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;
  29typedef struct elevator_queue elevator_t;
  30struct request_pm_state;
  31struct blk_trace;
  32struct request;
  33struct sg_io_hdr;
  34
  35#define BLKDEV_MIN_RQ   4
  36#define BLKDEV_MAX_RQ   128     /* Default maximum */
  37
  38struct request;
  39typedef void (rq_end_io_fn)(struct request *, int);
  40
  41struct request_list {
  42        int count[2];
  43        int starved[2];
  44        int elvpriv;
  45        mempool_t *rq_pool;
  46        wait_queue_head_t wait[2];
  47};
  48
  49/*
  50 * request command types
  51 */
  52enum rq_cmd_type_bits {
  53        REQ_TYPE_FS             = 1,    /* fs request */
  54        REQ_TYPE_BLOCK_PC,              /* scsi command */
  55        REQ_TYPE_SENSE,                 /* sense request */
  56        REQ_TYPE_PM_SUSPEND,            /* suspend request */
  57        REQ_TYPE_PM_RESUME,             /* resume request */
  58        REQ_TYPE_PM_SHUTDOWN,           /* shutdown request */
  59        REQ_TYPE_SPECIAL,               /* driver defined type */
  60        REQ_TYPE_LINUX_BLOCK,           /* generic block layer message */
  61        /*
  62         * for ATA/ATAPI devices. this really doesn't belong here, ide should
  63         * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
  64         * private REQ_LB opcodes to differentiate what type of request this is
  65         */
  66        REQ_TYPE_ATA_TASKFILE,
  67        REQ_TYPE_ATA_PC,
  68};
  69
  70/*
  71 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
  72 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
  73 * SCSI cdb.
  74 *
  75 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
  76 * typically to differentiate REQ_TYPE_SPECIAL requests.
  77 *
  78 */
  79enum {
  80        REQ_LB_OP_EJECT = 0x40,         /* eject request */
  81        REQ_LB_OP_FLUSH = 0x41,         /* flush request */
  82        REQ_LB_OP_DISCARD = 0x42,       /* discard sectors */
  83};
  84
  85/*
  86 * request type modified bits. first two bits match BIO_RW* bits, important
  87 */
  88enum rq_flag_bits {
  89        __REQ_RW,               /* not set, read. set, write */
  90        __REQ_FAILFAST_DEV,     /* no driver retries of device errors */
  91        __REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
  92        __REQ_FAILFAST_DRIVER,  /* no driver retries of driver errors */
  93        __REQ_DISCARD,          /* request to discard sectors */
  94        __REQ_SORTED,           /* elevator knows about this request */
  95        __REQ_SOFTBARRIER,      /* may not be passed by ioscheduler */
  96        __REQ_HARDBARRIER,      /* may not be passed by drive either */
  97        __REQ_FUA,              /* forced unit access */
  98        __REQ_NOMERGE,          /* don't touch this for merging */
  99        __REQ_STARTED,          /* drive already may have started this one */
 100        __REQ_DONTPREP,         /* don't call prep for this one */
 101        __REQ_QUEUED,           /* uses queueing */
 102        __REQ_ELVPRIV,          /* elevator private data attached */
 103        __REQ_FAILED,           /* set if the request failed */
 104        __REQ_QUIET,            /* don't worry about errors */
 105        __REQ_PREEMPT,          /* set for "ide_preempt" requests */
 106        __REQ_ORDERED_COLOR,    /* is before or after barrier */
 107        __REQ_RW_SYNC,          /* request is sync (O_DIRECT) */
 108        __REQ_ALLOCED,          /* request came from our alloc pool */
 109        __REQ_RW_META,          /* metadata io request */
 110        __REQ_COPY_USER,        /* contains copies of user pages */
 111        __REQ_INTEGRITY,        /* integrity metadata has been remapped */
 112        __REQ_NR_BITS,          /* stops here */
 113};
 114
 115#define REQ_RW          (1 << __REQ_RW)
 116#define REQ_FAILFAST_DEV        (1 << __REQ_FAILFAST_DEV)
 117#define REQ_FAILFAST_TRANSPORT  (1 << __REQ_FAILFAST_TRANSPORT)
 118#define REQ_FAILFAST_DRIVER     (1 << __REQ_FAILFAST_DRIVER)
 119#define REQ_DISCARD     (1 << __REQ_DISCARD)
 120#define REQ_SORTED      (1 << __REQ_SORTED)
 121#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
 122#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
 123#define REQ_FUA         (1 << __REQ_FUA)
 124#define REQ_NOMERGE     (1 << __REQ_NOMERGE)
 125#define REQ_STARTED     (1 << __REQ_STARTED)
 126#define REQ_DONTPREP    (1 << __REQ_DONTPREP)
 127#define REQ_QUEUED      (1 << __REQ_QUEUED)
 128#define REQ_ELVPRIV     (1 << __REQ_ELVPRIV)
 129#define REQ_FAILED      (1 << __REQ_FAILED)
 130#define REQ_QUIET       (1 << __REQ_QUIET)
 131#define REQ_PREEMPT     (1 << __REQ_PREEMPT)
 132#define REQ_ORDERED_COLOR       (1 << __REQ_ORDERED_COLOR)
 133#define REQ_RW_SYNC     (1 << __REQ_RW_SYNC)
 134#define REQ_ALLOCED     (1 << __REQ_ALLOCED)
 135#define REQ_RW_META     (1 << __REQ_RW_META)
 136#define REQ_COPY_USER   (1 << __REQ_COPY_USER)
 137#define REQ_INTEGRITY   (1 << __REQ_INTEGRITY)
 138
 139#define BLK_MAX_CDB     16
 140
 141/*
 142 * try to put the fields that are referenced together in the same cacheline.
