Re: [PATCH RFC v3 07/21] ACPI: Rename acpi_processor_hotadd_init and remove pre-processor guards

Jonathan Cameron
2023-12-14T17:43:41Z

On Wed, 13 Dec 2023 12:49:47 +0000
Russell King (Oracle) <rmk+kernel@armlinux.org.uk> wrote:

> From: James Morse <james.morse@arm.com>
>
> acpi_processor_hotadd_init() will make a CPU present by mapping it
> based on its hardware id.
>
> 'hotadd_init' is ambiguous once there are two different behaviours
> for cpu hotplug. This is for toggling the _STA present bit. Subsequent
> patches will add support for toggling the _STA enabled bit, named
> acpi_processor_make_enabled().
>
> Rename it acpi_processor_make_present() to make it clear this is
> for CPUs that were not previously present.
>
> Expose the function prototypes it uses to allow the preprocessor
> guards to be removed. The IS_ENABLED() check will let the compiler
> dead-code elimination pass remove this if it isn't going to be
> used.
>
> Signed-off-by: James Morse <james.morse@arm.com>
> Tested-by: Miguel Luis <miguel.luis@oracle.com>
> Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> Tested-by: Jianyong Wu <jianyong.wu@arm.com>
> ---
> Outstanding comments:
> https://lore.kernel.org/r/20230914151720.00007105@Huawei.com

If it's not caused a build warning yet, chances are high this is fine.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> https://lore.kernel.org/r/b8f430c1-c30f-191f-18c6-f750fa6ba476@redhat.com
> For this comment, we use IS_ENABLED() in multiple places in the kernel in
> this way, and it isn't a problem.
> ---
> drivers/acpi/acpi_processor.c | 14 +++++---------
> include/linux/acpi.h | 2 --
> 2 files changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index c8e960ff0aca..26e3efb74614 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -183,13 +183,15 @@ static void __init acpi_pcc_cpufreq_init(void) {}
> #endif /* CONFIG_X86 */
>
> /* Initialization */
> -#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU
> -static int acpi_processor_hotadd_init(struct acpi_processor *pr)
> +static int acpi_processor_make_present(struct acpi_processor *pr)
> {
> unsigned long long sta;
> acpi_status status;
> int ret;
>
> + if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU))
> + return -ENODEV;
> +
> if (invalid_phys_cpuid(pr->phys_id))
> return -ENODEV;
>
> @@ -223,12 +225,6 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr)
> cpu_maps_update_done();
> return ret;
> }
> -#else
> -static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
> -{
> - return -ENODEV;
> -}
> -#endif /* CONFIG_ACPI_HOTPLUG_PRESENT_CPU */
>
> static int acpi_processor_get_info(struct acpi_device *device)
> {
> @@ -335,7 +331,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
> * because cpuid <-> apicid mapping is persistent now.
> */
> if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {
> - int ret = acpi_processor_hotadd_init(pr);
> + int ret = acpi_processor_make_present(pr);
>
> if (ret)
> return ret;
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 36071bc11acd..19d009ca9e7a 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -301,12 +301,10 @@ static inline int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
> }
> #endif
>
> -#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU
> /* Arch dependent functions for cpu hotplug support */
> int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, u32 acpi_id,
> int *pcpu);
> int acpi_unmap_cpu(int cpu);
> -#endif /* CONFIG_ACPI_HOTPLUG_PRESENT_CPU */
>
> #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
> int acpi_get_ioapic_id(acpi_handle handle, u32 gsi_base, u64 *phys_addr);