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| author | Christoph Hellwig | 2015-05-22 15:14:04 +0200 |
|---|---|---|
| committer | Jens Axboe | 2015-05-22 16:58:57 +0200 |
| commit | 5f1b670d0bef508a5554d92525f5f6d00d640b38 (patch) | |
| tree | 18aaa4b5ead87568214b3d9c0f501d8a98c2a787 /include/linux/blkdev.h | |
| parent | block: remove management of bi_remaining when restoring original bi_end_io (diff) | |
| download | kernel-qcow2-linux-5f1b670d0bef508a5554d92525f5f6d00d640b38.tar.gz kernel-qcow2-linux-5f1b670d0bef508a5554d92525f5f6d00d640b38.tar.xz kernel-qcow2-linux-5f1b670d0bef508a5554d92525f5f6d00d640b38.zip | |
block, dm: don't copy bios for request clones
Currently dm-multipath has to clone the bios for every request sent
to the lower devices, which wastes cpu cycles and ties down memory.
This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio
to not complete bios attached to a request, which we set on clone
requests similar to bios in a flush sequence. With this change I/O
errors on a path failure only get propagated to dm-multipath, which
can then either resubmit the I/O or complete the bios on the original
request.
I've done some basic testing of this on a Linux target with ALUA support,
and it survives path failures during I/O nicely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'include/linux/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index bc917956a6d0..9ded80da2c16 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -775,11 +775,7 @@ 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 void blk_rq_prep_clone(struct request *rq, struct request *rq_src); extern int blk_insert_cloned_request(struct request_queue *q, struct request *rq); extern void blk_delay_queue(struct request_queue *, unsigned long); |