linux-kernel - Re: [PATCH v2] net: phy: leds: Add support for "link" trigger

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Message-ID: <698c7dea-7b32-e63c-11ac-feac163a65a1@maciej.szmigiero.name>
Date:   Thu, 2 Nov 2017 00:49:31 +0100
From:   "Maciej S. Szmigiero" <mail@...iej.szmigiero.name>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Florian Fainelli <f.fainelli@...il.com>, netdev@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] net: phy: leds: Add support for "link" trigger

Hi Andrew,

On 01.11.2017 13:33, Maciej S. Szmigiero wrote:
> On 01.11.2017 13:31, Andrew Lunn wrote:
>>> Yes, I did it the same way as the existing code did for phy->phy_led_triggers
>>> for reasons of both consistency and also to be on the safe side because
>>> maybe there is some non-obvious reason why it has to be freed
>>> explicitly (?).
>>  
>> Hi Maciej
>>
>> Occasionally, there is a need to call devm_kfree(). But i don't see
>> anything here why it is needed. So i would drop your devm_kfree(), and
>> if you feel like it, add an additional patch removing the existing
>> one.
> 
> OK, will do as you suggest.
> 

Upon closer inspection of the code it turned out that these devm_kfree()
calls actually had some purpose - the PHY core ignores the return value
of phy_led_triggers_register() and will successfully attach a PHY even
if this function returns an error.

In that case these LED trigger structures would unnecessary take some
memory, that's why (probably) the PHY LED code frees them on error
path.

Due to this I've decided to keep these calls to devm_kfree().

Maciej