Hi Jens, This 1st patch introduces BLK_STS_DEV_RESOURCE for dealing with IO hang when non-device resource is run out of and queue is idle, and this approach is suggested by you. The 2nd and 3rd patches cleans dm-rq a bit and prepares for applying blk_get_request_notify(). The 4th patch introduces blk_get_request_notify(), still suggested by you. The last patch applies blk_get_request_notify() and avoids one DM specific performance issue which is introduced by the 1st patch. These 5 patches are against both dm(dm-4.16) and block tree(for-4.16/block). Ming Lei (5): blk-mq: introduce BLK_STS_DEV_RESOURCE dm-rq: handle dispatch exception in dm_dispatch_clone_request() dm-rq: return BLK_STS_* from map_request() blk-mq: introduce blk_get_request_notify dm-mpath: use blk_mq_alloc_request_notify for allocating blk-mq req block/blk-core.c | 1 + block/blk-mq-tag.c | 27 +++++++++++++++++++++- block/blk-mq.c | 43 +++++++++++++++++++++++++++++------ block/blk-mq.h | 1 + drivers/block/null_blk.c | 2 +- drivers/block/virtio_blk.c | 2 +- drivers/block/xen-blkfront.c | 2 +- drivers/md/dm-mpath.c | 50 ++++++++++++++++++++++++++++++++++++++++- drivers/md/dm-rq.c | 53 +++++++++++++++++++++++++++----------------- drivers/md/dm.c | 1 + drivers/scsi/scsi_lib.c | 6 ++--- include/linux/blk-mq.h | 5 +++++ include/linux/blk_types.h | 7 ++++++ 13 files changed, 165 insertions(+), 35 deletions(-) -- 2.9.5
