From ee1b6f7aff94019c09e73837054979063f722046 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 15 Jan 2015 17:32:25 -0800 Subject: block: support different tag allocation policy The libata tag allocation is using a round-robin policy. Next patch will make libata use block generic tag allocation, so let's add a policy to tag allocation. Currently two policies: FIFO (default) and round-robin. Cc: Jens Axboe Cc: Tejun Heo Cc: Christoph Hellwig Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'include/linux/blkdev.h') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 4c4b732d7556..6f388fd1c11c 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -272,7 +272,11 @@ struct blk_queue_tag { 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 */ + int alloc_policy; /* tag allocation policy */ + int next_tag; /* next tag */ }; +#define BLK_TAG_ALLOC_FIFO 0 /* allocate starting from 0 */ +#define BLK_TAG_ALLOC_RR 1 /* allocate starting from last allocated tag */ #define BLK_SCSI_MAX_CMDS (256) #define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8)) @@ -1139,11 +1143,11 @@ static inline bool blk_needs_flush_plug(struct task_struct *tsk) 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 int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int); 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 struct blk_queue_tag *blk_init_tags(int, int); extern void blk_free_tags(struct blk_queue_tag *); static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt, -- cgit v1.2.3