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ipv4: do not abuse GFP_ATOMIC in inet_netconf_notify_devconf()

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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: edc9e74893 ("rtnl/ipv4: use netconf msg to advertise forwarding status")
Fixes: 9e5511106f ("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>
This commit is contained in:
Eric Dumazet
2016-07-08 05:18:24 +02:00
committed by David S. Miller
parent db9a1ba55a
commit fa17806cde
1 changed files with 6 additions and 6 deletions
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12
net/ipv4/devinet.c
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@@ -1834,7 +1834,7 @@ void inet_netconf_notify_devconf(struct net *net, int type, int ifindex,
struct sk_buff *skb; struct sk_buff *skb;
int err = -ENOBUFS; 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) if (!skb)
goto errout; goto errout;
@@ -1846,7 +1846,7 @@ void inet_netconf_notify_devconf(struct net *net, int type, int ifindex,
kfree_skb(skb); kfree_skb(skb);
goto errout; 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; return;
errout: errout:
if (err < 0) if (err < 0)
@@ -1903,7 +1903,7 @@ static int inet_netconf_get_devconf(struct sk_buff *in_skb,
} }
err = -ENOBUFS; 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) if (!skb)
goto errout; goto errout;
@@ -2027,16 +2027,16 @@ static void inet_forward_change(struct net *net)
for_each_netdev(net, dev) { for_each_netdev(net, dev) {
struct in_device *in_dev; struct in_device *in_dev;
if (on) if (on)
dev_disable_lro(dev); dev_disable_lro(dev);
rcu_read_lock();
in_dev = __in_dev_get_rcu(dev); in_dev = __in_dev_get_rtnl(dev);
if (in_dev) { if (in_dev) {
IN_DEV_CONF_SET(in_dev, FORWARDING, on); IN_DEV_CONF_SET(in_dev, FORWARDING, on);
inet_netconf_notify_devconf(net, NETCONFA_FORWARDING, inet_netconf_notify_devconf(net, NETCONFA_FORWARDING,
dev->ifindex, &in_dev->cnf); dev->ifindex, &in_dev->cnf);
} }
rcu_read_unlock();
} }
} }