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73c1010119
kernel-ark/include/linux/blkdev.h
Jens Axboe 73c1010119 block: initial patch for on-stack per-task plugging 
This patch adds support for creating a queuing context outside
of the queue itself. This enables us to batch up pieces of IO
before grabbing the block device queue lock and submitting them to
the IO scheduler.

The context is created on the stack of the process and assigned in
the task structure, so that we can auto-unplug it if we hit a schedule
event.

The current queue plugging happens implicitly if IO is submitted to
an empty device, yet callers have to remember to unplug that IO when
they are going to wait for it. This is an ugly API and has caused bugs
in the past. Additionally, it requires hacks in the vm (->sync_page()
callback) to handle that logic. By switching to an explicit plugging
scheme we make the API a lot nicer and can get rid of the ->sync_page()
hack in the vm.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-10 08:45:54 +01:00

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#ifndef _LINUX_BLKDEV_H
#define _LINUX_BLKDEV_H
#ifdef CONFIG_BLOCK
#include <linux/sched.h>
#include <linux/major.h>
#include <linux/genhd.h>
#include <linux/list.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/module.h>
#include <linux/stringify.h>
#include <linux/gfp.h>
#include <linux/bsg.h>
#include <linux/smp.h>
#include <asm/scatterlist.h>
struct scsi_ioctl_command;
struct request_queue;
struct elevator_queue;
struct request_pm_state;
struct blk_trace;
struct request;
struct sg_io_hdr;
#define BLKDEV_MIN_RQ 4
#define BLKDEV_MAX_RQ 128 /* Default maximum */
struct request;
typedef void (rq_end_io_fn)(struct request *, int);
struct request_list {
/*
* count[], starved[], and wait[] are indexed by
* BLK_RW_SYNC/BLK_RW_ASYNC
*/
int count[2];
int starved[2];
int elvpriv;
mempool_t *rq_pool;
wait_queue_head_t wait[2];
};
/*
* 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, be sure to check block/blk-core.c:rq_init()
* as well!
*/
struct request {
struct list_head queuelist;
struct call_single_data csd;
struct request_queue *q;
unsigned int 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;
struct hlist_node hash; /* merge hash */
/*
* 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 three elevator_private pointers.
*/
union {
void *elevator_private[3];
struct {
unsigned int seq;
struct list_head list;
} flush;
};
struct gendisk *rq_disk;
struct hd_struct *part;
unsigned long start_time;
#ifdef CONFIG_BLK_CGROUP
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;
int ref_count;
void *special; /* opaque pointer available for LLD use */
char *buffer; /* kaddr of the current segment if available */
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>
typedef void (request_fn_proc) (struct request_queue *q);
typedef int (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 *);
typedef void (unplug_fn) (struct request_queue *);
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);
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 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 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;
signed char discard_zeroes_data;
};
struct request_queue
{
/*
* Together with queue_head for cacheline sharing
*/
struct list_head queue_head;
struct request *last_merge;
struct elevator_queue *elevator;
/*
* the queue request freelist, one for reads and one for writes
*/
struct request_list rq;
request_fn_proc *request_fn;
make_request_fn *make_request_fn;
prep_rq_fn *prep_rq_fn;
unprep_rq_fn *unprep_rq_fn;
unplug_fn *unplug_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;
/*
* Dispatch queue sorting
*/
sector_t end_sector;
struct request *boundary_rq;
/*
* Auto-unplugging state
*/
struct timer_list unplug_timer;
int unplug_thresh; /* After this many requests */
unsigned long unplug_delay; /* After this many jiffies */
struct work_struct unplug_work;
/*
* 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;
/*
* queue needs bounce pages for pages above this limit
*/
gfp_t bounce_gfp;
/*
* various queue flags, see QUEUE_* below
*/
unsigned long queue_flags;
/*
* 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;
/*
* queue settings
*/
unsigned long nr_requests; /* Max # of requests */
unsigned int nr_congestion_on;
unsigned int nr_congestion_off;
unsigned int nr_batching;
void *dma_drain_buffer;
unsigned int dma_drain_size;
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];
unsigned int rq_timeout;
struct timer_list timeout;
struct list_head timeout_list;
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_pending_idx:1;
unsigned int flush_running_idx:1;
unsigned long flush_pending_since;
struct list_head flush_queue[2];
