[3/5] netdev: HH_DATA_OFF bugfix

[Jiri Benc <jbenc@xxxxxxx>]

When the hardware header size is a multiple of HH_DATA_MOD, HH_DATA_OFF()
incorrectly returns HH_DATA_MOD (instead of 0).

Signed-off-by: Jiri Benc <jbenc@xxxxxxx>

--- linux/include/linux/netdevice.h
+++ work/include/linux/netdevice.h
@@ -204,7 +209,7 @@
        /* cached hardware header; allow for machine alignment needs.        */
 #define HH_DATA_MOD    16
 #define HH_DATA_OFF(__len) \
-       (HH_DATA_MOD - ((__len) & (HH_DATA_MOD - 1)))
+       (HH_DATA_MOD - (((__len - 1) & (HH_DATA_MOD - 1)) + 1))
 #define HH_DATA_ALIGN(__len) \
        (((__len)+(HH_DATA_MOD-1))&~(HH_DATA_MOD - 1))
        unsigned long   hh_data[HH_DATA_ALIGN(LL_MAX_HEADER) / sizeof(long)];


--
Jiri Benc
SUSE Labs