[PATCH net-next] net-sysfs: trigger netlink notification on ifalias change via sysfs

[Roopa Prabhu]

From: Roopa Prabhu <ro...@cumulusnetworks.com>

This patch adds netlink notifications on iflias changes via sysfs.
makes it consistent with the netlink path which also calls
netdev_state_change. Also makes it consistent with other sysfs
netdev_store operations.

Signed-off-by: Roopa Prabhu <ro...@cumulusnetworks.com>
---
 net/core/net-sysfs.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 51d5836..799b752 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -382,7 +382,7 @@ static ssize_t ifalias_store(struct device *dev, struct 
device_attribute *attr,
        struct net_device *netdev = to_net_dev(dev);
        struct net *net = dev_net(netdev);
        size_t count = len;
-       ssize_t ret;
+       ssize_t ret = 0;
 
        if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
                return -EPERM;
@@ -391,9 +391,20 @@ static ssize_t ifalias_store(struct device *dev, struct 
device_attribute *attr,
        if (len >  0 && buf[len - 1] == '\n')
                --count;
 
-       ret = dev_set_alias(netdev, buf, count);
+       if (!rtnl_trylock())
+               return restart_syscall();
+
+       if (dev_isalive(netdev)) {
+               ret = dev_set_alias(netdev, buf, count);
+               if (ret < 0)
+                       goto err;
+               ret = len;
+               netdev_state_change(netdev);
+       }
+err:
+       rtnl_unlock();
 
-       return ret < 0 ? ret : len;
+       return ret;
 }
 
 static ssize_t ifalias_show(struct device *dev,
-- 
2.1.4