struct list_head flush_data_in_flight;
struct request flush_rq;
struct mutex sysfs_lock;
#if defined(CONFIG_BLK_DEV_BSG)
struct bsg_class_device bsg_dev;
#endif
#ifdef CONFIG_BLK_DEV_THROTTLING
/* Throttle data */
struct throtl_data *td;
#endif
};
#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_DEAD 5 /* queue being torn down */
#define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
#define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
#define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
#define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
#define QUEUE_FLAG_NOMERGES 10 /* disable merge attempts */
#define QUEUE_FLAG_SAME_COMP 11 /* force complete on same CPU */
#define QUEUE_FLAG_FAIL_IO 12 /* fake timeout */
#define QUEUE_FLAG_STACKABLE 13 /* supports request stacking */
#define QUEUE_FLAG_NONROT 14 /* non-rotational device (SSD) */
#define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */
#define QUEUE_FLAG_IO_STAT 15 /* do IO stats */
#define QUEUE_FLAG_DISCARD 16 /* supports DISCARD */
#define QUEUE_FLAG_NOXMERGES 17 /* No extended merges */
#define QUEUE_FLAG_ADD_RANDOM 18 /* Contributes to random pool */
#define QUEUE_FLAG_SECDISCARD 19 /* supports SECDISCARD */
#define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
(1 << QUEUE_FLAG_STACKABLE) | \
(1 << QUEUE_FLAG_SAME_COMP) | \
(1 << QUEUE_FLAG_ADD_RANDOM))
static inline int queue_is_locked(struct request_queue *q)
{
#ifdef CONFIG_SMP
spinlock_t *lock = q->queue_lock;
return lock && spin_is_locked(lock);
#else
return 1;
#endif
}
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)
{
WARN_ON_ONCE(!queue_is_locked(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)
{
WARN_ON_ONCE(!queue_is_locked(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)
{
WARN_ON_ONCE(!queue_is_locked(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)
{
WARN_ON_ONCE(!queue_is_locked(q));
__clear_bit(flag, &q->queue_flags);
}
#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(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_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 || \
((rq)->cmd_flags & REQ_DISCARD)))
#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)
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 int blk_queue_full(struct request_queue *q, int sync)
{
if (sync)
return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
}
static inline void blk_set_queue_full(struct request_queue *q, int sync)
{
if (sync)
queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
else
queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
}
static inline void blk_clear_queue_full(struct request_queue *q, int sync)
{
if (sync)
queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
else
queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
}
/*
* mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
* it already be started by driver.
*/
#define RQ_NOMERGE_FLAGS \
(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
#define rq_mergeable(rq) \
(!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
(((rq)->cmd_flags & REQ_DISCARD) || \
(rq)->cmd_type == REQ_TYPE_FS))
/*
* 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 {
int i;
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.i)
#define rq_iter_last(rq, _iter) \
(_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
#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_insert_request(struct request_queue *, struct request *, int, void *);
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_plug_device(struct request_queue *);
extern void blk_plug_device_unlocked(struct request_queue *);
extern int blk_remove_plug(struct request_queue *);
extern void blk_delay_queue(struct request_queue *, unsigned long);
extern void blk_recount_segments(struct request_queue *, struct bio *);
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 *);
/*
* 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 *);
extern void blk_run_queue(struct request_queue *);
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 *, 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 *);
extern void blk_unplug(struct request_queue *q);
static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
{
return bdev->bd_disk->queue;
}
/*
* 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;
}
/*
* 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 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_abort_queue(struct request_queue *);
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_allocated_queue_node(struct request_queue *,
request_fn_proc *,
spinlock_t *, 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_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_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 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 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 void blk_dump_rq_flags(struct request *, char *);
