Commit fbf33a28 authored May 08, 2015 by Kretschmer, Mathias Committed by David S. Miller May 10, 2015

af_packet / TX_RING not fully non-blocking (w/ MSG_DONTWAIT).

This patch fixes an issue where the send(MSG_DONTWAIT) call
on a TX_RING is not fully non-blocking in cases where the device's sndBuf is
full. We pass nonblock=true to sock_alloc_send_skb() and return any possibly
occuring error code (most likely EGAIN) to the caller. As the fast-path stays
as it is, we keep the unlikely() around skb == NULL.

Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent cd9c3997

net/packet/af_packet.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -2311,11 +2311,14 @@ static int tpacket_snd(struct packet_sock po, struct msghdr msg)
		tlen = dev->needed_tailroom;
		skb = sock_alloc_send_skb(&po->sk,
		hlen + tlen + sizeof(struct sockaddr_ll),
		0, &err);
		!need_wait, &err);

		if (unlikely(skb == NULL))
		if (unlikely(skb == NULL)) {
		/* we assume the socket was initially writeable ... */
		if (likely(len_sum > 0))
		err = len_sum;
		goto out_status;

		}
		tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto,
		addr, hlen);
		if (tp_len > dev->mtu + dev->hard_header_len) {