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authorDan Williams <dan.j.williams@intel.com>2011-12-29 09:16:28 +0100
committerJens Axboe <axboe@kernel.dk>2011-12-29 09:16:28 +0100
commitf2b20d436534f22ccc3f5ad172499fcb013bb315 (patch)
tree5c5df70a252ea14da6063d2c6c3de4a4e769ecae /block
parent609f6ea1c9cdfe0c43a927e13205a57d0c266d5a (diff)
downloadlinux-linaro-stable-f2b20d436534f22ccc3f5ad172499fcb013bb315.tar.gz
block: fix blk_queue_end_tag()
Commit 5e081591 "block: warn if tag is greater than real_max_depth" cleaned up blk_queue_end_tag() to warn when the tag is truly invalid (greater than real_max_depth). However, it changed behavior in the tag < max_depth case to not end the request. Leading to triggering of BUG_ON(blk_queued_rq(rq)) in the request completion path: http://marc.info/?l=linux-kernel&m=132204370518629&w=2 In order to allow blk_queue_resize_tags() to shrink the tag space blk_queue_end_tag() must always complete tags with a value less than real_max_depth regardless of the current max_depth. The comment about "handling the shrink case" seems to be what prompted changes in this space, so remove it and BUG on all invalid tags (made even simpler by Matthew's suggestion to use an unsigned compare). Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Tao Ma <boyu.mt@taobao.com> Cc: Matthew Wilcox <matthew@wil.cx> Reported-by: Meelis Roos <mroos@ut.ee> Reported-by: Ed Nadolski <edmund.nadolski@intel.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-tag.c13
1 files changed, 2 insertions, 11 deletions
diff --git a/block/blk-tag.c b/block/blk-tag.c
index e74d6d13838f..4af6f5cc1167 100644
--- a/block/blk-tag.c
+++ b/block/blk-tag.c
@@ -282,18 +282,9 @@ EXPORT_SYMBOL(blk_queue_resize_tags);
void blk_queue_end_tag(struct request_queue *q, struct request *rq)
{
struct blk_queue_tag *bqt = q->queue_tags;
- int tag = rq->tag;
+ unsigned tag = rq->tag; /* negative tags invalid */
- BUG_ON(tag == -1);
-
- if (unlikely(tag >= bqt->max_depth)) {
- /*
- * This can happen after tag depth has been reduced.
- * But tag shouldn't be larger than real_max_depth.
- */
- WARN_ON(tag >= bqt->real_max_depth);
- return;
- }
+ BUG_ON(tag >= bqt->real_max_depth);
list_del_init(&rq->queuelist);
rq->cmd_flags &= ~REQ_QUEUED;