#ifndef _LINUX_BLKDEV_H #define _LINUX_BLKDEV_H #include <linux/sched.h> #ifdef CONFIG_BLOCK #include <linux/major.h> #include <linux/genhd.h> #include <linux/list.h> #include <linux/llist.h> #include <linux/timer.h> #include <linux/workqueue.h> #include <linux/pagemap.h> #include <linux/backing-dev.h> #include <linux/wait.h> #include <linux/mempool.h> #include <linux/bio.h> #include <linux/stringify.h> #include <linux/gfp.h> #include <linux/bsg.h> #include <linux/smp.h> #include <linux/rcupdate.h> #include <linux/percpu-refcount.h> #include <asm/scatterlist.h> struct module; struct scsi_ioctl_command; struct request_queue; struct elevator_queue; struct request_pm_state; struct blk_trace; struct request; struct sg_io_hdr; struct bsg_job; struct blkcg_gq; struct blk_flush_queue; #define BLKDEV_MIN_RQ 4 #define BLKDEV_MAX_RQ 128 /* Default maximum */ /* * Maximum number of blkcg policies allowed to be registered concurrently. * Defined here to simplify include dependency. */ #define BLKCG_MAX_POLS 2 struct request; typedef void (rq_end_io_fn)(struct request *, int); #define BLK_RL_SYNCFULL (1U << 0) #define BLK_RL_ASYNCFULL (1U << 1) struct request_list { struct request_queue *q; /* the queue this rl belongs to */ #ifdef CONFIG_BLK_CGROUP struct blkcg_gq *blkg; /* blkg this request pool belongs to */ #endif /* * count[], starved[], and wait[] are indexed by * BLK_RW_SYNC/BLK_RW_ASYNC */ int count[2]; int starved[2]; mempool_t *rq_pool; wait_queue_head_t wait[2]; unsigned int flags; }; /* * request command types */ enum rq_cmd_type_bits { REQ_TYPE_FS = 1, /* fs request */ REQ_TYPE_BLOCK_PC, /* scsi command */ REQ_TYPE_SENSE, /* sense request */ REQ_TYPE_PM_SUSPEND, /* suspend request */ REQ_TYPE_PM_RESUME, /* resume request */ REQ_TYPE_PM_SHUTDOWN, /* shutdown request */ REQ_TYPE_SPECIAL, /* driver defined type */ /* * for ATA/ATAPI devices. this really doesn't belong here, ide should * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver * private REQ_LB opcodes to differentiate what type of request this is */ REQ_TYPE_ATA_TASKFILE, REQ_TYPE_ATA_PC, }; #define BLK_MAX_CDB 16 /* * Try to put the fields that are referenced together in the same cacheline. * * If you modify this structure, make sure to update blk_rq_init() and * especially blk_mq_rq_ctx_init() to take care of the added fields. */ struct request { struct list_head queuelist; union { struct call_single_data csd; unsigned long fifo_time; }; struct request_queue *q; struct blk_mq_ctx *mq_ctx; u64 cmd_flags; enum rq_cmd_type_bits cmd_type; unsigned long atomic_flags; int cpu; /* the following two fields are internal, NEVER access directly */ unsigned int __data_len; /* total data len */ sector_t __sector; /* sector cursor */ struct bio *bio; struct bio *biotail; /* * The hash is used inside the scheduler, and killed once the * request reaches the dispatch list. The ipi_list is only used * to queue the request for softirq completion, which is long * after the request has been unhashed (and even removed from * the dispatch list). */ union { struct hlist_node hash; /* merge hash */ struct list_head ipi_list; }; /* * The rb_node is only used inside the io scheduler, requests * are pruned when moved to the dispatch queue. So let the * completion_data share space with the rb_node. */ union { struct rb_node rb_node; /* sort/lookup */ void *completion_data; }; /* * Three pointers are available for the IO schedulers, if they need * more they have to dynamically allocate it. Flush requests are * never put on the IO scheduler. So let the flush fields share * space with the elevator data. */ union { struct { struct io_cq *icq; void *priv[2]; } elv; struct { unsigned int seq; struct list_head list; rq_end_io_fn *saved_end_io; } flush; }; struct gendisk *rq_disk; struct hd_struct *part; unsigned long start_time; #ifdef CONFIG_BLK_CGROUP struct request_list *rl; /* rl this rq is alloced from */ unsigned long long start_time_ns; unsigned long long io_start_time_ns; /* when passed to hardware */ #endif /* Number of scatter-gather DMA addr+len pairs after * physical address coalescing is performed. */ unsigned short nr_phys_segments; #if defined(CONFIG_BLK_DEV_INTEGRITY) unsigned short nr_integrity_segments; #endif unsigned short ioprio; void *special; /* opaque pointer available for LLD use */ int tag; int errors; /* * when request is used as a packet command carrier */ unsigned char __cmd[BLK_MAX_CDB]; unsigned char *cmd; unsigned short cmd_len; unsigned int extra_len; /* length of alignment and padding */ unsigned int sense_len; unsigned int resid_len; /* residual count */ void *sense; unsigned long deadline; struct list_head timeout_list; unsigned int timeout; int retries; /* * completion callback. */ rq_end_io_fn *end_io; void *end_io_data; /* for bidi */ struct request *next_rq; }; static inline unsigned short req_get_ioprio(struct request *req) { return req->ioprio; } /* * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME * requests. Some step values could eventually be made generic. */ struct request_pm_state { /* PM state machine step value, currently driver specific */ int pm_step; /* requested PM state value (S1, S2, S3, S4, ...) */ u32 pm_state; void* data; /* for driver use */ }; #include <linux/elevator.h> struct blk_queue_ctx; typedef void (request_fn_proc) (struct request_queue *q); typedef void (make_request_fn) (struct request_queue *q, struct bio *bio); typedef int (prep_rq_fn) (struct request_queue *, struct request *); typedef void (unprep_rq_fn) (struct request_queue *, struct request *); struct bio_vec; struct bvec_merge_data { struct block_device *bi_bdev; sector_t