1 files changed, 8 insertions, 12 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index a85d863c4419..60111a0fc201 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -212,12 +212,12 @@ void tcp_select_initial_window(int __space, __u32 mss,
 
         /* If no clamp set the clamp to the max possible scaled window */
         if (*window_clamp == 0)
-                (*window_clamp) = (65535 << 14);
+                (*window_clamp) = (U16_MAX << TCP_MAX_WSCALE);
         space = min(*window_clamp, space);
 
         /* Quantize space offering to a multiple of mss if possible. */
         if (space > mss)
-                space = (space / mss) * mss;
+                space = rounddown(space, mss);
 
         /* NOTE: offering an initial window larger than 32767
          * will break some buggy TCP stacks. If the admin tells us
@@ -234,13 +234,11 @@ void tcp_select_initial_window(int __space, __u32 mss,
 
         (*rcv_wscale) = 0;
         if (wscale_ok) {
-                /* Set window scaling on max possible window
-                 * See RFC1323 for an explanation of the limit to 14
-                 */
+                /* Set window scaling on max possible window */
                 space = max_t(u32, space, sysctl_tcp_rmem[2]);
                 space = max_t(u32, space, sysctl_rmem_max);
                 space = min_t(u32, space, *window_clamp);
-                while (space > 65535 && (*rcv_wscale) < 14) {
+                while (space > U16_MAX && (*rcv_wscale) < TCP_MAX_WSCALE) {
                         space >>= 1;
                         (*rcv_wscale)++;
                 }
@@ -253,7 +251,7 @@ void tcp_select_initial_window(int __space, __u32 mss,
         }
 
         /* Set the clamp no higher than max representable value */
-        (*window_clamp) = min(65535U << (*rcv_wscale), *window_clamp);
+        (*window_clamp) = min_t(__u32, U16_MAX << (*rcv_wscale), *window_clamp);
 }
 EXPORT_SYMBOL(tcp_select_initial_window);
 
@@ -2566,7 +2564,6 @@ 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;
 
@@ -2574,10 +2571,9 @@ 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
@@ -2587,7 +2583,7 @@ 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;