Messages in this thread Patch in this message | | | Subject | [PATCH] block: fix blk_queue_end_tag() | From | Dan Williams <> | Date | Tue, 20 Dec 2011 15:33:49 -0800 |
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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.
Cc: Tao Ma <boyu.mt@taobao.com> Reported-by: Meelis Roos <mroos@ut.ee> Reported-by: Ed Nadolski <edmund.nadolski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- Functionally the same as Tao Ma's fix [1], but just moves the warn into the if() directly.
[1]: http://marc.info/?l=linux-scsi&m=132439698602441&w=2
-- Dan
block/blk-tag.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/block/blk-tag.c b/block/blk-tag.c index e74d6d1..6e61262 100644 --- a/block/blk-tag.c +++ b/block/blk-tag.c @@ -286,12 +286,13 @@ void blk_queue_end_tag(struct request_queue *q, struct request *rq) BUG_ON(tag == -1); - if (unlikely(tag >= bqt->max_depth)) { + if (WARN_ONCE(tag >= bqt->real_max_depth, + "%s: tag %d greater than tag map size: %d\n", + __func__, tag, bqt->real_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; }
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