[PATCH 5.4 056/132] nvme-tcp: fix reset hang if controller died in the middle of a reset

Greg Kroah-Hartman
2020-09-16T00:08:28Z

From: Sagi Grimberg <sagi@grimberg.me>

[ Upstream commit e5c01f4f7f623e768e868bcc08d8e7ceb03b75d0 ]

If the controller becomes unresponsive in the middle of a reset, we will
hang because we are waiting for the freeze to complete, but that cannot
happen since we have commands that are inflight holding the
q_usage_counter, and we can't blindly fail requests that times out.

So give a timeout and if we cannot wait for queue freeze before
unfreezing, fail and have the error handling take care how to proceed
(either schedule a reconnect of remove the controller).

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/tcp.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 98a045429293e..9b81763b44d99 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1693,7 +1693,15 @@ static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)

if (!new) {
nvme_start_queues(ctrl);
- nvme_wait_freeze(ctrl);
+ if (!nvme_wait_freeze_timeout(ctrl, NVME_IO_TIMEOUT)) {
+ /*
+ * If we timed out waiting for freeze we are likely to
+ * be stuck. Fail the controller initialization just
+ * to be safe.
+ */
+ ret = -ENODEV;
+ goto out_wait_freeze_timed_out;
+ }
blk_mq_update_nr_hw_queues(ctrl->tagset,
ctrl->queue_count - 1);
nvme_unfreeze(ctrl);
@@ -1701,6 +1709,9 @@ static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)

return 0;

+out_wait_freeze_timed_out:
+ nvme_stop_queues(ctrl);
+ nvme_tcp_stop_io_queues(ctrl);
out_cleanup_connect_q:
if (new)
blk_cleanup_queue(ctrl->connect_q);
--
2.25.1