Re: [PATCH RFC 03/15] drivers/base: Allocate/free platform-msi interrupts by group

Dey, Megha
2020-05-04T00:08:49Z

Hi Thomas,

On 4/25/2020 2:23 PM, Thomas Gleixner wrote:
> Dave Jiang <dave.jiang@intel.com> writes:
>> From: Megha Dey <megha.dey@linux.intel.com>
>> --- a/include/linux/msi.h
>> +++ b/include/linux/msi.h
>> @@ -135,6 +135,12 @@ enum platform_msi_type {
>> GEN_PLAT_MSI = 1,
>> };
>>
>> +struct platform_msi_group_entry {
>> + unsigned int group_id;
>> + struct list_head group_list;
>> + struct list_head entry_list;
>
> I surely told you before that struct members want to be written tabular.

yep, you surely did :) I will use tabs henceforth!
>
>> +};
>> +
>> /* Helpers to hide struct msi_desc implementation details */
>> #define msi_desc_to_dev(desc) ((desc)->dev)
>> #define dev_to_msi_list(dev) (&(dev)->msi_list)
>> @@ -145,21 +151,31 @@ enum platform_msi_type {
>> #define for_each_msi_entry_safe(desc, tmp, dev) \
>> list_for_each_entry_safe((desc), (tmp), dev_to_msi_list((dev)), list)
>>
>> -#define dev_to_platform_msi_list(dev) (&(dev)->platform_msi_list)
>> -#define first_platform_msi_entry(dev) \
>> - list_first_entry(dev_to_platform_msi_list((dev)), struct msi_desc, list)
>> -#define for_each_platform_msi_entry(desc, dev) \
>> - list_for_each_entry((desc), dev_to_platform_msi_list((dev)), list)
>> -#define for_each_platform_msi_entry_safe(desc, tmp, dev) \
>> - list_for_each_entry_safe((desc), (tmp), dev_to_platform_msi_list((dev)), list)
>> +#define dev_to_platform_msi_group_list(dev) (&(dev)->platform_msi_list)
>> +
>> +#define first_platform_msi_group_entry(dev) \
>> + list_first_entry(dev_to_platform_msi_group_list((dev)), \
>> + struct platform_msi_group_entry, group_list)
>>
>> -#define first_msi_entry_common(dev) \
>> - list_first_entry_select((dev)->platform_msi_type, dev_to_platform_msi_list((dev)), \
>> +#define platform_msi_current_group_entry_list(dev) \
>> + (&((list_last_entry(dev_to_platform_msi_group_list((dev)), \
>> + struct platform_msi_group_entry, \
>> + group_list))->entry_list))
>> +
>> +#define first_msi_entry_current_group(dev) \
>> + list_first_entry_select((dev)->platform_msi_type, \
>> + platform_msi_current_group_entry_list((dev)), \
>> dev_to_msi_list((dev)), struct msi_desc, list)
>>
>> -#define for_each_msi_entry_common(desc, dev) \
>> - list_for_each_entry_select((dev)->platform_msi_type, desc, dev_to_platform_msi_list((dev)), \
>> - dev_to_msi_list((dev)), list) \
>> +#define for_each_msi_entry_current_group(desc, dev) \
>> + list_for_each_entry_select((dev)->platform_msi_type, desc, \
>> + platform_msi_current_group_entry_list((dev)),\
>> + dev_to_msi_list((dev)), list)
>> +
>> +#define for_each_platform_msi_entry_in_group(desc, platform_msi_group, group, dev) \
>> + list_for_each_entry((platform_msi_group), dev_to_platform_msi_group_list((dev)), group_list) \
>> + if (((platform_msi_group)->group_id) == (group)) \
>> + list_for_each_entry((desc), (&(platform_msi_group)->entry_list), list)
>
> Yet more unreadable macro maze to obfuscate what the code is actually
> doing.

hmm I will i guess add some more documentation either in the commit
message or somewhere in documentation to make it clearer about the
purpose of these macros.

>
>> /* When an MSI domain is used as an intermediate domain */
>> int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
>> diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
>> index bc5f9e32387f..899ade394ec8 100644
>> --- a/kernel/irq/msi.c
>> +++ b/kernel/irq/msi.c
>> @@ -320,7 +320,7 @@ int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
>> struct msi_desc *desc;
>> int ret = 0;
>>
>> - for_each_msi_entry_common(desc, dev) {
>> + for_each_msi_entry_current_group(desc, dev) {
>
> How is anyone supposed to figure out what the heck this means without
> going through several layers of macro maze and some magic type/group
> storage in struct device?
>

Point noted. I think I am better off committing smaller logical changes
in each patch.

> Again, function arguments exist for a reason.

ok makes sense, I will do this in the next version.

>
> Thanks,
>
> tglx
>