bi_sector; unsigned bi_size; unsigned long bi_rw; }; typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *, struct bio_vec *); typedef void (softirq_done_fn)(struct request *); typedef int (dma_drain_needed_fn)(struct request *); typedef int (lld_busy_fn) (struct request_queue *q); typedef int (bsg_job_fn) (struct bsg_job *); enum blk_eh_timer_return { BLK_EH_NOT_HANDLED, BLK_EH_HANDLED, BLK_EH_RESET_TIMER, }; typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *); enum blk_queue_state { Queue_down, Queue_up, }; struct blk_queue_tag { struct request **tag_index; /* map of busy tags */ unsigned long *tag_map; /* bit map of free/busy tags */ int busy; /* current depth */ int max_depth; /* what we will send to device */ int real_max_depth; /* what the array can hold */ atomic_t refcnt; /* map can be shared */ }; #define BLK_SCSI_MAX_CMDS (256) #define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8)) struct queue_limits { unsigned long bounce_pfn; unsigned long seg_boundary_mask; unsigned int max_hw_sectors; unsigned int chunk_sectors; unsigned int max_sectors; unsigned int max_segment_size; unsigned int physical_block_size; unsigned int alignment_offset; unsigned int io_min; unsigned int io_opt; unsigned int max_discard_sectors; unsigned int max_write_same_sectors; unsigned int discard_granularity; unsigned int discard_alignment; unsigned short logical_block_size; unsigned short max_segments; unsigned short max_integrity_segments; unsigned char misaligned; unsigned char discard_misaligned; unsigned char cluster; unsigned char discard_zeroes_data; unsigned char raid_partial_stripes_expensive; }; struct request_queue { /* * Together with queue_head for cacheline sharing */ struct list_head queue_head; struct request *last_merge; struct elevator_queue *elevator; int nr_rqs[2]; /* # allocated [a]sync rqs */ int nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */ /* * If blkcg is not used, @q->root_rl serves all requests. If blkcg * is used, root blkg allocates from @q->root_rl and all other * blkgs from their own blkg->rl. Which one to use should be * determined using bio_request_list(). */ struct request_list root_rl; request_fn_proc *request_fn; make_request_fn *make_request_fn; prep_rq_fn *prep_rq_fn; unprep_rq_fn *unprep_rq_fn; merge_bvec_fn *merge_bvec_fn; softirq_done_fn *softirq_done_fn; rq_timed_out_fn *rq_timed_out_fn; dma_drain_needed_fn *dma_drain_needed; lld_busy_fn *lld_busy_fn; struct blk_mq_ops *mq_ops; unsigned int *mq_map; /* sw queues */ struct blk_mq_ctx __percpu *queue_ctx; unsigned int nr_queues; /* hw dispatch queues */ struct blk_mq_hw_ctx **queue_hw_ctx; unsigned int nr_hw_queues; /* * Dispatch queue sorting */ sector_t end_sector; struct request *boundary_rq; /* * Delayed queue handling */ struct delayed_work delay_work; struct backing_dev_info backing_dev_info; /* * The queue owner gets to use this for whatever they like. * ll_rw_blk doesn't touch it. */ void *queuedata; /* * various queue flags, see QUEUE_* below */ unsigned long queue_flags; /* * ida allocated id for this queue. Used to index queues from * ioctx. */ int id; /* * queue needs bounce pages for pages above this limit */ gfp_t bounce_gfp; /* * protects queue structures from reentrancy. ->__queue_lock should * _never_ be used directly, it is queue private. always use * ->queue_lock. */ spinlock_t __queue_lock; spinlock_t *queue_lock; /* * queue kobject */ struct kobject kobj; /* * mq queue kobject */ struct kobject mq_kobj; #ifdef CONFIG_PM_RUNTIME struct device *dev; int rpm_status; unsigned int nr_pending; #endif /* * queue settings */ unsigned long nr_requests; /* Max # of requests */ unsigned int nr_congestion_on; unsigned int nr_congestion_off; unsigned int nr_batching; unsigned int dma_drain_size; void *dma_drain_buffer; unsigned int dma_pad_mask; unsigned int dma_alignment; struct blk_queue_tag *queue_tags; struct list_head tag_busy_list; unsigned int nr_sorted; unsigned int in_flight[2]; /* * Number of active block driver functions for which blk_drain_queue() * must wait. Must be incremented around functions that unlock the * queue_lock internally, e.g. scsi_request_fn(). */ unsigned int request_fn_active; unsigned int rq_timeout; struct timer_list timeout; struct list_head timeout_list; struct list_head icq_list; #ifdef CONFIG_BLK_CGROUP DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS); struct blkcg_gq *root_blkg; struct list_head blkg_list; #endif struct queue_limits limits; /* * sg stuff */ unsigned int sg_timeout; unsigned int sg_reserved_size; int node; #ifdef CONFIG_BLK_DEV_IO_TRACE struct blk_trace *blk_trace; #endif /* * for flush operations */ unsigned int flush_flags; unsigned int flush_not_queueable:1; struct blk_flush_queue *fq; struct list_head requeue_list; spinlock_t requeue_lock; struct work_struct requeue_work; struct mutex sysfs_lock; int bypass_depth; int mq_freeze_depth; #if defined(CONFIG_BLK_DEV_BSG) bsg_job_fn *bsg_job_fn; int bsg_job_size; struct bsg_class_device bsg_dev; #endif #ifdef CONFIG_BLK_DEV_THROTTLING /* Throttle data */ struct throtl_data *td; #endif struct rcu_head rcu_head; wait_queue_head_t mq_freeze_wq; struct percpu_ref mq_usage_counter; struct list_head all_q_node; struct blk_mq_tag_set *tag_set; struct list_head tag_set_list; }; #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */ #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */ #define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */ #define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */ #define QUEUE_FLAG_DYING 5 /* queue being torn down */ #define QUEUE_FLAG_BYPASS 6 /* act as dumb FIFO queue */ #define QUEUE_FLAG_BIDI 7 /* queue supports bidi requests */ #define QUEUE_FLAG_NOMERGES 8 /* disable merge attempts */ #define QUEUE_FLAG_SAME_COMP 9 /* complete on same CPU-group */ #define QUEUE_FLAG_FAIL_IO 10 /* fake timeout */ #define QUEUE_FLAG_STACKABLE 11 /* supports request stacking */ #define QUEUE_FLAG_NONROT 12 /* non-rotational device (SSD) */ #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */ #define QUEUE_FLAG_IO_STAT 13 /* do IO stats */ #define QUEUE_FLAG_DISCARD 14 /* supports DISCARD */ #define QUEUE_FLAG_NOXMERGES 15 /* No extended merges */ #define QUEUE_FLAG_ADD_RANDOM 16 /* Contributes to random pool */ #define QUEUE_FLAG_SECDISCARD 17 /* supports SECDISCARD */ #define QUEUE_FLAG_SAME_FORCE 18 /* force complete on same CPU */ #define QUEUE_FLAG_DEAD 19 /* queue tear-down finished */ #define QUEUE_FLAG_INIT_DONE 20 /* queue is initialized */ #define QUEUE_FLAG_NO_SG_MERGE 21 /* don't attempt to merge SG segments*/ #define QUEUE_FLAG_SG_GAPS 22 /* queue doesn't support SG gaps */ #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_STACKABLE) | \ (1 << QUEUE_FLAG_SAME_COMP) | \ (1 << QUEUE_FLAG_ADD_RANDOM)) #define QUEUE_FLAG_MQ_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_SAME_COMP)) static inline void queue_lockdep_assert_held(struct request_queue *q) { if (q->queue_lock) lockdep_assert_held(q->queue_lock); } static inline void queue_flag_set_unlocked(unsigned int flag, struct request_queue *q) { __set_bit(flag, &q->queue_flags); } static inline int queue_flag_test_and_clear(unsigned int flag, struct request_queue *q) { queue_lockdep_assert_held(q); if (test_bit(flag, &q->queue_flags)) { __clear_bit(flag, &q->queue_flags); return 1; } return 0; } static inline int queue_flag_test_and_set(unsigned int flag, struct request_queue *q) { queue_lockdep_assert_held(q); if (!test_bit(flag, &q->queue_flags)) { __set_bit(flag, &q->queue_flags); return 0; } return 1; } static inline void queue_flag_set(unsigned int flag, struct request_queue *q) { queue_lockdep_assert_held(q); __set_bit(flag, &q->queue_flags); } static inline void queue_flag_clear_unlocked(unsigned int flag, struct request_queue *q) { __clear_bit(flag, &q->queue_flags); } static inline int queue_in_flight(struct request_queue *q) { return q->in_flight[0] + q->in_flight[1]; } static inline void queue_flag_clear(unsigned int flag, struct request_queue *q) { queue_lockdep_assert_held(q); __clear_bit(flag, &q->queue_flags); } #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags) #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags) #define blk_queue_dying(q) test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags) #define blk_queue_dead(q) test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags) #define blk_queue_bypass(q) test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags) #define blk_queue_init_done(q) test_bit(QUEUE_FLAG_INIT_DONE, &(q)->queue_flags) #define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags) #define blk_queue_noxmerges(q) \ test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags) #define blk_queue_nonrot(q) test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags) #define blk_queue_io_stat(q) test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags) #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags) #define blk_queue_stackable(q) \ test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags) #define blk_queue_discard(q) test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags) #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \ test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags)) #define blk_noretry_request(rq) \ ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \ REQ_FAILFAST_DRIVER)) #define blk_account_rq(rq) \ (((rq)->cmd_flags & REQ_STARTED) && \ ((rq)->cmd_type == REQ_TYPE_FS)) #define blk_pm_request(rq) \ ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \ (rq)->cmd_type == REQ_TYPE_PM_RESUME) #define blk_rq_cpu_valid(rq) ((rq)->cpu != -1) #define blk_bidi_rq(rq) ((rq)->next_rq != NULL) /* rq->queuelist of dequeued request must be list_empty() */ #define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist)) #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist) #define rq_data_dir(rq) (((rq)->cmd_flags & 1) != 0) /* * Driver can handle struct request, if it either has an old style * request_fn defined, or is blk-mq based. */ static inline bool queue_is_rq_based(struct request_queue *q) { return q->request_fn || q->mq_ops; } static inline unsigned int blk_queue_cluster(struct request_queue *q) { return q->limits.cluster; } /* * We regard a request as sync, if either a read or a sync write */ static inline bool rw_is_sync(unsigned int rw_flags) { return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC); } static inline bool rq_is_sync(struct request *rq) { return rw_is_sync(rq->cmd_flags); } static inline bool blk_rl_full(struct request_list *rl, bool sync) { unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL; return rl->flags & flag; } static inline void blk_set_rl_full(struct request_list *rl, bool sync) { unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL; rl->flags |= flag; } static inline void blk_clear_rl_full(struct request_list *rl, bool sync) { unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL; rl->flags &= ~flag; } static inline bool rq_mergeable(struct request *rq) { if (rq->cmd_type != REQ_TYPE_FS) return false; if (rq->cmd_flags & REQ_NOMERGE_FLAGS) return false; return true; } static inline bool blk_check_merge_flags(unsigned int flags1, unsigned int flags2) { if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD)) return