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| author | Ming Lei <ming.lei@canonical.com> | 2014-09-02 23:02:59 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-09-02 10:25:12 -0600 |
| commit | 0738854939e6ec9b9111a8cfc0ca1dfa3cff6b2e (patch) | |
| tree | 617923e115af85896590d7ff7ba96baf16f4399f /block/blk-merge.c | |
| parent | 7505ceaf863590b24a4c0c83b64817d26e0d51e3 (diff) | |
| download | linux-0738854939e6ec9b9111a8cfc0ca1dfa3cff6b2e.tar.gz | |
blk-merge: fix blk_recount_segments
QUEUE_FLAG_NO_SG_MERGE is set at default for blk-mq devices, so bio->bi_phys_segment computed may be bigger than queue_max_segments(q) for blk-mq devices, then drivers will fail to handle the case, for example, BUG_ON() in virtio_queue_rq() can be triggerd for virtio-blk: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1359146 This patch fixes the issue by ignoring the QUEUE_FLAG_NO_SG_MERGE flag if the computed bio->bi_phys_segment is bigger than queue_max_segments(q), and the regression is caused by commit 05f1dd53152173(block: add queue flag for disabling SG merging). Reported-by: Kick In <pierre-andre.morey@canonical.com> Tested-by: Chris J Arges <chris.j.arges@canonical.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-merge.c')
| -rw-r--r-- | block/blk-merge.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index 54535831f1e1..77881798f793 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -10,10 +10,11 @@ #include "blk.h" static unsigned int __blk_recalc_rq_segments(struct request_queue *q, - struct bio *bio) + struct bio *bio, + bool no_sg_merge) { struct bio_vec bv, bvprv = { NULL }; - int cluster, high, highprv = 1, no_sg_merge; + int cluster, high, highprv = 1; unsigned int seg_size, nr_phys_segs; struct bio *fbio, *bbio; struct bvec_iter iter; @@ -35,7 +36,6 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, cluster = blk_queue_cluster(q); seg_size = 0; nr_phys_segs = 0; - no_sg_merge = test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags); high = 0; for_each_bio(bio) { bio_for_each_segment(bv, bio, iter) { @@ -88,18 +88,23 @@ new_segment: void blk_recalc_rq_segments(struct request *rq) { - rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio); + bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE, + &rq->q->queue_flags); + + rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio, + no_sg_merge); } void blk_recount_segments(struct request_queue *q, struct bio *bio) { - if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags)) + if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) && + bio->bi_vcnt < queue_max_segments(q)) bio->bi_phys_segments = bio->bi_vcnt; else { struct bio *nxt = bio->bi_next; bio->bi_next = NULL; - bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio); + bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, false); bio->bi_next = nxt; } |