netdev - Re: [PATCH net-next] net: phy: convert further flags in struct phy

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Date:   Fri, 25 May 2018 08:22:29 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        David Miller <davem@...emloft.net>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next] net: phy: convert further flags in struct
 phy_device to bit-field

Am 25.05.2018 um 01:03 schrieb Florian Fainelli:
> On 05/24/2018 01:15 PM, Heiner Kallweit wrote:
>> This patch is a follow-up to 87e5808d52b6 ("net: phy: replace bool
>> members in struct phy_device with bit-fields") and converts further
>> flags to bit-fields.
> 
> This looks fine, but then you would also have to clean-up all code that
> does phydev->asym_pause = 1 and phydev->pause = 1 to use true/false
> instead, I am not sure there is much value in doing that for these
> fields considering that they are exposed to drivers so there is a risk
> of possible breakage.
> 
I grepped over drivers/net and all assignments to pause / asym_pause
use 0, 1, or the result of a logical operation only.

However you're right, there's one potential issue:
struct ethtool_pauseparam defines rx_pause and tx_pause as __u32
and mentions in the kernel doc only flag autoneg to be sanitized
(even though rx_pause and tx_pause are called "flags").
So basically all drivers implementing ethtool callback set_pauseparam
don't check user space input for both values.

However this could be easily fixed by implementing these checks in the
core. In ethtool_set_pauseparam() we could do for autoneg, rx_pause
and tx_pause: val = !!val to sanitize them.
How would you see it after adding this?

Heiner

> Thanks!
> 
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
>> ---
>>  include/linux/phy.h | 17 ++++++++---------
>>  1 file changed, 8 insertions(+), 9 deletions(-)
>>
>> diff --git a/include/linux/phy.h b/include/linux/phy.h
>> index 6cd090984..cc66f2834 100644
>> --- a/include/linux/phy.h
>> +++ b/include/linux/phy.h
>> @@ -418,21 +418,20 @@ struct phy_device {
>>  	/* The most recently read link state */
>>  	unsigned link:1;
>>  
>> +	/* forced speed & duplex (no autoneg)
>> +	 * partner speed & duplex & pause (autoneg)
>> +	 */
>> +	unsigned pause:1;
>> +	unsigned asym_pause:1;
>> +	int speed;
>> +	int duplex;
>> +
>>  	enum phy_state state;
>>  
>>  	u32 dev_flags;
>>  
>>  	phy_interface_t interface;
>>  
>> -	/*
>> -	 * forced speed & duplex (no autoneg)
>> -	 * partner speed & duplex & pause (autoneg)
>> -	 */
>> -	int speed;
>> -	int duplex;
>> -	int pause;
>> -	int asym_pause;
>> -
>>  	/* Enabled Interrupts */
>>  	u32 interrupts;
>>  
>>
> 
>