net: relax rcvbuf limits

skb->truesize might be big even for a small packet.

Its even bigger after commit 87fb4b7b533 (net: more accurate skb
truesize) and big MTU.

We should allow queueing at least one packet per receiver, even with a
low RCVBUF setting.

Reported-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 5 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index 4ed7b1d12f5e..b23f174ab84c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -288,11 +288,7 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
         unsigned long flags;
         struct sk_buff_head *list = &sk->sk_receive_queue;
 
-        /* Cast sk->rcvbuf to unsigned... It's pointless, but reduces
-           number of warnings when compiling with -W --ANK
-         */
-        if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
-            (unsigned)sk->sk_rcvbuf) {
+        if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) {
                 atomic_inc(&sk->sk_drops);
                 trace_sock_rcvqueue_full(sk, skb);
                 return -ENOMEM;