[PATCH 0/2] blk-mq: fix I/O hang during system resume

[Ming Lei <ming.lei@redhat.com>]

Hi,

This two patches fix SCSI I/O hang during system resume.

The cause is that when SCSI device is put into SCSI's
quiesce state, normal I/O request can't be dispatched to lld
any more, only request with RQF_PREEMPT is allowed to be
sent to drive.

In current blk-mq implementation, if there is request in ->dispatch,
no new request can't be dispatched to driver any more.

This two patches fix the issue reported by Oleksandr.

Thanks,
Ming

Ming Lei (2):
  blk-mq: add requests in the tail of hctx->dispatch
  blk-mq: align to legacy's implementation of blk_execute_rq

 block/blk-core.c     |  2 +-
 block/blk-exec.c     |  2 +-
 block/blk-flush.c    |  2 +-
 block/blk-mq-sched.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 block/blk-mq-sched.h |  2 ++
 block/blk-mq.c       |  2 +-
 6 files changed, 65 insertions(+), 5 deletions(-)

-- 
2.9.5