linux/include/linux/blkdev.h
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   1#ifndef _LINUX_BLKDEV_H
   2#define _LINUX_BLKDEV_H
   3
   4#ifdef CONFIG_BLOCK
   5
   6#include <linux/sched.h>
   7#include <linux/major.h>
   8#include <linux/genhd.h>
   9#include <linux/list.h>
  10#include <linux/timer.h>
  11#include <linux/workqueue.h>
  12#include <linux/pagemap.h>
  13#include <linux/backing-dev.h>
  14#include <linux/wait.h>
  15#include <linux/mempool.h>
  16#include <linux/bio.h>
  17#include <linux/module.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 scsi_ioctl_command;
  26
  27struct request_queue;
  28struct elevator_queue;
  29struct request_pm_state;
  30struct blk_trace;
  31struct request;
  32struct sg_io_hdr;
  33
  34#define BLKDEV_MIN_RQ   4
  35#define BLKDEV_MAX_RQ   128     /* Default maximum */
  36
  37struct request;
  38typedef void (rq_end_io_fn)(struct request *, int);
  39
  40struct request_list {
  41        /*
  42         * count[], starved[], and wait[] are indexed by
  43         * BLK_RW_SYNC/BLK_RW_ASYNC
  44         */
  45        int count[2];
  46        int starved[2];
  47        int elvpriv;
  48        mempool_t *rq_pool;
  49        wait_queue_head_t wait[2];
  50};
  51
  52/*
  53 * request command types
  54 */
  55enum rq_cmd_type_bits {
  56        REQ_TYPE_FS             = 1,    /* fs request */
  57        REQ_TYPE_BLOCK_PC,              /* scsi command */
  58        REQ_TYPE_SENSE,                 /* sense request */
  59        REQ_TYPE_PM_SUSPEND,            /* suspend request */
  60        REQ_TYPE_PM_RESUME,             /* resume request */
  61        REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
  62        REQ_TYPE_SPECIAL,               /* driver defined type */
  63        REQ_TYPE_LINUX_BLOCK,           /* generic block layer message */
  64        /*
  65         * for ATA/ATAPI devices. this really doesn't belong here, ide should
  66         * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  67         * private REQ_LB opcodes to differentiate what type of request this is
  68         */
  69        REQ_TYPE_ATA_TASKFILE,
  70        REQ_TYPE_ATA_PC,
  71};
  72
  73/*
  74 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
  75 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
  76 * SCSI cdb.
  77 *
  78 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
  79 * typically to differentiate REQ_TYPE_SPECIAL requests.
  80 *
  81 */
  82enum {
  83        REQ_LB_OP_EJECT = 0x40,         /* eject request */
  84        REQ_LB_OP_FLUSH = 0x41,         /* flush request */
  85};
  86
  87/*
  88 * request type modified bits. first four bits match BIO_RW* bits, important
  89 */
  90enum rq_flag_bits {
  91        __REQ_RW,               /* not set, read. set, write */
  92        __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
  93        __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
  94        __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
  95        /* above flags must match BIO_RW_* */
  96        __REQ_DISCARD,          /* request to discard sectors */
  97        __REQ_SORTED,           /* elevator knows about this request */
  98        __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
  99        __REQ_HARDBARRIER,      /* may not be passed by drive either */
 100        __REQ_FUA,              /* forced unit access */
 101        __REQ_NOMERGE,          /* don't touch this for merging */
 102        __REQ_STARTED,          /* drive already may have started this one */
 103        __REQ_DONTPREP,         /* don't call prep for this one */
 104        __REQ_QUEUED,           /* uses queueing */
 105        __REQ_ELVPRIV,          /* elevator private data attached */
 106        __REQ_FAILED,           /* set if the request failed */
 107        __REQ_QUIET,            /* don't worry about errors */
 108        __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 109        __REQ_ORDERED_COLOR,    /* is before or after barrier */
 110        __REQ_RW_SYNC,          /* request is sync (sync write or read) */
 111        __REQ_ALLOCED,          /* request came from our alloc pool */
 112        __REQ_RW_META,          /* metadata io request */
 113        __REQ_COPY_USER,        /* contains copies of user pages */
 114        __REQ_INTEGRITY,        /* integrity metadata has been remapped */
 115        __REQ_NOIDLE,           /* Don't anticipate more IO after this one */
 116        __REQ_IO_STAT,          /* account I/O stat */
 117        __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
 118        __REQ_NR_BITS,          /* stops here */
 119};
 120
 121#define REQ_RW          (1 << __REQ_RW)
 122#define REQ_FAILFAST_DEV        (1 << __REQ_FAILFAST_DEV)
 123#define REQ_FAILFAST_TRANSPORT  (1 << __REQ_FAILFAST_TRANSPORT)
 124#define REQ_FAILFAST_DRIVER     (1 << __REQ_FAILFAST_DRIVER)
 125#define REQ_DISCARD     (1 << __REQ_DISCARD)
 126#define REQ_SORTED      (1 << __REQ_SORTED)
 127#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
 128#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
 129#define REQ_FUA         (1 << __REQ_FUA)
 130#define REQ_NOMERGE     (1 << __REQ_NOMERGE)
 131#define REQ_STARTED     (1 << __REQ_STARTED)
 132#define REQ_DONTPREP    (1 << __REQ_DONTPREP)
 133#define REQ_QUEUED      (1 << __REQ_QUEUED)
 134#define REQ_ELVPRIV     (1 << __REQ_ELVPRIV)
 135#define REQ_FAILED      (1 << __REQ_FAILED)
 136#define REQ_QUIET       (1 << __REQ_QUIET)
 137#define REQ_PREEMPT     (1 << __REQ_PREEMPT)
 138#define REQ_ORDERED_COLOR       (1 << __REQ_ORDERED_COLOR)
 139#define REQ_RW_SYNC     (1 << __REQ_RW_SYNC)
 140#define REQ_ALLOCED     (1 << __REQ_ALLOCED)
 141#define REQ_RW_META     (1 << __REQ_RW_META)
 142#define REQ_COPY_USER   (1 << __REQ_COPY_USER)
 143#define REQ_INTEGRITY   (1 << __REQ_INTEGRITY)
 144#define REQ_NOIDLE      (1 << __REQ_NOIDLE)
 145#define REQ_IO_STAT     (1 << __REQ_IO_STAT)
 146#define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE)
 147
 148#define REQ_FAILFAST_MASK       (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | \
 149                                 REQ_FAILFAST_DRIVER)
 150
 151#define BLK_MAX_CDB     16
 152
 153/*
 154 * try to put the fields that are referenced together in the same cacheline.
