{
 475        queue_lockdep_assert_held(q);
 476
 477        if (test_bit(flag, &q->queue_flags)) {
 478                __clear_bit(flag, &q->queue_flags);
 479                return 1;
 480        }
 481
 482        return 0;
 483}
 484
 485static inline int queue_flag_test_and_set(unsigned int flag,
 486                                          struct request_queue *q)
 487{
 488        queue_lockdep_assert_held(q);
 489
 490        if (!test_bit(flag, &q->queue_flags)) {
 491                __set_bit(flag, &q->queue_flags);
 492                return 0;
 493        }
 494
 495        return 1;
 496}
 497
 498static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 499{
 500        queue_lockdep_assert_held(q);
 501        __set_bit(flag, &q->queue_flags);
 502}
 503
 504static inline void queue_flag_clear_unlocked(unsigned int flag,
 505                                             struct request_queue *q)
 506{
 507        __clear_bit(flag, &q->queue_flags);
 508}
 509
 510static inline int queue_in_flight(struct request_queue *q)
 511{
 512        return q->in_flight[0] + q->in_flight[1];
 513}
 514
 515static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 516{
 517        queue_lockdep_assert_held(q);
 518        __clear_bit(flag, &q->queue_flags);
 519}
 520
 521#define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 522#define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 523#define blk_queue_dead(q)       test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 524#define blk_queue_bypass(q)     test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
 525#define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 526#define blk_queue_noxmerges(q)  \
 527        test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
 528#define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 529#define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 530#define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
 531#define blk_queue_stackable(q)  \
 532        test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 533#define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
 534#define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
 535        test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
 536
 537#define blk_noretry_request(rq) \
 538        ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
 539                             REQ_FAILFAST_DRIVER))
 540
 541#define blk_account_rq(rq) \
 542        (((rq)->cmd_flags & REQ_STARTED) && \
 543         ((rq)->cmd_type == REQ_TYPE_FS || \
 544          ((rq)->cmd_flags & REQ_DISCARD)))
 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
 598
 599/*
 600 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 601 * it already be started by driver.
 602 */
 603#define RQ_NOMERGE_FLAGS        \
 604        (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA | REQ_DISCARD)
 605#define rq_mergeable(rq)        \
 606        (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 607         (((rq)->cmd_flags & REQ_DISCARD) || \
 608          (rq)->cmd_type == REQ_TYPE_FS))
 609
 610/*
 611 * q->prep_rq_fn return values
 612 */
 613#define BLKPREP_OK              0       /* serve it */
 614#define BLKPREP_KILL            1       /* fatal error, kill */
 615#define BLKPREP_DEFER           2       /* leave on queue */
 616
 617extern unsigned long blk_max_low_pfn, blk_max_pfn;
 618
 619/*
 620 * standard bounce addresses:
 621 *
 622 * BLK_BOUNCE_HIGH      : bounce all highmem pages
 623 * BLK_BOUNCE_ANY       : don't bounce anything
 624 * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 625 */
 626
 627#if BITS_PER_LONG == 32
 628#define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 629#else
 630#define BLK_BOUNCE_HIGH         -1ULL
 631#endif
 632#define BLK_BOUNCE_ANY          (-1ULL)
 633#define BLK_BOUNCE_ISA          (DMA_BIT_MASK(24))
 634
 635/*
 636 * default timeout for SG_IO if none specified
 637 */
 638#define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 639#define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 640
 641#ifdef CONFIG_BOUNCE
 642extern int init_emergency_isa_pool(void);
 643extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 644#else
 645static inline int init_emergency_isa_pool(void)
 646{
 647        return 0;
 648}
 649static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 650{
 651}
 652#endif /* CONFIG_MMU */
 653
 654struct rq_map_data {
 655        struct page **pages;
 656        int page_order;
 657        int nr_entries;
 658        unsigned long offset;
 659        int null_mapped;
 660        int from_user;
 661};
 662
 663struct req_iterator {
 664        int i;
 665        struct bio *bio;
 666};
 667
 668/* This should not be used directly - use rq_for_each_segment */
 669#define for_each_bio(_bio)              \
 670        for (; _bio; _bio = _bio->bi_next)
 671#define __rq_for_each_bio(_bio, rq)     \
 672        if ((rq->bio))                  \
 673                for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 674
 675#define rq_for_each_segment(bvl, _rq, _iter)                    \
 676        __rq_for_each_bio(_iter.bio, _rq)                       \
 677                bio_for_each_segment(bvl, _iter.bio, _iter.i)
 678
 679#define rq_iter_last(rq, _iter)                                 \
 680                (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 681
