[v4,07/19] PCI/MSI: Let pci_msi_get_domain use struct device's msi_domain

Now that we can easily find which MSI domain a PCI device is
using, use dev_get_msi_domain as a way to retrieve the information.

The original code is still used as a fallback.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/pci/msi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Hi Marc,

On Wed, Jul 15, 2015 at 01:16:41PM +0100, Marc Zyngier wrote:
> Now that we can easily find which MSI domain a PCI device is
> using, use dev_get_msi_domain as a way to retrieve the information.
> 
> The original code is still used as a fallback.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  drivers/pci/msi.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index ef4ec6e..c77fdaf 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -41,7 +41,8 @@ static struct irq_domain *pci_msi_get_domain(struct pci_dev *dev)
>  {
>  	struct irq_domain *domain = NULL;
>  
> -	if (dev->bus->msi)
> +	domain = dev_get_msi_domain(&dev->dev);
> +	if (!domain && dev->bus->msi)
>  		domain = dev->bus->msi->domain;
>  	if (!domain)
>  		domain = arch_get_pci_msi_domain(dev);

I think this would be slightly easier to read as:

    struct irq_domain *domain;

    domain = dev_get_msi_domain(&dev->dev);
    if (domain)
	return domain;

    if (dev->bus->msi && (domain = dev->bus->msi->domain))
	return domain;

    return arch_get_pci_msi_domain(dev);

I'm not a huge fan of assignments inside "if" conditions, and checkpatch
might even complain about it, but it exposes the fallback order pretty well
here.  I guess we could also just repeat the dev->bus->msi->domain
expression:

    if (dev->bus->msi && dev->bus->msi->domain)
	return dev->bus->msi->domain;

We can at least get rid of the superfluous initialization of domain to
NULL.

Bjorn
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On 21/07/15 22:17, Bjorn Helgaas wrote:
> Hi Marc,
> 
> On Wed, Jul 15, 2015 at 01:16:41PM +0100, Marc Zyngier wrote:
>> Now that we can easily find which MSI domain a PCI device is
>> using, use dev_get_msi_domain as a way to retrieve the information.
>>
>> The original code is still used as a fallback.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>>  drivers/pci/msi.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
>> index ef4ec6e..c77fdaf 100644
>> --- a/drivers/pci/msi.c
>> +++ b/drivers/pci/msi.c
>> @@ -41,7 +41,8 @@ static struct irq_domain *pci_msi_get_domain(struct pci_dev *dev)
>>  {
>>  	struct irq_domain *domain = NULL;
>>  
>> -	if (dev->bus->msi)
>> +	domain = dev_get_msi_domain(&dev->dev);
>> +	if (!domain && dev->bus->msi)
>>  		domain = dev->bus->msi->domain;
>>  	if (!domain)
>>  		domain = arch_get_pci_msi_domain(dev);
> 
> I think this would be slightly easier to read as:
> 
>     struct irq_domain *domain;
> 
>     domain = dev_get_msi_domain(&dev->dev);
>     if (domain)
> 	return domain;
> 
>     if (dev->bus->msi && (domain = dev->bus->msi->domain))
> 	return domain;
> 
>     return arch_get_pci_msi_domain(dev);
> 
> I'm not a huge fan of assignments inside "if" conditions, and checkpatch
> might even complain about it, but it exposes the fallback order pretty well
> here.  I guess we could also just repeat the dev->bus->msi->domain
> expression:
> 
>     if (dev->bus->msi && dev->bus->msi->domain)
> 	return dev->bus->msi->domain;
> 
> We can at least get rid of the superfluous initialization of domain to
> NULL.

Yeah, that's better, considering that (as you've noticed) the ugly
assignment is removed in the last patch.

Thanks,

	M.