 143 * if you modify this structure, be sure to check block/blk-core.c:rq_init()
 144 * as well!
 145 */
 146struct request {
 147        struct list_head queuelist;
 148        struct call_single_data csd;
 149        int cpu;
 150
 151        struct request_queue *q;
 152
 153        unsigned int cmd_flags;
 154        enum rq_cmd_type_bits cmd_type;
 155        unsigned long atomic_flags;
 156
 157        /* Maintain bio traversal state for part by part I/O submission.
 158         * hard_* are block layer internals, no driver should touch them!
 159         */
 160
 161        sector_t sector;                /* next sector to submit */
 162        sector_t hard_sector;           /* next sector to complete */
 163        unsigned long nr_sectors;       /* no. of sectors left to submit */
 164        unsigned long hard_nr_sectors;  /* no. of sectors left to complete */
 165        /* no. of sectors left to submit in the current segment */
 166        unsigned int current_nr_sectors;
 167
 168        /* no. of sectors left to complete in the current segment */
 169        unsigned int hard_cur_sectors;
 170
 171        struct bio *bio;
 172        struct bio *biotail;
 173
 174        struct hlist_node hash; /* merge hash */
 175        /*
 176         * The rb_node is only used inside the io scheduler, requests
 177         * are pruned when moved to the dispatch queue. So let the
 178         * completion_data share space with the rb_node.
 179         */
 180        union {
 181                struct rb_node rb_node; /* sort/lookup */
 182                void *completion_data;
 183        };
 184
 185        /*
 186         * two pointers are available for the IO schedulers, if they need
 187         * more they have to dynamically allocate it.
 188         */
 189        void *elevator_private;
 190        void *elevator_private2;
 191
 192        struct gendisk *rq_disk;
 193        unsigned long start_time;
 194
 195        /* Number of scatter-gather DMA addr+len pairs after
 196         * physical address coalescing is performed.
 197         */
 198        unsigned short nr_phys_segments;
 199
 200        unsigned short ioprio;
 201
 202        void *special;
 203        char *buffer;
 204
 205        int tag;
 206        int errors;
 207
 208        int ref_count;
 209
 210        /*
 211         * when request is used as a packet command carrier
 212         */
 213        unsigned short cmd_len;
 214        unsigned char __cmd[BLK_MAX_CDB];
 215        unsigned char *cmd;
 216
 217        unsigned int data_len;
 218        unsigned int extra_len; /* length of alignment and padding */
 219        unsigned int sense_len;
 220        void *data;
 221        void *sense;
 222
 223        unsigned long deadline;
 224        struct list_head timeout_list;
 225        unsigned int timeout;
 226        int retries;
 227
 228        /*
 229         * completion callback.
 230         */
 231        rq_end_io_fn *end_io;
 232        void *end_io_data;
 233
 234        /* for bidi */
 235        struct request *next_rq;
 236};
 237
 238static inline unsigned short req_get_ioprio(struct request *req)
 239{
 240        return req->ioprio;
 241}
 242
 243/*
 244 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
 245 * requests. Some step values could eventually be made generic.
