Re: [PATCH v2 2/2] bonding: reuse neigh_setup from slave neigh_parms
From: Kuniyuki Iwashima <kuniyu@google.com>
Date: 2026-07-03 06:41:10
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From: Paritosh Potukuchi <redacted> Date: Wed, 1 Jul 2026 08:16:00 +0000
quoted hunk ↗ jump to hunk
bond_neigh_init() currently relies on the slave device's ndo_neigh_setup() callback to obtain a neigh_setup() handler. When an initialized neigh_parms instance already exists for the slave device, reuse the neigh_setup() callback stored in it instead of invoking ndo_neigh_setup() again. If no neigh_parms instance is found, or no neigh_setup() callback is present, retain the existing ndo_neigh_setup() fallback path. This avoids unnecessary ndo_neigh_setup() invocations while preserving existing behaviour. Signed-off-by: Paritosh Potukuchi <redacted> --- drivers/net/bonding/bond_main.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index e044fc733b8c..d2e4dae4e97c 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c@@ -4719,7 +4719,7 @@ static int bond_neigh_init(struct neighbour *n) { struct bonding *bond = netdev_priv(n->dev); const struct net_device_ops *slave_ops; - struct neigh_parms parms; + struct neigh_parms parms, *p; struct slave *slave; int ret = 0;@@ -4727,6 +4727,14 @@ static int bond_neigh_init(struct neighbour *n) slave = bond_first_slave_rcu(bond); if (!slave) goto out; + + p = neigh_parms_lookup_dev(n->tbl, slave->dev);
This introduces O(n) list traversal while it can be done with fixed costs (3 dereferences + 1 call). Since neigh_table is global (arp_tbl or nd_tbl), the O(n) list traversal could take longer and rather de-optimise.
+
+ if (p && p->neigh_setup) {
+ ret = p->neigh_setup(n);
+ goto out;
+ }
+
slave_ops = slave->dev->netdev_ops;
if (!slave_ops->ndo_neigh_setup)
goto out;
--
2.43.0