From: Eric Dumazet edumazet@google.com
commit fa17806cde76fb1087532f07e72aa757a30e0500 upstream.
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: edc9e748934c ("rtnl/ipv4: use netconf msg to advertise forwarding status") Fixes: 9e5511106f99 ("rtnl/ipv4: add support of RTM_GETNETCONF") Signed-off-by: Eric Dumazet edumazet@google.com Cc: Nicolas Dichtel nicolas.dichtel@6wind.com Acked-by: Nicolas Dichtel nicolas.dichtel@6wind.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/ipv4/devinet.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
--- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1814,7 +1814,7 @@ void inet_netconf_notify_devconf(struct 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;
@@ -1826,7 +1826,7 @@ void inet_netconf_notify_devconf(struct 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) @@ -1883,7 +1883,7 @@ static int inet_netconf_get_devconf(stru }
err = -ENOBUFS; - skb = nlmsg_new(inet_netconf_msgsize_devconf(-1), GFP_ATOMIC); + skb = nlmsg_new(inet_netconf_msgsize_devconf(-1), GFP_KERNEL); if (!skb) goto errout;
@@ -2007,16 +2007,16 @@ static void inet_forward_change(struct n
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(); } }