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nvme-tcp: fix potential unbalanced freeze & unfreeze
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commit 99dc264 upstream.

Move start_freeze into nvme_tcp_configure_io_queues(), and there is
at least two benefits:

1) fix unbalanced freeze and unfreeze, since re-connection work may
fail or be broken by removal

2) IO during error recovery can be failfast quickly because nvme fabrics
unquiesces queues after teardown.

One side-effect is that !mpath request may timeout during connecting
because of queue topo change, but that looks not one big deal:

1) same problem exists with current code base

2) compared with !mpath, mpath use case is dominant

Fixes: 2875b0a ("nvme-tcp: fix controller reset hang during traffic")
Cc: stable@vger.kernel.org
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Ming Lei authored and gregkh committed Aug 16, 2023
1 parent bf67802 commit cddbaa8
Showing 1 changed file with 2 additions and 1 deletion.
3 changes: 2 additions & 1 deletion drivers/nvme/host/tcp.c
Expand Up @@ -1890,6 +1890,7 @@ static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)
goto out_cleanup_connect_q;

if (!new) {
nvme_start_freeze(ctrl);
nvme_start_queues(ctrl);
if (!nvme_wait_freeze_timeout(ctrl, NVME_IO_TIMEOUT)) {
/*
Expand All @@ -1898,6 +1899,7 @@ static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)
* to be safe.
*/
ret = -ENODEV;
nvme_unfreeze(ctrl);
goto out_wait_freeze_timed_out;
}
blk_mq_update_nr_hw_queues(ctrl->tagset,
Expand Down Expand Up @@ -2002,7 +2004,6 @@ static void nvme_tcp_teardown_io_queues(struct nvme_ctrl *ctrl,
if (ctrl->queue_count <= 1)
return;
nvme_stop_admin_queue(ctrl);
nvme_start_freeze(ctrl);
nvme_stop_queues(ctrl);
nvme_sync_io_queues(ctrl);
nvme_tcp_stop_io_queues(ctrl);
Expand Down

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