Re: [Patch V4 08/42] x86, ACPI, irq: enhance error handling in function acpi_register_gsi()

Jiang Liu
2014-06-10T05:49:50Z

On 2014/6/10 7:19, Thomas Gleixner wrote:
> On Mon, 9 Jun 2014, Jiang Liu wrote:
>
>> Function mp_register_gsi() may return invalid GSI if error happens,
>> so enhance acpi_register_gsi() to handle possible error cases.
>
> Can you please explain how that happens? I think I know it, but it'd
> be nice if it would be documented.
Sure.

>
>> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
>> ---
>> arch/x86/kernel/acpi/boot.c | 10 ++++++----
>> 1 file changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
>> index 392360c607dc..f201579cd0df 100644
>> --- a/arch/x86/kernel/acpi/boot.c
>> +++ b/arch/x86/kernel/acpi/boot.c
>> @@ -97,6 +97,8 @@ static u32 isa_irq_to_gsi[NR_IRQS_LEGACY] __read_mostly = {
>> 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
>> };
>>
>> +#define ACPI_INVALID_GSI INT_MIN
>> +
>> static unsigned int gsi_to_irq(unsigned int gsi)
>> {
>> unsigned int irq = gsi + NR_IRQS_LEGACY;
>> @@ -441,7 +443,7 @@ static int mp_register_gsi(struct device *dev, u32 gsi, int trigger,
>> polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
>> ret = io_apic_set_pci_routing(dev, gsi_to_irq(gsi), &irq_attr);
>> if (ret < 0)
>> - gsi = INT_MIN;
>> + gsi = ACPI_INVALID_GSI;
>>
>> return gsi;
>> }
>> @@ -666,13 +668,13 @@ int (*acpi_suspend_lowlevel)(void);
>> */
>> int acpi_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
>> {
>> - unsigned int irq;
>> unsigned int plat_gsi = gsi;
>
> The assignemend of gsi to plat_gsi is pointless
This was done in patch 21. And eventually function acpi_register_gsi()
will be simplified as below by patch 21 and 22.
int acpi_register_gsi(struct device *dev, u32 gsi, int trigger, int
polarity)
{
return (*__acpi_register_gsi)(dev, gsi, trigger, polarity);
}

I will rework and resend patch 8, 21 and 22.
>
>> plat_gsi = (*__acpi_register_gsi)(dev, gsi, trigger, polarity);
>
> __acpi_register_gsi is a function pointer, so
>
> plat_gsi = __acpi_register_gsi(dev, gsi, trigger, polarity);
>
> is completely correct and way simpler to read.
Thanks, will change to the simpler way.

>
>> - irq = gsi_to_irq(plat_gsi);
>> + if (plat_gsi != ACPI_INVALID_GSI)
>> + return gsi_to_irq(plat_gsi);
>>
>> - return irq;
>> + return -1;
>> }
>> EXPORT_SYMBOL_GPL(acpi_register_gsi);
>
> No need to repost the whole series. Just reply with a new version to
> this.
>
> Thanks,
>
> tglx
>