[PATCH] net: move padding in struct skb_shared_info

[Alexey Dobriyan]

commit 7f564528a480084e2318cd48caba7aef4a54a77f
("skbuff: Extend gso_type to unsigned int.") created padding as first
field of struct skb_shared_info requiring [R64+imm8] addressing mode
for all fields.

Patch bubbles up padding brinding code size down to original levels and
even smaller:

        add/remove: 0/0 grow/shrink: 4/304 up/down: 20/-720 (-700)
        function                                     old     new   delta
        iwl_trans_pcie_tx                           3994    4006     +12
        tap_do_read                                 1070    1074      +4
        packet_recvmsg                              1155    1157      +2
        be_xmit                                     2038    2040      +2
        zerocopy_sg_from_iter                        455     454      -1
                ...
        __ef4_rx_packet                             1358    1349      -9
        hix5hd2_poll                                1787    1777     -10
        e1000_clean_jumbo_rx_irq                    3599    3587     -12
        skb_try_coalesce                            1118    1105     -13
        xenvif_tx_build_gops                        5057    5043     -14

Signed-off-by: Alexey Dobriyan <adobri...@gmail.com>
---

 include/linux/skbuff.h |    1 -
 1 file changed, 1 deletion(-)

--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -413,7 +413,6 @@ struct ubuf_info {
  * the end of the header data, ie. at skb->end.
  */
 struct skb_shared_info {
-       unsigned short  _unused;
        unsigned char   nr_frags;
        __u8            tx_flags;
        unsigned short  gso_size;