From 4703174764ab41a80fbbab9cc1d5e029b9defbe7 Mon Sep 17 00:00:00 2001 From: Parav Pandit Date: Tue, 16 Sep 2025 14:11:01 +0300 Subject: [PATCH] RDMA/core: Resolve MAC of next-hop device without ARP support [ Upstream commit 200651b9b8aadfbbec852f0e5d042d9abe75e2ab ] Currently, if the next-hop netdevice does not support ARP resolution, the destination MAC address is silently set to zero without reporting an error. This leads to incorrect behavior and may result in packet transmission failures. Fix this by deferring MAC resolution to the IP stack via neighbour lookup, allowing proper resolution or error reporting as appropriate. Fixes: 7025fcd36bd6 ("IB: address translation to map IP toIB addresses (GIDs)") Signed-off-by: Parav Pandit Reviewed-by: Vlad Dumitrescu Signed-off-by: Edward Srouji Link: https://patch.msgid.link/20250916111103.84069-3-edwards@nvidia.com Signed-off-by: Leon Romanovsky Signed-off-by: Sasha Levin --- drivers/infiniband/core/addr.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c index f253295795f0..cdb3b99e057c 100644 --- a/drivers/infiniband/core/addr.c +++ b/drivers/infiniband/core/addr.c @@ -460,14 +460,10 @@ static int addr_resolve_neigh(const struct dst_entry *dst, { int ret = 0; - if (ndev_flags & IFF_LOOPBACK) { + if (ndev_flags & IFF_LOOPBACK) memcpy(addr->dst_dev_addr, addr->src_dev_addr, MAX_ADDR_LEN); - } else { - if (!(ndev_flags & IFF_NOARP)) { - /* If the device doesn't do ARP internally */ - ret = fetch_ha(dst, addr, dst_in, seq); - } - } + else + ret = fetch_ha(dst, addr, dst_in, seq); return ret; }