[PATCH 5.15 067/123] netfilter: ctnetlink: fix compilation warning after data race fixes in ct mark

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>

[ Upstream commit 1feeae071507ad65cf9f462a1bdd543a4bf89e71 ]

All warnings (new ones prefixed by >>):

   net/netfilter/nf_conntrack_netlink.c: In function '__ctnetlink_glue_build':
>> net/netfilter/nf_conntrack_netlink.c:2674:13: warning: unused variable 'mark' [-Wunused-variable]
    2674 |         u32 mark;
         |             ^~~~

Fixes: 52d1aa8b8249 ("netfilter: conntrack: Fix data-races around ct mark")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Tested-by: Ivan Babrou <ivan@ivan.computer>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/netfilter/nf_conntrack_netlink.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 1727a4c4764f..2cc6092b4f86 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -322,8 +322,13 @@ ctnetlink_dump_timestamp(struct sk_buff *skb, const struct nf_conn *ct)
 }
 
 #ifdef CONFIG_NF_CONNTRACK_MARK
-static int ctnetlink_dump_mark(struct sk_buff *skb, u32 mark)
+static int ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct)
 {
+	u32 mark = READ_ONCE(ct->mark);
+
+	if (!mark)
+		return 0;
+
 	if (nla_put_be32(skb, CTA_MARK, htonl(mark)))
 		goto nla_put_failure;
 	return 0;
@@ -537,7 +542,7 @@ static int ctnetlink_dump_extinfo(struct sk_buff *skb,
 static int ctnetlink_dump_info(struct sk_buff *skb, struct nf_conn *ct)
 {
 	if (ctnetlink_dump_status(skb, ct) < 0 ||
-	    ctnetlink_dump_mark(skb, READ_ONCE(ct->mark)) < 0 ||
+	    ctnetlink_dump_mark(skb, ct) < 0 ||
 	    ctnetlink_dump_secctx(skb, ct) < 0 ||
 	    ctnetlink_dump_id(skb, ct) < 0 ||
 	    ctnetlink_dump_use(skb, ct) < 0 ||
@@ -716,7 +721,6 @@ ctnetlink_conntrack_event(unsigned int events, const struct nf_ct_event *item)
 	struct sk_buff *skb;
 	unsigned int type;
 	unsigned int flags = 0, group;
-	u32 mark;
 	int err;
 
 	if (events & (1 << IPCT_DESTROY)) {
@@ -821,9 +825,8 @@ ctnetlink_conntrack_event(unsigned int events, const struct nf_ct_event *item)
 	}
 
 #ifdef CONFIG_NF_CONNTRACK_MARK
-	mark = READ_ONCE(ct->mark);
-	if ((events & (1 << IPCT_MARK) || mark) &&
-	    ctnetlink_dump_mark(skb, mark) < 0)
+	if (events & (1 << IPCT_MARK) &&
+	    ctnetlink_dump_mark(skb, ct) < 0)
 		goto nla_put_failure;
 #endif
 	nlmsg_end(skb, nlh);
@@ -2692,7 +2695,6 @@ static int __ctnetlink_glue_build(struct sk_buff *skb, struct nf_conn *ct)
 {
 	const struct nf_conntrack_zone *zone;
 	struct nlattr *nest_parms;
-	u32 mark;
 
 	zone = nf_ct_zone(ct);
 
@@ -2754,8 +2756,7 @@ static int __ctnetlink_glue_build(struct sk_buff *skb, struct nf_conn *ct)
 		goto nla_put_failure;
 
 #ifdef CONFIG_NF_CONNTRACK_MARK
-	mark = READ_ONCE(ct->mark);
-	if (mark && ctnetlink_dump_mark(skb, mark) < 0)
+	if (ctnetlink_dump_mark(skb, ct) < 0)
 		goto nla_put_failure;
 #endif
 	if (ctnetlink_dump_labels(skb, ct) < 0)
-- 
2.35.1