diff mbox

[3.5.y.z,extended,stable] Patch "ipv6: Don't depend on per socket memory for neighbour" has been added to staging queue

Message ID 1379705658-15479-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques Sept. 20, 2013, 7:34 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    ipv6: Don't depend on per socket memory for neighbour

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

From 3af0722891ccd3cc89826b3a415f5c97b471eda5 Mon Sep 17 00:00:00 2001
From: Thomas Graf <tgraf@suug.ch>
Date: Tue, 3 Sep 2013 13:37:01 +0200
Subject: [PATCH] ipv6: Don't depend on per socket memory for neighbour
 discovery messages

commit 25a6e6b84fba601eff7c28d30da8ad7cfbef0d43 upstream.

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 <tgraf@suug.ch>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Fabio Estevam <festevam@gmail.com>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 net/ipv6/ndisc.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

--
1.8.3.2
diff mbox

Patch

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 35bfebc..fbe0f9f 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -429,7 +429,6 @@  struct sk_buff *ndisc_build_skb(struct net_device *dev,
 	int hlen = LL_RESERVED_SPACE(dev);
 	int tlen = dev->needed_tailroom;
 	int len;
-	int err;
 	u8 *opt;

 	if (!dev->addr_len)
@@ -439,13 +438,11 @@  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 + hlen + tlen),
-				  1, &err);
+	skb = alloc_skb((MAX_HEADER + sizeof(struct ipv6hdr) +
+			 len + hlen + tlen), GFP_ATOMIC);
 	if (!skb) {
-		ND_PRINTK(0, err, "ND: %s failed to allocate an skb, err=%d\n",
-			  __func__, err);
+		ND_PRINTK(0, err, "ND: %s failed to allocate an skb\n",
+			  __func__);
 		return NULL;
 	}

@@ -473,6 +470,11 @@  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;
 }