linux-kernel - Re: [PATCH] i2c: xiic: Fix reference count leaks.

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Message-ID: <0a43d56a-edb3-95f9-b8ba-f37bcecaae2d@xilinx.com>
Date:   Mon, 13 Jul 2020 09:54:05 +0200
From:   Michal Simek <michal.simek@...inx.com>
To:     David Laight <David.Laight@...LAB.COM>,
        "'Wolfram Sang'" <wsa@...nel.org>,
        "wu000273@....edu" <wu000273@....edu>
Cc:     "kjlu@....edu" <kjlu@....edu>,
        Michal Simek <michal.simek@...inx.com>,
        Rob Herring <robh@...nel.org>,
        Shubhrajyoti Datta <shubhraj@...inx.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] i2c: xiic: Fix reference count leaks.

Hi Qiushi,

On 17. 06. 20 16:30, David Laight wrote:
> From: Wolfram Sang
>> Sent: 14 June 2020 10:10
>>
>> On Sat, Jun 13, 2020 at 04:59:23PM -0500, wu000273@....edu wrote:
>>> From: Qiushi Wu <wu000273@....edu>
>>>
>>> pm_runtime_get_sync() increments the runtime PM usage counter even
>>> when it returns an error code. Thus call pm_runtime_put_noidle()
>>> if pm_runtime_get_sync() fails.
>>
>> Can you point me to a discussion where it was decided that this is a
>> proper fix? I'd think we rather should fix pm_runtime_get_sync() but
>> maybe there are technical reasons against it.
> 
> Or, if there is one place that actually needs the reference split the
> code so that unusual case keeps the reference.
> 
> In one of the patches I also spotted:
> 	ret = pm_runtime_get_sync();
> 	if (ret < 0 && ret != _EAGAIN)
> 		...
> 
> (I think it was EAGAIN.)
> I can't help feeling that is just wrong somewhere.

Qiushi: Any update on this one?

Thanks,
Michal