Hello Jens,

Multiple block drivers need the functionality to stop a request queue 
and to wait until all ongoing request_fn() / queue_rq() calls have 
finished without waiting until all outstanding requests have finished. 
Hence this patch series that introduces the blk_mq_quiesce_queue() and 
blk_mq_resume_queue() functions. The dm-mq, SRP and nvme patches in this 
patch series are three examples of where these functions are useful. 
These patches apply on top of the September 21 version of your 
for-4.9/block branch.

The changes compared to the previous version of this patch series are:
- Dropped the non-blk-mq changes from this patch series.
- Added support for harware queues with BLK_MQ_F_BLOCKING set.
- Added a call stack to the description of the dm race fix patch.
- Dropped the non-scsi-mq changes from the SRP patch.
- Added a patch that introduces blk_mq_queue_stopped() in the dm driver.

The individual patches in this series are:

0001-blk-mq-Introduce-blk_mq_queue_stopped.patch
0002-dm-Use-BLK_MQ_S_STOPPED-instead-of-QUEUE_FLAG_STOPPE.patch
0003-RFC-nvme-Use-BLK_MQ_S_STOPPED-instead-of-QUEUE_FLAG_.patch
0004-blk-mq-Introduce-blk_quiesce_queue-and-blk_resume_qu.patch
0005-dm-Fix-a-race-condition-related-to-stopping-and-star.patch
0006-SRP-transport-Port-srp_wait_for_queuecommand-to-scsi.patch
0007-RFC-nvme-Fix-a-race-condition.patch

Thanks,

Bart.