linux-kernel - [PATCH] net: bpfilter: fallback to netfilter if failed to load bpfilter kernel module

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Date:   Wed, 15 May 2019 14:40:52 +0300
From:   Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        Alexei Starovoitov <ast@...nel.org>,
        linux-kernel@...r.kernel.org,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH] net: bpfilter: fallback to netfilter if failed to load
 bpfilter kernel module

If bpfilter is not available return ENOPROTOOPT to fallback to netfilter.

Function request_module() returns both errors and userspace exit codes.
Just ignore them. Rechecking bpfilter_ops is enough.

Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
---
 net/ipv4/bpfilter/sockopt.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/bpfilter/sockopt.c b/net/ipv4/bpfilter/sockopt.c
index 15427163a041..0480918bfc7c 100644
--- a/net/ipv4/bpfilter/sockopt.c
+++ b/net/ipv4/bpfilter/sockopt.c
@@ -30,13 +30,11 @@ static int bpfilter_mbox_request(struct sock *sk, int optname,
 	mutex_lock(&bpfilter_ops.lock);
 	if (!bpfilter_ops.sockopt) {
 		mutex_unlock(&bpfilter_ops.lock);
-		err = request_module("bpfilter");
+		request_module("bpfilter");
 		mutex_lock(&bpfilter_ops.lock);
 
-		if (err)
-			goto out;
 		if (!bpfilter_ops.sockopt) {
-			err = -ECHILD;
+			err = -ENOPROTOOPT;
 			goto out;
 		}
 	}