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| author | Jens Axboe <axboe@fb.com> | 2014-12-15 08:30:26 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-12-15 08:30:26 -0700 |
| commit | 35d37c66356eed46700e0d5db87211844d43a241 (patch) | |
| tree | 6bfdbddaf04501ac9edcf6c526e1e54dd00444b8 | |
| parent | 67e2c3883828b39548cee2091b36656787775d95 (diff) | |
| download | linux-35d37c66356eed46700e0d5db87211844d43a241.tar.bz2 | |
Revert "blk-mq: Micro-optimize bt_get()"
This reverts commit 52f7eb945f2ba62b324bb9ae16d945326a961dcf.
The optimization is only really safe for a single queue, otherwise
'bs' and 'bt' can indeed change, and if we don't do a finish_wait()
for each loop, we'll potentially change the wait structure and
corrupt task wait list.
Reported-by: Jan Kara <jack@suse.cz>
| -rw-r--r-- | block/blk-mq-tag.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index e3d4e4043b49..32e8dbb9ad1c 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -248,8 +248,8 @@ static int bt_get(struct blk_mq_alloc_data *data, if (!(data->gfp & __GFP_WAIT)) return -1; + bs = bt_wait_ptr(bt, hctx); do { - bs = bt_wait_ptr(bt, hctx); prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE); tag = __bt_get(hctx, bt, last_tag); @@ -285,6 +285,8 @@ static int bt_get(struct blk_mq_alloc_data *data, hctx = data->hctx; bt = &hctx->tags->bitmap_tags; } + finish_wait(&bs->wait, &wait); + bs = bt_wait_ptr(bt, hctx); } while (1); finish_wait(&bs->wait, &wait); |