examples/vhost: fix strict aliasing

Fixes following error on gcc 4.4.7:

examples/vhost/main.c: In function ‘new_device’:
rte_ring.h:740: error:
    dereferencing pointer ‘mbuf.486’ does break strict-aliasing rules
examples/vhost/main.c:1503: note: initialized from here
...
rte_ring.h:740: error:
    dereferencing pointer ‘({anonymous})’ does break strict-aliasing rules
examples/vhost/main.c:1804: note: initialized from here

Fixes: d19533e8 ("examples/vhost: copy old vhost example")

Reported-by: Qian Xu <qian.q.xu@intel.com>
Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Acked-by: Huawei Xie <huawei.xie@intel.com>

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index dc3a012..b30f1bd 100644 (file)
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -1449,7 +1449,8 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
        uint64_t buff_addr, phys_addr;
        struct vhost_virtqueue *vq;
        struct vring_desc *desc;
-       struct rte_mbuf *mbuf = NULL;
+       void *obj = NULL;
+       struct rte_mbuf *mbuf;
        struct vpool *vpool;
        hpa_type addr_type;
        struct vhost_dev *vdev = (struct vhost_dev *)dev->priv;
@@ -1500,7 +1501,8 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
                }
        } while (unlikely(phys_addr == 0));
 
-       rte_ring_sc_dequeue(vpool->ring, (void **)&mbuf);
+       rte_ring_sc_dequeue(vpool->ring, &obj);
+       mbuf = obj;
        if (unlikely(mbuf == NULL)) {
                LOG_DEBUG(VHOST_DATA,
                        "(%"PRIu64") in attach_rxmbuf_zcp: "
@@ -1517,7 +1519,7 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
                        "size required: %d\n",
                        dev->device_fh, desc->len, desc_idx, vpool->buf_size);
                put_desc_to_used_list_zcp(vq, desc_idx);
-               rte_ring_sp_enqueue(vpool->ring, (void *)mbuf);
+               rte_ring_sp_enqueue(vpool->ring, obj);
                return;
        }
 
@@ -1789,7 +1791,8 @@ virtio_tx_route_zcp(struct virtio_net *dev, struct rte_mbuf *m,
 {
        struct mbuf_table *tx_q;
        struct rte_mbuf **m_table;
-       struct rte_mbuf *mbuf = NULL;
+       void *obj = NULL;
+       struct rte_mbuf *mbuf;
        unsigned len, ret, offset = 0;
        struct vpool *vpool;
        uint16_t vlan_tag = (uint16_t)vlan_tags[(uint16_t)dev->device_fh];
@@ -1801,7 +1804,8 @@ virtio_tx_route_zcp(struct virtio_net *dev, struct rte_mbuf *m,
 
        /* Allocate an mbuf and populate the structure. */
        vpool = &vpool_array[MAX_QUEUES + vmdq_rx_q];
-       rte_ring_sc_dequeue(vpool->ring, (void **)&mbuf);
+       rte_ring_sc_dequeue(vpool->ring, &obj);
+       mbuf = obj;
        if (unlikely(mbuf == NULL)) {
                struct vhost_virtqueue *vq = dev->virtqueue[VIRTIO_TXQ];
                RTE_LOG(ERR, VHOST_DATA,