From 1935299d9c946ac37eba3f820d2ce20885ec0739 Mon Sep 17 00:00:00 2001 From: Gao Feng Date: Thu, 30 Mar 2017 06:49:19 +0800 Subject: [PATCH] net: tcp: Refine the __tcp_select_window 1. Move the "window = tp->rcv_wnd;" into the condition block without tp->rx_opt.rcv_wscale. Because it is unnecessary when enable wscale; 2. Use the macro ALIGN instead of two statements. The two statements are used to make window align to 1< Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 22548b5f05cb..13971942211b 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2561,7 +2561,6 @@ u32 __tcp_select_window(struct sock *sk) /* Don't do rounding if we are using window scaling, since the * scaled window will not line up with the MSS boundary anyway. */ - window = tp->rcv_wnd; if (tp->rx_opt.rcv_wscale) { window = free_space; @@ -2569,10 +2568,9 @@ u32 __tcp_select_window(struct sock *sk) * Import case: prevent zero window announcement if * 1< mss. */ - if (((window >> tp->rx_opt.rcv_wscale) << tp->rx_opt.rcv_wscale) != window) - window = (((window >> tp->rx_opt.rcv_wscale) + 1) - << tp->rx_opt.rcv_wscale); + window = ALIGN(window, (1 << tp->rx_opt.rcv_wscale)); } else { + window = tp->rcv_wnd; /* Get the largest window that is a nice multiple of mss. * Window clamp already applied above. * If our current window offering is within 1 mss of the @@ -2582,7 +2580,7 @@ u32 __tcp_select_window(struct sock *sk) * is too small. */ if (window <= free_space - mss || window > free_space) - window = (free_space / mss) * mss; + window = rounddown(free_space, mss); else if (mss == full_space && free_space > window + (full_space >> 1)) window = free_space; -- 2.20.1