In preparation of next patch, this function allows to check if a device
is a master, be it direct or indirect, of another one. It walks up the
master chain until it finds the device, or there is no more master.
This allows to check e.g. if br-blue is a master of eth0:
+----------+
| vrf-blue |
+----+-----+
|
+----+----+
| br-blue |
+----+----+
|
+---+---+
| bond0 |
+--+-+--+
| |
+--+ +--+
| |
+---+--+ +--+---+
| eth0 | | eth1 |
+------+ +------+
Signed-off-by: Alexis Bauvin <abau...@scaleway.com>
Reviewed-by: Amine Kherbouche <akherbou...@scaleway.com>
Tested-by: Amine Kherbouche <akherbou...@scaleway.com>
---
include/linux/netdevice.h | 1 +
net/core/dev.c | 17 +++++++++++++++++
2 files changed, 18 insertions(+)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d837dad24b4c..102f79337d7c 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4212,6 +4212,7 @@ void *netdev_lower_dev_get_private(struct net_device *dev,
struct net_device *lower_dev);
void netdev_lower_state_changed(struct net_device *lower_dev,
void *lower_state_info);
+bool netdev_is_upper_master(struct net_device *dev, struct net_device *master);
/* RSS keys are 40 or 52 bytes long */
#define NETDEV_RSS_KEY_LEN 52
diff --git a/net/core/dev.c b/net/core/dev.c
index 93243479085f..12459036d0da 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7225,6 +7225,23 @@ void netdev_lower_state_changed(struct net_device
*lower_dev,
}
EXPORT_SYMBOL(netdev_lower_state_changed);
+/**
+ * netdev_is_upper_master - Test if a device is a master, direct or indirect,
+ * of another one.
+ * @dev: device to start looking from
+ * @master: device to test if master of dev
+ */
+bool netdev_is_upper_master(struct net_device *dev, struct net_device *master)
+{
+ if (!dev)
+ return false;
+
+ if (dev->ifindex == master->ifindex)
+ return true;
+ return netdev_is_upper_master(netdev_master_upper_dev_get(dev), master);
+}
+EXPORT_SYMBOL(netdev_is_upper_master);
+
static void dev_change_rx_flags(struct net_device *dev, int flags)
{
const struct net_device_ops *ops = dev->netdev_ops;
--