 682#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 683# error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 684#endif
 685#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 686extern void rq_flush_dcache_pages(struct request *rq);
 687#else
 688static inline void rq_flush_dcache_pages(struct request *rq)
 689{
 690}
 691#endif
 692
 693extern int blk_register_queue(struct gendisk *disk);
 694extern void blk_unregister_queue(struct gendisk *disk);
 695extern void generic_make_request(struct bio *bio);
 696extern void blk_rq_init(struct request_queue *q, struct request *rq);
 697extern void blk_put_request(struct request *);
 698extern void __blk_put_request(struct request_queue *, struct request *);
 699extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 700extern struct request *blk_make_request(struct request_queue *, struct bio *,
 701                                        gfp_t);
 702extern void blk_requeue_request(struct request_queue *, struct request *);
 703extern void blk_add_request_payload(struct request *rq, struct page *page,
 704                unsigned int len);
 705extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 706extern int blk_lld_busy(struct request_queue *q);
 707extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 708                             struct bio_set *bs, gfp_t gfp_mask,
 709                             int (*bio_ctr)(struct bio *, struct bio *, void *),
 710                             void *data);
 711extern void blk_rq_unprep_clone(struct request *rq);
 712extern int blk_insert_cloned_request(struct request_queue *q,
 713                                     struct request *rq);
 714extern void blk_delay_queue(struct request_queue *, unsigned long);
 715extern void blk_recount_segments(struct request_queue *, struct bio *);
 716extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
 717extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
 718                              unsigned int, void __user *);
 719extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 720                          unsigned int, void __user *);
 721extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 722                         struct scsi_ioctl_command __user *);
 723
 724extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
 725
 726/*
 727 * A queue has just exitted congestion.  Note this in the global counter of
 728 * congested queues, and wake up anyone who was waiting for requests to be
 729 * put back.
 730 */
 731static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 732{
 733        clear_bdi_congested(&q->backing_dev_info, sync);
 734}
 735
 736/*
 737 * A queue has just entered congestion.  Flag that in the queue's VM-visible
 738 * state flags and increment the global gounter of congested queues.
 739 */
 740static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 741{
 742        set_bdi_congested(&q->backing_dev_info, sync);
 743}
 744
 745extern void blk_start_queue(struct request_queue *q);
 746extern void blk_stop_queue(struct request_queue *q);
 747extern void blk_sync_queue(struct request_queue *q);
 748extern void __blk_stop_queue(struct request_queue *q);
 749extern void __blk_run_queue(struct request_queue *q);
 750extern void blk_run_queue(struct request_queue *);
 751extern void blk_run_queue_async(struct request_queue *q);
 752extern int blk_rq_map_user(struct request_queue *, struct request *,
 753                           struct rq_map_data *, void __user *, unsigned long,
 754                           gfp_t);
 755extern int blk_rq_unmap_user(struct bio *);
 756extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 757extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 758                               struct rq_map_data *, struct sg_iovec *, int,
 759                               unsigned int, gfp_t);
 760extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 761                          struct request *, int);
 762extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 763                                  struct request *, int, rq_end_io_fn *);
 764
 765static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 766{
 767        return bdev->bd_disk->queue;
 768}
 769
 770/*
 771 * blk_rq_pos()                 : the current sector
 772 * blk_rq_bytes()               : bytes left in the entire request
 773 * blk_rq_cur_bytes()           : bytes left in the current segment
 774 * blk_rq_err_bytes()           : bytes left till the next error boundary
 775 * blk_rq_sectors()             : sectors left in the entire request
 776 * blk_rq_cur_sectors()         : sectors left in the current segment
 777 */
 778static inline sector_t blk_rq_pos(const struct request *rq)
 779{
 780        return rq->__sector;
 781}
 782
 783static inline unsigned int blk_rq_bytes(const struct request *rq)
 784{
 785        return rq->__data_len;
 786}
 787
 788static inline int blk_rq_cur_bytes(const struct request *rq)
 789{
 790        return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 791}
 792
 793extern unsigned int blk_rq_err_bytes(const struct request *rq);
 794
 795static inline unsigned int blk_rq_sectors(const struct request *rq)
 796{
 797        return blk_rq_bytes(rq) >> 9;
 798}
 799
 800static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 801{
 802        return blk_rq_cur_bytes(rq) >> 9;
 803}
 804
 805/*
 806 * Request issue related functions.
