Hi, This patchset avoids to allocate driver tag beforehand for flush rq in case of I/O scheduler, then flush rq isn't treated specially wrt. get/put driver tag, code gets cleanup much, such as, reorder_tags_to_front() is removed, and we needn't to worry about request order in dispatch list for avoiding I/O deadlock. 'dbench -t 30 -s -F 64' has been run on different devices(shared tag, multi-queue, singele queue, ...), and no issues are observed, even very low queue depth(1) test are run, debench still works well. Any comments are welcome! V2: - release driver tag before requeue - warning on inserting a req with driver tag Ming Lei (7): blk-flush: don't run queue for requests of bypassing flush block: pass 'run_queue' to blk_mq_request_bypass_insert blk-flush: use blk_mq_request_bypass_insert() blk-mq: decide how to handle flush rq via RQF_FLUSH_SEQ blk-mq: move blk_mq_put_driver_tag*() into blk-mq.h blk-mq: don't allocate driver tag beforehand for flush rq blk-mq-sched: warning on inserting a req with driver tag allocated block/blk-core.c | 2 +- block/blk-flush.c | 43 +++++++++++++++++++++++----- block/blk-mq-sched.c | 65 ++++++++++++----------------------------- block/blk-mq.c | 81 +++++++++------------------------------------------- block/blk-mq.h | 35 ++++++++++++++++++++++- 5 files changed, 102 insertions(+), 124 deletions(-) -- 2.9.5
