skmsg: Lock ingress_skb when purging

Currently we purge the ingress_skb queue only when psock
refcnt goes down to 0, so locking the queue is not necessary,
but in order to be called during ->close, we have to lock it
here.

Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Jakub Sitnicki <[email protected]>
Acked-by: John Fastabend <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

Author: Cong Wang

net/core/skmsg.c

@@ -634,7 +634,7 @@ static void sk_psock_zap_ingress(struct sk_psock *psock)
 {
 	struct sk_buff *skb;
 
-	while ((skb = __skb_dequeue(&psock->ingress_skb)) != NULL) {
+	while ((skb = skb_dequeue(&psock->ingress_skb)) != NULL) {
 		skb_bpf_redirect_clear(skb);
 		kfree_skb(skb);
 	}