[PATCH v3 net-next 2/5] ice: switch: unobscurify bitops loop in ice_fill_adv_dummy_packet()

From: Alexander Lobakin
Date: Fri Mar 18 2022 - 12:21:23 EST


A loop performing header modification according to the provided mask
in ice_fill_adv_dummy_packet() is very cryptic (and error-prone).
Replace two identical cast-deferences with a variable. Replace three
struct-member-array-accesses with a variable. Invert the condition,
reduce the indentation by one -> eliminate line wraps.

Signed-off-by: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@xxxxxxxxxxxxxxx>
Tested-by: Marcin Szycik <marcin.szycik@xxxxxxxxxxxxxxx>
---
drivers/net/ethernet/intel/ice/ice_switch.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_switch.c b/drivers/net/ethernet/intel/ice/ice_switch.c
index 075df2474688..0936d39de70c 100644
--- a/drivers/net/ethernet/intel/ice/ice_switch.c
+++ b/drivers/net/ethernet/intel/ice/ice_switch.c
@@ -5810,13 +5810,15 @@ ice_fill_adv_dummy_packet(struct ice_adv_lkup_elem *lkups, u16 lkups_cnt,
* indicated by the mask to make sure we don't improperly write
* over any significant packet data.
*/
- for (j = 0; j < len / sizeof(u16); j++)
- if (lkups[i].m_raw[j])
- ((u16 *)(pkt + offset))[j] =
- (((u16 *)(pkt + offset))[j] &
- ~lkups[i].m_raw[j]) |
- (lkups[i].h_raw[j] &
- lkups[i].m_raw[j]);
+ for (j = 0; j < len / sizeof(u16); j++) {
+ u16 *ptr = (u16 *)(pkt + offset);
+ u16 mask = lkups[i].m_raw[j];
+
+ if (!mask)
+ continue;
+
+ ptr[j] = (ptr[j] & ~mask) | (lkups[i].h_raw[j] & mask);
+ }
}

s_rule->pdata.lkup_tx_rx.hdr_len = cpu_to_le16(pkt_len);
--
2.35.1