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authorLinus Torvalds <torvalds@linux-foundation.org>2014-12-15 17:25:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-15 17:25:20 -0800
commit9b8ec916df67ba31614796037caf606b763e2e79 (patch)
tree686e3d85b8c5af57d54265354ffab61f4803856e
parent27cb8823e26cecd03c00d82dfb501f6c144b3445 (diff)
parent35d37c66356eed46700e0d5db87211844d43a241 (diff)
Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull core block fix from Jens Axboe: "Jan reported a problem this morning with a crash in blk-mq, and after looking over the recent changes, it's obvious that the blk-mq-tag waitqueue handling change is buggy. We could end up _not_ doing finish_wait() before switching to a new waitqueue, thus corrupting the wait task list" * 'for-linus' of git://git.kernel.dk/linux-block: Revert "blk-mq: Micro-optimize bt_get()"
-rw-r--r--block/blk-mq-tag.c4
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);