 246 */
 247struct request_pm_state
 248{
 249        /* PM state machine step value, currently driver specific */
 250        int     pm_step;
 251        /* requested PM state value (S1, S2, S3, S4, ...) */
 252        u32     pm_state;
 253        void*   data;           /* for driver use */
 254};
 255
 256#include <linux/elevator.h>
 257
 258typedef void (request_fn_proc) (struct request_queue *q);
 259typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
 260typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 261typedef void (unplug_fn) (struct request_queue *);
 262typedef int (prepare_discard_fn) (struct request_queue *, struct request *);
 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 blk_cmd_filter {
 304        unsigned long read_ok[BLK_SCSI_CMD_PER_LONG];
 305        unsigned long write_ok[BLK_SCSI_CMD_PER_LONG];
 306        struct kobject kobj;
 307};
 308
 309struct request_queue
 310{
 311        /*
 312         * Together with queue_head for cacheline sharing
 313         */
 314        struct list_head        queue_head;
 315        struct request          *last_merge;
 316        elevator_t              *elevator;
 317
 318        /*
 319         * the queue request freelist, one for reads and one for writes
 320         */
 321        struct request_list     rq;
 322
 323        request_fn_proc         *request_fn;
 324        make_request_fn         *make_request_fn;
 325        prep_rq_fn              *prep_rq_fn;
 326        unplug_fn               *unplug_fn;
 327        prepare_discard_fn      *prepare_discard_fn;
 328        merge_bvec_fn           *merge_bvec_fn;
 329        prepare_flush_fn        *prepare_flush_fn;
 330        softirq_done_fn         *softirq_done_fn;
 331        rq_timed_out_fn         *rq_timed_out_fn;
 332        dma_drain_needed_fn     *dma_drain_needed;
 333        lld_busy_fn             *lld_busy_fn;
 334
 335        /*
 336         * Dispatch queue sorting
 337         */
 338        sector_t                end_sector;
 339        struct request          *boundary_rq;
 340
 341        /*
 342         * Auto-unplugging state
 343         */
 344        struct timer_list       unplug_timer;
 345        int                     unplug_thresh;  /* After this many requests */
 346        unsigned long           unplug_delay;   /* After this many jiffies */
 347        struct work_struct      unplug_work;
 348
 349        struct backing_dev_info backing_dev_info;
 350
 351        /*
 352         * The queue owner gets to use this for whatever they like.
 353         * ll_rw_blk doesn't touch it.
 354         */
 355        void                    *queuedata;
 356
 357        /*
 358         * queue needs bounce pages for pages above this limit
 359         */
 360        unsigned long           bounce_pfn;
 361        gfp_t                   bounce_gfp;
 362
 363        /*
 364         * various queue flags, see QUEUE_* below
 365         */
 366        unsigned long           queue_flags;
 367
 368        /*
 369         * protects queue structures from reentrancy. ->__queue_lock should
 370         * _never_ be used directly, it is queue private. always use
 371         * ->queue_lock.
 372         */
 373        spinlock_t              __queue_lock;
 374        spinlock_t              *queue_lock;
 375
 376        /*
 377         * queue kobject
 378         */
 379        struct kobject kobj;
 380
 381        /*
 382         * queue settings
 383         */
 384        unsigned long           nr_requests;    /* Max # of requests */
 385        unsigned int            nr_congestion_on;
 386        unsigned int            nr_congestion_off;
 387        unsigned int            nr_batching;
 388
 389        unsigned int            max_sectors;
 390        unsigned int            max_hw_sectors;
 391        unsigned short          max_phys_segments;
 392        unsigned short          max_hw_segments;
 393        unsigned short          hardsect_size;
 394        unsigned int            max_segment_size;
 395
 396        unsigned long           seg_boundary_mask;
 397        void                    *dma_drain_buffer;
 398        unsigned int            dma_drain_size;
 399        unsigned int            dma_pad_mask;
 400        unsigned int            dma_alignment;
 401
 402        struct blk_queue_tag    *queue_tags;
 403        struct list_head        tag_busy_list;
 404
 405        unsigned int            nr_sorted;
 406        unsigned int            in_flight;
 407
 408        unsigned int            rq_timeout;
 409        struct timer_list       timeout;
 410        struct list_head        timeout_list;
 411
 412        /*
 413         * sg stuff
 414         */
 415        unsigned int            sg_timeout;
 416        unsigned int            sg_reserved_size;
 417        int                     node;
 418#ifdef CONFIG_BLK_DEV_IO_TRACE
 419        struct blk_trace        *blk_trace;
 420#endif
 421        /*
 422         * reserved for flush operations
 423         */
 424        unsigned int            ordered, next_ordered, ordseq;
 425        int                     orderr, ordcolor;
 426        struct request          pre_flush_rq, bar_rq, post_flush_rq;
