[PATCH net-next] net: sched: cls_u32: use struct_size() helper

From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Jamal Hadi Salim <jhs@mojatatu.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Jiri Pirko <jiri@resnulli.us>,
	"David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH net-next] net: sched: cls_u32: use struct_size() helper
Date: Wed, 1 May 2019 11:23:15 -0500	[thread overview]
Message-ID: <20190501162315.GA27166@embeddedor> (raw)

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes, in particular in the
context in which this code is being used.

So, replace code of the following form:

sizeof(*s) + s->nkeys*sizeof(struct tc_u32_key)

with:

struct_size(s, keys, s->nkeys)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 net/sched/cls_u32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 04e9ef088535..4b8710a266cc 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -847,7 +847,7 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp,
 	/* Similarly success statistics must be moved as pointers */
 	new->pcpu_success = n->pcpu_success;
 #endif
-	memcpy(&new->sel, s, sizeof(*s) + s->nkeys*sizeof(struct tc_u32_key));
+	memcpy(&new->sel, s, struct_size(s, keys, s->nkeys));
 
 	if (tcf_exts_init(&new->exts, net, TCA_U32_ACT, TCA_U32_POLICE)) {
 		kfree(new);
-- 
2.21.0

