tree 6354be68a6e49f6b3579289e33cf15b75f6baa14
parent 8a58d1f1f373238cb0d6d7f8d3dd723aa164b8ac
author Jens Axboe <axboe@fb.com> 1408128248 -0600
committer Jens Axboe <axboe@fb.com> 1408671465 -0500

blk-mq: don't allow merges if turned off for the queue

blk-mq uses BLK_MQ_F_SHOULD_MERGE, as set by the driver at init time,
to determine whether it should merge IO or not. However, this could
also be disabled by the admin, if merging is switched off through
sysfs. So check the general queue state as well before attempting
to merge IO.

Reported-by: Rob Elliott <Elliott@hp.com>
Tested-by: Rob Elliott <Elliott@hp.com>
Signed-off-by: Jens Axboe <axboe@fb.com>