1 files changed, 32 insertions, 16 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index e0e57083d442..7106932c6f88 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -225,6 +225,9 @@ struct virtnet_info {
 	/* I like... big packets and I cannot lie! */
 	bool big_packets;
 
+	/* number of sg entries allocated for big packets */
+	unsigned int big_packets_num_skbfrags;
+
 	/* Host will merge rx buffers for big packets (shake it! shake it!) */
 	bool mergeable_rx_bufs;
 
@@ -1331,10 +1334,10 @@ static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
 	char *p;
 	int i, err, offset;
 
-	sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
+	sg_init_table(rq->sg, vi->big_packets_num_skbfrags + 2);
 
-	/* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
-	for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
+	/* page in rq->sg[vi->big_packets_num_skbfrags + 1] is list tail */
+	for (i = vi->big_packets_num_skbfrags + 1; i > 1; --i) {
 		first = get_a_page(rq, gfp);
 		if (!first) {
 			if (list)
@@ -1365,7 +1368,7 @@ static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
 
 	/* chain first in list head */
 	first->private = (unsigned long)list;
-	err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
+	err = virtqueue_add_inbuf(rq->vq, rq->sg, vi->big_packets_num_skbfrags + 2,
 				  first, gfp);
 	if (err < 0)
 		give_pages(rq, first);
@@ -3682,13 +3685,35 @@ static int virtnet_validate(struct virtio_device *vdev)
 	return 0;
 }
 
+static bool virtnet_check_guest_gso(const struct virtnet_info *vi)
+{
+	return virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
+		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6) ||
+		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) ||
+		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO);
+}
+
+static void virtnet_set_big_packets(struct virtnet_info *vi, const int mtu)
+{
+	bool guest_gso = virtnet_check_guest_gso(vi);
+
+	/* If device can receive ANY guest GSO packets, regardless of mtu,
+	 * allocate packets of maximum size, otherwise limit it to only
+	 * mtu size worth only.
+	 */
+	if (mtu > ETH_DATA_LEN || guest_gso) {
+		vi->big_packets = true;
+		vi->big_packets_num_skbfrags = guest_gso ? MAX_SKB_FRAGS : DIV_ROUND_UP(mtu, PAGE_SIZE);
+	}
+}
+
 static int virtnet_probe(struct virtio_device *vdev)
 {
 	int i, err = -ENOMEM;
 	struct net_device *dev;
 	struct virtnet_info *vi;
 	u16 max_queue_pairs;
-	int mtu;
+	int mtu = 0;
 
 	/* Find if host supports multiqueue/rss virtio_net device */
 	max_queue_pairs = 1;
@@ -3776,13 +3801,6 @@ static int virtnet_probe(struct virtio_device *vdev)
 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
 	spin_lock_init(&vi->refill_lock);
 
-	/* If we can receive ANY GSO packets, we must allocate large ones. */
-	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
-	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
-	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
-	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
-		vi->big_packets = true;
-
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
 		vi->mergeable_rx_bufs = true;
 
@@ -3848,12 +3866,10 @@ static int virtnet_probe(struct virtio_device *vdev)
 
 		dev->mtu = mtu;
 		dev->max_mtu = mtu;
-
-		/* TODO: size buffers correctly in this case. */
-		if (dev->mtu > ETH_DATA_LEN)
-			vi->big_packets = true;
 	}
 
+	virtnet_set_big_packets(vi, mtu);
+
 	if (vi->any_header_sg)
 		dev->needed_headroom = vi->hdr_len;