netdev - Re: [PATCH net-next v2] dsa:mv88e6xxx: dispose irq mapping for chip->irq

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Date:   Wed, 7 Dec 2016 17:40:12 +0100
From:   Volodymyr Bendiuga <volodymyr.bendiuga@...termo.se>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     vivien.didelot@...oirfairelinux.com, f.fainelli@...il.com,
        netdev@...r.kernel.org, volodymyr.bendiuga@...il.com,
        Rob Herring <robh@...nel.org>, devicetree@...r.kernel.org
Subject: Re: [PATCH net-next v2] dsa:mv88e6xxx: dispose irq mapping for
 chip->irq

Yes, most of the users of of_irq_get() do not use irq_dispose_mapping().

But some of them do (some irq chips), and I believe the correct way of 
doing this is to

dispose irq mapping, as the description for this function says that it 
unmaps

the irq, which is mapped by of_irq_parse_and_map(). Not disposing irq 
might not make

any affect on most drivers, but some, that get EPROBE_DEFER error do 
need to dispose.

This is what I get when I run the code.

of_irq_put() could be implemented, and it would be a wrapper for 
irq_dispose_mapping()

as I can see it. Should I do it this way?


On 2016-12-07 15:11, Andrew Lunn wrote:
> On Wed, Dec 07, 2016 at 11:35:07AM +0100, Volodymyr Bendiuga wrote:
>> Signed-off-by: Volodymyr Bendiuga <volodymyr.bendiuga@...termo.se>
> You need some text in the Change log. Say why this change is needed,
> etc.
>
> Looking through other users of of_irq_get(), i don't see any disposing
> of the mapping. It is not obvious you need to do this. The name does
> not give any hint.
>
> Maybe we should add an of_irq_put() which would clean up the mapping?
>
>        Andrew
>
>
>> ---
>>   drivers/net/dsa/mv88e6xxx/chip.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
>> index 173ea97..0c3271d 100644
>> --- a/drivers/net/dsa/mv88e6xxx/chip.c
>> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
>> @@ -4483,7 +4483,7 @@ static int mv88e6xxx_probe(struct mdio_device *mdiodev)
>>   		mutex_unlock(&chip->reg_lock);
>>   
>>   		if (err)
>> -			goto out;
>> +			goto out_dispose;
>>   
>>   		if (mv88e6xxx_has(chip, MV88E6XXX_FLAG_G2_INT)) {
>>   			err = mv88e6xxx_g2_irq_setup(chip);
>> @@ -4513,6 +4513,9 @@ static int mv88e6xxx_probe(struct mdio_device *mdiodev)
>>   		mv88e6xxx_g1_irq_free(chip);
>>   		mutex_unlock(&chip->reg_lock);
>>   	}
>> +
>> +out_dispose:
>> +	irq_dispose_mapping(chip->irq);
>>   out:
>>   	return err;
>>   }
>> @@ -4530,6 +4533,7 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
>>   		if (mv88e6xxx_has(chip, MV88E6XXX_FLAG_G2_INT))
>>   			mv88e6xxx_g2_irq_free(chip);
>>   		mv88e6xxx_g1_irq_free(chip);
>> +		irq_dispose_mapping(chip->irq);
>>   	}
>>   }
>>   
>> -- 
>> 2.7.4
>>