bpf: Fix unused-var without NETDEVICES

A recent commit added new variables only used if CONFIG_NETDEVICES is
set. A simple fix would be to only declare these variables if the same
condition is valid but Alexei suggested an even simpler solution:

    since CONFIG_NETDEVICES doesn't change anything in .h I think the
    best is to remove #ifdef CONFIG_NETDEVICES from net/core/filter.c
    and rely on sock_bindtoindex() returning ENOPROTOOPT in the extreme
    case of oddly configured kernels.

Fixes: bf02402702f4 ("bpf: Allow SO_BINDTODEVICE opt in bpf_setsockopt")
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200603190347.2310320-1-matthieu.baerts@tessares.net

diff --git a/net/core/filter.c b/net/core/filter.c
index d01a244b5087af8313bbe905a7ca77aceb1a5aaa..90d2eb77002fc7389d4cdb86d48dcf20fca43cdb 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4340,8 +4340,6 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
                        }
                        break;
                case SO_BINDTODEVICE:
-                       ret = -ENOPROTOOPT;
-#ifdef CONFIG_NETDEVICES
                        optlen = min_t(long, optlen, IFNAMSIZ - 1);
                        strncpy(devname, optval, optlen);
                        devname[optlen] = 0;
@@ -4360,7 +4358,6 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
                                dev_put(dev);
                        }
                        ret = sock_bindtoindex(sk, ifindex, false);
-#endif
                        break;
                default:
                        ret = -EINVAL;