 427        struct request          *orig_bar_rq;
 428
 429        struct mutex            sysfs_lock;
 430
 431#if defined(CONFIG_BLK_DEV_BSG)
 432        struct bsg_class_device bsg_dev;
 433#endif
 434        struct blk_cmd_filter cmd_filter;
 435};
 436
 437#define QUEUE_FLAG_CLUSTER      0       /* cluster several segments into 1 */
 438#define QUEUE_FLAG_QUEUED       1       /* uses generic tag queueing */
 439#define QUEUE_FLAG_STOPPED      2       /* queue is stopped */
 440#define QUEUE_FLAG_READFULL     3       /* read queue has been filled */
 441#define QUEUE_FLAG_WRITEFULL    4       /* write queue has been filled */
 442#define QUEUE_FLAG_DEAD         5       /* queue being torn down */
 443#define QUEUE_FLAG_REENTER      6       /* Re-entrancy avoidance */
 444#define QUEUE_FLAG_PLUGGED      7       /* queue is plugged */
 445#define QUEUE_FLAG_ELVSWITCH    8       /* don't use elevator, just do FIFO */
 446#define QUEUE_FLAG_BIDI         9       /* queue supports bidi requests */
 447#define QUEUE_FLAG_NOMERGES    10       /* disable merge attempts */
 448#define QUEUE_FLAG_SAME_COMP   11       /* force complete on same CPU */
 449#define QUEUE_FLAG_FAIL_IO     12       /* fake timeout */
 450#define QUEUE_FLAG_STACKABLE   13       /* supports request stacking */
 451#define QUEUE_FLAG_NONROT      14       /* non-rotational device (SSD) */
 452
 453static inline int queue_is_locked(struct request_queue *q)
 454{
 455#ifdef CONFIG_SMP
 456        spinlock_t *lock = q->queue_lock;
 457        return lock && spin_is_locked(lock);
 458#else
 459        return 1;
 460#endif
 461}
 462
 463static inline void queue_flag_set_unlocked(unsigned int flag,
 464                                           struct request_queue *q)
 465{
 466        __set_bit(flag, &q->queue_flags);
 467}
 468
 469static inline int queue_flag_test_and_clear(unsigned int flag,
 470                                            struct request_queue *q)
 471{
 472        WARN_ON_ONCE(!queue_is_locked(q));
 473
 474        if (test_bit(flag, &q->queue_flags)) {
 475                __clear_bit(flag, &q->queue_flags);
 476                return 1;
 477        }
 478
 479        return 0;
 480}
 481
 482static inline int queue_flag_test_and_set(unsigned int flag,
 483                                          struct request_queue *q)
 484{
 485        WARN_ON_ONCE(!queue_is_locked(q));
 486
 487        if (!test_bit(flag, &q->queue_flags)) {
 488                __set_bit(flag, &q->queue_flags);
 489                return 0;
 490        }
 491
 492        return 1;
 493}
 494
 495static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
 496{
 497        WARN_ON_ONCE(!queue_is_locked(q));
 498        __set_bit(flag, &q->queue_flags);
 499}
 500
 501static inline void queue_flag_clear_unlocked(unsigned int flag,
 502                                             struct request_queue *q)
 503{
 504        __clear_bit(flag, &q->queue_flags);
 505}
 506
 507static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 508{
 509        WARN_ON_ONCE(!queue_is_locked(q));
 510        __clear_bit(flag, &q->queue_flags);
 511}
 512
 513enum {
 514        /*
 515         * Hardbarrier is supported with one of the following methods.
 516         *
 517         * NONE         : hardbarrier unsupported
 518         * DRAIN        : ordering by draining is enough
 519         * DRAIN_FLUSH  : ordering by draining w/ pre and post flushes
 520         * DRAIN_FUA    : ordering by draining w/ pre flush and FUA write
 521         * TAG          : ordering by tag is enough
 522         * TAG_FLUSH    : ordering by tag w/ pre and post flushes
 523         * TAG_FUA      : ordering by tag w/ pre flush and FUA write
 524         */
 525        QUEUE_ORDERED_NONE      = 0x00,
 526        QUEUE_ORDERED_DRAIN     = 0x01,
 527        QUEUE_ORDERED_TAG       = 0x02,
 528
 529        QUEUE_ORDERED_PREFLUSH  = 0x10,
 530        QUEUE_ORDERED_POSTFLUSH = 0x20,
 531        QUEUE_ORDERED_FUA       = 0x40,
 532
 533        QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
 534                        QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 535        QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
 536                        QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 537        QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
 538                        QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
 539        QUEUE_ORDERED_TAG_FUA   = QUEUE_ORDERED_TAG |
 540                        QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
 541
 542        /*
 543         * Ordered operation sequence
 544         */
 545        QUEUE_ORDSEQ_STARTED    = 0x01, /* flushing in progress */
 546        QUEUE_ORDSEQ_DRAIN      = 0x02, /* waiting for the queue to be drained */
 547        QUEUE_ORDSEQ_PREFLUSH   = 0x04, /* pre-flushing in progress */
 548        QUEUE_ORDSEQ_BAR        = 0x08, /* original barrier req in progress */
 549        QUEUE_ORDSEQ_POSTFLUSH  = 0x10, /* post-flushing in progress */
 550        QUEUE_ORDSEQ_DONE       = 0x20,
 551};
 552
 553#define blk_queue_plugged(q)    test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