 155 * if you modify this structure, be sure to check block/blk-core.c:rq_init()
 156 * as well!
 157 */
 158struct request {
 159        struct list_head queuelist;
 160        struct call_single_data csd;
 161        int cpu;
 162
 163        struct request_queue *q;
 164
 165        unsigned int cmd_flags;
 166        enum rq_cmd_type_bits cmd_type;
 167        unsigned long atomic_flags;
 168
 169        /* the following two fields are internal, NEVER access directly */
 170        sector_t __sector;              /* sector cursor */
 171        unsigned int __data_len;        /* total data len */
 172
 173        struct bio *bio;
 174        struct bio *biotail;
 175
 176        struct hlist_node hash; /* merge hash */
 177        /*
 178         * The rb_node is only used inside the io scheduler, requests
 179         * are pruned when moved to the dispatch queue. So let the
 180         * completion_data share space with the rb_node.
 181         */
 182        union {
 183                struct rb_node rb_node; /* sort/lookup */
 184                void *completion_data;
 185        };
 186
 187        /*
 188         * two pointers are available for the IO schedulers, if they need
 189         * more they have to dynamically allocate it.
 190         */
 191        void *elevator_private;
 192        void *elevator_private2;
 193
 194        struct gendisk *rq_disk;
 195        unsigned long start_time;
 196
 197        /* Number of scatter-gather DMA addr+len pairs after
 198         * physical address coalescing is performed.
 199         */
 200        unsigned short nr_phys_segments;
 201
 202        unsigned short ioprio;
 203
 204        void *special;          /* opaque pointer available for LLD use */
 205        char *buffer;           /* kaddr of the current segment if available */
 206
 207        int tag;
 208        int errors;
 209
 210        int ref_count;
 211
 212        /*
 213         * when request is used as a packet command carrier
 214         */
 215        unsigned short cmd_len;
 216        unsigned char __cmd[BLK_MAX_CDB];
 217        unsigned char *cmd;
 218
 219        unsigned int extra_len; /* length of alignment and padding */
 220        unsigned int sense_len;
 221        unsigned int resid_len; /* residual count */
 222        void *sense;
 223
 224        unsigned long deadline;
 225        struct list_head timeout_list;
 226        unsigned int timeout;
 227        int retries;
 228
 229        /*
 230         * completion callback.
 231         */
 232        rq_end_io_fn *end_io;
 233        void *end_io_data;
 234
 235        /* for bidi */
 236        struct request *next_rq;
 237};
 238
 239static inline unsigned short req_get_ioprio(struct request *req)
 240{
 241        return req->ioprio;
 242}
 243
 244/*
 245 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 246 * requests. Some step values could eventually be made generic.
 247 */
 248struct request_pm_state
 249{
 250        /* PM state machine step value, currently driver specific */
 251        int     pm_step;
 252        /* requested PM state value (S1, S2, S3, S4, ...) */
 253        u32     pm_state;
 254        void*   data;           /* for driver use */
 255};
 256
 257#include <linux/elevator.h>
 258
 259typedef void (request_fn_proc) (struct request_queue *q);
 260typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
 261typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 262typedef void (unplug_fn) (struct request_queue *);
 263
 264struct bio_vec;
 265struct bvec_merge_data {
 266        struct block_device *bi_bdev;
 267        sector_t bi_sector;
 268        unsigned bi_size;
 269        unsigned long bi_rw;
 270};
 271typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
 272                             struct bio_vec *);
 273typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
 274typedef void (softirq_done_fn)(struct request *);
 275typedef int (dma_drain_needed_fn)(struct request *);
 276typedef int (lld_busy_fn) (struct request_queue *q);
 277
 278enum blk_eh_timer_return {
 279        BLK_EH_NOT_HANDLED,
 280        BLK_EH_HANDLED,
 281        BLK_EH_RESET_TIMER,
 282};
 283
 284typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
 285
 286enum blk_queue_state {
 287        Queue_down,
 288        Queue_up,
 289};
 290
 291struct blk_queue_tag {
 292        struct request **tag_index;     /* map of busy tags */
 293        unsigned long *tag_map;         /* bit map of free/busy tags */
 294        int busy;                       /* current depth */
 295        int max_depth;                  /* what we will send to device */
 296        int real_max_depth;             /* what the array can hold */
 297        atomic_t refcnt;                /* map can be shared */
 298};
 299
 300#define BLK_SCSI_MAX_CMDS       (256)
 301#define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 302
 303struct queue_limits {
 304        unsigned long           bounce_pfn;
 305        unsigned long           seg_boundary_mask;
 306
 307        unsigned int            max_hw_sectors;
 308        unsigned int            max_sectors;
 309        unsigned int            max_segment_size;
 310        unsigned int            physical_block_size;
 311        unsigned int            alignment_offset;
 312        unsigned int            io_min;
 313        unsigned int            io_opt;
 314        unsigned int            max_discard_sectors;
 315        unsigned int            discard_granularity;
 316        unsigned int            discard_alignment;
 317
 318        unsigned short          logical_block_size;
 319        unsigned short          max_hw_segments;
 320        unsigned short          max_phys_segments;
 321
 322        unsigned char           misaligned;
 323        unsigned char           discard_misaligned;
 324        unsigned char           no_cluster;
 325        signed char             discard_zeroes_data;
 326};
 327
 328struct request_queue
 329{
 330        /*
 331         * Together with queue_head for cacheline sharing
 332         */
 333        struct list_head        queue_head;
 334        struct request          *last_merge;
 335        struct elevator_queue   *elevator;
 336
 337        /*
 338         * the queue request freelist, one for reads and one for writes
 339         */
 340        struct request_list     rq;
 341
 342        request_fn_proc         *request_fn;
 343        make_request_fn         *make_request_fn;
 344        prep_rq_fn              *prep_rq_fn;
 345        unplug_fn               *unplug_fn;
 346        merge_bvec_fn           *merge_bvec_fn;
 347        prepare_flush_fn        *prepare_flush_fn;
 348        softirq_done_fn         *softirq_done_fn;
 349        rq_timed_out_fn         *rq_timed_out_fn;