 807 */
 808extern struct request *blk_peek_request(struct request_queue *q);
 809extern void blk_start_request(struct request *rq);
 810extern struct request *blk_fetch_request(struct request_queue *q);
 811
 812/*
 813 * Request completion related functions.
 814 *
 815 * blk_update_request() completes given number of bytes and updates
 816 * the request without completing it.
 817 *
 818 * blk_end_request() and friends.  __blk_end_request() must be called
 819 * with the request queue spinlock acquired.
 820 *
 821 * Several drivers define their own end_request and call
 822 * blk_end_request() for parts of the original function.
 823 * This prevents code duplication in drivers.
 824 */
 825extern bool blk_update_request(struct request *rq, int error,
 826                               unsigned int nr_bytes);
 827extern bool blk_end_request(struct request *rq, int error,
 828                            unsigned int nr_bytes);
 829extern void blk_end_request_all(struct request *rq, int error);
 830extern bool blk_end_request_cur(struct request *rq, int error);
 831extern bool blk_end_request_err(struct request *rq, int error);
 832extern bool __blk_end_request(struct request *rq, int error,
 833                              unsigned int nr_bytes);
 834extern void __blk_end_request_all(struct request *rq, int error);
 835extern bool __blk_end_request_cur(struct request *rq, int error);
 836extern bool __blk_end_request_err(struct request *rq, int error);
 837
 838extern void blk_complete_request(struct request *);
 839extern void __blk_complete_request(struct request *);
 840extern void blk_abort_request(struct request *);
 841extern void blk_unprep_request(struct request *);
 842
 843/*
 844 * Access functions for manipulating queue properties
 845 */
 846extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 847                                        spinlock_t *lock, int node_id);
 848extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 849extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
 850                                                      request_fn_proc *, spinlock_t *);
 851extern void blk_cleanup_queue(struct request_queue *);
 852extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 853extern void blk_queue_bounce_limit(struct request_queue *, u64);
 854extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
 855extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 856extern void blk_queue_max_segments(struct request_queue *, unsigned short);
 857extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 858extern void blk_queue_max_discard_sectors(struct request_queue *q,
 859                unsigned int max_discard_sectors);
 860extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 861extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
 862extern void blk_queue_alignment_offset(struct request_queue *q,
 863                                       unsigned int alignment);
 864extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 865extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 866extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 867extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 868extern void blk_set_default_limits(struct queue_limits *lim);
 869extern void blk_set_stacking_limits(struct queue_limits *lim);
 870extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 871                            sector_t offset);
 872extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
 873                            sector_t offset);
 874extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 875                              sector_t offset);
 876extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 877extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 878extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 879extern int blk_queue_dma_drain(struct request_queue *q,
 880                               dma_drain_needed_fn *dma_drain_needed,
 881                               void *buf, unsigned int size);
 882extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 883extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 884extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 885extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
 886extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 887extern void blk_queue_dma_alignment(struct request_queue *, int);
 888extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 889extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 890extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 891extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 892extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
 893extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
 894extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 895
 896extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 897extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
 898                          struct scatterlist *sglist);
 899extern void blk_dump_rq_flags(struct request *, char *);
 900extern long nr_blockdev_pages(void);
 901
 902bool __must_check blk_get_queue(struct request_queue *);
 903struct request_queue *blk_alloc_queue(gfp_t);
 904struct request_queue *blk_alloc_queue_node(gfp_t, int);
 905extern void blk_put_queue(struct request_queue *);
 906
 907/*
 908 * blk_plug permits building a queue of related requests by holding the I/O
 909 * fragments for a short period. This allows merging of sequential requests
 910 * into single larger request. As the requests are moved from a per-task list to
 911 * the device's request_queue in a batch, this results in improved scalability
 912 * as the lock contention for request_queue lock is reduced.
