[PATCH net-next 3/5] net: change sk_filter_reason() to return the reason by value

[Eric Dumazet <edumazet@google.com>]

sk_filter_trim_cap will soon return the reason by value,
do the same for sk_filter_reason().

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-21 (-21)
Function                                     old     new   delta
sock_queue_rcv_skb_reason                    128     126      -2
tun_net_xmit                                1146    1127     -19
Total: Before=29722661, After=29722640, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 drivers/net/tun.c      | 8 +++++---
 include/linux/filter.h | 9 ++++++---
 net/core/sock.c        | 4 ++--
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index c492fda6fc15a79c13f56cb15dc273331b854422..b183189f185354051bded95f43bd77ee4f7cde24 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1031,9 +1031,11 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto drop;
 	}
 
-	if (tfile->socket.sk->sk_filter &&
-	    sk_filter_reason(tfile->socket.sk, skb, &drop_reason))
-		goto drop;
+	if (tfile->socket.sk->sk_filter) {
+		drop_reason = sk_filter_reason(tfile->socket.sk, skb);
+		if (drop_reason)
+			goto drop;
+	}
 
 	len = run_ebpf_filter(tun, skb, len);
 	if (len == 0) {
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 44d7ae95ddbccd0ba72740b5547e91e1990686f2..59931e5810b4fcff5788616a3875767421dba3bc 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1102,10 +1102,13 @@ static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
 	return sk_filter_trim_cap(sk, skb, 1, &ignore_reason);
 }
 
-static inline int sk_filter_reason(struct sock *sk, struct sk_buff *skb,
-				   enum skb_drop_reason *reason)
+static inline enum skb_drop_reason
+sk_filter_reason(struct sock *sk, struct sk_buff *skb)
 {
-	return sk_filter_trim_cap(sk, skb, 1, reason);
+	enum skb_drop_reason drop_reason;
+
+	sk_filter_trim_cap(sk, skb, 1, &drop_reason);
+	return drop_reason;
 }
 
 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err);
diff --git a/net/core/sock.c b/net/core/sock.c
index d39a4d6ccafd9e03f4e82482d3f3e46ce5d58771..1ffcb15d0fc5e39201aab24616d40a37aa41c823 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -526,8 +526,8 @@ sock_queue_rcv_skb_reason(struct sock *sk, struct sk_buff *skb)
 	enum skb_drop_reason drop_reason;
 	int err;
 
-	err = sk_filter_reason(sk, skb, &drop_reason);
-	if (err)
+	drop_reason = sk_filter_reason(sk, skb);
+	if (drop_reason)
 		return drop_reason;
 
 	err = __sock_queue_rcv_skb(sk, skb);
-- 
2.53.0.1213.gd9a14994de-goog