 350        dma_drain_needed_fn     *dma_drain_needed;
 351        lld_busy_fn             *lld_busy_fn;
 352
 353        /*
 354         * Dispatch queue sorting
 355         */
 356        sector_t                end_sector;
 357        struct request          *boundary_rq;
 358
 359        /*
 360         * Auto-unplugging state
 361         */
 362        struct timer_list       unplug_timer;
 363        int                     unplug_thresh;  /* After this many requests */
 364        unsigned long           unplug_delay;   /* After this many jiffies */
 365        struct work_struct      unplug_work;
 366
 367        struct backing_dev_info backing_dev_info;
 368
 369        /*
 370         * The queue owner gets to use this for whatever they like.
 371         * ll_rw_blk doesn't touch it.
 372         */
 373        void                    *queuedata;
 374
 375        /*
 376         * queue needs bounce pages for pages above this limit
 377         */
 378        gfp_t                   bounce_gfp;
 379
 380        /*
 381         * various queue flags, see QUEUE_* below
 382         */
 383        unsigned long           queue_flags;
 384
 385        /*
 386         * protects queue structures from reentrancy. ->__queue_lock should
 387         * _never_ be used directly, it is queue private. always use
 388         * ->queue_lock.
 389         */
 390        spinlock_t              __queue_lock;
 391        spinlock_t              *queue_lock;
 392
 393        /*
 394         * queue kobject
 395         */
 396        struct kobject kobj;
 397
 398        /*
 399         * queue settings
 400         */
 401        unsigned long           nr_requests;    /* Max # of requests */
 402        unsigned int            nr_congestion_on;
 403        unsigned int            nr_congestion_off;
 404        unsigned int            nr_batching;
 405
 406        void                    *dma_drain_buffer;
 407        unsigned int            dma_drain_size;
 408        unsigned int            dma_pad_mask;
 409        unsigned int            dma_alignment;
 410
 411        struct blk_queue_tag    *queue_tags;
 412        struct list_head        tag_busy_list;
 413
 414        unsigned int            nr_sorted;
 415        unsigned int            in_flight[2];
 416
 417        unsigned int            rq_timeout;
 418        struct timer_list       timeout;
 419        struct list_head        timeout_list;
 420
 421        struct queue_limits     limits;
 422
 423        /*
 424         * sg stuff
 425         */
 426        unsigned int            sg_timeout;
 427        unsigned int            sg_reserved_size;
 428        int                     node;
 429#ifdef CONFIG_BLK_DEV_IO_TRACE
 430        struct blk_trace        *blk_trace;
 431#endif
 432        /*
 433         * reserved for flush operations
 434         */
 435        unsigned int            ordered, next_ordered, ordseq;
 436        int                     orderr, ordcolor;
 437        struct request          pre_flush_rq, bar_rq, post_flush_rq;
 438        struct request          *orig_bar_rq;
 439
 440        struct mutex            sysfs_lock;
 441
 442#if defined(CONFIG_BLK_DEV_BSG)
 443        struct bsg_class_device bsg_dev;
 444#endif
 445};
 446
 447#define QUEUE_FLAG_CLUSTER      0       /* cluster several segments into 1 */
 448#define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 449#define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 450#define QUEUE_FLAG_SYNCFULL     3       /* read queue has been filled */
 451#define QUEUE_FLAG_ASYNCFULL    4       /* write queue has been filled */
 452#define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 453#define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 454#define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
 455#define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 456#define QUEUE_FLAG_BIDI         9       /* queue supports bidi requests */
 457#define QUEUE_FLAG_NOMERGES    10       /* disable merge attempts */
 458#define QUEUE_FLAG_SAME_COMP   11       /* force complete on same CPU */
 459#define QUEUE_FLAG_FAIL_IO     12       /* fake timeout */
 460#define QUEUE_FLAG_STACKABLE   13       /* supports request stacking */
 461#define QUEUE_FLAG_NONROT      14       /* non-rotational device (SSD) */
 462#define QUEUE_FLAG_VIRT        QUEUE_FLAG_NONROT /* paravirt device */
 463#define QUEUE_FLAG_IO_STAT     15       /* do IO stats */
 464#define QUEUE_FLAG_DISCARD     16       /* supports DISCARD */
 465
 466#define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
 467                                 (1 << QUEUE_FLAG_CLUSTER) |            \
 468                                 (1 << QUEUE_FLAG_STACKABLE)    |       \
 469                                 (1 << QUEUE_FLAG_SAME_COMP))
 470
 471static inline int queue_is_locked(struct request_queue *q)
 472{
 473#ifdef CONFIG_SMP
 474        spinlock_t *lock = q->queue_lock;
 475        return lock && spin_is_locked(lock);
 476#else
 477        return 1;
 478#endif
 479}
 480
 481static inline void queue_flag_set_unlocked(unsigned int flag,
 482                                           struct request_queue *q)
 483{
 484        __set_bit(flag, &q->queue_flags);
 485}
 486
 487static inline int queue_flag_test_and_clear(unsigned int flag,
 488                                            struct request_queue *q)
 489{
 490        WARN_ON_ONCE(!queue_is_locked(q));
 491
 492        if (test_bit(flag, &q->queue_flags)) {
 493                __clear_bit(flag, &q->queue_flags);
 494                return 1;
 495        }
 496
 497        return 0;
 498}
 499
 500static inline int queue_flag_test_and_set(unsigned int flag,
 501                                          struct request_queue *q)
 502{
 503        WARN_ON_ONCE(!queue_is_locked(q));
 504
 505        if (!test_bit(flag, &q->queue_flags)) {
 506                __set_bit(flag, &q->queue_flags);
 507                return 0;
 508        }
 509
 510        return 1;
 511}
 512
 513static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 514{
 515        WARN_ON_ONCE(!queue_is_locked(q));
 516        __set_bit(flag, &q->queue_flags);
 517}
 518
 519static inline void queue_flag_clear_unlocked(unsigned int flag,
 520                                             struct request_queue *q)
 521{
 522        __clear_bit(flag, &q->queue_flags);
 523}
 524
 525static inline int queue_in_flight(struct request_queue *q)
 526{
 527        return q->in_flight[0] + q->in_flight[1];
 528}
 529
 530static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 531{
 532        WARN_ON_ONCE(!queue_is_locked(q));
 533        __clear_bit(flag, &q->queue_flags);
 534}
 535
 536enum {
 537        /*
 538         * Hardbarrier is supported with one of the following methods.