 554#define blk_queue_tagged(q)     test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 555#define blk_queue_stopped(q)    test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 556#define blk_queue_nomerges(q)   test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 557#define blk_queue_nonrot(q)     test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
 558#define blk_queue_flushing(q)   ((q)->ordseq)
 559#define blk_queue_stackable(q)  \
 560        test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 561
 562#define blk_fs_request(rq)      ((rq)->cmd_type == REQ_TYPE_FS)
 563#define blk_pc_request(rq)      ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
 564#define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
 565#define blk_sense_request(rq)   ((rq)->cmd_type == REQ_TYPE_SENSE)
 566
 567#define blk_failfast_dev(rq)    ((rq)->cmd_flags & REQ_FAILFAST_DEV)
 568#define blk_failfast_transport(rq) ((rq)->cmd_flags & REQ_FAILFAST_TRANSPORT)
 569#define blk_failfast_driver(rq) ((rq)->cmd_flags & REQ_FAILFAST_DRIVER)
 570#define blk_noretry_request(rq) (blk_failfast_dev(rq) ||        \
 571                                 blk_failfast_transport(rq) ||  \
 572                                 blk_failfast_driver(rq))
 573#define blk_rq_started(rq)      ((rq)->cmd_flags & REQ_STARTED)
 574
 575#define blk_account_rq(rq)      (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq))) 
 576
 577#define blk_pm_suspend_request(rq)      ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
 578#define blk_pm_resume_request(rq)       ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
 579#define blk_pm_request(rq)      \
 580        (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
 581
 582#define blk_rq_cpu_valid(rq)    ((rq)->cpu != -1)
 583#define blk_sorted_rq(rq)       ((rq)->cmd_flags & REQ_SORTED)
 584#define blk_barrier_rq(rq)      ((rq)->cmd_flags & REQ_HARDBARRIER)
 585#define blk_fua_rq(rq)          ((rq)->cmd_flags & REQ_FUA)
 586#define blk_discard_rq(rq)      ((rq)->cmd_flags & REQ_DISCARD)
 587#define blk_bidi_rq(rq)         ((rq)->next_rq != NULL)
 588#define blk_empty_barrier(rq)   (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
 589/* rq->queuelist of dequeued request must be list_empty() */
 590#define blk_queued_rq(rq)       (!list_empty(&(rq)->queuelist))
 591
 592#define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 593
 594#define rq_data_dir(rq)         ((rq)->cmd_flags & 1)
 595
 596/*
 597 * We regard a request as sync, if it's a READ or a SYNC write.
 598 */
 599#define rq_is_sync(rq)          (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
 600#define rq_is_meta(rq)          ((rq)->cmd_flags & REQ_RW_META)
 601
 602static inline int blk_queue_full(struct request_queue *q, int rw)
 603{
 604        if (rw == READ)
 605                return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
 606        return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
 607}
 608
 609static inline void blk_set_queue_full(struct request_queue *q, int rw)
 610{
 611        if (rw == READ)
 612                queue_flag_set(QUEUE_FLAG_READFULL, q);
 613        else
 614                queue_flag_set(QUEUE_FLAG_WRITEFULL, q);
 615}
 616
 617static inline void blk_clear_queue_full(struct request_queue *q, int rw)
 618{
 619        if (rw == READ)
 620                queue_flag_clear(QUEUE_FLAG_READFULL, q);
 621        else
 622                queue_flag_clear(QUEUE_FLAG_WRITEFULL, q);
 623}
 624
 625
 626/*
 627 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
 628 * it already be started by driver.
 629 */
 630#define RQ_NOMERGE_FLAGS        \
 631        (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
 632#define rq_mergeable(rq)        \
 633        (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
 634         (blk_discard_rq(rq) || blk_fs_request((rq))))
 635
 636/*
 637 * q->prep_rq_fn return values
 638 */
 639#define BLKPREP_OK              0       /* serve it */
 640#define BLKPREP_KILL            1       /* fatal error, kill */
 641#define BLKPREP_DEFER           2       /* leave on queue */
 642
 643extern unsigned long blk_max_low_pfn, blk_max_pfn;
 644
 645/*
 646 * standard bounce addresses:
 647 *
 648 * BLK_BOUNCE_HIGH      : bounce all highmem pages
 649 * BLK_BOUNCE_ANY       : don't bounce anything
 650 * BLK_BOUNCE_ISA       : bounce pages above ISA DMA boundary
 651 */
 652
 653#if BITS_PER_LONG == 32
 654#define BLK_BOUNCE_HIGH         ((u64)blk_max_low_pfn << PAGE_SHIFT)
 655#else
 656#define BLK_BOUNCE_HIGH         -1ULL
 657#endif
 658#define BLK_BOUNCE_ANY          (-1ULL)
 659#define BLK_BOUNCE_ISA          (ISA_DMA_THRESHOLD)
 660
 661/*
 662 * default timeout for SG_IO if none specified
 663 */
 664#define BLK_DEFAULT_SG_TIMEOUT  (60 * HZ)
 665#define BLK_MIN_SG_TIMEOUT      (7 * HZ)
 666
 667#ifdef CONFIG_BOUNCE
 668extern int init_emergency_isa_pool(void);
 669extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
 670#else
 671static inline int init_emergency_isa_pool(void)
 672{
 673        return 0;
 674}
 675static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 676{
 677}
 678#endif /* CONFIG_MMU */
