netdev - [PATCH net-next 04/27] skbuff: drop zero check from skb_zcopy

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Date:   Sun,  3 Apr 2022 14:06:16 +0100
From:   Pavel Begunkov <asml.silence@...il.com>
To:     netdev@...r.kernel.org, "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     Eric Dumazet <edumazet@...gle.com>, Wei Liu <wei.liu@...nel.org>,
        Paul Durrant <paul@....org>,
        Pavel Begunkov <asml.silence@...il.com>
Subject: [PATCH net-next 04/27] skbuff: drop zero check from skb_zcopy_set

Only two skb_zcopy_set() callers may pass a null skb, so kill a null
check from the function, which can't be easily compiled out and hand
code where needed. This will also help with further patches.

Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
 include/linux/skbuff.h | 2 +-
 net/ipv4/ip_output.c   | 3 ++-
 net/ipv6/ip6_output.c  | 3 ++-
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 3a30cae8b0a5..f5de5c9cc3da 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1679,7 +1679,7 @@ static inline void skb_zcopy_init(struct sk_buff *skb, struct ubuf_info *uarg)
 static inline void skb_zcopy_set(struct sk_buff *skb, struct ubuf_info *uarg,
 				 bool *have_ref)
 {
-	if (skb && uarg && !skb_zcopy(skb)) {
+	if (uarg && !skb_zcopy(skb)) {
 		if (unlikely(have_ref && *have_ref))
 			*have_ref = false;
 		else
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 00b4bf26fd93..f864b8c48e42 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1027,7 +1027,8 @@ static int __ip_append_data(struct sock *sk,
 			paged = true;
 		} else {
 			uarg->zerocopy = 0;
-			skb_zcopy_set(skb, uarg, &extra_uref);
+			if (skb)
+				skb_zcopy_set(skb, uarg, &extra_uref);
 		}
 	}
 
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index e23f058166af..e9b039f56637 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1529,7 +1529,8 @@ static int __ip6_append_data(struct sock *sk,
 			paged = true;
 		} else {
 			uarg->zerocopy = 0;
-			skb_zcopy_set(skb, uarg, &extra_uref);
+			if (skb)
+				skb_zcopy_set(skb, uarg, &extra_uref);
 		}
 	}
 
-- 
2.35.1