 539         *
 540         * NONE         : hardbarrier unsupported
 541         * DRAIN        : ordering by draining is enough
 542         * DRAIN_FLUSH  : ordering by draining w/ pre and post flushes
 543         * DRAIN_FUA    : ordering by draining w/ pre flush and FUA write
 544         * TAG          : ordering by tag is enough
 545         * TAG_FLUSH    : ordering by tag w/ pre and post flushes
 546         * TAG_FUA      : ordering by tag w/ pre flush and FUA write
 547         */
 548        QUEUE_ORDERED_BY_DRAIN          = 0x01,
 549        QUEUE_ORDERED_BY_TAG            = 0x02,
 550        QUEUE_ORDERED_DO_PREFLUSH       = 0x10,
 551        QUEUE_ORDERED_DO_BAR            = 0x20,
 552        QUEUE_ORDERED_DO_POSTFLUSH      = 0x40,
 553        QUEUE_ORDERED_DO_FUA            = 0x80,
 554
 555        QUEUE_ORDERED_NONE              = 0x00,
 556
 557        QUEUE_ORDERED_DRAIN             = QUEUE_ORDERED_BY_DRAIN |
 558                                          QUEUE_ORDERED_DO_BAR,
 559        QUEUE_ORDERED_DRAIN_FLUSH       = QUEUE_ORDERED_DRAIN |
 560                                          QUEUE_ORDERED_DO_PREFLUSH |
 561                                          QUEUE_ORDERED_DO_POSTFLUSH,
 562        QUEUE_ORDERED_DRAIN_FUA         = QUEUE_ORDERED_DRAIN |
 563                                          QUEUE_ORDERED_DO_PREFLUSH |
 564                                          QUEUE_ORDERED_DO_FUA,
 565
 566        QUEUE_ORDERED_TAG               = QUEUE_ORDERED_BY_TAG |
 567                                          QUEUE_ORDERED_DO_BAR,
 568        QUEUE_ORDERED_TAG_FLUSH         = QUEUE_ORDERED_TAG |
 569                                          QUEUE_ORDERED_DO_PREFLUSH |
 570                                          QUEUE_ORDERED_DO_POSTFLUSH,
 571        QUEUE_ORDERED_TAG_FUA           = QUEUE_ORDERED_TAG |
 572                                          QUEUE_ORDERED_DO_PREFLUSH |
 573                                          QUEUE_ORDERED_DO_FUA,
 574
 575        /*
 576         * Ordered operation sequence
 577         */
 578        QUEUE_ORDSEQ_STARTED    = 0x01, /* flushing in progress */
 579        QUEUE_ORDSEQ_DRAIN      = 0x02, /* waiting for the queue to be drained */
 580        QUEUE_ORDSEQ_PREFLUSH   = 0x04, /* pre-flushing in progress */
 581        QUEUE_ORDSEQ_BAR        = 0x08, /* original barrier req in progress */
 582        QUEUE_ORDSEQ_POSTFLUSH  = 0x10, /* post-flushing in progress */
 583        QUEUE_ORDSEQ_DONE       = 0x20,
 584};
 585
 586#define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 587#define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 588#define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 589#define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 590#define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 591#define blk_queue_io_stat(q)    test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 592#define blk_queue_flushing(q)   ((q)->ordseq)
 593#define blk_queue_stackable(q)  \
 594        test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 595#define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
 596
 597#define blk_fs_request(rq)      ((rq)->cmd_type == REQ_TYPE_FS)
 598#define blk_pc_request(rq)      ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
 599#define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
 600#define blk_sense_request(rq)   ((rq)->cmd_type == REQ_TYPE_SENSE)
 601
 602#define blk_failfast_dev(rq)    ((rq)->cmd_flags & REQ_FAILFAST_DEV)
 603#define blk_failfast_transport(rq) ((rq)->cmd_flags & REQ_FAILFAST_TRANSPORT)
 604#define blk_failfast_driver(rq) ((rq)->cmd_flags & REQ_FAILFAST_DRIVER)
 605#define blk_noretry_request(rq) (blk_failfast_dev(rq) ||        \
 606                                 blk_failfast_transport(rq) ||  \
 607                                 blk_failfast_driver(rq))
 608#define blk_rq_started(rq)      ((rq)->cmd_flags & REQ_STARTED)
 609#define blk_rq_io_stat(rq)      ((rq)->cmd_flags & REQ_IO_STAT)
 610#define blk_rq_quiet(rq)        ((rq)->cmd_flags & REQ_QUIET)
 611
 612#define blk_account_rq(rq)      (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq))) 
 613
 614#define blk_pm_suspend_request(rq)      ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
 615#define blk_pm_resume_request(rq)       ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
 616#define blk_pm_request(rq)      \
 617        (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
 618
 619#define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 620#define blk_sorted_rq(rq)       ((rq)->cmd_flags & REQ_SORTED)
 621#define blk_barrier_rq(rq)      ((rq)->cmd_flags & REQ_HARDBARRIER)
 622#define blk_fua_rq(rq)          ((rq)->cmd_flags & REQ_FUA)
 623#define blk_discard_rq(rq)      ((rq)->cmd_flags & REQ_DISCARD)
 624#define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 625/* rq->queuelist of dequeued request must be list_empty() */
 626#define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 627
 628#define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 629
 630#define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 631
 632/*
 633 * We regard a request as sync, if either a read or a sync write
 634 */
 635static inline bool rw_is_sync(unsigned int rw_flags)
 636{
 637        return !(rw_flags & REQ_RW) || (rw_flags & REQ_RW_SYNC);
 638}
 639
 640static inline bool rq_is_sync(struct request *rq)
 641{
 642        return rw_is_sync(rq->cmd_flags);
 643}
 644
 645#define rq_is_meta(rq)          ((rq)->cmd_flags & REQ_RW_META)
 646#define rq_noidle(rq)           ((rq)->cmd_flags & REQ_NOIDLE)
 647
 648static inline int blk_queue_full(struct request_queue *q, int sync)
 649{
 650        if (sync)