 679
 680struct rq_map_data {
 681        struct page **pages;
 682        int page_order;
 683        int nr_entries;
 684};
 685
 686struct req_iterator {
 687        int i;
 688        struct bio *bio;
 689};
 690
 691/* This should not be used directly - use rq_for_each_segment */
 692#define __rq_for_each_bio(_bio, rq)     \
 693        if ((rq->bio))                  \
 694                for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 695
 696#define rq_for_each_segment(bvl, _rq, _iter)                    \
 697        __rq_for_each_bio(_iter.bio, _rq)                       \
 698                bio_for_each_segment(bvl, _iter.bio, _iter.i)
 699
 700#define rq_iter_last(rq, _iter)                                 \
 701                (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
 702
 703extern int blk_register_queue(struct gendisk *disk);
 704extern void blk_unregister_queue(struct gendisk *disk);
 705extern void register_disk(struct gendisk *dev);
 706extern void generic_make_request(struct bio *bio);
 707extern void blk_rq_init(struct request_queue *q, struct request *rq);
 708extern void blk_put_request(struct request *);
 709extern void __blk_put_request(struct request_queue *, struct request *);
 710extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 711extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
 712extern void blk_requeue_request(struct request_queue *, struct request *);
 713extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
 714extern int blk_lld_busy(struct request_queue *q);
 715extern int blk_insert_cloned_request(struct request_queue *q,
 716                                     struct request *rq);
 717extern void blk_plug_device(struct request_queue *);
 718extern void blk_plug_device_unlocked(struct request_queue *);
 719extern int blk_remove_plug(struct request_queue *);
 720extern void blk_recount_segments(struct request_queue *, struct bio *);
 721extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 722                          unsigned int, void __user *);
 723extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 724                         struct scsi_ioctl_command __user *);
 725
 726/*
 727 * Temporary export, until SCSI gets fixed up.
 728 */
 729extern int blk_rq_append_bio(struct request_queue *q, struct request *rq,
 730                             struct bio *bio);
 731
 732/*
 733 * A queue has just exitted congestion.  Note this in the global counter of
 734 * congested queues, and wake up anyone who was waiting for requests to be
 735 * put back.
 736 */
 737static inline void blk_clear_queue_congested(struct request_queue *q, int rw)
 738{
 739        clear_bdi_congested(&q->backing_dev_info, rw);
 740}
 741
 742/*
 743 * A queue has just entered congestion.  Flag that in the queue's VM-visible
 744 * state flags and increment the global gounter of congested queues.
 745 */
 746static inline void blk_set_queue_congested(struct request_queue *q, int rw)
 747{
 748        set_bdi_congested(&q->backing_dev_info, rw);
 749}
 750
 751extern void blk_start_queue(struct request_queue *q);
 752extern void blk_stop_queue(struct request_queue *q);
 753extern void blk_sync_queue(struct request_queue *q);
 754extern void __blk_stop_queue(struct request_queue *q);
 755extern void __blk_run_queue(struct request_queue *);
 756extern void blk_run_queue(struct request_queue *);
 757extern void blk_start_queueing(struct request_queue *);
 758extern int blk_rq_map_user(struct request_queue *, struct request *,
 759                           struct rq_map_data *, void __user *, unsigned long,
 760                           gfp_t);
 761extern int blk_rq_unmap_user(struct bio *);
 762extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
 763extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
 764                               struct rq_map_data *, struct sg_iovec *, int,
 765                               unsigned int, gfp_t);
 766extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 767                          struct request *, int);
 768extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 769                                  struct request *, int, rq_end_io_fn *);
 770extern void blk_unplug(struct request_queue *q);
 771
 772static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 773{
 774        return bdev->bd_disk->queue;
 775}
 776
 777static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
 778                                       struct page *page)
 779{
 780        if (bdi && bdi->unplug_io_fn)
 781                bdi->unplug_io_fn(bdi, page);
 782}
 783
 784static inline void blk_run_address_space(struct address_space *mapping)
 785{
 786        if (mapping)
 787                blk_run_backing_dev(mapping->backing_dev_info, NULL);
 788}
 789
 790extern void blkdev_dequeue_request(struct request *req);
 791
 792/*
 793 * blk_end_request() and friends.
 794 * __blk_end_request() and end_request() must be called with
 795 * the request queue spinlock acquired.
 796 *
 797 * Several drivers define their own end_request and call
 798 * blk_end_request() for parts of the original function.
 799 * This prevents code duplication in drivers.
