From 7c02c5a8976d0c9f8606630923af846c8c9a278f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 8 Jul 2016 05:18:24 +0200 Subject: [PATCH] ipv4: do not abuse GFP_ATOMIC in inet_netconf_notify_devconf() inet_forward_change() runs with RTNL held. We are allowed to sleep if required. If we use __in_dev_get_rtnl() instead of __in_dev_get_rcu(), we no longer have to use GFP_ATOMIC allocations in inet_netconf_notify_devconf(), meaning we are less likely to miss notifications under memory pressure, and wont touch precious memory reserves either and risk dropping incoming packets. inet_netconf_get_devconf() can also use GFP_KERNEL allocation. Fixes: 10e0db62f60a ("rtnl/ipv4: use netconf msg to advertise forwarding status") Fixes: 9b98a7fc8848 ("rtnl/ipv4: add support of RTM_GETNETCONF") Signed-off-by: Eric Dumazet Cc: Nicolas Dichtel Acked-by: Nicolas Dichtel Signed-off-by: David S. Miller --- net/ipv4/devinet.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index e333bc86bd39d..415e117967c77 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1834,7 +1834,7 @@ void inet_netconf_notify_devconf(struct net *net, int type, int ifindex, struct sk_buff *skb; int err = -ENOBUFS; - skb = nlmsg_new(inet_netconf_msgsize_devconf(type), GFP_ATOMIC); + skb = nlmsg_new(inet_netconf_msgsize_devconf(type), GFP_KERNEL); if (!skb) goto errout; @@ -1846,7 +1846,7 @@ void inet_netconf_notify_devconf(struct net *net, int type, int ifindex, kfree_skb(skb); goto errout; } - rtnl_notify(skb, net, 0, RTNLGRP_IPV4_NETCONF, NULL, GFP_ATOMIC); + rtnl_notify(skb, net, 0, RTNLGRP_IPV4_NETCONF, NULL, GFP_KERNEL); return; errout: if (err < 0) @@ -1903,7 +1903,7 @@ static int inet_netconf_get_devconf(struct sk_buff *in_skb, } err = -ENOBUFS; - skb = nlmsg_new(inet_netconf_msgsize_devconf(NETCONFA_ALL), GFP_ATOMIC); + skb = nlmsg_new(inet_netconf_msgsize_devconf(NETCONFA_ALL), GFP_KERNEL); if (!skb) goto errout; @@ -2027,16 +2027,16 @@ static void inet_forward_change(struct net *net) for_each_netdev(net, dev) { struct in_device *in_dev; + if (on) dev_disable_lro(dev); - rcu_read_lock(); - in_dev = __in_dev_get_rcu(dev); + + in_dev = __in_dev_get_rtnl(dev); if (in_dev) { IN_DEV_CONF_SET(in_dev, FORWARDING, on); inet_netconf_notify_devconf(net, NETCONFA_FORWARDING, dev->ifindex, &in_dev->cnf); } - rcu_read_unlock(); } } -- 2.39.5