false; if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE)) return false; if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME)) return false; return true; } static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b) { if (bio_data(a) == bio_data(b)) return true; return false; } /* * q->prep_rq_fn return values */ #define BLKPREP_OK 0 /* serve it */ #define BLKPREP_KILL 1 /* fatal error, kill */ #define BLKPREP_DEFER 2 /* leave on queue */ extern unsigned long blk_max_low_pfn, blk_max_pfn; /* * standard bounce addresses: * * BLK_BOUNCE_HIGH : bounce all highmem pages * BLK_BOUNCE_ANY : don't bounce anything * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary */ #if BITS_PER_LONG == 32 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT) #else #define BLK_BOUNCE_HIGH -1ULL #endif #define BLK_BOUNCE_ANY (-1ULL) #define BLK_BOUNCE_ISA (DMA_BIT_MASK(24)) /* * default timeout for SG_IO if none specified */ #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ) #define BLK_MIN_SG_TIMEOUT (7 * HZ) #ifdef CONFIG_BOUNCE extern int init_emergency_isa_pool(void); extern void blk_queue_bounce(struct request_queue *q, struct bio **bio); #else static inline int init_emergency_isa_pool(void) { return 0; } static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio) { } #endif /* CONFIG_MMU */ struct rq_map_data { struct page **pages; int page_order; int nr_entries; unsigned long offset; int null_mapped; int from_user; }; struct req_iterator { struct bvec_iter iter; struct bio *bio; }; /* This should not be used directly - use rq_for_each_segment */ #define for_each_bio(_bio) \ for (; _bio; _bio = _bio->bi_next) #define __rq_for_each_bio(_bio, rq) \ if ((rq->bio)) \ for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next) #define rq_for_each_segment(bvl, _rq, _iter) \ __rq_for_each_bio(_iter.bio, _rq) \ bio_for_each_segment(bvl, _iter.bio, _iter.iter) #define rq_iter_last(bvec, _iter) \ (_iter.bio->bi_next == NULL && \ bio_iter_last(bvec, _iter.iter)) #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform" #endif #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE extern void rq_flush_dcache_pages(struct request *rq); #else static inline void rq_flush_dcache_pages(struct request *rq) { } #endif extern int blk_register_queue(struct gendisk *disk); extern void blk_unregister_queue(struct gendisk *disk); extern void generic_make_request(struct bio *bio); extern void blk_rq_init(struct request_queue *q, struct request *rq); extern void blk_put_request(struct request *); extern void __blk_put_request(struct request_queue *, struct request *); extern struct request *blk_get_request(struct request_queue *, int, gfp_t); extern struct request *blk_make_request(struct request_queue *, struct bio *, gfp_t); extern void blk_rq_set_block_pc(struct request *); extern void blk_requeue_request(struct request_queue *, struct request *); extern void blk_add_request_payload(struct request *rq, struct page *page, unsigned int len); extern int blk_rq_check_limits(struct request_queue *q, struct request *rq); extern int blk_lld_busy(struct request_queue *q); extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src, struct bio_set *bs, gfp_t gfp_mask, int (*bio_ctr)(struct bio *, struct bio *, void *), void *data); extern void blk_rq_unprep_clone(struct request *rq); extern int blk_insert_cloned_request(struct request_queue *q, struct request *rq); extern void blk_delay_queue(struct request_queue *, unsigned long); extern void blk_recount_segments(struct request_queue *, struct bio *); extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int); extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t, unsigned int, void __user *); extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t, unsigned int, void __user *); extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t, struct scsi_ioctl_command __user *); extern void blk_queue_bio(struct request_queue *q, struct bio *bio); /* * A queue has just exitted congestion. Note this in the global counter of * congested queues, and wake up anyone who was waiting for requests to be * put back. */ static inline void blk_clear_queue_congested(struct request_queue *q, int sync) { clear_bdi_congested(&q->backing_dev_info, sync); } /* * A queue has just entered congestion. Flag that in the queue's VM-visible * state flags and increment the global gounter of congested queues. */ static inline void blk_set_queue_congested(struct request_queue *q, int sync) { set_bdi_congested(&q->backing_dev_info, sync); } extern void blk_start_queue(struct request_queue *q); extern void blk_stop_queue(struct request_queue *q); extern void blk_sync_queue(struct request_queue *q); extern void __blk_stop_queue(struct request_queue *q); extern void __blk_run_queue(struct request_queue *q); extern void blk_run_queue(struct request_queue *); extern void blk_run_queue_async(struct request_queue *q); extern int blk_rq_map_user(struct request_queue *, struct request *, struct rq_map_data *, void __user *, unsigned long, gfp_t); extern int blk_rq_unmap_user(struct bio *); extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t); extern int blk_rq_map_user_iov(struct request_queue *, struct request *, struct rq_map_data *, const struct sg_iovec *, int, unsigned int, gfp_t); extern int blk_execute_rq(struct request_queue *, struct gendisk *, struct request *, int); extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *, struct request *, int, rq_end_io_fn *); static inline struct request_queue *bdev_get_queue(struct block_device *bdev) { return bdev->bd_disk->queue; /* this is never