 651                return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
 652        return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
 653}
 654
 655static inline void blk_set_queue_full(struct request_queue *q, int sync)
 656{
 657        if (sync)
 658                queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
 659        else
 660                queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
 661}
 662
 663static inline void blk_clear_queue_full(struct request_queue *q, int sync)
 664{
 665        if (sync)
 666                queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
 667        else
 668                queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
 669}
 670
 671
 672/*
 673 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 674 * it already be started by driver.
 675 */
 676#define RQ_NOMERGE_FLAGS        \
 677        (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
 678#define rq_mergeable(rq)        \
 679        (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 680         (blk_discard_rq(rq) || blk_fs_request((rq))))
 681
 682/*
 683 * q->prep_rq_fn return values
 684 */
 685#define BLKPREP_OK              0       /* serve it */
 686#define BLKPREP_KILL            1       /* fatal error, kill */
 687#define BLKPREP_DEFER           2       /* leave on queue */
 688
 689extern unsigned long blk_max_low_pfn, blk_max_pfn;
 690
 691/*
 692 * standard bounce addresses:
 693 *
 694 * BLK_BOUNCE_HIGH      : bounce all highmem pages
 695 * BLK_BOUNCE_ANY       : don't bounce anything
 696 * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 697 */
 698
 699#if BITS_PER_LONG == 32
 700#define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 701#else
 702#define BLK_BOUNCE_HIGH         -1ULL
 703#endif
 704#define BLK_BOUNCE_ANY          (-1ULL)
 705#define BLK_BOUNCE_ISA          (ISA_DMA_THRESHOLD)
 706
 707/*
 708 * default timeout for SG_IO if none specified
 709 */
 710#define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 711#define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 712
 713#ifdef CONFIG_BOUNCE
 714extern int init_emergency_isa_pool(void);
 715extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 716#else
 717static inline int init_emergency_isa_pool(void)
 718{
 719        return 0;
 720}
 721static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 722{
 723}
 724#endif /* CONFIG_MMU */
 725
 726struct rq_map_data {
 727        struct page **pages;
 728        int page_order;
 729        int nr_entries;
 730        unsigned long offset;
 731        int null_mapped;
 732        int from_user;
 733};
 734
 735struct req_iterator {
 736        int i;
 737        struct bio *bio;
 738};
 739
 740/* This should not be used directly - use rq_for_each_segment */
 741#define for_each_bio(_bio)              \
 742        for (; _bio; _bio = _bio->bi_next)
 743#define __rq_for_each_bio(_bio, rq)     \
 744        if ((rq->bio))                  \
 745                for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 746
 747#define rq_for_each_segment(bvl, _rq, _iter)                    \
 748        __rq_for_each_bio(_iter.bio, _rq)                       \
 749                bio_for_each_segment(bvl, _iter.bio, _iter.i)
 750
 751#define rq_iter_last(rq, _iter)                                 \
 752                (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 753
 754#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 755# error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 756#endif
 757#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 758extern void rq_flush_dcache_pages(struct request *rq);
 759#else
 760static inline void rq_flush_dcache_pages(struct request *rq)
 761{
 762}
 763#endif
 764
 765extern int blk_register_queue(struct gendisk *disk);
 766extern void blk_unregister_queue(struct gendisk *disk);
 767extern void register_disk(struct gendisk *dev);
 768extern void generic_make_request(struct bio *bio);
 769extern void blk_rq_init(struct request_queue *q, struct request *rq);
 770extern void blk_put_request(struct request *);
 771extern void __blk_put_request(struct request_queue *, struct request *);
 772extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 773extern struct request *blk_make_request(struct request_queue *, struct bio *,
 774                                        gfp_t);
 775extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
 776extern void blk_requeue_request(struct request_queue *, struct request *);
 777extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 778extern int blk_lld_busy(struct request_queue *q);
 779extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
 780                             struct bio_set *bs, gfp_t gfp_mask,
 781                             int (*bio_ctr)(struct bio *, struct bio *, void *),
 782                             void *data);
 783extern void blk_rq_unprep_clone(struct request *rq);
 784extern int blk_insert_cloned_request(struct request_queue *q,
 785                                     struct request *rq);
 786extern void blk_plug_device(struct request_queue *);
 787extern void blk_plug_device_unlocked(struct request_queue *);
 788extern int blk_remove_plug(struct request_queue *);
 789extern void blk_recount_segments(struct request_queue *, struct bio *);
 790extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 791                          unsigned int, void __user *);
 792extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 793                         struct scsi_ioctl_command __user *);
 794
 795/*
 796 * A queue has just exitted congestion.  Note this in the global counter of
 797 * congested queues, and wake up anyone who was waiting for requests to be
 798 * put back.