 913 *
 914 * It is ok not to disable preemption when adding the request to the plug list
 915 * or when attempting a merge, because blk_schedule_flush_list() will only flush
 916 * the plug list when the task sleeps by itself. For details, please see
 917 * schedule() where blk_schedule_flush_plug() is called.
 918 */
 919struct blk_plug {
 920        unsigned long magic; /* detect uninitialized use-cases */
 921        struct list_head list; /* requests */
 922        struct list_head cb_list; /* md requires an unplug callback */
 923        unsigned int should_sort; /* list to be sorted before flushing? */
 924};
 925#define BLK_MAX_REQUEST_COUNT 16
 926
 927struct blk_plug_cb;
 928typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
 929struct blk_plug_cb {
 930        struct list_head list;
 931        blk_plug_cb_fn callback;
 932        void *data;
 933};
 934extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
 935                                             void *data, int size);
 936extern void blk_start_plug(struct blk_plug *);
 937extern void blk_finish_plug(struct blk_plug *);
 938extern void blk_flush_plug_list(struct blk_plug *, bool);
 939
 940static inline void blk_flush_plug(struct task_struct *tsk)
 941{
 942        struct blk_plug *plug = tsk->plug;
 943
 944        if (plug)
 945                blk_flush_plug_list(plug, false);
 946}
 947
 948static inline void blk_schedule_flush_plug(struct task_struct *tsk)
 949{
 950        struct blk_plug *plug = tsk->plug;
 951
 952        if (plug)
 953                blk_flush_plug_list(plug, true);
 954}
 955
 956static inline bool blk_needs_flush_plug(struct task_struct *tsk)
 957{
 958        struct blk_plug *plug = tsk->plug;
 959
 960        return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
 961}
 962
 963/*
 964 * tag stuff
 965 */
 966#define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 967extern int blk_queue_start_tag(struct request_queue *, struct request *);
 968extern struct request *blk_queue_find_tag(struct request_queue *, int);
 969extern void blk_queue_end_tag(struct request_queue *, struct request *);
 970extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 971extern void blk_queue_free_tags(struct request_queue *);
 972extern int blk_queue_resize_tags(struct request_queue *, int);
 973extern void blk_queue_invalidate_tags(struct request_queue *);
 974extern struct blk_queue_tag *blk_init_tags(int);
 975extern void blk_free_tags(struct blk_queue_tag *);
 976
 977static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 978                                                int tag)
 979{
 980        if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 981                return NULL;
 982        return bqt->tag_index[tag];
 983}
 984
 985#define BLKDEV_DISCARD_SECURE  0x01    /* secure discard */
 986
 987extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
 988extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 989                sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
 990extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 991                        sector_t nr_sects, gfp_t gfp_mask);
 992static inline int sb_issue_discard(struct super_block *sb, sector_t block,
 993                sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
 994{
 995        return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
 996                                    nr_blocks << (sb->s_blocksize_bits - 9),
 997                                    gfp_mask, flags);
 998}
 999static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1000                sector_t nr_blocks, gfp_t gfp_mask)
1001{
1002        return blkdev_issue_zeroout(sb->s_bdev,
1003                                    block << (sb->s_blocksize_bits - 9),
1004                                    nr_blocks << (sb->s_blocksize_bits - 9),
1005                                    gfp_mask);
1006}
1007
1008extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1009
1010enum blk_default_limits {
1011        BLK_MAX_SEGMENTS        = 128,
1012        BLK_SAFE_MAX_SECTORS    = 255,
1013        BLK_DEF_MAX_SECTORS     = 1024,
1014        BLK_MAX_SEGMENT_SIZE    = 65536,
1015        BLK_SEG_BOUNDARY_MASK   = 0xFFFFFFFFUL,
1016};
1017
1018#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1019
1020static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1021{
1022        return q->limits.bounce_pfn;
1023}
1024
1025static inline unsigned long queue_segment_boundary(struct request_queue *q)