NULL */ } /* * blk_rq_pos() : the current sector * blk_rq_bytes() : bytes left in the entire request * blk_rq_cur_bytes() : bytes left in the current segment * blk_rq_err_bytes() : bytes left till the next error boundary * blk_rq_sectors() : sectors left in the entire request * blk_rq_cur_sectors() : sectors left in the current segment */ static inline sector_t blk_rq_pos(const struct request *rq) { return rq->__sector; } static inline unsigned int blk_rq_bytes(const struct request *rq) { return rq->__data_len; } static inline int blk_rq_cur_bytes(const struct request *rq) { return rq->bio ? bio_cur_bytes(rq->bio) : 0; } extern unsigned int blk_rq_err_bytes(const struct request *rq); static inline unsigned int blk_rq_sectors(const struct request *rq) { return blk_rq_bytes(rq) >> 9; } static inline unsigned int blk_rq_cur_sectors(const struct request *rq) { return blk_rq_cur_bytes(rq) >> 9; } static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q, unsigned int cmd_flags) { if (unlikely(cmd_flags & REQ_DISCARD)) return min(q->limits.max_discard_sectors, UINT_MAX >> 9); if (unlikely(cmd_flags & REQ_WRITE_SAME)) return q->limits.max_write_same_sectors; return q->limits.max_sectors; } /* * Return maximum size of a request at given offset. Only valid for * file system requests. */ static inline unsigned int blk_max_size_offset(struct request_queue *q, sector_t offset) { if (!q->limits.chunk_sectors) return q->limits.max_sectors; return q->limits.chunk_sectors - (offset & (q->limits.chunk_sectors - 1)); } static inline unsigned int blk_rq_get_max_sectors(struct request *rq) { struct request_queue *q = rq->q; if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC)) return q->limits.max_hw_sectors; if (!q->limits.chunk_sectors) return blk_queue_get_max_sectors(q, rq->cmd_flags); return min(blk_max_size_offset(q, blk_rq_pos(rq)), blk_queue_get_max_sectors(q, rq->cmd_flags)); } static inline unsigned int blk_rq_count_bios(struct request *rq) { unsigned int nr_bios = 0; struct bio *bio; __rq_for_each_bio(bio, rq) nr_bios++; return nr_bios; } /* * Request issue related functions. */ extern struct request *blk_peek_request(struct request_queue *q); extern void blk_start_request(struct request *rq); extern struct request *blk_fetch_request(struct request_queue *q); /* * Request completion related functions. * * blk_update_request() completes given number of bytes and updates * the request without completing it. * * blk_end_request() and friends. __blk_end_request() must be called * with the request queue spinlock acquired. * * Several drivers define their own end_request and call * blk_end_request() for parts of the original function. * This prevents code duplication in drivers. */ extern bool blk_update_request(struct request *rq, int error, unsigned int nr_bytes); extern void blk_finish_request(struct request *rq, int error); extern bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes); extern void blk_end_request_all(struct request *rq, int error); extern bool blk_end_request_cur(struct request *rq, int error); extern bool blk_end_request_err(struct request *rq, int error); extern bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes); extern void __blk_end_request_all(struct request *rq, int error); extern bool __blk_end_request_cur(struct request *rq, int error); extern bool __blk_end_request_err(struct request *rq, int error); extern void blk_complete_request(struct request *); extern void __blk_complete_request(struct request *); extern void blk_abort_request(struct request *); extern void blk_unprep_request(struct request *); /* * Access functions for manipulating queue properties */ extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id); extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *); extern struct request_queue *blk_init_allocated_queue(struct request_queue *, request_fn_proc *, spinlock_t *); extern void blk_cleanup_queue(struct request_queue *); extern void blk_queue_make_request(struct request_queue *, make_request_fn *); extern void blk_queue_bounce_limit(struct request_queue *, u64); extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int); extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int); extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int); extern void blk_queue_max_segments(struct request_queue *, unsigned short); extern void blk_queue_max_segment_size(struct request_queue *, unsigned int); extern void blk_queue_max_discard_sectors(struct request_queue *q, unsigned int max_discard_sectors); extern void blk_queue_max_write_same_sectors(struct request_queue *q, unsigned int max_write_same_sectors); extern void blk_queue_logical_block_size(struct request_queue *, unsigned short); extern void blk_queue_physical_block_size(struct request_queue *, unsigned int); extern void blk_queue_alignment_offset(struct request_queue *q, unsigned int alignment); extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min); extern void blk_queue_io_min(struct request_queue *q, unsigned int min); extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt); extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt); extern void blk_set_default_limits(struct queue_limits *lim); extern void blk_set_stacking_limits(struct queue_limits *lim); extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, sector_t offset); extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev, sector_t offset); extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, sector_t offset); extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b); extern void blk_queue_dma_pad(struct request_queue *, unsigned int); extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int); extern int blk_queue_dma_drain(struct request_queue *q, dma_drain_needed_fn *dma_drain_needed, void *buf, unsigned int size); extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn); extern void blk_queue_segment_boundary(struct request_queue *, unsigned long); extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn); extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn); extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *); extern void blk_queue_dma_alignment(struct request_queue *, int); extern void blk_queue_update_dma_alignment(struct request_queue *, int); extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *); extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *); extern void blk_queue_rq_timeout(struct request_queue *, unsigned int); extern void blk_queue_flush(struct request_queue *q, unsigned int flush); extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable); extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio, struct scatterlist *sglist); extern void blk_dump_rq_flags(struct request *, char *); extern long nr_blockdev_pages(void); bool __must_check blk_get_queue(struct request_queue *); struct request_queue *blk_alloc_queue(gfp_t); struct request_queue *blk_alloc_queue_node(gfp_t, int); extern void blk_put_queue(struct request_queue *); /* * block layer runtime pm functions */ #ifdef CONFIG_PM_RUNTIME extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev); extern int blk_pre_runtime_suspend(struct request_queue *q); extern void blk_post_runtime_suspend(struct request_queue *q, int err); extern void blk_pre_runtime_resume(struct request_queue *q); extern void blk_post_runtime_resume(struct request_queue *q, int err); #else static inline void blk_pm_runtime_init(struct request_queue *q, struct device *dev) {} static inline int blk_pre_runtime_suspend(struct request_queue *q) { return -ENOSYS; } static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {} static inline void blk_pre_runtime_resume(struct request_queue *q) {} static inline void blk_post_runtime_resume(struct request_queue *q, int err) {} #endif /* * blk_plug permits building a queue of related requests by holding the I/O * fragments for a short period. This allows merging of sequential requests * into single larger request. As the requests are moved from a per-task list to * the device's request_queue in a batch, this results in improved scalability * as the lock contention for request_queue lock is reduced. * * It is ok not to disable preemption when adding the request to the plug list * or when attempting a merge, because blk_schedule_flush_list() will only flush * the plug list when the task sleeps by itself. For details, please see * schedule() where blk_schedule_flush_plug() is called. */ struct blk_plug { struct list_head list; /* requests */ struct list_head mq_list; /* blk-mq requests */ struct list_head cb_list; /* md requires an unplug callback */ }; #define BLK_MAX_REQUEST_COUNT 16 struct blk_plug_cb; typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool); struct blk_plug_cb { struct list_head list; blk_plug_cb_fn callback; void *data; }; extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, int size); extern void blk_start_plug(struct blk_plug *); extern void blk_finish_plug(struct blk_plug *); extern void blk_flush_plug_list(struct blk_plug *, bool); static inline void blk_flush_plug(struct task_struct *tsk) { struct blk_plug *plug = tsk->plug; if (plug) blk_flush_plug_list(plug, false); } static inline void blk_schedule_flush_plug(struct task_struct *tsk) { struct blk_plug *plug = tsk->plug; if (plug) blk_flush_plug_list(plug, true); } static inline bool blk_needs_flush_plug(struct task_struct *tsk) { struct blk_plug *plug = tsk->plug; return plug && (!list_empty(&plug->list) || !list_empty(&plug->mq_list) || !list_empty(&plug->cb_list)); } /* * tag stuff */ #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED) extern int blk_queue_start_tag(struct request_queue *, struct request *); extern struct request *blk_queue_find_tag(struct request_queue *, int); extern void blk_queue_end_tag(struct request_queue *, struct request *); extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *); extern void blk_queue_free_tags(struct request_queue *); extern int blk_queue_resize_tags(struct request_queue *, int); extern void blk_queue_invalidate_tags(struct request_queue *); extern struct blk_queue_tag *blk_init_tags(int); extern void blk_free_tags(struct blk_queue_tag *); static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt, int tag) { if (unlikely(bqt == NULL || tag >= bqt->real_max_depth)) return NULL; return bqt->tag_index[tag]; } #define BLKDEV_DISCARD_SECURE 0x01 /* secure discard */ extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *); extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, unsigned long flags); extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, struct page *page); extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask); static inline int sb_issue_discard(struct super_block *sb, sector_t block, sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags) { return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9), nr_blocks << (sb->s_blocksize_bits - 9), gfp_mask, flags); } static inline int sb_issue_zeroout(struct super_block *sb, sector_t block, sector_t nr_blocks, gfp_t gfp_mask) { return blkdev_issue_zeroout(sb->s_bdev, block << (sb->s_blocksize_bits - 9), nr_blocks << (sb->s_blocksize_bits - 9), gfp_mask); } extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm); enum blk_default_limits { BLK_MAX_SEGMENTS = 128, BLK_SAFE_MAX_SECTORS = 255, BLK_DEF_MAX_SECTORS = 1024, BLK_MAX_SEGMENT_SIZE = 65536, BLK_SEG_BOUNDARY_MASK = 0xFFFFFFFFUL, }; #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist) static inline unsigned long queue_bounce_pfn(struct request_queue *q) { return q->limits.bounce_pfn; } static inline unsigned long queue_segment_boundary(struct request_queue *q) { return q->limits.seg_boundary_mask; } static inline unsigned int queue_max_sectors(struct request_queue *q) { return q->limits.max_sectors; } static inline unsigned int queue_max_hw_sectors(struct request_queue *q) { return q->limits.max_hw_sectors; } static inline unsigned short queue_max_segments(struct request_queue *q) { return q->limits.max_segments; } static inline unsigned int queue_max_segment_size(struct request_queue *q) { return q->limits.max_segment_size; } static inline unsigned short queue_logical_block_size(struct request_queue *q) { int retval = 512; if (q && q->limits.logical_block_size) retval = q->limits.logical_block_size; return retval; } static inline unsigned short bdev_logical_block_size(struct block_device *bdev) { return queue_logical_block_size(bdev_get_queue(bdev)); } static inline unsigned int queue_physical_block_size(struct request_queue *q) { return q->limits.physical_block_size; } static inline unsigned int bdev_physical_block_size(struct block_device *bdev) { return queue_physical_block_size(bdev_get_queue(bdev)); } static inline unsigned int queue_io_min(struct request_queue *q) { return q->limits.io_min; } static inline int bdev_io_min(struct block_device *bdev) { return queue_io_min(bdev_get_queue(bdev)); } static inline unsigned int queue_io_opt(struct request_queue *q) { return q->limits.io_opt; } static inline int bdev_io_opt(struct block_device *bdev) { return queue_io_opt(bdev_get_queue(bdev)); } static inline int queue_alignment_offset(struct request_queue *q) { if (q->limits.misaligned) return -1; return q->limits.alignment_offset; } static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector) { unsigned int granularity = max(lim->physical_block_size, lim->io_min); unsigned int alignment = sector_div(sector, granularity >> 9) << 9; return (granularity + lim->alignment_offset - alignment) % granularity; } static inline int bdev_alignment_offset(struct block_device *bdev) { struct request_queue *q = bdev_get_queue(bdev); if (q->limits.misaligned) return -1; if (bdev != bdev->bd_contains) return bdev->bd_part->alignment_offset; return q->limits.alignment_offset; } static inline int queue_discard_alignment(struct request_queue *q) { if (q->limits.discard_misaligned) return -1; return q->limits.discard_alignment; } static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector) { unsigned int alignment, granularity, offset; if (!lim->max_discard_sectors) return 0; /* Why are these in bytes, not sectors? */ alignment = lim->discard_alignment >> 9; granularity = lim->discard_granularity >> 9; if (!granularity) return 0; /* Offset of the partition start in 'granularity' sectors */ offset = sector_div(sector, granularity); /* And why do we do this modulus *again* in blkdev_issue_discard()? */ offset = (granularity + alignment - offset) % granularity; /* Turn it back into bytes, gaah */ return offset << 9; } static inline int bdev_discard_alignment(struct block_device *bdev) { struct request_queue *q = bdev_get_queue(bdev); if (bdev != bdev->bd_contains) return bdev->bd_part->discard_alignment; return q->limits.discard_alignment; } static inline unsigned int queue_discard_zeroes_data(struct request_queue *q) { if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1) return 1; return 0; } static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev) { return queue_discard_zeroes_data(bdev_get_queue(bdev)); } static inline unsigned int bdev_write_same(struct block_device *bdev) { struct request_queue *q = bdev_get_queue(bdev); if (q) return q->limits.max_write_same_sectors; return 0; } static inline int queue_dma_alignment(struct request_queue *q) { return q ? q->dma_alignment : 511; } static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr, unsigned int len) { unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask; return !(addr & alignment) && !(len & alignment); } /* assumes size > 256 */ static inline unsigned int blksize_bits(unsigned int size) { unsigned int bits = 8; do { bits++; size >>= 1; } while (size > 256); return bits; } static inline unsigned int block_size(struct block_device *bdev) { return bdev->bd_block_size; } static inline bool queue_flush_queueable(struct request_queue *q) { return !q->flush_not_queueable; } typedef struct {struct page *v;} Sector; unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *); static inline void put_dev_sector(Sector p) { page_cache_release(p.v); } struct work_struct; int kblockd_schedule_work(struct work_struct *work); int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay); int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay); #ifdef CONFIG_BLK_CGROUP /* * This should not be using sched_clock(). A real patch is in progress * to fix this up, until that is in place we need to disable preemption * around sched_clock() in this function and set_io_start_time_ns(). */ static inline void set_start_time_ns(struct request *req) { preempt_disable(); req->start_time_ns = sched_clock(); preempt_enable(); } static inline void set_io_start_time_ns(struct request *req) { preempt_disable(); req->io_start_time_ns = sched_clock(); preempt_enable(); } static inline uint64_t rq_start_time_ns(struct request *req) { return req->start_time_ns; } static inline uint64_t