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alistair23-linux/drivers/nvme
Sagi Grimberg 8d93603bf6 nvme: don't protect ns mutation with ns->head->lock
[ Upstream commit e164471dcf ]

Right now ns->head->lock is protecting namespace mutation
which is wrong and unneeded. Move it to only protect
against head mutations. While we're at it, remove unnecessary
ns->head reference as we already have head pointer.

The problem with this is that the head->lock spans
mpath disk node I/O that may block under some conditions (if
for example the controller is disconnecting or the path
became inaccessible), The locking scheme does not allow any
other path to enable itself, preventing blocked I/O to complete
and forward-progress from there.

This is a preparation patch for the fix in a subsequent patch
where the disk I/O will also be done outside the head->lock.

Fixes: 0d0b660f21 ("nvme: add ANA support")
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-30 15:37:00 -04:00
..
host nvme: don't protect ns mutation with ns->head->lock 2020-06-30 15:37:00 -04:00
target nvme-fc: Revert "add module to ops template to allow module references" 2020-04-17 10:50:10 +02:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00