[PATCH v2 49/54] net/e1000/base: fix mac addr hash bit_shift

[Anatoly Burakov]

From: Loktionov Aleksandr <aleksandr.loktionov at intel.com>

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 at dpdk.org

Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov at intel.com>
Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 drivers/net/intel/e1000/base/e1000_mac.c | 4 ++--
 drivers/net/intel/e1000/base/e1000_vf.c  | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/intel/e1000/base/e1000_mac.c b/drivers/net/intel/e1000/base/e1000_mac.c
index 0ba03e6a04..4ec7cab7ab 100644
--- a/drivers/net/intel/e1000/base/e1000_mac.c
+++ b/drivers/net/intel/e1000/base/e1000_mac.c
@@ -488,7 +488,7 @@ int e1000_rar_set_generic(struct e1000_hw *hw, u8 *addr, u32 index)
 u32 e1000_hash_mc_addr_generic(struct e1000_hw *hw, u8 *mc_addr)
 {
 	u32 hash_value, hash_mask;
-	u8 bit_shift = 0;
+	u8 bit_shift = 1;
 
 	DEBUGFUNC("e1000_hash_mc_addr_generic");
 
@@ -498,7 +498,7 @@ u32 e1000_hash_mc_addr_generic(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
diff --git a/drivers/net/intel/e1000/base/e1000_vf.c b/drivers/net/intel/e1000/base/e1000_vf.c
index 7d20150b59..bb314e2f12 100644
--- a/drivers/net/intel/e1000/base/e1000_vf.c
+++ b/drivers/net/intel/e1000/base/e1000_vf.c
@@ -331,7 +331,7 @@ STATIC int e1000_rar_set_vf(struct e1000_hw *hw, u8 *addr,
 STATIC u32 e1000_hash_mc_addr_vf(struct e1000_hw *hw, u8 *mc_addr)
 {
 	u32 hash_value, hash_mask;
-	u8 bit_shift = 0;
+	u8 bit_shift = 1;
 
 	DEBUGFUNC("e1000_hash_mc_addr_generic");
 
@@ -342,7 +342,7 @@ STATIC u32 e1000_hash_mc_addr_vf(struct e1000_hw *hw, u8 *mc_addr)
 	 * The 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++;
 
 	hash_value = hash_mask & (((mc_addr[4] >> (8 - bit_shift)) |
-- 
2.43.5