rq_io_start_time_ns(struct request *req) { return req->io_start_time_ns; } #else static inline void set_start_time_ns(struct request *req) {} static inline void set_io_start_time_ns(struct request *req) {} static inline uint64_t rq_start_time_ns(struct request *req) { return 0; } static inline uint64_t rq_io_start_time_ns(struct request *req) { return 0; } #endif #define MODULE_ALIAS_BLOCKDEV(major,minor) \ MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor)) #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \ MODULE_ALIAS("block-major-" __stringify(major) "-*") #if defined(CONFIG_BLK_DEV_INTEGRITY) enum blk_integrity_flags { BLK_INTEGRITY_VERIFY = 1 << 0, BLK_INTEGRITY_GENERATE = 1 << 1, BLK_INTEGRITY_DEVICE_CAPABLE = 1 << 2, BLK_INTEGRITY_IP_CHECKSUM = 1 << 3, }; struct blk_integrity_iter { void *prot_buf; void *data_buf; sector_t seed; unsigned int data_size; unsigned short interval; const char *disk_name; }; typedef int (integrity_processing_fn) (struct blk_integrity_iter *); struct blk_integrity { integrity_processing_fn *generate_fn; integrity_processing_fn *verify_fn; unsigned short flags; unsigned short tuple_size; unsigned short interval; unsigned short tag_size; const char *name; struct kobject kobj; }; extern bool blk_integrity_is_initialized(struct gendisk *); extern int blk_integrity_register(struct gendisk *, struct blk_integrity *); extern void blk_integrity_unregister(struct gendisk *); extern int blk_integrity_compare(struct gendisk *, struct gendisk *); extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *, struct scatterlist *); extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *); extern bool blk_integrity_merge_rq(struct request_queue *, struct request *, struct request *); extern bool blk_integrity_merge_bio(struct request_queue *, struct request *, struct bio *); static inline struct blk_integrity *bdev_get_integrity(struct block_device *bdev) { return bdev->bd_disk->integrity; } static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk) { return disk->integrity; } static inline bool blk_integrity_rq(struct request *rq) { return rq->cmd_flags & REQ_INTEGRITY; } static inline void blk_queue_max_integrity_segments(struct request_queue *q, unsigned int segs) { q->limits.max_integrity_segments = segs; } static inline unsigned short queue_max_integrity_segments(struct request_queue *q) { return q->limits.max_integrity_segments; } #else /* CONFIG_BLK_DEV_INTEGRITY */ struct bio; struct block_device; struct gendisk; struct blk_integrity; static inline int blk_integrity_rq(struct request *rq) { return 0; } static inline int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *b) { return 0; } static inline int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *b, struct scatterlist *s) { return 0; } static inline struct blk_integrity *bdev_get_integrity(struct block_device *b) { return NULL; } static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk) { return NULL; } static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b) { return 0; } static inline int blk_integrity_register(struct gendisk *d, struct blk_integrity *b) { return 0; } static inline void blk_integrity_unregister(struct gendisk *d) { } static inline void blk_queue_max_integrity_segments(struct request_queue *q, unsigned int segs) { } static inline unsigned short queue_max_integrity_segments(struct request_queue *q) { return 0; } static inline bool blk_integrity_merge_rq(struct request_queue *rq, struct request *r1, struct request *r2) { return true; } static inline bool blk_integrity_merge_bio(struct request_queue *rq, struct request *r, struct bio *b) { return true; } static inline bool blk_integrity_is_initialized(struct gendisk *g) { return 0; } #endif /* CONFIG_BLK_DEV_INTEGRITY */ struct block_device_operations { int (*open) (struct block_device *, fmode_t); void (*release) (struct gendisk *, fmode_t); int (*rw_page)(struct block_device *, sector_t, struct page *, int rw); int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long); int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long); int (*direct_access) (struct block_device *, sector_t, void **, unsigned long *); unsigned int (*check_events) (struct gendisk *disk, unsigned int clearing); /* ->media_changed() is DEPRECATED, use ->check_events() instead */ int (*media_changed) (struct gendisk *); void (*unlock_native_capacity) (struct gendisk *); int (*revalidate_disk) (struct gendisk *); int (*getgeo)(struct block_device *, struct hd_geometry *); /* this callback is with swap_lock and sometimes page table lock held */ void (*swap_slot_free_notify) (struct block_device *, unsigned long); struct module *owner; }; extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int, unsigned long); extern int bdev_read_page(struct block_device *, sector_t, struct page *); extern int bdev_write_page(struct block_device *, sector_t, struct page *, struct writeback_control *); #else /* CONFIG_BLOCK */ struct block_device; /* * stubs for when the block layer is configured out */ #define buffer_heads_over_limit 0 static inline long nr_blockdev_pages(void) { return 0; } struct blk_plug { }; static inline void blk_start_plug(struct blk_plug *plug) { } static inline void blk_finish_plug(struct blk_plug *plug) { } static inline void blk_flush_plug(struct task_struct *task) { } static inline void blk_schedule_flush_plug(struct task_struct *task) { } static inline bool blk_needs_flush_plug(struct task_struct *tsk) { return false; } static inline int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask, sector_t *error_sector) { return 0; } #endif /* CONFIG_BLOCK */ #endif