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: a7b39b4e96
("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>
This commit is contained in:
parent
b2c3fa5467
commit
d459d853c2
20
block/bio.c
20
block/bio.c
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@ -2083,6 +2083,26 @@ int bio_associate_create_blkg(struct request_queue *q, struct bio *bio)
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return ret;
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}
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/**
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* bio_reassociate_blkg - reassociate a bio with a blkg from q
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* @q: request_queue where bio is going
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* @bio: target bio
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*
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* When submitting a bio, multiple recursive calls to make_request() may occur.
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* This causes the initial associate done in blkcg_bio_issue_check() to be
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* incorrect and reference the prior request_queue. This performs reassociation
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* when this situation happens.
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*/
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int bio_reassociate_blkg(struct request_queue *q, struct bio *bio)
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{
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if (bio->bi_blkg) {
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blkg_put(bio->bi_blkg);
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bio->bi_blkg = NULL;
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}
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return bio_associate_create_blkg(q, bio);
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}
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/**
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* bio_disassociate_task - undo bio_associate_current()
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* @bio: target bio
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@ -2433,6 +2433,7 @@ blk_qc_t generic_make_request(struct bio *bio)
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if (q)
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blk_queue_exit(q);
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q = bio->bi_disk->queue;
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bio_reassociate_blkg(q, bio);
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flags = 0;
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if (bio->bi_opf & REQ_NOWAIT)
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flags = BLK_MQ_REQ_NOWAIT;
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@ -514,6 +514,7 @@ int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg);
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int bio_associate_blkg_from_css(struct bio *bio,
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struct cgroup_subsys_state *css);
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int bio_associate_create_blkg(struct request_queue *q, struct bio *bio);
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int bio_reassociate_blkg(struct request_queue *q, struct bio *bio);
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void bio_disassociate_task(struct bio *bio);
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void bio_clone_blkg_association(struct bio *dst, struct bio *src);
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#else /* CONFIG_BLK_CGROUP */
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@ -522,6 +523,8 @@ static inline int bio_associate_blkg_from_css(struct bio *bio,
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{ return 0; }
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static inline int bio_associate_create_blkg(struct request_queue *q,
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struct bio *bio) { return 0; }
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static inline int bio_reassociate_blkg(struct request_queue *q, struct bio *bio)
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{ return 0; }
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static inline void bio_disassociate_task(struct bio *bio) { }
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static inline void bio_clone_blkg_association(struct bio *dst,
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struct bio *src) { }
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