 799 */
 800static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
 801{
 802        clear_bdi_congested(&q->backing_dev_info, sync);
 803}
 804
 805/*
 806 * A queue has just entered congestion.  Flag that in the queue's VM-visible
 807 * state flags and increment the global gounter of congested queues.
 808 */
 809static inline void blk_set_queue_congested(struct request_queue *q, int sync)
 810{
 811        set_bdi_congested(&q->backing_dev_info, sync);
 812}
 813
 814extern void blk_start_queue(struct request_queue *q);
 815extern void blk_stop_queue(struct request_queue *q);
 816extern void blk_sync_queue(struct request_queue *q);
 817extern void __blk_stop_queue(struct request_queue *q);
 818extern void __blk_run_queue(struct request_queue *);
 819extern void blk_run_queue(struct request_queue *);
 820extern int blk_rq_map_user(struct request_queue *, struct request *,
 821                           struct rq_map_data *, void __user *, unsigned long,
 822                           gfp_t);
 823extern int blk_rq_unmap_user(struct bio *);
 824extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 825extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 826                               struct rq_map_data *, struct sg_iovec *, int,
 827                               unsigned int, gfp_t);
 828extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 829                          struct request *, int);
 830extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 831                                  struct request *, int, rq_end_io_fn *);
 832extern void blk_unplug(struct request_queue *q);
 833
 834static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 835{
 836        return bdev->bd_disk->queue;
 837}
 838
 839/*
 840 * blk_rq_pos()                 : the current sector
 841 * blk_rq_bytes()               : bytes left in the entire request
 842 * blk_rq_cur_bytes()           : bytes left in the current segment
 843 * blk_rq_err_bytes()           : bytes left till the next error boundary
 844 * blk_rq_sectors()             : sectors left in the entire request
 845 * blk_rq_cur_sectors()         : sectors left in the current segment
 846 */
 847static inline sector_t blk_rq_pos(const struct request *rq)
 848{
 849        return rq->__sector;
 850}
 851
 852static inline unsigned int blk_rq_bytes(const struct request *rq)
 853{
 854        return rq->__data_len;
 855}
 856
 857static inline int blk_rq_cur_bytes(const struct request *rq)
 858{
 859        return rq->bio ? bio_cur_bytes(rq->bio) : 0;
 860}
 861
 862extern unsigned int blk_rq_err_bytes(const struct request *rq);
 863
 864static inline unsigned int blk_rq_sectors(const struct request *rq)
 865{
 866        return blk_rq_bytes(rq) >> 9;
 867}
 868
 869static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
 870{
 871        return blk_rq_cur_bytes(rq) >> 9;
 872}
 873
 874/*
 875 * Request issue related functions.
 876 */
 877extern struct request *blk_peek_request(struct request_queue *q);
 878extern void blk_start_request(struct request *rq);
 879extern struct request *blk_fetch_request(struct request_queue *q);
 880
 881/*
 882 * Request completion related functions.
 883 *
 884 * blk_update_request() completes given number of bytes and updates
 885 * the request without completing it.
 886 *
 887 * blk_end_request() and friends.  __blk_end_request() must be called
 888 * with the request queue spinlock acquired.
 889 *
 890 * Several drivers define their own end_request and call
 891 * blk_end_request() for parts of the original function.
 892 * This prevents code duplication in drivers.
