git: cba56bc3427d - main - igc: fix MAC address hash bit shift
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Date: Tue, 11 Aug 2026 21:00:03 UTC
The branch main has been updated by kbowling:
URL: https://cgit.FreeBSD.org/src/commit/?id=cba56bc3427db0bb4efc3d0117cda4bdc7717f98
commit cba56bc3427db0bb4efc3d0117cda4bdc7717f98
Author: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
AuthorDate: 2026-08-11 19:34:01 +0000
Commit: Kevin Bowling <kbowling@FreeBSD.org>
CommitDate: 2026-08-11 20:59:32 +0000
igc: fix MAC address hash bit shift
DPDK commit message
net/e1000/base: fix MAC address hash bit shift
In e1000_hash_mc_addr_generic() the expression:
"mc_addr[4] >> 8 - bit_shift", right shifting "mc_addr[4]"
shift by more than 7 bits always yields zero, so hash becomes not so
different. Add initialization with bit_shift = 1, and add a loop
condition to ensure bit_shift will be always in [1..8] range.
Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Obtained from: DPDK (1749e662f6)
MFC after: 2 weeks
---
sys/dev/igc/igc_mac.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sys/dev/igc/igc_mac.c b/sys/dev/igc/igc_mac.c
index 6a00867c7a8e..2c32f0c7a606 100644
--- a/sys/dev/igc/igc_mac.c
+++ b/sys/dev/igc/igc_mac.c
@@ -301,7 +301,7 @@ int igc_rar_set_generic(struct igc_hw *hw, u8 *addr, u32 index)
u32 igc_hash_mc_addr_generic(struct igc_hw *hw, u8 *mc_addr)
{
u32 hash_value, hash_mask;
- u8 bit_shift = 0;
+ u8 bit_shift = 1;
DEBUGFUNC("igc_hash_mc_addr_generic");
@@ -311,7 +311,7 @@ u32 igc_hash_mc_addr_generic(struct igc_hw *hw, u8 *mc_addr)
/* For a mc_filter_type of 0, bit_shift is the number of left-shifts
* where 0xFF would still fall within the hash mask.
*/
- while (hash_mask >> bit_shift != 0xFF)
+ while (bit_shift < 4 && hash_mask >> bit_shift != 0xFF)
bit_shift++;
/* The portion of the address that is used for the hash table