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author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-04 11:16:35 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-04 11:16:35 -0800 |
commit | 64b28683deba132f301d1cecfc25c32e295f53a1 (patch) | |
tree | be38a4e77c530fb129339f983a9d307c60312df8 /block/blk-merge.c | |
parent | Merge tag 'ntb-4.16' of git://github.com/jonmason/ntb (diff) | |
parent | block: skd: fix incorrect linux/slab_def.h inclusion (diff) | |
download | linux-dev-64b28683deba132f301d1cecfc25c32e295f53a1.tar.xz linux-dev-64b28683deba132f301d1cecfc25c32e295f53a1.zip |
Merge tag 'for-linus-20180204' of git://git.kernel.dk/linux-block
Pull more block updates from Jens Axboe:
"Most of this is fixes and not new code/features:
- skd fix from Arnd, fixing a build error dependent on sla allocator
type.
- blk-mq scheduler discard merging fixes, one from me and one from
Keith. This fixes a segment miscalculation for blk-mq-sched, where
we mistakenly think two segments are physically contigious even
though the request isn't carrying real data. Also fixes a bio-to-rq
merge case.
- Don't re-set a bit on the buffer_head flags, if it's already set.
This can cause scalability concerns on bigger machines and
workloads. From Kemi Wang.
- Add BLK_STS_DEV_RESOURCE return value to blk-mq, allowing us to
distuingish between a local (device related) resource starvation
and a global one. The latter might happen without IO being in
flight, so it has to be handled a bit differently. From Ming"
* tag 'for-linus-20180204' of git://git.kernel.dk/linux-block:
block: skd: fix incorrect linux/slab_def.h inclusion
buffer: Avoid setting buffer bits that are already set
blk-mq-sched: Enable merging discard bio into request
blk-mq: fix discard merge with scheduler attached
blk-mq: introduce BLK_STS_DEV_RESOURCE
Diffstat (limited to 'block/blk-merge.c')
-rw-r--r-- | block/blk-merge.c | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index 8452fc7164cc..782940c65d8a 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -550,6 +550,24 @@ static bool req_no_special_merge(struct request *req) return !q->mq_ops && req->special; } +static bool req_attempt_discard_merge(struct request_queue *q, struct request *req, + struct request *next) +{ + unsigned short segments = blk_rq_nr_discard_segments(req); + + if (segments >= queue_max_discard_segments(q)) + goto no_merge; + if (blk_rq_sectors(req) + bio_sectors(next->bio) > + blk_rq_get_max_sectors(req, blk_rq_pos(req))) + goto no_merge; + + req->nr_phys_segments = segments + blk_rq_nr_discard_segments(next); + return true; +no_merge: + req_set_nomerge(q, req); + return false; +} + static int ll_merge_requests_fn(struct request_queue *q, struct request *req, struct request *next) { @@ -683,9 +701,13 @@ static struct request *attempt_merge(struct request_queue *q, * If we are allowed to merge, then append bio list * from next to rq and release next. merge_requests_fn * will have updated segment counts, update sector - * counts here. + * counts here. Handle DISCARDs separately, as they + * have separate settings. */ - if (!ll_merge_requests_fn(q, req, next)) + if (req_op(req) == REQ_OP_DISCARD) { + if (!req_attempt_discard_merge(q, req, next)) + return NULL; + } else if (!ll_merge_requests_fn(q, req, next)) return NULL; /* @@ -715,7 +737,8 @@ static struct request *attempt_merge(struct request_queue *q, req->__data_len += blk_rq_bytes(next); - elv_merge_requests(q, req, next); + if (req_op(req) != REQ_OP_DISCARD) + elv_merge_requests(q, req, next); /* * 'next' is going away, so update stats accordingly |