netdev - Re: [PATCH net-next 2/4] net: phy: sfp: Use correct endian for sfp->id.ext.options

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Message-ID: <20171108085636.GO9463@n2100.armlinux.org.uk>
Date:   Wed, 8 Nov 2017 08:56:36 +0000
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     netdev@...r.kernel.org, davem@...emloft.net, andrew@...n.ch
Subject: Re: [PATCH net-next 2/4] net: phy: sfp: Use correct endian for
 sfp->id.ext.options

On Tue, Nov 07, 2017 at 07:49:09PM -0800, Florian Fainelli wrote:
> The extended ID options 16-bit value is big-endian (and actually annotated as
> such), but we would be accessing it with our CPU endian, which would not
> allow the correct detection of whether the LOS signal is inverted or not.
> 
> Fixes: 73970055450e ("sfp: add SFP module support")
> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
> ---
>  drivers/net/phy/sfp.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
> index 942288aa9cdb..dfb28b269687 100644
> --- a/drivers/net/phy/sfp.c
> +++ b/drivers/net/phy/sfp.c
> @@ -355,7 +355,7 @@ static void sfp_sm_link_check_los(struct sfp *sfp)
>  	 * SFP_OPTIONS_LOS_NORMAL are set?  For now, we assume
>  	 * the same as SFP_OPTIONS_LOS_NORMAL set.
>  	 */
> -	if (sfp->id.ext.options & SFP_OPTIONS_LOS_INVERTED)
> +	if (be16_to_cpu(sfp->id.ext.options) & SFP_OPTIONS_LOS_INVERTED)

It would be more efficient to convert the constants to BE16 rather
than an indeterminant number to CPU endian.  The compiler can optimise
the constant.  Same for the other two hunks.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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