From cab2cd77005187828273adfec04f3ad18a63cb3d Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Tue, 15 Feb 2022 19:02:10 +0200 Subject: [PATCH] net: bridge: vlan: make __vlan_add_flags react only to PVID and UNTAGGED Currently there is a very subtle aspect to the behavior of __vlan_add_flags(): it changes the struct net_bridge_vlan flags and pvid, yet it returns true ("changed") even if none of those changed, just a transition of br_vlan_is_brentry(v) took place from false to true. This can be seen in br_vlan_add_existing(), however we do not actually rely on this subtle behavior, since the "if" condition that checks that the vlan wasn't a brentry before had a useless (until now) assignment: *changed = true; Make things more obvious by actually making __vlan_add_flags() do what's written on the box, and be more specific about what is actually written on the box. This is needed because further transformations will be done to __vlan_add_flags(). Signed-off-by: Vladimir Oltean Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- net/bridge/br_vlan.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c index 33c879c1ecf3..f9c0e034c5b4 100644 --- a/net/bridge/br_vlan.c +++ b/net/bridge/br_vlan.c @@ -58,7 +58,9 @@ static bool __vlan_delete_pvid(struct net_bridge_vlan_group *vg, u16 vid) return true; } -/* return true if anything changed, false otherwise */ +/* Returns true if the BRIDGE_VLAN_INFO_PVID and BRIDGE_VLAN_INFO_UNTAGGED bits + * of @flags produced any change onto @v, false otherwise + */ static bool __vlan_add_flags(struct net_bridge_vlan *v, u16 flags) { struct net_bridge_vlan_group *vg; @@ -80,7 +82,7 @@ static bool __vlan_add_flags(struct net_bridge_vlan *v, u16 flags) else v->flags &= ~BRIDGE_VLAN_INFO_UNTAGGED; - return ret || !!(old_flags ^ v->flags); + return ret || !!((old_flags ^ v->flags) & BRIDGE_VLAN_INFO_UNTAGGED); } static int __vlan_vid_add(struct net_device *dev, struct net_bridge *br,