[PATCH V2 3/3] nvme-rdma: fix potential unbalanced freeze & unfreeze

[Ming Lei]

Move start_freeze into nvme_rdma_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: 9f98772ba307 ("nvme-rdma: fix controller reset hang during traffic")
Cc: stable at vger.kernel.org
Signed-off-by: Ming Lei <ming.lei at redhat.com>
---
 drivers/nvme/host/rdma.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index d433b2ec07a6..337a624a537c 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -883,6 +883,7 @@ static int nvme_rdma_configure_io_queues(struct nvme_rdma_ctrl *ctrl, bool new)
 		goto out_cleanup_tagset;
 
 	if (!new) {
+		nvme_start_freeze(&ctrl->ctrl);
 		nvme_unquiesce_io_queues(&ctrl->ctrl);
 		if (!nvme_wait_freeze_timeout(&ctrl->ctrl, NVME_IO_TIMEOUT)) {
 			/*
@@ -891,6 +892,7 @@ static int nvme_rdma_configure_io_queues(struct nvme_rdma_ctrl *ctrl, bool new)
 			 * to be safe.
 			 */
 			ret = -ENODEV;
+			nvme_unfreeze(&ctrl->ctrl);
 			goto out_wait_freeze_timed_out;
 		}
 		blk_mq_update_nr_hw_queues(ctrl->ctrl.tagset,
@@ -940,7 +942,6 @@ static void nvme_rdma_teardown_io_queues(struct nvme_rdma_ctrl *ctrl,
 		bool remove)
 {
 	if (ctrl->ctrl.queue_count > 1) {
-		nvme_start_freeze(&ctrl->ctrl);
 		nvme_quiesce_io_queues(&ctrl->ctrl);
 		nvme_sync_io_queues(&ctrl->ctrl);
 		nvme_rdma_stop_io_queues(ctrl);
-- 
2.40.1