mlxsw: Fix bug in __mlxsw_item_bit_array_offset

When calculating the shift needed in order to access a bit array element
in a byte, we should multiply the index by the element size and not
assume it is fixed at 2-bits.

Fixes: 93c1edb27f9e ("mlxsw: Introduce Mellanox switch driver core")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/item.h b/drivers/net/ethernet/mellanox/mlxsw/item.h
index ffd55d030ce28dbf902f6990a0dfb7f96b08a766..36fb1cec53c98e9c7dad0cb7b9b59051d7e0c352 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/item.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/item.h
@@ -187,6 +187,7 @@ __mlxsw_item_bit_array_offset(struct mlxsw_item *item, u16 index, u8 *shift)
 {
        u16 max_index, be_index;
        u16 offset;             /* byte offset inside the array */
+       u8 in_byte_index;
 
        BUG_ON(index && !item->element_size);
        if (item->offset % sizeof(u32) != 0 ||
@@ -199,7 +200,8 @@ __mlxsw_item_bit_array_offset(struct mlxsw_item *item, u16 index, u8 *shift)
        max_index = (item->size.bytes << 3) / item->element_size - 1;
        be_index = max_index - index;
        offset = be_index * item->element_size >> 3;
-       *shift = index % (BITS_PER_BYTE / item->element_size) << 1;
+       in_byte_index  = index % (BITS_PER_BYTE / item->element_size);
+       *shift = in_byte_index * item->element_size;
 
        return item->offset + offset;
 }