From: Geliang Tang <tanggeliang@kylinos.cn>

Instead of using sock_kmalloc() to allocate an ip_options and then
immediately duplicate another ip_options to the newly allocated one in
ipv6_dup_options(), mptcp_copy_ip_options() and sctp_v4_copy_ip_options(),
the newly added sock_kmemdup() helper can be used to simplify the code.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/ipv6/exthdrs.c   | 3 +--
 net/mptcp/protocol.c | 7 ++-----
 net/sctp/protocol.c  | 7 ++-----
 3 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 6789623b2b0d..457de0745a33 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -1204,10 +1204,9 @@ ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
 {
 	struct ipv6_txoptions *opt2;
 
-	opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
+	opt2 = sock_kmemdup(sk, opt, opt->tot_len, GFP_ATOMIC);
 	if (opt2) {
 		long dif = (char *)opt2 - (char *)opt;
-		memcpy(opt2, opt, opt->tot_len);
 		if (opt2->hopopt)
 			*((char **)&opt2->hopopt) += dif;
 		if (opt2->dst0opt)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 6b61b7dee33b..ec23e65ef0f1 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3178,12 +3178,9 @@ static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk)
 	rcu_read_lock();
 	inet_opt = rcu_dereference(inet->inet_opt);
 	if (inet_opt) {
-		newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
+		newopt = sock_kmemdup(newsk, inet_opt, sizeof(*inet_opt) +
 				      inet_opt->opt.optlen, GFP_ATOMIC);
-		if (newopt)
-			memcpy(newopt, inet_opt, sizeof(*inet_opt) +
-			       inet_opt->opt.optlen);
-		else
+		if (!newopt)
 			net_warn_ratelimited("%s: Failed to copy ip options\n", __func__);
 	}
 	RCU_INIT_POINTER(newinet->inet_opt, newopt);
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 29727ed1008e..5407a3922101 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -185,12 +185,9 @@ static void sctp_v4_copy_ip_options(struct sock *sk, struct sock *newsk)
 	rcu_read_lock();
 	inet_opt = rcu_dereference(inet->inet_opt);
 	if (inet_opt) {
-		newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
+		newopt = sock_kmemdup(newsk, inet_opt, sizeof(*inet_opt) +
 				      inet_opt->opt.optlen, GFP_ATOMIC);
-		if (newopt)
-			memcpy(newopt, inet_opt, sizeof(*inet_opt) +
-			       inet_opt->opt.optlen);
-		else
+		if (!newopt)
 			pr_err("%s: Failed to copy ip options\n", __func__);
 	}
 	RCU_INIT_POINTER(newinet->inet_opt, newopt);
-- 
2.43.0

From: Geliang Tang <geliang@kernel.org>
Date: Fri, 28 Feb 2025 18:01:32 +0800
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> Instead of using sock_kmalloc() to allocate an ip_options and then
> immediately duplicate another ip_options to the newly allocated one in
> ipv6_dup_options(), mptcp_copy_ip_options() and sctp_v4_copy_ip_options(),
> the newly added sock_kmemdup() helper can be used to simplify the code.
> 
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>

Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>