From 9eb5bf838d06aa6ddebe4aca6b5cedcf2eb53b86 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 3 Jul 2013 05:02:22 -0700
Subject: [PATCH] net: sock: fix TCP_SKB_MIN_TRUESIZE
commit eea86af6b1e18d ("net: sock: adapt SOCK_MIN_RCVBUF and
SOCK_MIN_SNDBUF") forgot the sk_buff alignment taken into account
in __alloc_skb() : skb->truesize = SKB_TRUESIZE(size);
While above commit fixed the sender issue, the receiver is still
dropping the second packet (on loopback device), because the receiver
socket can not really hold two skbs :
First packet truesize already is above sk_rcvbuf, so even TCP coalescing
cannot help.
On a typical 64bit build, each tcp skb truesize is 2304, instead of 2272
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Tested-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/net/sock.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index ea6206ccc896..95a5a2c6925a 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2052,7 +2052,7 @@ static inline void sk_wake_async(struct sock *sk, int how, int band)
* Note: for send buffers, TCP works better if we can build two skbs at
* minimum.
*/
-#define TCP_SKB_MIN_TRUESIZE (2048 + sizeof(struct sk_buff))
+#define TCP_SKB_MIN_TRUESIZE (2048 + SKB_DATA_ALIGN(sizeof(struct sk_buff)))
#define SOCK_MIN_SNDBUF (TCP_SKB_MIN_TRUESIZE * 2)
#define SOCK_MIN_RCVBUF TCP_SKB_MIN_TRUESIZE
--
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