Patch "mptcp: diag: switch to context structure" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    mptcp: diag: switch to context structure

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mptcp-diag-switch-to-context-structure.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 2482ba8f5be230a53a8b5f0392878c7ec331a4a7
Author: Florian Westphal <fw@xxxxxxxxx>
Date:   Fri Apr 8 12:45:58 2022 -0700

    mptcp: diag: switch to context structure
    
    [ Upstream commit 6b9ea5c81ea2bed80dc98a38d475124a87e7ab5d ]
    
    Raw access to cb->arg[] is deprecated, use a context structure.
    
    Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
    Signed-off-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Stable-dep-of: 871019b22d1b ("net: set SOCK_RCU_FREE before inserting socket into hashtable")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/mptcp/mptcp_diag.c b/net/mptcp/mptcp_diag.c
index 292374fb07792..fb98b438b2c90 100644
--- a/net/mptcp/mptcp_diag.c
+++ b/net/mptcp/mptcp_diag.c
@@ -66,20 +66,28 @@ static int mptcp_diag_dump_one(struct netlink_callback *cb,
 	return err;
 }
 
+struct mptcp_diag_ctx {
+	long s_slot;
+	long s_num;
+};
+
 static void mptcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 			    const struct inet_diag_req_v2 *r)
 {
 	bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN);
+	struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx;
 	struct net *net = sock_net(skb->sk);
 	struct inet_diag_dump_data *cb_data;
 	struct mptcp_sock *msk;
 	struct nlattr *bc;
 
+	BUILD_BUG_ON(sizeof(cb->ctx) < sizeof(*diag_ctx));
+
 	cb_data = cb->data;
 	bc = cb_data->inet_diag_nla_bc;
 
-	while ((msk = mptcp_token_iter_next(net, &cb->args[0], &cb->args[1])) !=
-	       NULL) {
+	while ((msk = mptcp_token_iter_next(net, &diag_ctx->s_slot,
+					    &diag_ctx->s_num)) != NULL) {
 		struct inet_sock *inet = (struct inet_sock *)msk;
 		struct sock *sk = (struct sock *)msk;
 		int ret = 0;
@@ -101,7 +109,7 @@ static void mptcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 		sock_put(sk);
 		if (ret < 0) {
 			/* will retry on the same position */
-			cb->args[1]--;
+			diag_ctx->s_num--;
 			break;
 		}
 		cond_resched();