linux-kernel - Re: [PATCH v2 04/12] i2c: riic: Use pm_runtime_resume_and

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <dc232ee9-b28d-486f-a878-0320be84d1b9@tuxon.dev>
Date: Mon, 8 Jul 2024 08:19:18 +0300
From: claudiu beznea <claudiu.beznea@...on.dev>
To: Geert Uytterhoeven <geert@...ux-m68k.org>,
 Andi Shyti <andi.shyti@...nel.org>
Cc: chris.brandt@...esas.com, robh@...nel.org, krzk+dt@...nel.org,
 conor+dt@...nel.org, magnus.damm@...il.com, mturquette@...libre.com,
 sboyd@...nel.org, p.zabel@...gutronix.de, wsa+renesas@...g-engineering.com,
 linux-renesas-soc@...r.kernel.org, linux-i2c@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-clk@...r.kernel.org, Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH v2 04/12] i2c: riic: Use pm_runtime_resume_and_get()



On 05.07.2024 10:19, Geert Uytterhoeven wrote:
> Hi Andi,
> 
> On Fri, Jul 5, 2024 at 12:42 AM Andi Shyti <andi.shyti@...nel.org> wrote:
>>> diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
>>> index 83e4d5e14ab6..002b11b020fa 100644
>>> --- a/drivers/i2c/busses/i2c-riic.c
>>> +++ b/drivers/i2c/busses/i2c-riic.c
>>> @@ -113,6 +113,8 @@ struct riic_irq_desc {
>>>       char *name;
>>>  };
>>>
>>> +static const char * const riic_rpm_err_msg = "Failed to runtime resume";
>>
>> Please, don't do this. Much clearer to write the message
>> explicitly.
> 
> And the compiler will merge all identical strings, emitting
> just a single string.
> 
>>
>>> +
>>>  static inline void riic_writeb(struct riic_dev *riic, u8 val, u8 offset)
>>>  {
>>>       writeb(val, riic->base + riic->info->regs[offset]);
>>> @@ -133,10 +135,14 @@ static int riic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>>>       struct riic_dev *riic = i2c_get_adapdata(adap);
>>>       struct device *dev = adap->dev.parent;
>>>       unsigned long time_left;
>>> -     int i;
>>> +     int i, ret;
>>>       u8 start_bit;
>>>
>>> -     pm_runtime_get_sync(dev);
>>> +     ret = pm_runtime_resume_and_get(dev);
>>
>> In principle I like the error message to be always checked and I
> 
> s/message/condition/?
> 
>> will always approve it. Whenever there is a return value, even
>> when we are sure it's always '0', it needs to be checked.
>>
>> I had lots of discussions in the past about this topic but I
>> haven't always found support. I'd love to have the ack from a
>> renesas maintainer here.
> 
> I don't mind checking for the error here.
> 
>>
>>> +     if (ret) {
>>> +             dev_err(dev, riic_rpm_err_msg);
> 
> Do you need to print these error messages?

No. I have it here as a result of some internal reviews.

Thank you,
Claudiu Beznea

> AFAIU, this cannot happen anyway.
> Ultimately, I expect the device driver that requested the transfer to
> handle failures, and print a message when needed.
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
>