net/virtio: fix Tx checksum offloads

Missing parenthesis around expression before type cast to struct
virtio_net_hdr pointer makes the arithmetic to be in
sizeof(struct virtio_net_hdr) units.

Use rte_pktmbuf_mtod_offset() to fix the problem.

Type of head_size is changed to signed since some compilers bark
on unary minus applied to unsigned.

Fixes: 1ae55ad38e5e ("net/virtio: fix mbuf data and packet length mismatch")
Cc: stable@dpdk.org
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 0959250..752faa0 100644 (file)
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -635,7 +635,7 @@ virtqueue_enqueue_xmit_inorder(struct virtnet_tx *txvq,
        struct vring_desc *start_dp;
        struct virtio_net_hdr *hdr;
        uint16_t idx;
-       uint16_t head_size = vq->hw->vtnet_hdr_size;
+       int16_t head_size = vq->hw->vtnet_hdr_size;
        uint16_t i = 0;
 
        idx = vq->vq_desc_head_idx;
@@ -648,8 +648,8 @@ virtqueue_enqueue_xmit_inorder(struct virtnet_tx *txvq,
                dxp->ndescs = 1;
                virtio_update_packet_stats(&txvq->stats, cookies[i]);
 
-               hdr = (struct virtio_net_hdr *)(char *)cookies[i]->buf_addr +
-                       cookies[i]->data_off - head_size;
+               hdr = rte_pktmbuf_mtod_offset(cookies[i],
+                               struct virtio_net_hdr *, -head_size);
 
                /* if offload disabled, hdr is not zeroed yet, do it now */
                if (!vq->hw->has_tx_offload)
@@ -682,7 +682,7 @@ virtqueue_enqueue_xmit_packed_fast(struct virtnet_tx *txvq,
        struct vring_packed_desc *dp;
        struct vq_desc_extra *dxp;
        uint16_t idx, id, flags;
-       uint16_t head_size = vq->hw->vtnet_hdr_size;
+       int16_t head_size = vq->hw->vtnet_hdr_size;
        struct virtio_net_hdr *hdr;
 
        id = in_order ? vq->vq_avail_idx : vq->vq_desc_head_idx;
@@ -696,8 +696,8 @@ virtqueue_enqueue_xmit_packed_fast(struct virtnet_tx *txvq,
        flags = vq->vq_packed.cached_flags;
 
        /* prepend cannot fail, checked by caller */
-       hdr = (struct virtio_net_hdr *)(char *)cookie->buf_addr +
-               cookie->data_off - head_size;
+       hdr = rte_pktmbuf_mtod_offset(cookie, struct virtio_net_hdr *,
+                                     -head_size);
 
        /* if offload disabled, hdr is not zeroed yet, do it now */
        if (!vq->hw->has_tx_offload)
@@ -734,7 +734,7 @@ virtqueue_enqueue_xmit_packed(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
        struct virtqueue *vq = txvq->vq;
        struct vring_packed_desc *start_dp, *head_dp;
        uint16_t idx, id, head_idx, head_flags;
-       uint16_t head_size = vq->hw->vtnet_hdr_size;
+       int16_t head_size = vq->hw->vtnet_hdr_size;
        struct virtio_net_hdr *hdr;
        uint16_t prev;
        bool prepend_header = false;
@@ -756,8 +756,8 @@ virtqueue_enqueue_xmit_packed(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
 
        if (can_push) {
                /* prepend cannot fail, checked by caller */
-               hdr = (struct virtio_net_hdr *)(char *)cookie->buf_addr +
-                       cookie->data_off - head_size;
+               hdr = rte_pktmbuf_mtod_offset(cookie, struct virtio_net_hdr *,
+                                             -head_size);
                prepend_header = true;
 
                /* if offload disabled, it is not zeroed below, do it now */
@@ -832,7 +832,7 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
        struct vring_desc *start_dp;
        uint16_t seg_num = cookie->nb_segs;
        uint16_t head_idx, idx;
-       uint16_t head_size = vq->hw->vtnet_hdr_size;
+       int16_t head_size = vq->hw->vtnet_hdr_size;
        bool prepend_header = false;
        struct virtio_net_hdr *hdr;
 
@@ -849,8 +849,8 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
 
        if (can_push) {
                /* prepend cannot fail, checked by caller */
-               hdr = (struct virtio_net_hdr *)(char *)cookie->buf_addr +
-                       cookie->data_off - head_size;
+               hdr = rte_pktmbuf_mtod_offset(cookie, struct virtio_net_hdr *,
+                                             -head_size);
                prepend_header = true;
 
                /* if offload disabled, it is not zeroed below, do it now */