nvme: paring quiesce/unquiesce

mainline inclusion
from mainline-v5.16
commit 9e6a6b12
category: bugfix
bugzilla: 182378 https://gitee.com/openeuler/kernel/issues/I4DDEL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9e6a6b1212100148c109675e003369e3e219dbd9



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The current blk_mq_quiesce_queue() and blk_mq_unquiesce_queue() always
stops and starts the queue unconditionally. And there can be concurrent
quiesce/unquiesce coming from different unrelated code paths, so
unquiesce may come unexpectedly and start queue too early.

Prepare for supporting concurrent quiesce/unquiesce from multiple
contexts, so that we can address the above issue.

NVMe has very complicated quiesce/unquiesce use pattern, add one atomic
bit for makeiing sure that blk-mq quiece/unquiesce is always called in
pair.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211014081710.1871747-5-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Conflict: commit 8c4dfea9 ("nvme-fabrics: reject I/O to offline
device") is not backported, struct nvme_ctrl doesn't have member flags
yet. The commit is a feature and contains a lot of code changes, thus
introduce the new member in this patch.
 - drivers/nvme/host/nvme.h
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>