On Mon, Nov 15, 2021 at 07:28:14PM +0100, Hauke Mehrtens wrote: > On 11/15/21 5:56 PM, Greg Kroah-Hartman wrote: > > From: Vladimir Oltean <vladimir.oltean@xxxxxxx> > > > > [ Upstream commit 49753a75b9a32de4c0393bb8d1e51ea223fda8e4 ] > > > > Looking at the code, the GSWIP switch appears to hold bridging service > > structures (VLANs, FDBs, forwarding rules) in PCE table entries. > > Hardware access to the PCE table is non-atomic, and is comprised of > > several register reads and writes. > > > > These accesses are currently serialized by the rtnl_lock, but DSA is > > changing its driver API and that lock will no longer be held when > > calling ->port_fdb_add() and ->port_fdb_del(). > > > > So this driver needs to serialize the access to the PCE table using its > > own locking scheme. This patch adds that. > > > > Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx> > > Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx> > > Acked-by: Hauke Mehrtens <hauke@xxxxxxxxxx> > > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > > --- > > drivers/net/dsa/lantiq_gswip.c | 28 +++++++++++++++++++++++----- > > 1 file changed, 23 insertions(+), 5 deletions(-) > > Hi Greg and Vladimir, > > I understood this is only needed when we apply the complete patch series > from Vladimir. This would only be needed when we also apply this patch: > > commit 5cdfde49a07f38663c277ddf2e56345ea1706fc2 > > Author: Vladimir Oltean <vladimir.oltean@xxxxxxx> > > Date: Fri Oct 22 21:43:10 2021 +0300 > > > > net: dsa: drop rtnl_lock from dsa_slave_switchdev_event_work > This was added in v5.16-rc1. > > Without this patch the sections are protected by rtnl_lock(). This is correct, this patch does not need to be backported, and unless it is needed for purposes other than fixing a bug, it should be dropped.
