diff options
| author | Ming Lei <ming.lei@redhat.com> | 2021-07-29 05:42:26 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-08-09 22:37:47 +0200 |
| commit | 866663b7b52d2da267b28e12eed89ee781b8fed1 (patch) | |
| tree | dffdcd640e5dc188e662a604cffaa68daa54d349 /include | |
| parent | block: remove the bd_bdi in struct block_device (diff) | |
| download | linux-866663b7b52d2da267b28e12eed89ee781b8fed1.tar.xz linux-866663b7b52d2da267b28e12eed89ee781b8fed1.zip | |
block: return ELEVATOR_DISCARD_MERGE if possible
When merging one bio to request, if they are discard IO and the queue
supports multi-range discard, we need to return ELEVATOR_DISCARD_MERGE
because both block core and related drivers(nvme, virtio-blk) doesn't
handle mixed discard io merge(traditional IO merge together with
discard merge) well.
Fix the issue by returning ELEVATOR_DISCARD_MERGE in this situation,
so both blk-mq and drivers just need to handle multi-range discard.
Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Fixes: 2705dfb20947 ("block: fix discard request merge")
Link: https://lore.kernel.org/r/20210729034226.1591070-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blkdev.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 23e1253a8d88..07eef02325b4 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1519,6 +1519,22 @@ static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector return offset << SECTOR_SHIFT; } +/* + * Two cases of handling DISCARD merge: + * If max_discard_segments > 1, the driver takes every bio + * as a range and send them to controller together. The ranges + * needn't to be contiguous. + * Otherwise, the bios/requests will be handled as same as + * others which should be contiguous. + */ +static inline bool blk_discard_mergable(struct request *req) +{ + if (req_op(req) == REQ_OP_DISCARD && + queue_max_discard_segments(req->q) > 1) + return true; + return false; +} + static inline int bdev_discard_alignment(struct block_device *bdev) { struct request_queue *q = bdev_get_queue(bdev); |