net: llc: drop VLA in llc_sap_mcast() (678f4bda) · Commits · 戴 / test

Avoid a VLA[1] by using a real constant expression instead of a variable. The compiler should be able to optimize the original code and avoid using an actual VLA. Anyway this change is useful because it will avoid a false positive with -Wvla, it might also help the compiler generating better code. [1] https://lkml.org/lkml/2018/3/7/621 Signed-off-by:

Salvatore Mesoraca <s.mesoraca16@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/llc/llc_sap.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -394,8 +394,9 @@ static void llc_sap_mcast(struct llc_sap *sap,
		const struct llc_addr *laddr,
		struct sk_buff *skb)
		{
		int i = 0, count = 256 / sizeof(struct sock *);
		struct sock sk, stack[count];
		int i = 0;
		struct sock *sk;
		struct sock stack[256 / sizeof(struct sock )];
		struct llc_sock *llc;
		struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);

		@@ -408,7 +409,7 @@ static void llc_sap_mcast(struct llc_sap *sap,
		continue;

		sock_hold(sk);
		if (i < count)
		if (i < ARRAY_SIZE(stack))
		stack[i++] = sk;
		else {
		llc_do_mcast(sap, skb, stack, i);

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