mptcp: define more local variables sk

'(struct sock *)msk' is used several times in mptcp_nl_cmd_announce(),
mptcp_nl_cmd_remove() or mptcp_userspace_pm_set_flags() in pm_userspace.c,
it's worth adding a local variable sk to point it.

Reviewed-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20231025-send-net-next-20231025-v1-8-db8f25f798eb@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: geliangtang

net/mptcp/pm_userspace.c

@@ -152,6 +152,7 @@ int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
 	struct mptcp_pm_addr_entry addr_val;
 	struct mptcp_sock *msk;
 	int err = -EINVAL;
+	struct sock *sk;
 	u32 token_val;
 
 	if (!addr || !token) {
@@ -167,6 +168,8 @@ int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
 		return err;
 	}
 
+	sk = (struct sock *)msk;
+
 	if (!mptcp_pm_is_userspace(msk)) {
 		GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
 		goto announce_err;
@@ -190,7 +193,7 @@ int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
 		goto announce_err;
 	}
 
-	lock_sock((struct sock *)msk);
+	lock_sock(sk);
 	spin_lock_bh(&msk->pm.lock);
 
 	if (mptcp_pm_alloc_anno_list(msk, &addr_val.addr)) {
@@ -200,11 +203,11 @@ int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	spin_unlock_bh(&msk->pm.lock);
-	release_sock((struct sock *)msk);
+	release_sock(sk);
 
 	err = 0;
  announce_err:
-	sock_put((struct sock *)msk);
+	sock_put(sk);
 	return err;
 }
 
@@ -251,6 +254,7 @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 	struct mptcp_sock *msk;
 	LIST_HEAD(free_list);
 	int err = -EINVAL;
+	struct sock *sk;
 	u32 token_val;
 	u8 id_val;
 
@@ -268,6 +272,8 @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 		return err;
 	}
 
+	sk = (struct sock *)msk;
+
 	if (!mptcp_pm_is_userspace(msk)) {
 		GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
 		goto remove_err;
@@ -278,7 +284,7 @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 		goto remove_err;
 	}
 
-	lock_sock((struct sock *)msk);
+	lock_sock(sk);
 
 	list_for_each_entry(entry, &msk->pm.userspace_pm_local_addr_list, list) {
 		if (entry->addr.id == id_val) {
@@ -289,23 +295,23 @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 
 	if (!match) {
 		GENL_SET_ERR_MSG(info, "address with specified id not found");
-		release_sock((struct sock *)msk);
+		release_sock(sk);
 		goto remove_err;
 	}
 
 	list_move(&match->list, &free_list);
 
 	mptcp_pm_remove_addrs(msk, &free_list);
 
-	release_sock((struct sock *)msk);
+	release_sock(sk);
 
 	list_for_each_entry_safe(match, entry, &free_list, list) {
-		sock_kfree_s((struct sock *)msk, match, sizeof(*match));
+		sock_kfree_s(sk, match, sizeof(*match));
 	}
 
 	err = 0;
  remove_err:
-	sock_put((struct sock *)msk);
+	sock_put(sk);
 	return err;
 }
 
@@ -518,6 +524,7 @@ int mptcp_userspace_pm_set_flags(struct net *net, struct nlattr *token,
 {
 	struct mptcp_sock *msk;
 	int ret = -EINVAL;
+	struct sock *sk;
 	u32 token_val;
 
 	token_val = nla_get_u32(token);
@@ -526,18 +533,20 @@ int mptcp_userspace_pm_set_flags(struct net *net, struct nlattr *token,
 	if (!msk)
 		return ret;
 
+	sk = (struct sock *)msk;
+
 	if (!mptcp_pm_is_userspace(msk))
 		goto set_flags_err;
 
 	if (loc->addr.family == AF_UNSPEC ||
 	    rem->addr.family == AF_UNSPEC)
 		goto set_flags_err;
 
-	lock_sock((struct sock *)msk);
+	lock_sock(sk);
 	ret = mptcp_pm_nl_mp_prio_send_ack(msk, &loc->addr, &rem->addr, bkup);
-	release_sock((struct sock *)msk);
+	release_sock(sk);
 
 set_flags_err:
-	sock_put((struct sock *)msk);
+	sock_put(sk);
 	return ret;
 }