[PATCH net] dev_ioctl: add missing NETDEV_CHANGE_TX_QUEUE_LEN event notification

[Xin Long]

When changing dev tx_queue_len via netlink or net-sysfs,
a NETDEV_CHANGE_TX_QUEUE_LEN event notification will be
called.

But dev_ioctl missed this event notification, which could
cause no userspace notification would be sent.

Signed-off-by: Xin Long <lucien....@gmail.com>
---
 net/core/dev_ioctl.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 709a4e6..f9c7a88 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -303,7 +303,18 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, 
unsigned int cmd)
        case SIOCSIFTXQLEN:
                if (ifr->ifr_qlen < 0)
                        return -EINVAL;
-               dev->tx_queue_len = ifr->ifr_qlen;
+               if (dev->tx_queue_len ^ ifr->ifr_qlen) {
+                       unsigned int orig_len = dev->tx_queue_len;
+
+                       dev->tx_queue_len = ifr->ifr_qlen;
+                       err = call_netdevice_notifiers(
+                                       NETDEV_CHANGE_TX_QUEUE_LEN, dev);
+                       err = notifier_to_errno(err);
+                       if (err) {
+                               dev->tx_queue_len = orig_len;
+                               return err;
+                       }
+               }
                return 0;
 
        case SIOCSIFNAME:
-- 
2.1.0