nvme-tcp: serialize controller teardown sequences

In the timeout handler we may need to complete a request because the
request that timed out may be an I/O that is a part of a serial sequence
of controller teardown or initialization. In order to complete the
request, we need to fence any other context that may compete with us
and complete the request that is timing out.

In this case, we could have a potential double completion in case
a hard-irq or a different competing context triggered error recovery
and is running inflight request cancellation concurrently with the
timeout handler.

Protect using a ctrl teardown_lock to serialize contexts that may
complete a cancelled request due to error recovery or a reset.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 3be4749dbf1127c050ab805e0f2399a4e0ced440..d58a6e2a4ab1262369110a17fcbf350198472a25 100644 (file)
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -124,6 +124,7 @@ struct nvme_tcp_ctrl {
        struct sockaddr_storage src_addr;
        struct nvme_ctrl        ctrl;
 
+       struct mutex            teardown_lock;
        struct work_struct      err_work;
        struct delayed_work     connect_work;
        struct nvme_tcp_request async_req;
@@ -1527,7 +1528,6 @@ static void nvme_tcp_stop_queue(struct nvme_ctrl *nctrl, int qid)
 
        if (!test_and_clear_bit(NVME_TCP_Q_LIVE, &queue->flags))
                return;
-
        __nvme_tcp_stop_queue(queue);
 }
 
@@ -1875,6 +1875,7 @@ out_free_queue:
 static void nvme_tcp_teardown_admin_queue(struct nvme_ctrl *ctrl,
                bool remove)
 {
+       mutex_lock(&to_tcp_ctrl(ctrl)->teardown_lock);
        blk_mq_quiesce_queue(ctrl->admin_q);
        nvme_tcp_stop_queue(ctrl, 0);
        if (ctrl->admin_tagset) {
@@ -1885,13 +1886,16 @@ static void nvme_tcp_teardown_admin_queue(struct nvme_ctrl *ctrl,
        if (remove)
                blk_mq_unquiesce_queue(ctrl->admin_q);
        nvme_tcp_destroy_admin_queue(ctrl, remove);
+       mutex_unlock(&to_tcp_ctrl(ctrl)->teardown_lock);
 }
 
 static void nvme_tcp_teardown_io_queues(struct nvme_ctrl *ctrl,
                bool remove)
 {
+       mutex_lock(&to_tcp_ctrl(ctrl)->teardown_lock);
        if (ctrl->queue_count <= 1)
-               return;
+               goto out;
+       blk_mq_quiesce_queue(ctrl->admin_q);
        nvme_start_freeze(ctrl);
        nvme_stop_queues(ctrl);
        nvme_tcp_stop_io_queues(ctrl);
@@ -1903,6 +1907,8 @@ static void nvme_tcp_teardown_io_queues(struct nvme_ctrl *ctrl,
        if (remove)
                nvme_start_queues(ctrl);
        nvme_tcp_destroy_io_queues(ctrl, remove);
+out:
+       mutex_unlock(&to_tcp_ctrl(ctrl)->teardown_lock);
 }
 
 static void nvme_tcp_reconnect_or_remove(struct nvme_ctrl *ctrl)
@@ -2423,6 +2429,7 @@ static struct nvme_ctrl *nvme_tcp_create_ctrl(struct device *dev,
                        nvme_tcp_reconnect_ctrl_work);
        INIT_WORK(&ctrl->err_work, nvme_tcp_error_recovery_work);
        INIT_WORK(&ctrl->ctrl.reset_work, nvme_reset_ctrl_work);
+       mutex_init(&ctrl->teardown_lock);
 
        if (!(opts->mask & NVMF_OPT_TRSVCID)) {
                opts->trsvcid =