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| author | Dennis Zhou <dennis@kernel.org> | 2018-10-20 14:56:12 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-10-20 15:39:55 -0600 |
| commit | d459d853c2edc793135e4bfa4e345c758f1cc859 (patch) | |
| tree | bef29425e5ddb78a788cca764e926b4f5601f473 | |
| parent | b2c3fa546705944e748666b474ffdaebaec0569f (diff) | |
| download | linux-d459d853c2edc793135e4bfa4e345c758f1cc859.tar.gz linux-d459d853c2edc793135e4bfa4e345c758f1cc859.tar.bz2 linux-d459d853c2edc793135e4bfa4e345c758f1cc859.zip | |
blkcg: reassociate bios when make_request() is called recursively
When submitting a bio, multiple recursive calls to make_request() may
occur. This causes the initial associate done in blkcg_bio_issue_check()
to be incorrect and reference the prior request_queue. This introduces
a helper to do reassociation when make_request() is recursively called.
Fixes: a7b39b4e961c ("blkcg: always associate a bio with a blkg")
Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Tested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/bio.c | 20 | ||||
| -rw-r--r-- | block/blk-core.c | 1 | ||||
| -rw-r--r-- | include/linux/bio.h | 3 |
3 files changed, 24 insertions, 0 deletions
diff --git a/block/bio.c b/block/bio.c index 17a8b0aa7050..bbfeb4ee2892 100644 --- a/block/bio.c +++ b/block/bio.c @@ -2084,6 +2084,26 @@ int bio_associate_create_blkg(struct request_queue *q, struct bio *bio) } /** + * bio_reassociate_blkg - reassociate a bio with a blkg from q + * @q: request_queue where bio is going + * @bio: target bio + * + * When submitting a bio, multiple recursive calls to make_request() may occur. + * This causes the initial associate done in blkcg_bio_issue_check() to be + * incorrect and reference the prior request_queue. This performs reassociation + * when this situation happens. + */ +int bio_reassociate_blkg(struct request_queue *q, struct bio *bio) +{ + if (bio->bi_blkg) { + blkg_put(bio->bi_blkg); + bio->bi_blkg = NULL; + } + + return bio_associate_create_blkg(q, bio); +} + +/** * bio_disassociate_task - undo bio_associate_current() * @bio: target bio */ diff --git a/block/blk-core.c b/block/blk-core.c index cdfabc5646da..3ed60723e242 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2433,6 +2433,7 @@ blk_qc_t generic_make_request(struct bio *bio) if (q) blk_queue_exit(q); q = bio->bi_disk->queue; + bio_reassociate_blkg(q, bio); flags = 0; if (bio->bi_opf & REQ_NOWAIT) flags = BLK_MQ_REQ_NOWAIT; diff --git a/include/linux/bio.h b/include/linux/bio.h index f447b0ebb288..b47c7f716731 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -514,6 +514,7 @@ int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg); int bio_associate_blkg_from_css(struct bio *bio, struct cgroup_subsys_state *css); int bio_associate_create_blkg(struct request_queue *q, struct bio *bio); +int bio_reassociate_blkg(struct request_queue *q, struct bio *bio); void bio_disassociate_task(struct bio *bio); void bio_clone_blkg_association(struct bio *dst, struct bio *src); #else /* CONFIG_BLK_CGROUP */ @@ -522,6 +523,8 @@ static inline int bio_associate_blkg_from_css(struct bio *bio, { return 0; } static inline int bio_associate_create_blkg(struct request_queue *q, struct bio *bio) { return 0; } +static inline int bio_reassociate_blkg(struct request_queue *q, struct bio *bio) +{ return 0; } static inline void bio_disassociate_task(struct bio *bio) { } static inline void bio_clone_blkg_association(struct bio *dst, struct bio *src) { } |