[PATCH net] net: mv __dev_notify_flags from void to int

[PATCH net] net: mv __dev_notify_flags from void to int

[Hangbin Liu]

As call_netdevice_notifiers() and call_netdevice_notifiers_info() have return
values, we should also return the values in function __dev_notify_flags().

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
 include/linux/netdevice.h |  2 +-
 net/core/dev.c            | 30 ++++++++++++++++++++----------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3d0cc0b..b1c145e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3411,7 +3411,7 @@ int dev_ethtool(struct net *net, struct ifreq *);
 unsigned int dev_get_flags(const struct net_device *);
 int __dev_change_flags(struct net_device *, unsigned int flags);
 int dev_change_flags(struct net_device *, unsigned int);
-void __dev_notify_flags(struct net_device *, unsigned int old_flags,
+int __dev_notify_flags(struct net_device *, unsigned int old_flags,
 			unsigned int gchanges);
 int dev_change_name(struct net_device *, const char *);
 int dev_set_alias(struct net_device *, const char *, size_t);
diff --git a/net/core/dev.c b/net/core/dev.c
index a5aa1c7..0994533 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6798,8 +6798,10 @@ static int __dev_set_promiscuity(struct net_device *dev, int inc, bool notify)
 
 		dev_change_rx_flags(dev, IFF_PROMISC);
 	}
+
 	if (notify)
-		__dev_notify_flags(dev, old_flags, IFF_PROMISC);
+		return __dev_notify_flags(dev, old_flags, IFF_PROMISC);
+
 	return 0;
 }
 
@@ -6854,8 +6856,8 @@ static int __dev_set_allmulti(struct net_device *dev, int inc, bool notify)
 		dev_change_rx_flags(dev, IFF_ALLMULTI);
 		dev_set_rx_mode(dev);
 		if (notify)
-			__dev_notify_flags(dev, old_flags,
-					   dev->gflags ^ old_gflags);
+			return  __dev_notify_flags(dev, old_flags,
+						   dev->gflags ^ old_gflags);
 	}
 	return 0;
 }
@@ -7016,21 +7018,26 @@ int __dev_change_flags(struct net_device *dev, unsigned int flags)
 	return ret;
 }
 
-void __dev_notify_flags(struct net_device *dev, unsigned int old_flags,
-			unsigned int gchanges)
+int __dev_notify_flags(struct net_device *dev, unsigned int old_flags,
+		       unsigned int gchanges)
 {
 	unsigned int changes = dev->flags ^ old_flags;
+	int err = 0;
 
 	if (gchanges)
 		rtmsg_ifinfo(RTM_NEWLINK, dev, gchanges, GFP_ATOMIC);
 
 	if (changes & IFF_UP) {
 		if (dev->flags & IFF_UP)
-			call_netdevice_notifiers(NETDEV_UP, dev);
+			err = call_netdevice_notifiers(NETDEV_UP, dev);
 		else
-			call_netdevice_notifiers(NETDEV_DOWN, dev);
+			err = call_netdevice_notifiers(NETDEV_DOWN, dev);
 	}
 
+	err = notifier_to_errno(err);
+	if (err)
+		goto out;
+
 	if (dev->flags & IFF_UP &&
 	    (changes & ~(IFF_UP | IFF_PROMISC | IFF_ALLMULTI | IFF_VOLATILE))) {
 		struct netdev_notifier_change_info change_info = {
@@ -7040,8 +7047,12 @@ void __dev_notify_flags(struct net_device *dev, unsigned int old_flags,
 			.flags_changed = changes,
 		};
 
-		call_netdevice_notifiers_info(NETDEV_CHANGE, &change_info.info);
+		err = call_netdevice_notifiers_info(NETDEV_CHANGE, &change_info.info);
+		err = notifier_to_errno(err);
 	}
+
+out:
+	return err;
 }
 
 /**
@@ -7062,8 +7073,7 @@ int dev_change_flags(struct net_device *dev, unsigned int flags)
 		return ret;
 
 	changes = (old_flags ^ dev->flags) | (old_gflags ^ dev->gflags);
-	__dev_notify_flags(dev, old_flags, changes);
-	return ret;
+	return __dev_notify_flags(dev, old_flags, changes);
 }
 EXPORT_SYMBOL(dev_change_flags);
 
-- 
2.5.5

Re: [PATCH net] net: mv __dev_notify_flags from void to int

[David Miller]

From: Hangbin Liu <liuhangbin@gmail.com>
Date: Wed,  4 Jul 2018 14:29:46 +0800

> @@ -7062,8 +7073,7 @@ int dev_change_flags(struct net_device *dev, unsigned int flags)
>  		return ret;
>  
>  	changes = (old_flags ^ dev->flags) | (old_gflags ^ dev->gflags);
> -	__dev_notify_flags(dev, old_flags, changes);
> -	return ret;
> +	return __dev_notify_flags(dev, old_flags, changes);

By doing this, you will lose any error code returned from dev_open().
That is why we return 'ret' instead of plain '0' here.