From 6ca04e8fc4c799a55b011d489b71a5732a9ae8dd Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Tue, 3 Sep 2013 13:37:01 +0200 Subject: ipv6: Don't depend on per socket memory for neighbour discovery messages [ Upstream commit 25a6e6b84fba601eff7c28d30da8ad7cfbef0d43 ] Allocating skbs when sending out neighbour discovery messages currently uses sock_alloc_send_skb() based on a per net namespace socket and thus share a socket wmem buffer space. If a netdevice is temporarily unable to transmit due to carrier loss or for other reasons, the queued up ndisc messages will cosnume all of the wmem space and will thus prevent from any more skbs to be allocated even for netdevices that are able to transmit packets. The number of neighbour discovery messages sent is very limited, use of alloc_skb() bypasses the socket wmem buffer size enforcement while the manual call to skb_set_owner_w() maintains the socket reference needed for the IPv6 output path. This patch has orginally been posted by Eric Dumazet in a modified form. Signed-off-by: Thomas Graf Cc: Eric Dumazet Cc: Hannes Frederic Sowa Cc: Stephen Warren Cc: Fabio Estevam Tested-by: Fabio Estevam Tested-by: Stephen Warren Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ndisc.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'net') diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 31ba78c..f01c153 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -456,7 +456,6 @@ struct sk_buff *ndisc_build_skb(struct net_device *dev, struct sk_buff *skb; struct icmp6hdr *hdr; int len; - int err; u8 *opt; if (!dev->addr_len) @@ -466,14 +465,12 @@ struct sk_buff *ndisc_build_skb(struct net_device *dev, if (llinfo) len += ndisc_opt_addr_space(dev); - skb = sock_alloc_send_skb(sk, - (MAX_HEADER + sizeof(struct ipv6hdr) + - len + LL_ALLOCATED_SPACE(dev)), - 1, &err); + skb = alloc_skb((MAX_HEADER + sizeof(struct ipv6hdr) + + len + LL_ALLOCATED_SPACE(dev)), GFP_ATOMIC); if (!skb) { ND_PRINTK0(KERN_ERR - "ICMPv6 ND: %s() failed to allocate an skb, err=%d.\n", - __func__, err); + "ICMPv6 ND: %s() failed to allocate an skb.\n", + __func__); return NULL; } @@ -501,6 +498,11 @@ struct sk_buff *ndisc_build_skb(struct net_device *dev, csum_partial(hdr, len, 0)); + /* Manually assign socket ownership as we avoid calling + * sock_alloc_send_pskb() to bypass wmem buffer limits + */ + skb_set_owner_w(skb, sk); + return skb; } -- cgit v1.1