diff mbox series

[net-next,01/17] net: bridge: br_switchdev: Tolerate -EOPNOTSUPP when replaying MDB

Message ID 009406289387d9d34b76085fa858b8cd4d287851.1689763088.git.petrm@nvidia.com (mailing list archive)
State Accepted
Commit 989280d6ea70b2d91b8b0e20ac11a6529a37ac08
Delegated to: Netdev Maintainers
Headers show
Series mlxsw: Permit enslavement to netdevices with uppers | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches (and no cover letter)
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1342 this patch: 1342
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 1365 this patch: 1365
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1365 this patch: 1365
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 19 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Petr Machata July 19, 2023, 11:01 a.m. UTC 
There are two kinds of MDB entries to be replayed: port MDB entries, and
host MDB entries. They are both replayed by br_switchdev_mdb_replay(). If
the driver supports one kind, but lacks the other, the first -EOPNOTSUPP
returned terminates the whole replay, including any further still-supported
objects in the list.

For this to cause issues, there must be MDB entries for both the host and
the port being replayed. In that case, if the driver bails out from
handling the host entry, the port entries are never replayed. However, the
replay is currently only done when a switchdev port joins a bridge. There
would be no port memberships at that point. Thus despite being erroneous,
the code does not cause observable bugs.

This is not an issue with other object kinds either, because there, each
function replays one object kind. If a driver does not support that kind,
it makes sense to bail out early. -EOPNOTSUPP is then ignored in
nbp_switchdev_sync_objs().

For MDB, suppress the -EOPNOTSUPP error code in br_switchdev_mdb_replay()
already, so that the whole list gets replayed.

The reason we need this patch is that a future patch will introduce a
replay that should be used when a front-panel port netdevice is enslaved to
a bridge lower, in particular a LAG. The LAG netdevice can already have
both host and port MDB entries. The port entries need to be replayed so
that they are offloaded on the port that joins the LAG.

Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Ivan Vecera <ivecera@redhat.com>
Cc: Roopa Prabhu <roopa@nvidia.com>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Cc: bridge@lists.linux-foundation.org
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
---
 net/bridge/br_switchdev.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
index ba95c4d74a60..e92e0338afee 100644
--- a/net/bridge/br_switchdev.c
+++ b/net/bridge/br_switchdev.c
@@ -727,6 +727,8 @@  br_switchdev_mdb_replay(struct net_device *br_dev, struct net_device *dev,
 		err = br_switchdev_mdb_replay_one(nb, dev,
 						  SWITCHDEV_OBJ_PORT_MDB(obj),
 						  action, ctx, extack);
+		if (err == -EOPNOTSUPP)
+			err = 0;
 		if (err)
 			goto out_free_mdb;
 	}
@@ -759,8 +761,10 @@  static int nbp_switchdev_sync_objs(struct net_bridge_port *p, const void *ctx,
 
 	err = br_switchdev_mdb_replay(br_dev, dev, ctx, true, blocking_nb,
 				      extack);
-	if (err && err != -EOPNOTSUPP)
+	if (err) {
+		/* -EOPNOTSUPP not propagated from MDB replay. */
 		return err;
+	}
 
 	err = br_switchdev_fdb_replay(br_dev, ctx, true, atomic_nb);
 	if (err && err != -EOPNOTSUPP)