Re: [PATCH v3 2/2] r8169: Avoid pointer aliasing

From: Thierry Reding
Date: Wed Feb 06 2019 - 07:35:14 EST


On Wed, Feb 06, 2019 at 01:30:18PM +0100, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> Read MAC address 32-bit at a time and manually extract the individual
> bytes. This avoids pointer aliasing and gives the compiler a better
> chance of optimizing the operation.
>
> Suggested-by: Andrew Lunn <andrew@xxxxxxx>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> Applies to net-next.
>
> I tested this on a Jetson TX2 with an add-in Realtek ethernet card that
> has a properly programmed OTP to verify that I got the endianess right.
> Seems like everything works and the device behaves the same with or
> without this patch.
>
> Changes in v3:
> - align MAC address to u16 for is_valid_ether_addr()
>
> drivers/net/ethernet/realtek/r8169.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)

I also forgot Andrew's Reviewed-by here, but technically the patch has
changed, so I'll leave it up to him to confirm he's still okay with this
version.

Thierry

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