[PATCH net-next] net: vlan: Avoid using BUG() in vlan_proto_idx()

[Florian Fainelli]

While we should always make sure that we specify a valid VLAN protocol
to vlan_proto_idx(), killing the machine when an invalid value is
specified is too harsh and not helpful for debugging. All callers are
capable of dealing with an error returned by vlan_proto_idx() so check
the index value and propagate it accordingly.

Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
---
 net/8021q/vlan.c |  3 +++
 net/8021q/vlan.h | 17 ++++++++++++-----
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index d4bcfd8f95bf..6c08de1116c1 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -57,6 +57,9 @@ static int vlan_group_prealloc_vid(struct vlan_group *vg,
        ASSERT_RTNL();
 
        pidx  = vlan_proto_idx(vlan_proto);
+       if (pidx < 0)
+               return -EINVAL;
+
        vidx  = vlan_id / VLAN_GROUP_ARRAY_PART_LEN;
        array = vg->vlan_devices_arrays[pidx][vidx];
        if (array != NULL)
diff --git a/net/8021q/vlan.h b/net/8021q/vlan.h
index bb7ec1a3915d..143e9c12dbd6 100644
--- a/net/8021q/vlan.h
+++ b/net/8021q/vlan.h
@@ -44,8 +44,8 @@ static inline unsigned int vlan_proto_idx(__be16 proto)
        case htons(ETH_P_8021AD):
                return VLAN_PROTO_8021AD;
        default:
-               BUG();
-               return 0;
+               WARN(1, "invalid VLAN protocol: 0x%04x\n", htons(proto));
+               return -EINVAL;
        }
 }
 
@@ -64,17 +64,24 @@ static inline struct net_device 
*vlan_group_get_device(struct vlan_group *vg,
                                                       __be16 vlan_proto,
                                                       u16 vlan_id)
 {
-       return __vlan_group_get_device(vg, vlan_proto_idx(vlan_proto), vlan_id);
+       int pidx = vlan_proto_idx(vlan_proto);
+
+       if (pidx < 0)
+               return NULL;
+
+       return __vlan_group_get_device(vg, pidx, vlan_id);
 }
 
 static inline void vlan_group_set_device(struct vlan_group *vg,
                                         __be16 vlan_proto, u16 vlan_id,
                                         struct net_device *dev)
 {
+       int pdix = vlan_proto_idx(vlan_proto);
        struct net_device **array;
-       if (!vg)
+
+       if (!vg || pdix < 0)
                return;
-       array = vg->vlan_devices_arrays[vlan_proto_idx(vlan_proto)]
+       array = vg->vlan_devices_arrays[pdix]
                                       [vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
        array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN] = dev;
 }
-- 
2.25.1