linux-kernel - Re: [PATCH] irqdomain: handle the per-CPU irq trigger type settings

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Message-ID: <50f3537d-d2ba-fa45-4435-3b47394f6fa2@huawei.com>
Date:   Sat, 11 Mar 2017 13:00:39 +0800
From:   gengdongjiu <gengdongjiu@...wei.com>
To:     <tglx@...utronix.de>
CC:     <jason@...edaemon.net>, <benh@...nel.crashing.org>,
        <linux-kernel@...r.kernel.org>, <zhanghaibin7@...wei.com>,
        <huangshaoyu@...wei.com>
Subject: Re: [PATCH] irqdomain: handle the per-CPU irq trigger type settings

Hi Gleixner,
  Thank you very much for your comment and review, I will update it later.

> 
> 
> 
> On Fri, 10 Mar 2017, gengdongjiu wrote:
> 
>>     when devices parse and map an per-cpu interrupt into linux virq space
>>     using irq_of_parse_and_map API, it will always be failed if needs to set
>>     the specified irq trigger type, because irq_set_irq_type is only for 1-N
>>     mode interrupt source, not for per-cpu interrupt source. so handle per-cpu
>>     IRQs for this failure.
> 
> Please format your changelogs proper into sections:
> 
> 1) Context
> 
> 2) Problem
> 
> 3) Solution
> 
> Writing one big lump of a sentence is just unreadable.
> 
> Aside of that:
> 
> 1) No indentation of the changelog
> 2) Sentences start with upper case letters
> 3) Function references want () after the function name
> 
> Aside
> 
>>
>>     Signed-off-by: Dongjiu Geng <gengdongjiu@...wei.com>
>>                    Zhanghai bin <zhanghaibin7@...wei.com>
> 
> That SOB is bogus.
> 
>> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
>> index 9fd618d..8116cf2 100755
>> --- a/kernel/irq/irqdomain.c
>> +++ b/kernel/irq/irqdomain.c
>> @@ -542,8 +542,16 @@ unsigned int irq_create_of_mapping(struct of_phandle_args *irq_data)
>>
>>         /* Set type if specified and different than the current one */
>>         if (type != IRQ_TYPE_NONE &&
>> -           type != irq_get_trigger_type(virq))
>> -               irq_set_irq_type(virq, type);
>> +           type != irq_get_trigger_type(virq)) {
>> +               int ret = 0;
>> +               struct irq_data *irq_data = irq_get_irq_data(virq);
>> +
>> +               ret = irq_set_irq_type(virq, type);
>> +
>> +                /* Handle per-cpu IRQ: just save type in irq_data */
>> +               if (-EINVAL == ret && irq_data)
>> +                       irqd_set_trigger_type(irq_data, type);
> 
> This is completely broken. That stores a trigger type for any interrupt if
> the set type function fails.
> 
> You fail to explain
> 
>     - WHY irq_set_irq_type() fails for these per cpu interrupts
> 
>     - WHY storing the type in irqdata solves anything
> 
>     - WHAT sets the type in the actual interrupt hardware
> 
> That information should be in the changelog ....
> 
> Thanks,
> 
>         tglx
> 
> .
>