 800 */
 801extern int blk_end_request(struct request *rq, int error,
 802                                unsigned int nr_bytes);
 803extern int __blk_end_request(struct request *rq, int error,
 804                                unsigned int nr_bytes);
 805extern int blk_end_bidi_request(struct request *rq, int error,
 806                                unsigned int nr_bytes, unsigned int bidi_bytes);
 807extern void end_request(struct request *, int);
 808extern int blk_end_request_callback(struct request *rq, int error,
 809                                unsigned int nr_bytes,
 810                                int (drv_callback)(struct request *));
 811extern void blk_complete_request(struct request *);
 812extern void __blk_complete_request(struct request *);
 813extern void blk_abort_request(struct request *);
 814extern void blk_abort_queue(struct request_queue *);
 815extern void blk_update_request(struct request *rq, int error,
 816                               unsigned int nr_bytes);
 817
 818/*
 819 * blk_end_request() takes bytes instead of sectors as a complete size.
 820 * blk_rq_bytes() returns bytes left to complete in the entire request.
 821 * blk_rq_cur_bytes() returns bytes left to complete in the current segment.
 822 */
 823extern unsigned int blk_rq_bytes(struct request *rq);
 824extern unsigned int blk_rq_cur_bytes(struct request *rq);
 825
 826/*
 827 * Access functions for manipulating queue properties
 828 */
 829extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
 830                                        spinlock_t *lock, int node_id);
 831extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
 832extern void blk_cleanup_queue(struct request_queue *);
 833extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 834extern void blk_queue_bounce_limit(struct request_queue *, u64);
 835extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
 836extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
 837extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
 838extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 839extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
 840extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
 841extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
 842extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
 843extern int blk_queue_dma_drain(struct request_queue *q,
 844                               dma_drain_needed_fn *dma_drain_needed,
 845                               void *buf, unsigned int size);
 846extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 847extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
 848extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 849extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 850extern void blk_queue_dma_alignment(struct request_queue *, int);
 851extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 852extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 853extern void blk_queue_set_discard(struct request_queue *, prepare_discard_fn *);
 854extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
 855extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 856extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 857extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
 858extern int blk_do_ordered(struct request_queue *, struct request **);
 859extern unsigned blk_ordered_cur_seq(struct request_queue *);
 860extern unsigned blk_ordered_req_seq(struct request *);
 861extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int);
 862
 863extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
 864extern void blk_dump_rq_flags(struct request *, char *);
 865extern void generic_unplug_device(struct request_queue *);
 866extern long nr_blockdev_pages(void);
 867
 868int blk_get_queue(struct request_queue *);
 869struct request_queue *blk_alloc_queue(gfp_t);
 870struct request_queue *blk_alloc_queue_node(gfp_t, int);
 871extern void blk_put_queue(struct request_queue *);
 872
 873/*
 874 * tag stuff
 875 */
 876#define blk_rq_tagged(rq)               ((rq)->cmd_flags & REQ_QUEUED)
 877extern int blk_queue_start_tag(struct request_queue *, struct request *);
 878extern struct request *blk_queue_find_tag(struct request_queue *, int);
 879extern void blk_queue_end_tag(struct request_queue *, struct request *);
 880extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
 881extern void blk_queue_free_tags(struct request_queue *);
 882extern int blk_queue_resize_tags(struct request_queue *, int);
 883extern void blk_queue_invalidate_tags(struct request_queue *);
 884extern struct blk_queue_tag *blk_init_tags(int);
 885extern void blk_free_tags(struct blk_queue_tag *);
 886
 887static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 888                                                int tag)
 889{
 890        if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
 891                return NULL;
 892        return bqt->tag_index[tag];
 893}
 894
 895extern int blkdev_issue_flush(struct block_device *, sector_t *);
 896extern int blkdev_issue_discard(struct block_device *,
 897                                sector_t sector, sector_t nr_sects, gfp_t);
 898
 899static inline int sb_issue_discard(struct super_block *sb,
 900                                   sector_t block, sector_t nr_blocks)
 901{
 902        block <<= (sb->s_blocksize_bits - 9);
 903        nr_blocks <<= (sb->s_blocksize_bits - 9);
 904        return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, GFP_KERNEL);
 905}
 906
 907/*
 908* command filter functions
 909*/
 910extern int blk_verify_command(struct blk_cmd_filter *filter,
 911                              unsigned char *cmd, fmode_t has_write_perm);
 912extern void blk_unregister_filter(struct gendisk *disk);
 913extern void blk_set_cmd_filter_defaults(struct blk_cmd_filter *filter);
 914
 915#define MAX_PHYS_SEGMENTS 128