1026{
1027        return q->limits.seg_boundary_mask;
1028}
1029
1030static inline unsigned int queue_max_sectors(struct request_queue *q)
1031{
1032        return q->limits.max_sectors;
1033}
1034
1035static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1036{
1037        return q->limits.max_hw_sectors;
1038}
1039
1040static inline unsigned short queue_max_segments(struct request_queue *q)
1041{
1042        return q->limits.max_segments;
1043}
1044
1045static inline unsigned int queue_max_segment_size(struct request_queue *q)
1046{
1047        return q->limits.max_segment_size;
1048}
1049
1050static inline unsigned short queue_logical_block_size(struct request_queue *q)
1051{
1052        int retval = 512;
1053
1054        if (q && q->limits.logical_block_size)
1055                retval = q->limits.logical_block_size;
1056
1057        return retval;
1058}
1059
1060static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1061{
1062        return queue_logical_block_size(bdev_get_queue(bdev));
1063}
1064
1065static inline unsigned int queue_physical_block_size(struct request_queue *q)
1066{
1067        return q->limits.physical_block_size;
1068}
1069
1070static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1071{
1072        return queue_physical_block_size(bdev_get_queue(bdev));
1073}
1074
1075static inline unsigned int queue_io_min(struct request_queue *q)
1076{
1077        return q->limits.io_min;
1078}
1079
1080static inline int bdev_io_min(struct block_device *bdev)
1081{
1082        return queue_io_min(bdev_get_queue(bdev));
1083}
1084
1085static inline unsigned int queue_io_opt(struct request_queue *q)
1086{
1087        return q->limits.io_opt;
1088}
1089
1090static inline int bdev_io_opt(struct block_device *bdev)
1091{
1092        return queue_io_opt(bdev_get_queue(bdev));
1093}
1094
1095static inline int queue_alignment_offset(struct request_queue *q)
1096{
1097        if (q->limits.misaligned)
1098                return -1;
1099
1100        return q->limits.alignment_offset;
1101}
1102
1103static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1104{
1105        unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1106        unsigned int alignment = (sector << 9) & (granularity - 1);
1107
1108        return (granularity + lim->alignment_offset - alignment)
1109                & (granularity - 1);
1110}
1111
1112static inline int bdev_alignment_offset(struct block_device *bdev)
1113{
1114        struct request_queue *q = bdev_get_queue(bdev);
1115
1116        if (q->limits.misaligned)
1117                return -1;
1118
1119        if (bdev != bdev->bd_contains)
1120                return bdev->bd_part->alignment_offset;
1121
1122        return q->limits.alignment_offset;
1123}
1124
1125static inline int queue_discard_alignment(struct request_queue *q)
1126{
1127        if (q->limits.discard_misaligned)
1128                return -1;
1129
1130        return q->limits.discard_alignment;
1131}
1132
1133static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1134{
1135        unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1136
1137        if (!lim->max_discard_sectors)
1138                return 0;
1139
1140        return (lim->discard_granularity + lim->discard_alignment - alignment)
1141                & (lim->discard_granularity - 1);
1142}
1143
1144static inline int bdev_discard_alignment(struct block_device *bdev)
1145{
1146        struct request_queue *q = bdev_get_queue(bdev);
1147
1148        if (bdev != bdev->bd_contains)
1149                return bdev->bd_part->discard_alignment;
1150
1151        return q->limits.discard_alignment;
1152}
1153
1154static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1155{
1156        if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1157                return 1;
1158
1159        return 0;
1160}
1161
1162static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1163{
1164        return queue_discard_zeroes_data(bdev_get_queue(bdev));
1165}
1166
1167static inline int queue_dma_alignment(struct request_queue *q)
1168{
1169        return q ? q->dma_alignment : 511;
1170}
1171
1172static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1173                                 unsigned int len)
1174{
1175        unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1176        return !(addr & alignment) && !(len & alignment);
1177}
1178
1179/* assumes size > 256 */
1180static inline unsigned int blksize_bits(unsigned int size)