extern void generic_unplug_device(struct request_queue *);
extern long nr_blockdev_pages(void);
int 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 *);
struct blk_plug {
unsigned long magic;
struct list_head list;
unsigned int should_sort;
};
extern void blk_start_plug(struct blk_plug *);
extern void blk_finish_plug(struct blk_plug *);
extern void __blk_flush_plug(struct task_struct *, struct blk_plug *);
static inline void blk_flush_plug(struct task_struct *tsk)
{
struct blk_plug *plug = tsk->plug;
if (unlikely(plug))
__blk_flush_plug(tsk, plug);
}
static inline bool blk_needs_flush_plug(struct task_struct *tsk)
{
struct blk_plug *plug = tsk->plug;
return plug && !list_empty(&plug->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_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 << 9) & (granularity - 1);
return (granularity + lim->alignment_offset - alignment)
& (granularity - 1);
}
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 = (sector << 9) & (lim->discard_granularity - 1);
return (lim->discard_granularity + lim->discard_alignment - alignment)
& (lim->discard_granularity - 1);
}
static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
{
if (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 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;
}
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 request_queue *q, struct work_struct *work);
int kblockd_schedule_delayed_work(struct request_queue *q, 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
#ifdef CONFIG_BLK_DEV_THROTTLING
extern int blk_throtl_init(struct request_queue *q);
extern void blk_throtl_exit(struct request_queue *q);
extern int blk_throtl_bio(struct request_queue *q, struct bio **bio);
extern void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay);
extern void throtl_shutdown_timer_wq(struct request_queue *q);
#else /* CONFIG_BLK_DEV_THROTTLING */
static inline int blk_throtl_bio(struct request_queue *q, struct bio **bio)
{
return 0;
}
static inline int blk_throtl_init(struct request_queue *q) { return 0; }
static inline int blk_throtl_exit(struct request_queue *q) { return 0; }
static inline void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay) {}
static inline void throtl_shutdown_timer_wq(struct request_queue *q) {}
#endif /* CONFIG_BLK_DEV_THROTTLING */
#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)
#define INTEGRITY_FLAG_READ 2 /* verify data integrity on read */
#define INTEGRITY_FLAG_WRITE 4 /* generate data integrity on write */
struct blk_integrity_exchg {
void *prot_buf;
void *data_buf;
sector_t sector;
unsigned int data_size;
unsigned short sector_size;
const char *disk_name;
};
typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
struct blk_integrity {
integrity_gen_fn *generate_fn;
integrity_vrfy_fn *verify_fn;
integrity_set_tag_fn *set_tag_fn;
integrity_get_tag_fn *get_tag_fn;
unsigned short flags;
unsigned short tuple_size;
unsigned short sector_size;
unsigned short tag_size;
const char *name;
struct kobject kobj;
};
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 int blk_integrity_merge_rq(struct request_queue *, struct request *,
struct request *);
extern int 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 int blk_integrity_rq(struct request *rq)
{
if (rq->bio == NULL)
return 0;
return bio_integrity(rq->bio);
}
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 */
#define blk_integrity_rq(rq) (0)
#define blk_rq_count_integrity_sg(a, b) (0)
#define blk_rq_map_integrity_sg(a, b, c) (0)
#define bdev_get_integrity(a) (0)
#define blk_get_integrity(a) (0)
#define blk_integrity_compare(a, b) (0)
#define blk_integrity_register(a, b) (0)
#define blk_integrity_unregister(a) do { } while (0);
#define blk_queue_max_integrity_segments(a, b) do { } while (0);
#define queue_max_integrity_segments(a) (0)
#define blk_integrity_merge_rq(a, b, c) (0)
#define blk_integrity_merge_bio(a, b, c) (0)
#endif /* CONFIG_BLK_DEV_INTEGRITY */
struct block_device_operations {
int (*open) (struct block_device *, fmode_t);
int (*release) (struct gendisk *, fmode_t);
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);
#else /* CONFIG_BLOCK */
/*
* stubs for when the block layer is configured out
*/
#define buffer_heads_over_limit 0
static inline long nr_blockdev_pages(void)
{
return 0;
}
static inline void blk_start_plug(struct list_head *list)
{
}
static inline void blk_finish_plug(struct list_head *list)
{
}
static inline void blk_flush_plug(struct task_struct *tsk)
{
}
static inline bool blk_needs_flush_plug(struct task_struct *tsk)
{
return false;
}
#endif /* CONFIG_BLOCK */
#endif
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