 893 */
 894extern bool blk_update_request(struct request *rq, int error,
 895                               unsigned int nr_bytes);
 896extern bool blk_end_request(struct request *rq, int error,
 897                            unsigned int nr_bytes);
 898extern void blk_end_request_all(struct request *rq, int error);
 899extern bool blk_end_request_cur(struct request *rq, int error);
 900extern bool blk_end_request_err(struct request *rq, int error);
 901extern bool __blk_end_request(struct request *rq, int error,
 902                              unsigned int nr_bytes);
 903extern void __blk_end_request_all(struct request *rq, int error);
 904extern bool __blk_end_request_cur(struct request *rq, int error);
 905extern bool __blk_end_request_err(struct request *rq, int error);
 906
 907extern void blk_complete_request(struct request *);
 908extern void __blk_complete_request(struct request *);
 909extern void blk_abort_request(struct request *);
 910extern void blk_abort_queue(struct request_queue *);
 911
 912/*
 913 * Access functions for manipulating queue properties
 914 */
 915extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 916                                        spinlock_t *lock, int node_id);
 917extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 918extern void blk_cleanup_queue(struct request_queue *);
 919extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 920extern void blk_queue_bounce_limit(struct request_queue *, u64);
 921extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
 922extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
 923extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
 924extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
 925extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 926extern void blk_queue_max_discard_sectors(struct request_queue *q,
 927                unsigned int max_discard_sectors);
 928extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
 929extern void blk_queue_physical_block_size(struct request_queue *, unsigned short);
 930extern void blk_queue_alignment_offset(struct request_queue *q,
 931                                       unsigned int alignment);
 932extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 933extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
 934extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
 935extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 936extern void blk_set_default_limits(struct queue_limits *lim);
 937extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 938                            sector_t offset);
 939extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
 940                            sector_t offset);
 941extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 942                              sector_t offset);
 943extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 944extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 945extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 946extern int blk_queue_dma_drain(struct request_queue *q,
 947                               dma_drain_needed_fn *dma_drain_needed,
 948                               void *buf, unsigned int size);
 949extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 950extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 951extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 952extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 953extern void blk_queue_dma_alignment(struct request_queue *, int);
 954extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 955extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 956extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 957extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 958extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 959extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
 960extern bool blk_do_ordered(struct request_queue *, struct request **);
 961extern unsigned blk_ordered_cur_seq(struct request_queue *);
 962extern unsigned blk_ordered_req_seq(struct request *);
 963extern bool blk_ordered_complete_seq(struct request_queue *, unsigned, int);
 964
 965extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 966extern void blk_dump_rq_flags(struct request *, char *);
 967extern void generic_unplug_device(struct request_queue *);
 968extern long nr_blockdev_pages(void);
 969
 970int blk_get_queue(struct request_queue *);
 971struct request_queue *blk_alloc_queue(gfp_t);
 972struct request_queue *blk_alloc_queue_node(gfp_t, int);
 973extern void blk_put_queue(struct request_queue *);
 974
 975/*
 976 * tag stuff
 977 */
 978#define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 979extern int blk_queue_start_tag(struct request_queue *, struct request *);
 980extern struct request *blk_queue_find_tag(struct request_queue *, int);
 981extern void blk_queue_end_tag(struct request_queue *, struct request *);
 982extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 983extern void blk_queue_free_tags(struct request_queue *);
 984extern int blk_queue_resize_tags(struct request_queue *, int);
 985extern void blk_queue_invalidate_tags(struct request_queue *);
 986extern struct blk_queue_tag *blk_init_tags(int);
 987extern void blk_free_tags(struct blk_queue_tag *);
 988
 989static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 990                                                int tag)
 991{
 992        if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 993                return NULL;
 994        return bqt->tag_index[tag];
 995}
 996
 997extern int blkdev_issue_flush(struct block_device *, sector_t *);
 998#define DISCARD_FL_WAIT         0x01    /* wait for completion */
 999#define DISCARD_FL_BARRIER      0x02    /* issue DISCARD_BARRIER request */
1000extern int blkdev_issue_discard(struct block_device *, sector_t sector,
1001                sector_t nr_sects, gfp_t, int flags);
1002
1003static inline int sb_issue_discard(struct super_block *sb,
1004                                   sector_t block, sector_t nr_blocks)
1005{
1006        block <<= (sb->s_blocksize_bits - 9);
1007        nr_blocks <<= (sb->s_blocksize_bits - 9);
1008        return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, GFP_KERNEL,
1009                                    DISCARD_FL_BARRIER);
1010}
1011
1012extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1013
1014#define MAX_PHYS_SEGMENTS 128
1015#define MAX_HW_SEGMENTS 128
1016#define SAFE_MAX_SECTORS 255
1017#define BLK_DEF_MAX_SECTORS 1024
1018
1019#define MAX_SEGMENT_SIZE        65536
1020
1021#define BLK_SEG_BOUNDARY_MASK   0xFFFFFFFFUL
1022
1023#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1024
1025static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1026{
1027        return q->limits.bounce_pfn;
1028}
1029
1030static inline unsigned long queue_segment_boundary(struct request_queue *q)
1031{
1032        return q->limits.seg_boundary_mask;
1033}
1034
1035static inline unsigned int queue_max_sectors(struct request_queue *q)
1036{
1037        return q->limits.max_sectors;
1038}
1039
1040static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1041{
1042        return q->limits.max_hw_sectors;
1043}
1044
1045static inline unsigned short queue_max_hw_segments(struct request_queue *q)
1046{
1047        return q->limits.max_hw_segments;
1048}
1049
1050static inline unsigned short queue_max_phys_segments(struct request_queue *q)
1051{
1052        return q->limits.max_phys_segments;
1053}
1054
1055static inline unsigned int queue_max_segment_size(struct request_queue *q)
1056{
1057        return q->limits.max_segment_size;
1058}
1059
1060static inline unsigned short queue_logical_block_size(struct request_queue *q)
1061{
1062        int retval = 512;
1063
1064        if (q && q->limits.logical_block_size)
1065                retval = q->limits.logical_block_size;
1066
1067        return retval;
1068}
1069
1070static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1071{
1072        return queue_logical_block_size(bdev_get_queue(bdev));
1073}
1074
1075static inline unsigned int queue_physical_block_size(struct request_queue *q)