 916#define MAX_HW_SEGMENTS 128
 917#define SAFE_MAX_SECTORS 255
 918#define BLK_DEF_MAX_SECTORS 1024
 919
 920#define MAX_SEGMENT_SIZE        65536
 921
 922#define BLK_SEG_BOUNDARY_MASK   0xFFFFFFFFUL
 923
 924#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
 925
 926static inline int queue_hardsect_size(struct request_queue *q)
 927{
 928        int retval = 512;
 929
 930        if (q && q->hardsect_size)
 931                retval = q->hardsect_size;
 932
 933        return retval;
 934}
 935
 936static inline int bdev_hardsect_size(struct block_device *bdev)
 937{
 938        return queue_hardsect_size(bdev_get_queue(bdev));
 939}
 940
 941static inline int queue_dma_alignment(struct request_queue *q)
 942{
 943        return q ? q->dma_alignment : 511;
 944}
 945
 946static inline int blk_rq_aligned(struct request_queue *q, void *addr,
 947                                 unsigned int len)
 948{
 949        unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
 950        return !((unsigned long)addr & alignment) && !(len & alignment);
 951}
 952
 953/* assumes size > 256 */
 954static inline unsigned int blksize_bits(unsigned int size)
 955{
 956        unsigned int bits = 8;
 957        do {
 958                bits++;
 959                size >>= 1;
 960        } while (size > 256);
 961        return bits;
 962}
 963
 964static inline unsigned int block_size(struct block_device *bdev)
 965{
 966        return bdev->bd_block_size;
 967}
 968
 969typedef struct {struct page *v;} Sector;
 970
 971unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
 972
 973static inline void put_dev_sector(Sector p)
 974{
 975        page_cache_release(p.v);
 976}
 977
 978struct work_struct;
 979int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
 980void kblockd_flush_work(struct work_struct *work);
 981
 982#define MODULE_ALIAS_BLOCKDEV(major,minor) \
 983        MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
 984#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
 985        MODULE_ALIAS("block-major-" __stringify(major) "-*")
 986
 987#if defined(CONFIG_BLK_DEV_INTEGRITY)
 988
 989#define INTEGRITY_FLAG_READ     2       /* verify data integrity on read */
 990#define INTEGRITY_FLAG_WRITE    4       /* generate data integrity on write */
 991
 992struct blk_integrity_exchg {
 993        void                    *prot_buf;
 994        void                    *data_buf;
 995        sector_t                sector;
 996        unsigned int            data_size;
 997        unsigned short          sector_size;
 998        const char              *disk_name;
 999};
1000
1001typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1002typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1003typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1004typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1005
1006struct blk_integrity {
1007        integrity_gen_fn        *generate_fn;
1008        integrity_vrfy_fn       *verify_fn;
1009        integrity_set_tag_fn    *set_tag_fn;
1010        integrity_get_tag_fn    *get_tag_fn;
1011
1012        unsigned short          flags;
1013        unsigned short          tuple_size;
1014        unsigned short          sector_size;
1015        unsigned short          tag_size;
1016
1017        const char              *name;
1018
1019        struct kobject          kobj;
1020};
1021
1022extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1023extern void blk_integrity_unregister(struct gendisk *);
1024extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1025extern int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
1026extern int blk_rq_count_integrity_sg(struct request *);
1027
1028static inline
1029struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1030{
1031        return bdev->bd_disk->integrity;
1032}
1033
1034static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1035{
1036        return disk->integrity;
1037}
1038
1039static inline int blk_integrity_rq(struct request *rq)
1040{
1041        if (rq->bio == NULL)
1042                return 0;
1043
1044        return bio_integrity(rq->bio);
1045}
1046
1047#else /* CONFIG_BLK_DEV_INTEGRITY */
1048
1049#define blk_integrity_rq(rq)                    (0)
1050#define blk_rq_count_integrity_sg(a)            (0)
1051#define blk_rq_map_integrity_sg(a, b)           (0)
1052#define bdev_get_integrity(a)                   (0)
1053#define blk_get_integrity(a)                    (0)
1054#define blk_integrity_compare(a, b)             (0)
1055#define blk_integrity_register(a, b)            (0)
1056#define blk_integrity_unregister(a)             do { } while (0);
1057
1058#endif /* CONFIG_BLK_DEV_INTEGRITY */
1059
1060struct block_device_operations {
1061        int (*open) (struct block_device *, fmode_t);
1062        int (*release) (struct gendisk *, fmode_t);
1063        int (*locked_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1064        int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1065        int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1066        int (*direct_access) (struct block_device *, sector_t,
1067                                                void **, unsigned long *);
1068        int (*media_changed) (struct gendisk *);
1069        int (*revalidate_disk) (struct gendisk *);
1070        int (*getgeo)(struct block_device *, struct hd_geometry *);
1071        struct module *owner;
1072};
1073
1074extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1075                                 unsigned long);
1076#else /* CONFIG_BLOCK */
1077/*
1078 * stubs for when the block layer is configured out
1079 */
1080#define buffer_heads_over_limit 0
1081
1082static inline long nr_blockdev_pages(void)
1083{
1084        return 0;
1085}
1086
1087#endif /* CONFIG_BLOCK */
1088
1089#endif
1090
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