Commit 1935299d authored by Gao Feng's avatar Gao Feng Committed by David S. Miller
Browse files

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<<wscale.
Use the ALIGN is more clearer.

3. Use the rounddown to make codes clearer.

Signed-off-by: default avatarGao Feng <fgao@ikuai8.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bae76dd9

net/ipv4/tcp_output.c

+3 −5
Original line number Diff line number Diff line
@@ -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<<rcv_wscale > 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;

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