net: make struct net_device::min_header_len 8-bit

This field is never big enough to warrant 16-bitness.

8-bit accesses enjoy shorted encoding on i386/x86_64 than 16-bit
accesses:

	add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-10 (-10)
	function                                     old     new   delta
	loopback_setup                               169     164      -5
	ether_setup                                  148     143      -5

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 8ea8a8b707558e389015db7ecf8387d37944b55d..b0aa089ce67fe4acec70b518a399db7e99a435e0 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1715,7 +1715,7 @@ struct net_device {
        unsigned int            max_mtu;
        unsigned short          type;
        unsigned short          hard_header_len;
-       unsigned short          min_header_len;
+       unsigned char           min_header_len;
 
        unsigned short          needed_headroom;
        unsigned short          needed_tailroom;