On Mon, Jan 09, 2023 at 02:20:02PM +0200, Ido Schimmel wrote: > On Mon, Jan 09, 2023 at 01:56:53PM +0200, Vladimir Oltean wrote: > > On Mon, Jan 09, 2023 at 01:43:46PM +0200, Ido Schimmel wrote: > > > OK, thanks for confirming. Will send a patch later this week if Tobias > > > won't take care of it by then. First patch will probably be [1] to make > > > sure we dump the correct MST state to user space. It will also make it > > > easier to show the problem and validate the fix. > > > > > > [1] > > > diff --git a/net/bridge/br.c b/net/bridge/br.c > > > index 4f5098d33a46..f02a1ad589de 100644 > > > --- a/net/bridge/br.c > > > +++ b/net/bridge/br.c > > > @@ -286,7 +286,7 @@ int br_boolopt_get(const struct net_bridge *br, enum br_boolopt_id opt) > > > case BR_BOOLOPT_MCAST_VLAN_SNOOPING: > > > return br_opt_get(br, BROPT_MCAST_VLAN_SNOOPING_ENABLED); > > > case BR_BOOLOPT_MST_ENABLE: > > > - return br_opt_get(br, BROPT_MST_ENABLED); > > > + return br_mst_is_enabled(br); > > > > Well, this did report the correct MST state despite the incorrect static > > branch state, no? The users of br_mst_is_enabled(br) are broken, not > > those of br_opt_get(br, BROPT_MST_ENABLED). > > I should have said "actual"/"effective" instead of "correct". IMO, it's > better to use the same conditional in the both the data and control > paths to eliminate discrepancies. Without the patch, a user will see > that MST is supposedly enabled when it is actually disabled in the data > path. The discussion is about to get philosophical, but I don't know if it's necessary to make a bug more widespread before fixing it.. The br_mst_used is an optimization to avoid calling br_opt_get() when surely MST is not enabled. There should be no discrepancy between using and not using it, if the static branch works correctly (not the case here). I would also expect that consolidation to be part of net-next though. > > Anyway, I see there's a br_mst_is_enabled() and also a br_mst_enabled()?! > > One is used in the fast path and the other in the slow path. They should > > probably be merged, I guess. They both exist probably because somebody > > thought that the "if (!netif_is_bridge_master(dev))" test is redundant > > in the fast path. > > The single user of br_mst_enabled() (DSA) is not affected by the bug > (only the SW data path is), so I suggest making this consolidation in > net-next after the bug is fixed. OK? Yes, net-next, sure.
