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| author | Jens Axboe <axboe@suse.de> | 2006-02-04 23:27:38 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-02-05 11:06:51 -0800 |
| commit | 9a7a67af8bb02106f0fb01dd9d237332f874be9a (patch) | |
| tree | 6ad56122d38d118e6d53caa94a60037291294a25 /block/ll_rw_blk.c | |
| parent | 88a2a4ac6b671a4b0dd5d2d762418904c05f4104 (diff) | |
| download | linux-9a7a67af8bb02106f0fb01dd9d237332f874be9a.tar.gz linux-9a7a67af8bb02106f0fb01dd9d237332f874be9a.tar.bz2 linux-9a7a67af8bb02106f0fb01dd9d237332f874be9a.zip | |
[PATCH] fix ordering on requeued request drainage
Previously, if a fs request which was being drained failed and got
requeued, blk_do_ordered() didn't allow it to be reissued, which causes
queue stall. This patch makes blk_do_ordered() use the sequence of each
request to determine whether a request can be issued or not. This fixes
the bug and simplifies code.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'block/ll_rw_blk.c')
| -rw-r--r-- | block/ll_rw_blk.c | 38 |
1 files changed, 16 insertions, 22 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index e5aad8314585..ee5ed98db4cd 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -508,7 +508,7 @@ static inline struct request *start_ordered(request_queue_t *q, int blk_do_ordered(request_queue_t *q, struct request **rqp) { - struct request *rq = *rqp, *allowed_rq; + struct request *rq = *rqp; int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq); if (!q->ordseq) { @@ -532,32 +532,26 @@ int blk_do_ordered(request_queue_t *q, struct request **rqp) } } + /* + * Ordered sequence in progress + */ + + /* Special requests are not subject to ordering rules. */ + if (!blk_fs_request(rq) && + rq != &q->pre_flush_rq && rq != &q->post_flush_rq) + return 1; + if (q->ordered & QUEUE_ORDERED_TAG) { + /* Ordered by tag. Blocking the next barrier is enough. */ if (is_barrier && rq != &q->bar_rq) *rqp = NULL; - return 1; + } else { + /* Ordered by draining. Wait for turn. */ + WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q)); + if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q)) + *rqp = NULL; } - switch (blk_ordered_cur_seq(q)) { - case QUEUE_ORDSEQ_PREFLUSH: - allowed_rq = &q->pre_flush_rq; - break; - case QUEUE_ORDSEQ_BAR: - allowed_rq = &q->bar_rq; - break; - case QUEUE_ORDSEQ_POSTFLUSH: - allowed_rq = &q->post_flush_rq; - break; - default: - allowed_rq = NULL; - break; - } - - if (rq != allowed_rq && - (blk_fs_request(rq) || rq == &q->pre_flush_rq || - rq == &q->post_flush_rq)) - *rqp = NULL; - return 1; } |