nvme-tcp: avoid race between time out and tear down

Now use teardown_lock to serialize for time out and tear down. This may
cause abnormal: first cancel all request in tear down, then time out may
complete the request again, but the request may already be freed or
restarted.

To avoid race between time out and tear down, in tear down process,
first we quiesce the queue, and then delete the timer and cancel
the time out work for the queue. At the same time we need to delete
teardown_lock.

Signed-off-by: Chao Leng <lengchao@huawei.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index d6a3e148735428cac13e39e0ea7366ed38df84cf..19f86ea547bbc52e7a86c367b919d51a948dd950 100644 (file)
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -124,7 +124,6 @@ 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;
@@ -1886,8 +1885,8 @@ 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);
+       blk_sync_queue(ctrl->admin_q);
        nvme_tcp_stop_queue(ctrl, 0);
        if (ctrl->admin_tagset) {
                blk_mq_tagset_busy_iter(ctrl->admin_tagset,
@@ -1897,18 +1896,17 @@ 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)
-               goto out;
+               return;
        blk_mq_quiesce_queue(ctrl->admin_q);
        nvme_start_freeze(ctrl);
        nvme_stop_queues(ctrl);
+       nvme_sync_io_queues(ctrl);
        nvme_tcp_stop_io_queues(ctrl);
        if (ctrl->tagset) {
                blk_mq_tagset_busy_iter(ctrl->tagset,
@@ -1918,8 +1916,6 @@ 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)
@@ -2171,14 +2167,11 @@ static void nvme_tcp_complete_timed_out(struct request *rq)
        struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
        struct nvme_ctrl *ctrl = &req->queue->ctrl->ctrl;
 
-       /* fence other contexts that may complete the command */
-       mutex_lock(&to_tcp_ctrl(ctrl)->teardown_lock);
        nvme_tcp_stop_queue(ctrl, nvme_tcp_queue_id(req->queue));
        if (!blk_mq_request_completed(rq)) {
                nvme_req(rq)->status = NVME_SC_HOST_ABORTED_CMD;
                blk_mq_complete_request(rq);
        }
-       mutex_unlock(&to_tcp_ctrl(ctrl)->teardown_lock);
 }
 
 static enum blk_eh_timer_return
@@ -2455,7 +2448,6 @@ 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 =