Originally, in acpi_parse_x2apic(), when the apic_id is invalid and
enabled is false, the acpi_register_lapic() also can be executed.
This does not make sense.
Optimize the decision logic to avoid performing meaningless operations
if the apic_id is invalid.
Signed-off-by: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
---
arch/x86/kernel/acpi/boot.c | 33 +++++++++++++++++++++------------
1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index d642c95..343e752 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -203,17 +203,20 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, const unsigned long end)
apic_id = processor->local_apic_id;
enabled = processor->lapic_flags & ACPI_MADT_ENABLED;
#ifdef CONFIG_X86_X2APIC
+ if (!apic->apic_id_valid(apic_id)) {
+ if (enabled)
+ printk(KERN_WARNING PREFIX "x2apic entry ignored\n");
+ return -EINVAL;
+ }
+
/*
- * We need to register disabled CPU as well to permit
- * counting disabled CPUs. This allows us to size
- * cpus_possible_map more accurately, to permit
- * to not preallocating memory for all NR_CPUS
- * when we use CPU hotplug.
- */
- if (!apic->apic_id_valid(apic_id) && enabled)
- printk(KERN_WARNING PREFIX "x2apic entry ignored\n");
- else
- acpi_register_lapic(apic_id, processor->uid, enabled);
+ * We need to register disabled CPU as well to permit
+ * counting disabled CPUs. This allows us to size
+ * cpus_possible_map more accurately, to permit
+ * to not preallocating memory for all NR_CPUS
+ * when we use CPU hotplug.
+ */
+ acpi_register_lapic(apic_id, processor->uid, enabled);
#else
printk(KERN_WARNING PREFIX "x2apic entry ignored\n");
#endif
@@ -225,6 +228,7 @@ static int __init
acpi_parse_lapic(struct acpi_subtable_header * header, const unsigned long end)
{
struct acpi_madt_local_apic *processor = NULL;
+ u8 enabled;
processor = (struct acpi_madt_local_apic *)header;
@@ -233,9 +237,14 @@ acpi_parse_lapic(struct acpi_subtable_header * header, const unsigned long end)
acpi_table_print_madt_entry(header);
+ enabled = processor->lapic_flags & ACPI_MADT_ENABLED;
+
/* the 0xff is an invalid local APIC id */
- if (processor->id == 0xff)
+ if (processor->id == 0xff) {
+ if (enabled)
+ printk(KERN_WARNING PREFIX "lapic entry ignored\n");
return -EINVAL;
+ }
/*
* We need to register disabled CPU as well to permit
@@ -246,7 +255,7 @@ acpi_parse_lapic(struct acpi_subtable_header * header, const unsigned long end)
*/
acpi_register_lapic(processor->id, /* APIC ID */
processor->processor_id, /* ACPI ID */
- processor->lapic_flags & ACPI_MADT_ENABLED);
+ enabled);
return 0;
}
--
2.5.5
--
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