From 7a91b434e2bad554b709265db7603b1aa52dd92e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 26 Sep 2010 18:53:07 -0700 Subject: [PATCH] net: update SOCK_MIN_RCVBUF SOCK_MIN_RCVBUF current value is 256 bytes It doesnt permit to receive the smallest possible frame, considering socket sk_rmem_alloc/sk_rcvbuf account skb truesizes. On 64bit arches, sizeof(struct sk_buff) is 240 bytes. Add the typical 64 bytes of headroom, and we go over the limit. With old kernels and 32bit arches, we were under the limit, if netdriver was doing copybreak. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/sock.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/include/net/sock.h b/include/net/sock.h index 8ae97c4970df..73a4f9702a65 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1558,7 +1558,11 @@ static inline void sk_wake_async(struct sock *sk, int how, int band) } #define SOCK_MIN_SNDBUF 2048 -#define SOCK_MIN_RCVBUF 256 +/* + * Since sk_rmem_alloc sums skb->truesize, even a small frame might need + * sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak + */ +#define SOCK_MIN_RCVBUF (2048 + sizeof(struct sk_buff)) static inline void sk_stream_moderate_sndbuf(struct sock *sk) { -- 2.20.1