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

Thomas Gleixner
2020-04-25T21:23:50Z

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.

> +};
> +
> /* 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.

> /* 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?

Again, function arguments exist for a reason.

Thanks,

tglx