Hi, The 1st patch introduces percpu_ref_resurge() for implementing blk_mq_unfreeze_queue_no_drain_io(). The 2nd patch introdces blk_mq_unfreeze_queue_no_drain_io() for cases in which queue can be unfreeze without draininig IO. The 3rd patch applies blk_mq_unfreeze_queue_no_drain_io() to NVMe PCI timeout, so that IO hang may be avoided inside nvme_reset_work() when new IO timeout is triggered. Part of idea is from Jianchao's early work: https://marc.info/?l=linux-kernel&m=153612052611020&w=2 Ming Lei (3): lib/percpu-refcount: introduce percpu_ref_resurge() blk-mq: introduce blk_mq_unfreeze_queue_no_drain_io nvme: don't drain IO in nvme_reset_work() block/blk-mq.c | 25 ++++++++++++++-- drivers/nvme/host/core.c | 12 +++++--- drivers/nvme/host/nvme.h | 2 +- drivers/nvme/host/pci.c | 3 +- include/linux/blk-mq.h | 1 + include/linux/percpu-refcount.h | 1 + lib/percpu-refcount.c | 63 ++++++++++++++++++++++++++++++++++------- 7 files changed, 87 insertions(+), 20 deletions(-) Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx> Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx> Cc: linux-block@xxxxxxxxxxxxxxx Cc: Christoph Hellwig <hch@xxxxxx> Cc: linux-nvme@xxxxxxxxxxxxxxxxxxx Cc: Keith Busch <keith.busch@xxxxxxxxx> -- 2.9.5