1181{
1182        unsigned int bits = 8;
1183        do {
1184                bits++;
1185                size >>= 1;
1186        } while (size > 256);
1187        return bits;
1188}
1189
1190static inline unsigned int block_size(struct block_device *bdev)
1191{
1192        return bdev->bd_block_size;
1193}
1194
1195static inline bool queue_flush_queueable(struct request_queue *q)
1196{
1197        return !q->flush_not_queueable;
1198}
1199
1200typedef struct {struct page *v;} Sector;
1201
1202unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1203
1204static inline void put_dev_sector(Sector p)
1205{
1206        page_cache_release(p.v);
1207}
1208
1209struct work_struct;
1210int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1211
1212#ifdef CONFIG_BLK_CGROUP
1213/*
1214 * This should not be using sched_clock(). A real patch is in progress
1215 * to fix this up, until that is in place we need to disable preemption
1216 * around sched_clock() in this function and set_io_start_time_ns().
1217 */
1218static inline void set_start_time_ns(struct request *req)
1219{
1220        preempt_disable();
1221        req->start_time_ns = sched_clock();
1222        preempt_enable();
1223}
1224
1225static inline void set_io_start_time_ns(struct request *req)
1226{
1227        preempt_disable();
1228        req->io_start_time_ns = sched_clock();
1229        preempt_enable();
1230}
1231
1232static inline uint64_t rq_start_time_ns(struct request *req)
1233{
1234        return req->start_time_ns;
1235}
1236
1237static inline uint64_t rq_io_start_time_ns(struct request *req)
1238{
1239        return req->io_start_time_ns;
1240}
1241#else
1242static inline void set_start_time_ns(struct request *req) {}
1243static inline void set_io_start_time_ns(struct request *req) {}
1244static inline uint64_t rq_start_time_ns(struct request *req)
1245{
1246        return 0;
1247}
1248static inline uint64_t rq_io_start_time_ns(struct request *req)
1249{
1250        return 0;
1251}
1252#endif
1253
1254#define MODULE_ALIAS_BLOCKDEV(major,minor) \
1255        MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1256#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1257        MODULE_ALIAS("block-major-" __stringify(major) "-*")
1258
1259#if defined(CONFIG_BLK_DEV_INTEGRITY)
1260
1261#define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1262#define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1263
1264struct blk_integrity_exchg {
1265        void                    *prot_buf;
1266        void                    *data_buf;
1267        sector_t                sector;
1268        unsigned int            data_size;
1269        unsigned short          sector_size;
1270        const char              *disk_name;
1271};
1272
1273typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1274typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1275typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1276typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1277
1278struct blk_integrity {
1279        integrity_gen_fn        *generate_fn;
1280        integrity_vrfy_fn       *verify_fn;
1281        integrity_set_tag_fn    *set_tag_fn;
1282        integrity_get_tag_fn    *get_tag_fn;
1283
1284        unsigned short          flags;
1285        unsigned short          tuple_size;
1286        unsigned short          sector_size;
1287        unsigned short          tag_size;
1288
1289        const char              *name;
1290
1291        struct kobject          kobj;
1292};
1293
1294extern bool blk_integrity_is_initialized(struct gendisk *);
1295extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1296extern void blk_integrity_unregister(struct gendisk *);
1297extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1298extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1299                                   struct scatterlist *);
1300extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1301extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1302                                  struct request *);
1303extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1304                                   struct bio *);
1305
1306static inline
1307struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1308{
1309        return bdev->bd_disk->integrity;
1310}
1311
1312static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1313{
1314        return disk->integrity;
1315}
1316
1317static inline int blk_integrity_rq(struct request *rq)
