[RFC PATCH net-next 2/4] net: 8021q: vlan_core: allow use list of vlans for real device

[Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>]

It's redundancy for the drivers to hold the list of vlans when
absolutely the same list exists in vlan core. In most cases it's
needed only to traverse the vlan devices, their vids and sync some
settings with h/w, so add API to simplify this.

At least some of these drivers also can benefit:
grep "for_each.*vid" -r drivers/net/ethernet/

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c:
drivers/net/ethernet/synopsys/dwc-xlgmac-hw.c:
drivers/net/ethernet/qlogic/qlge/qlge_main.c:
drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c:
drivers/net/ethernet/via/via-rhine.c:
drivers/net/ethernet/via/via-velocity.c:
drivers/net/ethernet/intel/igb/igb_main.c:
drivers/net/ethernet/intel/ice/ice_main.c:
drivers/net/ethernet/intel/e1000/e1000_main.c:
drivers/net/ethernet/intel/i40e/i40e_main.c:
drivers/net/ethernet/intel/e1000e/netdev.c:
drivers/net/ethernet/intel/igbvf/netdev.c:
drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c:
drivers/net/ethernet/intel/ixgb/ixgb_main.c:
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c:
drivers/net/ethernet/amd/xgbe/xgbe-dev.c:
drivers/net/ethernet/emulex/benet/be_main.c:
drivers/net/ethernet/neterion/vxge/vxge-main.c:
drivers/net/ethernet/adaptec/starfire.c:
drivers/net/ethernet/brocade/bna/bnad.c:

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 include/linux/if_vlan.h | 10 ++++++++++
 net/8021q/vlan_core.c   | 27 +++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index 83ea4df6ab81..4ae3993f7166 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -133,6 +133,9 @@ struct vlan_pcpu_stats {
 
 extern struct net_device *__vlan_find_dev_deep_rcu(struct net_device *real_dev,
 					       __be16 vlan_proto, u16 vlan_id);
+extern int vlan_for_each(struct net_device *dev,
+			 int (*action)(struct net_device *dev, int vid,
+				       void *arg), void *arg);
 extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
 extern u16 vlan_dev_vlan_id(const struct net_device *dev);
 extern __be16 vlan_dev_vlan_proto(const struct net_device *dev);
@@ -236,6 +239,13 @@ __vlan_find_dev_deep_rcu(struct net_device *real_dev,
 	return NULL;
 }
 
+static inline int
+vlan_for_each(struct net_device *dev,
+	      int (*action)(struct net_device *dev, int vid, void *arg),
+	      void *arg)
+{
+}
+
 static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
 {
 	BUG();
diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index 4f60e86f4b8d..6308b5427a66 100644
--- a/net/8021q/vlan_core.c
+++ b/net/8021q/vlan_core.c
@@ -223,6 +223,33 @@ static int vlan_kill_rx_filter_info(struct net_device *dev, __be16 proto, u16 vi
 		return -ENODEV;
 }
 
+int vlan_for_each(struct net_device *dev,
+		  int (*action)(struct net_device *dev, int vid, void *arg),
+		  void *arg)
+{
+	struct vlan_vid_info *vid_info;
+	struct vlan_info *vlan_info;
+	struct net_device *vdev;
+	int ret;
+
+	ASSERT_RTNL();
+
+	vlan_info = rtnl_dereference(dev->vlan_info);
+	if (!vlan_info)
+		return 0;
+
+	list_for_each_entry(vid_info, &vlan_info->vid_list, list) {
+		vdev = vlan_group_get_device(&vlan_info->grp, vid_info->proto,
+					     vid_info->vid);
+		ret = action(vdev, vid_info->vid, arg);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(vlan_for_each);
+
 int vlan_filter_push_vids(struct vlan_info *vlan_info, __be16 proto)
 {
 	struct net_device *real_dev = vlan_info->real_dev;
-- 
2.17.1