net: introduce NETDEV_CHANGE_TX_QUEUE_LEN
This patch introduces a new event - NETDEV_CHANGE_TX_QUEUE_LEN, this
will be triggered when tx_queue_len. It could be used by net device
who want to do some processing at that time. An example is tun who may
want to resize tx array when tx_queue_len is changed.
Cc: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 7a0b616..6e4f347 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -322,7 +322,20 @@
static int change_tx_queue_len(struct net_device *dev, unsigned long new_len)
{
- dev->tx_queue_len = new_len;
+ int res, orig_len = dev->tx_queue_len;
+
+ if (new_len != orig_len) {
+ dev->tx_queue_len = new_len;
+ res = call_netdevice_notifiers(NETDEV_CHANGE_TX_QUEUE_LEN, dev);
+ res = notifier_to_errno(res);
+ if (res) {
+ netdev_err(dev,
+ "refused to change device tx_queue_len\n");
+ dev->tx_queue_len = orig_len;
+ return -EFAULT;
+ }
+ }
+
return 0;
}