From: Aleksandr Loktionov <aleksandr.loktionov@xxxxxxxxx>
[ Upstream commit 60d758659f1fb49e0d5b6ac2691ede8c0958795b ]
In igb_hash_mc_addr() 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: 9d5c824399de ("igb: PCI-Express 82575 Gigabit Ethernet driver")
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@xxxxxxxxx>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@xxxxxxxxx> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/ethernet/intel/igb/e1000_mac.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/e1000_mac.c b/drivers/net/ethernet/intel/igb/e1000_mac.c
index 205d577bdbbaa..caf91c6f52b4d 100644
--- a/drivers/net/ethernet/intel/igb/e1000_mac.c
+++ b/drivers/net/ethernet/intel/igb/e1000_mac.c
@@ -426,7 +426,7 @@ void igb_mta_set(struct e1000_hw *hw, u32 hash_value)
static u32 igb_hash_mc_addr(struct e1000_hw *hw, u8 *mc_addr)
{
u32 hash_value, hash_mask;
- u8 bit_shift = 0;
+ u8 bit_shift = 1;
/* Register count multiplied by bits per register */
hash_mask = (hw->mac.mta_reg_count * 32) - 1;
@@ -434,7 +434,7 @@ static u32 igb_hash_mc_addr(struct e1000_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 (hash_mask >> bit_shift != 0xFF && bit_shift < 4)
bit_shift++;
/* The portion of the address that is used for the hash table
--
2.39.2
