[dpdk-dev] [PATCH] vhost: fix dereference null return value

[Huawei Xie]

fixes the following coverity issues:
CID 107118 (#1 of 1): Dereference null return value (NULL_RETURNS)
CID 119262 (#1 of 1): Dereference null return value (NULL_RETURNS)

Fixes: 8f972312b8f4 ("vhost: support vhost-user")
Fixes: 77d20126b4c2 ("vhost-user: handle message to enable vring")

Signed-off-by: Huawei Xie <huawei.xie at intel.com>
---
 lib/librte_vhost/vhost_user/virtio-net-user.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/librte_vhost/vhost_user/virtio-net-user.c 
b/lib/librte_vhost/vhost_user/virtio-net-user.c
index 5803182..5844a42 100644
--- a/lib/librte_vhost/vhost_user/virtio-net-user.c
+++ b/lib/librte_vhost/vhost_user/virtio-net-user.c
@@ -283,6 +283,9 @@ user_set_vring_kick(struct vhost_device_ctx ctx, struct 
VhostUserMsg *pmsg)
        struct vhost_vring_file file;
        struct virtio_net *dev = get_device(ctx);

+       if (!dev)
+               return;
+
        file.index = pmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
        if (pmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK)
                file.fd = VIRTIO_INVALID_EVENTFD;
@@ -306,8 +309,9 @@ user_get_vring_base(struct vhost_device_ctx ctx,
 {
        struct virtio_net *dev = get_device(ctx);

-       if (dev == NULL)
+       if (!dev)
                return -1;
+
        /* We have to stop the queue (virtio) if it is running. */
        if (dev->flags & VIRTIO_DEV_RUNNING)
                notify_ops->destroy_device(dev);
@@ -341,6 +345,9 @@ user_set_vring_enable(struct vhost_device_ctx ctx,
        struct virtio_net *dev = get_device(ctx);
        int enable = (int)state->num;

+       if (!dev)
+               return -1;
+
        RTE_LOG(INFO, VHOST_CONFIG,
                "set queue enable: %d to qp idx: %d\n",
                enable, state->index);
@@ -361,7 +368,7 @@ user_set_protocol_features(struct vhost_device_ctx ctx,
        struct virtio_net *dev;

        dev = get_device(ctx);
-       if (dev == NULL || protocol_features & ~VHOST_USER_PROTOCOL_FEATURES)
+       if (!dev || protocol_features & ~VHOST_USER_PROTOCOL_FEATURES)
                return;

        dev->protocol_features = protocol_features;
-- 
1.8.1.4