net: add a limit parameter to sk_add_backlog()

sk_add_backlog() & sk_rcvqueues_full() hard coded sk_rcvbuf as the
memory limit. We need to make this limit a parameter for TCP use.

No functional change expected in this patch, all callers still using the
old sk_rcvbuf limit.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Cc: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 4 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 4cdb9b3..4e9d01e 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -709,17 +709,19 @@ static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
  * Do not take into account this skb truesize,
  * to allow even a single big packet to come.
  */
-static inline bool sk_rcvqueues_full(const struct sock *sk, const struct sk_buff *skb)
+static inline bool sk_rcvqueues_full(const struct sock *sk, const struct sk_buff *skb,
+				     unsigned int limit)
 {
 	unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
 
-	return qsize > sk->sk_rcvbuf;
+	return qsize > limit;
 }
 
 /* The per-socket spinlock must be held here. */
-static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb)
+static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
+					      unsigned int limit)
 {
-	if (sk_rcvqueues_full(sk, skb))
+	if (sk_rcvqueues_full(sk, skb, limit))
 		return -ENOBUFS;
 
 	__sk_add_backlog(sk, skb);