virtio_net: use correct accessors for scatterlists (8527bec5) · Commits · 戴 / test

Without this fix, virtio_net makes incorrect usage of scatterlists. It sets the end of the scatterlist chain after the first element, despite the fact that more entries come after it. If you try to run dma_map_sg() on one of the scatterlists given to you by add_buf(), you will get a null pointer oops. Signed-off-by:

Ira W. Snyder <iws@ovro.caltech.edu> Signed-off-by:

Rusty Russell <rusty@rustcorp.com.au> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/virtio_net.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -287,7 +287,7 @@ static void try_fill_recv_maxbufs(struct virtnet_info *vi)
		skb_put(skb, MAX_PACKET_LEN);

		hdr = skb_vnet_hdr(skb);
		sg_init_one(sg, hdr, sizeof(*hdr));
		sg_set_buf(sg, hdr, sizeof(*hdr));

		if (vi->big_packets) {
		for (i = 0; i < MAX_SKB_FRAGS; i++) {
		@@ -488,9 +488,9 @@ static int xmit_skb(struct virtnet_info vi, struct sk_buff skb)

		/* Encode metadata header at front. */
		if (vi->mergeable_rx_bufs)
		sg_init_one(sg, mhdr, sizeof(*mhdr));
		sg_set_buf(sg, mhdr, sizeof(*mhdr));
		else
		sg_init_one(sg, hdr, sizeof(*hdr));
		sg_set_buf(sg, hdr, sizeof(*hdr));

		num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;

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