diff options
| author | Jens Axboe <jens.axboe@oracle.com> | 2007-10-30 11:18:15 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-11-16 08:12:44 -0800 |
| commit | 0520fb16465a12dda986d51fc7be3eca6e82603b (patch) | |
| tree | 8ae08c4ff48af8606ff423d39088f94f179cfc65 /block | |
| parent | bba9d994eb41060c8a6e09207f659cf4e26e9384 (diff) | |
| download | lwn-0520fb16465a12dda986d51fc7be3eca6e82603b.tar.gz lwn-0520fb16465a12dda986d51fc7be3eca6e82603b.zip | |
BLOCK: Fix bad sharing of tag busy list on queues with shared tag maps
patch 6eca9004dfcb274a502438a591df5b197690afb1 in mainline.
For the locking to work, only the tag map and tag bit map may be shared
(incidentally, I was just explaining this to Nick yesterday, but I
apparently didn't review the code well enough myself). But we also share
the busy list! The busy_list must be queue private, or we need a
block_queue_tag covering lock as well.
So we have to move the busy_list to the queue. This'll work fine, and
it'll actually also fix a problem with blk_queue_invalidate_tags() which
will invalidate tags across all shared queues. This is a bit confusing,
the low level driver should call it for each queue seperately since
otherwise you cannot kill tags on just a single queue for eg a hard
drive that stops responding. Since the function has no callers
currently, it's not an issue.
This is fixed with commit 6eca9004dfcb274a502438a591df5b197690afb1 in
Linus' tree.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'block')
| -rw-r--r-- | block/ll_rw_blk.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index ed39313c4085..026cf2438d59 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -819,7 +819,6 @@ static int __blk_free_tags(struct blk_queue_tag *bqt) retval = atomic_dec_and_test(&bqt->refcnt); if (retval) { BUG_ON(bqt->busy); - BUG_ON(!list_empty(&bqt->busy_list)); kfree(bqt->tag_index); bqt->tag_index = NULL; @@ -931,7 +930,6 @@ static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q, if (init_tag_map(q, tags, depth)) goto fail; - INIT_LIST_HEAD(&tags->busy_list); tags->busy = 0; atomic_set(&tags->refcnt, 1); return tags; @@ -982,6 +980,7 @@ int blk_queue_init_tags(struct request_queue *q, int depth, */ q->queue_tags = tags; q->queue_flags |= (1 << QUEUE_FLAG_QUEUED); + INIT_LIST_HEAD(&q->tag_busy_list); return 0; fail: kfree(tags); @@ -1152,7 +1151,7 @@ int blk_queue_start_tag(struct request_queue *q, struct request *rq) rq->tag = tag; bqt->tag_index[tag] = rq; blkdev_dequeue_request(rq); - list_add(&rq->queuelist, &bqt->busy_list); + list_add(&rq->queuelist, &q->tag_busy_list); bqt->busy++; return 0; } @@ -1173,11 +1172,10 @@ EXPORT_SYMBOL(blk_queue_start_tag); **/ void blk_queue_invalidate_tags(struct request_queue *q) { - struct blk_queue_tag *bqt = q->queue_tags; struct list_head *tmp, *n; struct request *rq; - list_for_each_safe(tmp, n, &bqt->busy_list) { + list_for_each_safe(tmp, n, &q->tag_busy_list) { rq = list_entry_rq(tmp); if (rq->tag == -1) { |