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

[Russell King (Oracle)]

From: James Morse <james.morse at 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 at arm.com>
Tested-by: Miguel Luis <miguel.luis at oracle.com>
Tested-by: Vishnu Pajjuri <vishnu at os.amperecomputing.com>
Tested-by: Jianyong Wu <jianyong.wu at arm.com>
---
Outstanding comments:
 https://lore.kernel.org/r/20230914151720.00007105@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);
-- 
2.30.2