Commits
Shaohua Li committed 5b3f341f098
blk-mq: make plug work for mutiple disks and queues Last patch makes plug work for multiple queue case. However it only works for single disk case, because it assumes only one request in the plug list. If a task is accessing multiple disks, eg MD/DM, the assumption is wrong. Let blk_attempt_plug_merge() record request from the same queue. V2: use NULL parameter in !mq case. Fix a bug. Add comments in blk_attempt_plug_merge to make it less (hopefully) confusion. Cc: Jens Axboe <axboe@fb.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>