The variable num_group_tail_writes is initialized but never used otherwise.
The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@@
type T;
identifier i;
constant C;
@@
(
extern T i;
|
- T i;
  <+... when != i
- i = C;
  ...+>
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
        struct ixgb_buffer *buffer_info;
        struct sk_buff *skb;
        unsigned int i;
-       int num_group_tail_writes;
        long cleancount;
 
        i = rx_ring->next_to_use;
        buffer_info = &rx_ring->buffer_info[i];
        cleancount = IXGB_DESC_UNUSED(rx_ring);
 
-       num_group_tail_writes = IXGB_RX_BUFFER_WRITE;
 
        /* leave three descriptors unused */
        while(--cleancount > 2) {