1318{
1319        if (rq->bio == NULL)
1320                return 0;
1321
1322        return bio_integrity(rq->bio);
1323}
1324
1325static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1326                                                    unsigned int segs)
1327{
1328        q->limits.max_integrity_segments = segs;
1329}
1330
1331static inline unsigned short
1332queue_max_integrity_segments(struct request_queue *q)
1333{
1334        return q->limits.max_integrity_segments;
1335}
1336
1337#else /* CONFIG_BLK_DEV_INTEGRITY */
1338
1339struct bio;
1340struct block_device;
1341struct gendisk;
1342struct blk_integrity;
1343
1344static inline int blk_integrity_rq(struct request *rq)
1345{
1346        return 0;
1347}
1348static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1349                                            struct bio *b)
1350{
1351        return 0;
1352}
1353static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1354                                          struct bio *b,
1355                                          struct scatterlist *s)
1356{
1357        return 0;
1358}
1359static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1360{
1361        return 0;
1362}
1363static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1364{
1365        return NULL;
1366}
1367static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1368{
1369        return 0;
1370}
1371static inline int blk_integrity_register(struct gendisk *d,
1372                                         struct blk_integrity *b)
1373{
1374        return 0;
1375}
1376static inline void blk_integrity_unregister(struct gendisk *d)
1377{
1378}
1379static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1380                                                    unsigned int segs)
1381{
1382}
1383static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1384{
1385        return 0;
1386}
1387static inline int blk_integrity_merge_rq(struct request_queue *rq,
1388                                         struct request *r1,
1389                                         struct request *r2)
1390{
1391        return 0;
1392}
1393static inline int blk_integrity_merge_bio(struct request_queue *rq,
1394                                          struct request *r,
1395                                          struct bio *b)
1396{
1397        return 0;
1398}
1399static inline bool blk_integrity_is_initialized(struct gendisk *g)
1400{
1401        return 0;
1402}
1403
1404#endif /* CONFIG_BLK_DEV_INTEGRITY */
1405
1406struct block_device_operations {
1407        int (*open) (struct block_device *, fmode_t);
1408        int (*release) (struct gendisk *, fmode_t);
1409        int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1410        int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1411        int (*direct_access) (struct block_device *, sector_t,
1412                                                void **, unsigned long *);
1413        unsigned int (*check_events) (struct gendisk *disk,
1414                                      unsigned int clearing);
1415        /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1416        int (*media_changed) (struct gendisk *);
1417        void (*unlock_native_capacity) (struct gendisk *);
1418        int (*revalidate_disk) (struct gendisk *);
1419        int (*getgeo)(struct block_device *, struct hd_geometry *);
1420        /* this callback is with swap_lock and sometimes page table lock held */
1421        void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1422        struct module *owner;
1423};
1424
1425extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1426                                 unsigned long);
1427#else /* CONFIG_BLOCK */
1428/*
1429 * stubs for when the block layer is configured out
1430 */
1431#define buffer_heads_over_limit 0
1432
1433static inline long nr_blockdev_pages(void)
1434{
1435        return 0;
1436}
1437
1438struct blk_plug {
1439};
1440
1441static inline void blk_start_plug(struct blk_plug *plug)
1442{
1443}
1444
1445static inline void blk_finish_plug(struct blk_plug *plug)
1446{
1447}
1448
1449static inline void blk_flush_plug(struct task_struct *task)
1450{
1451}
1452
1453static inline void blk_schedule_flush_plug(struct task_struct *task)
1454{
1455}
1456
1457
1458static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1459{
1460        return false;
1461}
1462
1463#endif /* CONFIG_BLOCK */
1464
1465#endif
1466
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