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authorVeaceslav Falico <vfalico@redhat.com>2014-01-10 16:56:25 +0100
committerDavid S. Miller <davem@davemloft.net>2014-01-13 15:19:26 -0800
commit2315dc91a5059d7da9a8b9b9daf78d695c11383e (patch)
tree751234af7ab27daebdf18cb4b08ef8247cabb52e /net/core/dev.c
parent7e11daa7c19ec319fa4b750fd249a18957f17797 (diff)
downloadlinux-linaro-stable-2315dc91a5059d7da9a8b9b9daf78d695c11383e.tar.gz
net: make dev_set_mtu() honor notification return code
Currently, after changing the MTU for a device, dev_set_mtu() calls NETDEV_CHANGEMTU notification, however doesn't verify it's return code - which can be NOTIFY_BAD - i.e. some of the net notifier blocks refused this change, and continues nevertheless. To fix this, verify the return code, and if it's an error - then revert the MTU to the original one, notify again and pass the error code. CC: Jiri Pirko <jiri@resnulli.us> CC: "David S. Miller" <davem@davemloft.net> CC: Eric Dumazet <edumazet@google.com> CC: Alexander Duyck <alexander.h.duyck@intel.com> CC: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Veaceslav Falico <vfalico@redhat.com> Reviewed-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
-rw-r--r--net/core/dev.c34
1 files changed, 25 insertions, 9 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index a8280154c42a..87312dcf0aa8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5300,6 +5300,17 @@ int dev_change_flags(struct net_device *dev, unsigned int flags)
}
EXPORT_SYMBOL(dev_change_flags);
+static int __dev_set_mtu(struct net_device *dev, int new_mtu)
+{
+ const struct net_device_ops *ops = dev->netdev_ops;
+
+ if (ops->ndo_change_mtu)
+ return ops->ndo_change_mtu(dev, new_mtu);
+
+ dev->mtu = new_mtu;
+ return 0;
+}
+
/**
* dev_set_mtu - Change maximum transfer unit
* @dev: device
@@ -5309,8 +5320,7 @@ EXPORT_SYMBOL(dev_change_flags);
*/
int dev_set_mtu(struct net_device *dev, int new_mtu)
{
- const struct net_device_ops *ops = dev->netdev_ops;
- int err;
+ int err, orig_mtu;
if (new_mtu == dev->mtu)
return 0;
@@ -5322,14 +5332,20 @@ int dev_set_mtu(struct net_device *dev, int new_mtu)
if (!netif_device_present(dev))
return -ENODEV;
- err = 0;
- if (ops->ndo_change_mtu)
- err = ops->ndo_change_mtu(dev, new_mtu);
- else
- dev->mtu = new_mtu;
+ orig_mtu = dev->mtu;
+ err = __dev_set_mtu(dev, new_mtu);
- if (!err)
- call_netdevice_notifiers(NETDEV_CHANGEMTU, dev);
+ if (!err) {
+ err = call_netdevice_notifiers(NETDEV_CHANGEMTU, dev);
+ err = notifier_to_errno(err);
+ if (err) {
+ /* setting mtu back and notifying everyone again,
+ * so that they have a chance to revert changes.
+ */
+ __dev_set_mtu(dev, orig_mtu);
+ call_netdevice_notifiers(NETDEV_CHANGEMTU, dev);
+ }
+ }
return err;
}
EXPORT_SYMBOL(dev_set_mtu);