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authorVeaceslav Falico <vfalico@redhat.com>2014-01-16 00:02:18 +0100
committerDavid S. Miller <davem@davemloft.net>2014-01-16 17:15:41 -0800
commit1d486bfb66971ebacc2a46a23431ace9af70dc66 (patch)
treeb280bfff1e11a8857f9a2e967e92e6442a9d043b /net/core
parent31cf344caf444ca7411d89c8ac907d886eeab1a7 (diff)
net: add NETDEV_PRECHANGEMTU to notify before mtu change happens
Currently, if a device changes its mtu, first the change happens (invloving all the side effects), and after that the NETDEV_CHANGEMTU is sent so that other devices can catch up with the new mtu. However, if they return NOTIFY_BAD, then the change is reverted and error returned. This is a really long and costy operation (sometimes). To fix this, add NETDEV_PRECHANGEMTU notification which is called prior to any change actually happening, and if any callee returns NOTIFY_BAD - the change is aborted. This way we're skipping all the playing with apply/revert the mtu. CC: "David S. Miller" <davem@davemloft.net> CC: Jiri Pirko <jiri@resnulli.us> CC: Eric Dumazet <edumazet@google.com> CC: Nicolas Dichtel <nicolas.dichtel@6wind.com> CC: Cong Wang <amwang@redhat.com> Signed-off-by: Veaceslav Falico <vfalico@redhat.com> Acked-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/dev.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index b2c1869b04e3..f87bedd51eed 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5392,6 +5392,11 @@ int dev_set_mtu(struct net_device *dev, int new_mtu)
if (!netif_device_present(dev))
return -ENODEV;
+ err = call_netdevice_notifiers(NETDEV_PRECHANGEMTU, dev);
+ err = notifier_to_errno(err);
+ if (err)
+ return err;
+
orig_mtu = dev->mtu;
err = __dev_set_mtu(dev, new_mtu);