1076{
1077        return q->limits.physical_block_size;
1078}
1079
1080static inline int bdev_physical_block_size(struct block_device *bdev)
1081{
1082        return queue_physical_block_size(bdev_get_queue(bdev));
1083}
1084
1085static inline unsigned int queue_io_min(struct request_queue *q)
1086{
1087        return q->limits.io_min;
1088}
1089
1090static inline int bdev_io_min(struct block_device *bdev)
1091{
1092        return queue_io_min(bdev_get_queue(bdev));
1093}
1094
1095static inline unsigned int queue_io_opt(struct request_queue *q)
1096{
1097        return q->limits.io_opt;
1098}
1099
1100static inline int bdev_io_opt(struct block_device *bdev)
1101{
1102        return queue_io_opt(bdev_get_queue(bdev));
1103}
1104
1105static inline int queue_alignment_offset(struct request_queue *q)
1106{
1107        if (q->limits.misaligned)
1108                return -1;
1109
1110        return q->limits.alignment_offset;
1111}
1112
1113static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t offset)
1114{
1115        unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1116
1117        offset &= granularity - 1;
1118        return (granularity + lim->alignment_offset - offset) & (granularity - 1);
1119}
1120
1121static inline int queue_sector_alignment_offset(struct request_queue *q,
1122                                                sector_t sector)
1123{
1124        return queue_limit_alignment_offset(&q->limits, sector << 9);
1125}
1126
1127static inline int bdev_alignment_offset(struct block_device *bdev)
1128{
1129        struct request_queue *q = bdev_get_queue(bdev);
1130
1131        if (q->limits.misaligned)
1132                return -1;
1133
1134        if (bdev != bdev->bd_contains)
1135                return bdev->bd_part->alignment_offset;
1136
1137        return q->limits.alignment_offset;
1138}
1139
1140static inline int queue_discard_alignment(struct request_queue *q)
1141{
1142        if (q->limits.discard_misaligned)
1143                return -1;
1144
1145        return q->limits.discard_alignment;
1146}
1147
1148static inline int queue_sector_discard_alignment(struct request_queue *q,
1149                                                 sector_t sector)
1150{
1151        struct queue_limits *lim = &q->limits;
1152        unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1153
1154        return (lim->discard_granularity + lim->discard_alignment - alignment)
1155                & (lim->discard_granularity - 1);
1156}
1157
1158static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1159{
1160        if (q->limits.discard_zeroes_data == 1)
1161                return 1;
1162
1163        return 0;
1164}
1165
1166static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1167{
1168        return queue_discard_zeroes_data(bdev_get_queue(bdev));
1169}
1170
1171static inline int queue_dma_alignment(struct request_queue *q)
1172{
1173        return q ? q->dma_alignment : 511;
1174}
1175
1176static inline int blk_rq_aligned(struct request_queue *q, void *addr,
1177                                 unsigned int len)
1178{
1179        unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1180        return !((unsigned long)addr & alignment) && !(len & alignment);
1181}
1182
1183/* assumes size > 256 */
1184static inline unsigned int blksize_bits(unsigned int size)
1185{
1186        unsigned int bits = 8;
1187        do {
1188                bits++;
1189                size >>= 1;
1190        } while (size > 256);
1191        return bits;
1192}
1193
1194static inline unsigned int block_size(struct block_device *bdev)
1195{
1196        return bdev->bd_block_size;
1197}
1198
1199typedef struct {struct page *v;} Sector;
1200
1201unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1202
1203static inline void put_dev_sector(Sector p)
1204{
1205        page_cache_release(p.v);
1206}
1207
1208struct work_struct;
1209int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1210
1211#define MODULE_ALIAS_BLOCKDEV(major,minor) \
1212        MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1213#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1214        MODULE_ALIAS("block-major-" __stringify(major) "-*")
1215
1216#if defined(CONFIG_BLK_DEV_INTEGRITY)
1217
1218#define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
1219#define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
1220
1221struct blk_integrity_exchg {
1222        void                    *prot_buf;
1223        void                    *data_buf;
1224        sector_t                sector;
1225        unsigned int            data_size;
1226        unsigned short          sector_size;
1227        const char              *disk_name;
1228};
1229
1230typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1231typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1232typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1233typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1234
1235struct blk_integrity {
1236        integrity_gen_fn        *generate_fn;
1237        integrity_vrfy_fn       *verify_fn;
1238        integrity_set_tag_fn    *set_tag_fn;
1239        integrity_get_tag_fn    *get_tag_fn;
1240
1241        unsigned short          flags;
1242        unsigned short          tuple_size;
1243        unsigned short          sector_size;
1244        unsigned short          tag_size;
1245
1246        const char              *name;
1247
1248        struct kobject          kobj;
1249};
1250
1251extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1252extern void blk_integrity_unregister(struct gendisk *);
1253extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1254extern int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
1255extern int blk_rq_count_integrity_sg(struct request *);
1256
1257static inline
1258struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1259{
1260        return bdev->bd_disk->integrity;
1261}
1262
1263static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1264{
1265        return disk->integrity;
1266}
1267
1268static inline int blk_integrity_rq(struct request *rq)
1269{
1270        if (rq->bio == NULL)
1271                return 0;
1272
1273        return bio_integrity(rq->bio);
1274}
1275
1276#else /* CONFIG_BLK_DEV_INTEGRITY */
1277
1278#define blk_integrity_rq(rq)                    (0)
1279#define blk_rq_count_integrity_sg(a)            (0)
1280#define blk_rq_map_integrity_sg(a, b)           (0)
1281#define bdev_get_integrity(a)                   (0)
1282#define blk_get_integrity(a)                    (0)
1283#define blk_integrity_compare(a, b)             (0)
1284#define blk_integrity_register(a, b)            (0)
1285#define blk_integrity_unregister(a)             do { } while (0);
1286
1287#endif /* CONFIG_BLK_DEV_INTEGRITY */
1288
1289struct block_device_operations {
1290        int (*open) (struct block_device *, fmode_t);
1291        int (*release) (struct gendisk *, fmode_t);
1292        int (*locked_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1293        int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1294        int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1295        int (*direct_access) (struct block_device *, sector_t,
1296                                                void **, unsigned long *);
1297        int (*media_changed) (struct gendisk *);
1298        unsigned long long (*set_capacity) (struct gendisk *,
1299                                                unsigned long long);
1300        int (*revalidate_disk) (struct gendisk *);
1301        int (*getgeo)(struct block_device *, struct hd_geometry *);
1302        struct module *owner;
1303};
1304
1305extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1306                                 unsigned long);
1307#else /* CONFIG_BLOCK */
1308/*
1309 * stubs for when the block layer is configured out
1310 */
1311#define buffer_heads_over_limit 0
1312
1313static inline long nr_blockdev_pages(void)
1314{
1315        return 0;
1316}
1317
1318#endif /* CONFIG_BLOCK */
1319
1320#endif
1321
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