iucv: call skb_linearize() when needed (979f66b3) · Commits · 戴 / test

When the linear buffer of the received sk_buff is shorter than the header, use skb_linearize(). sk_buffs with short linear buffer happen on the sending side under high traffic, and some kernel configurations, when allocated buffer starts just before page boundary, and IUCV transport has to send it as two separate QDIO buffer elements, with fist element shorter than the header. Signed-off-by:

Eugene Crosser <Eugene.Crosser@ru.ibm.com> Signed-off-by:

Ursula Braun <ubraun@linux.vnet.ibm.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/iucv/af_iucv.c

+15 −5

Original line number	Diff line number	Diff line
		@@ -2085,10 +2085,6 @@ static int afiucv_hs_callback_rx(struct sock sk, struct sk_buff skb)
		}

		/* write stuff from iucv_msg to skb cb */
		if (skb->len < sizeof(struct af_iucv_trans_hdr)) {
		kfree_skb(skb);
		return NET_RX_SUCCESS;
		}
		skb_pull(skb, sizeof(struct af_iucv_trans_hdr));
		skb_reset_transport_header(skb);
		skb_reset_network_header(skb);
		@@ -2119,6 +2115,20 @@ static int afiucv_hs_rcv(struct sk_buff skb, struct net_device dev,
		char nullstring[8];
		int err = 0;

		if (skb->len < (ETH_HLEN + sizeof(struct af_iucv_trans_hdr))) {
		WARN_ONCE(1, "AF_IUCV too short skb, len=%d, min=%d",
		(int)skb->len,
		(int)(ETH_HLEN + sizeof(struct af_iucv_trans_hdr)));
		kfree_skb(skb);
		return NET_RX_SUCCESS;
		}
		if (skb_headlen(skb) < (ETH_HLEN + sizeof(struct af_iucv_trans_hdr)))
		if (skb_linearize(skb)) {
		WARN_ONCE(1, "AF_IUCV skb_linearize failed, len=%d",
		(int)skb->len);
		kfree_skb(skb);
		return NET_RX_SUCCESS;
		}
		skb_pull(skb, ETH_HLEN);
		trans_hdr = (struct af_iucv_trans_hdr *)skb->data;
		EBCASC(trans_hdr->destAppName, sizeof(trans_hdr->destAppName));

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