kni: fix kernel deadlock with bifurcated device

[dpdk.git] / kernel / linux / kni / kni_net.c

diff --git a/kernel/linux/kni/kni_net.c b/kernel/linux/kni/kni_net.c
index 6cf99da..f259327 100644 (file)
--- a/kernel/linux/kni/kni_net.c
+++ b/kernel/linux/kni/kni_net.c
@@ -113,6 +113,14 @@ kni_net_process_request(struct net_device *dev, struct rte_kni_request *req)
 
        ASSERT_RTNL();
 
+       /* If we need to wait and RTNL mutex is held
+        * drop the mutex and hold reference to keep device
+        */
+       if (req->async == 0) {
+               dev_hold(dev);
+               rtnl_unlock();
+       }
+
        mutex_lock(&kni->sync_lock);
 
        /* Construct data */
@@ -152,6 +160,10 @@ async:
 
 fail:
        mutex_unlock(&kni->sync_lock);
+       if (req->async == 0) {
+               rtnl_lock();
+               dev_put(dev);
+       }
        return ret;
 }
 
@@ -194,6 +206,10 @@ kni_net_release(struct net_device *dev)
 
        /* Setting if_up to 0 means down */
        req.if_up = 0;
+
+       /* request async because of the deadlock problem */
+       req.async = 1;
+
        ret = kni_net_process_request(dev, &req);
 
        return (ret == 0) ? req.result : ret;