diff options
Diffstat (limited to 'include/linux/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 48 |
1 files changed, 23 insertions, 25 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 0e67c45b3bc..c7a6d3b5bc7 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -14,7 +14,6 @@ #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> @@ -22,6 +21,7 @@ #include <asm/scatterlist.h> +struct module; struct scsi_ioctl_command; struct request_queue; @@ -30,6 +30,7 @@ struct request_pm_state; struct blk_trace; struct request; struct sg_io_hdr; +struct bsg_job; #define BLKDEV_MIN_RQ 4 #define BLKDEV_MAX_RQ 128 /* Default maximum */ @@ -117,6 +118,7 @@ struct request { struct { unsigned int seq; struct list_head list; + rq_end_io_fn *saved_end_io; } flush; }; @@ -193,7 +195,7 @@ struct request_pm_state #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 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 *); @@ -209,6 +211,7 @@ typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *, 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, @@ -375,6 +378,8 @@ struct request_queue { struct mutex sysfs_lock; #if defined(CONFIG_BLK_DEV_BSG) + bsg_job_fn *bsg_job_fn; + int bsg_job_size; struct bsg_class_device bsg_dev; #endif @@ -675,6 +680,8 @@ extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t, 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 @@ -858,17 +865,22 @@ struct request_queue *blk_alloc_queue_node(gfp_t, int); extern void blk_put_queue(struct request_queue *); /* - * Note: Code in between changing the blk_plug list/cb_list or element of such - * lists is preemptable, but such code can't do sleep (or be very careful), - * otherwise data is corrupted. For details, please check schedule() where - * blk_schedule_flush_plug() is called. + * 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 { - unsigned long magic; - struct list_head list; - struct list_head cb_list; - unsigned int should_sort; - unsigned int count; + unsigned long magic; /* detect uninitialized use-cases */ + struct list_head list; /* requests */ + struct list_head cb_list; /* md requires an unplug callback */ + unsigned int should_sort; /* list to be sorted before flushing? */ }; #define BLK_MAX_REQUEST_COUNT 16 @@ -1185,20 +1197,6 @@ static inline uint64_t rq_io_start_time_ns(struct request *req) } #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); -#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; } -#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) \ |