net: use unrcu_pointer() helper

[ Upstream commit b4cb4a13 ]

Toke mentioned unrcu_pointer() existence, allowing
to remove some of the ugly casts we have when using
xchg() for rcu protected pointers.

Also make inet_rcv_compat const.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20240604111603.45871-1-edumazet@google.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Stable-dep-of: eb02688c ("ipv6: release nexthop on device removal")
Signed-off-by: Sasha Levin <sashal@kernel.org>