From: Daniel Borkmann Date: Wed, 19 Jun 2013 10:51:20 +0000 (+0200) Subject: net: sock: adapt SOCK_MIN_RCVBUF and SOCK_MIN_SNDBUF X-Git-Tag: v3.11-rc1~16^2~46 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eea86af6b1e18d6fa8dc959e3ddc0100f27aff9f;p=pandora-kernel.git net: sock: adapt SOCK_MIN_RCVBUF and SOCK_MIN_SNDBUF The current situation is that SOCK_MIN_RCVBUF is 2048 + sizeof(struct sk_buff)) while SOCK_MIN_SNDBUF is 2048. Since in both cases, skb->truesize is used for sk_{r,w}mem_alloc accounting, we should have both sizes adjusted via defining a TCP_SKB_MIN_TRUESIZE. Further, as Eric Dumazet points out, the minimal skb truesize in transmit path is SKB_TRUESIZE(2048) after commit f07d960df33c5 ("tcp: avoid frag allocation for small frames"), and tcp_sendmsg() tries to limit skb size to half the congestion window, meaning we try to build two skbs at minimum. Thus, having SOCK_MIN_SNDBUF as 2048 can hit a small regression for some applications setting to low SO_SNDBUF / SO_RCVBUF. Note that we define a TCP_SKB_MIN_TRUESIZE, because SKB_TRUESIZE(2048) adds SKB_DATA_ALIGN(sizeof(struct skb_shared_info)), but in case of TCP skbs, the skb_shared_info is part of the 2048 bytes allocation for skb->head. The minor adaption in sk_stream_moderate_sndbuf() is to silence a warning by using a typed max macro, as similarly done in SOCK_MIN_RCVBUF occurences, that would appear otherwise. Suggested-by: Eric Dumazet Signed-off-by: Daniel Borkmann Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- Reading git-diff-tree failed