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| author | Jens Axboe <axboe@fb.com> | 2016-04-12 12:32:46 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2016-04-12 15:46:27 -0600 |
| commit | 93e9d8e836cb1a9a58b33eb6643bf061c6119ef2 (patch) | |
| tree | 17a50abdadaa58686983510230932323bf5d123c /include/linux/blkdev.h | |
| parent | e0489487ec9cd79ee1fa0dc5d3789c08b0e51a2c (diff) | |
| download | blackbird-obmc-linux-93e9d8e836cb1a9a58b33eb6643bf061c6119ef2.tar.gz blackbird-obmc-linux-93e9d8e836cb1a9a58b33eb6643bf061c6119ef2.zip | |
block: add ability to flag write back caching on a device
Add an internal helper and flag for setting whether a queue has
write back caching, or write through (or none). Add a sysfs file
to show this as well, and make it changeable from user space.
This will replace the (awkward) blk_queue_flush() interface that
drivers currently use to inform the block layer of write cache state
and capabilities.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'include/linux/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index bbaa76757018..ba72687c5654 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -491,6 +491,8 @@ struct request_queue { #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_POLL 22 /* IO polling enabled if set */ +#define QUEUE_FLAG_WC 23 /* Write back caching */ +#define QUEUE_FLAG_FUA 24 /* device supports FUA writes */ #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_STACKABLE) | \ @@ -1009,6 +1011,7 @@ 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 void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fua); 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 *); |
