cpumask: use work_on_cpu in acpi/cstate.c
Impact: use new cpumask API to reduce stack usage
Replace the saving of current->cpus_allowed and set_cpus_allowed_ptr() with
a work_on_cpu function for the acpi_processor_ffh_cstate_probe() function.
Basically splits acpi_processor_ffh_cstate_probe() into two functions, the
other being acpi_processor_ffh_cstate_probe_cpu which is the work function
run on the designated cpu.
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index c2502eb..cf5ec58 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -66,35 +66,15 @@
#define NATIVE_CSTATE_BEYOND_HALT (2)
-int acpi_processor_ffh_cstate_probe(unsigned int cpu,
- struct acpi_processor_cx *cx, struct acpi_power_register *reg)
+static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
{
- struct cstate_entry *percpu_entry;
- struct cpuinfo_x86 *c = &cpu_data(cpu);
-
- cpumask_t saved_mask;
- int retval;
+ struct acpi_processor_cx *cx = _cx;
+ long retval;
unsigned int eax, ebx, ecx, edx;
unsigned int edx_part;
unsigned int cstate_type; /* C-state type and not ACPI C-state type */
unsigned int num_cstate_subtype;
- if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF )
- return -1;
-
- if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)
- return -1;
-
- percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
- percpu_entry->states[cx->index].eax = 0;
- percpu_entry->states[cx->index].ecx = 0;
-
- /* Make sure we are running on right CPU */
- saved_mask = current->cpus_allowed;
- retval = set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
- if (retval)
- return -1;
-
cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
/* Check whether this particular cx_type (in CST) is supported or not */
@@ -114,21 +94,45 @@
retval = -1;
goto out;
}
- percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
-
- /* Use the hint in CST */
- percpu_entry->states[cx->index].eax = cx->address;
if (!mwait_supported[cstate_type]) {
mwait_supported[cstate_type] = 1;
- printk(KERN_DEBUG "Monitor-Mwait will be used to enter C-%d "
- "state\n", cx->type);
+ printk(KERN_DEBUG
+ "Monitor-Mwait will be used to enter C-%d "
+ "state\n", cx->type);
}
- snprintf(cx->desc, ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
- cx->address);
-
+ snprintf(cx->desc,
+ ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
+ cx->address);
out:
- set_cpus_allowed_ptr(current, &saved_mask);
+ return retval;
+}
+
+int acpi_processor_ffh_cstate_probe(unsigned int cpu,
+ struct acpi_processor_cx *cx, struct acpi_power_register *reg)
+{
+ struct cstate_entry *percpu_entry;
+ struct cpuinfo_x86 *c = &cpu_data(cpu);
+ long retval;
+
+ if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF)
+ return -1;
+
+ if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)
+ return -1;
+
+ percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
+ percpu_entry->states[cx->index].eax = 0;
+ percpu_entry->states[cx->index].ecx = 0;
+
+ /* Make sure we are running on right CPU */
+
+ retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx);
+ if (retval == 0) {
+ /* Use the hint in CST */
+ percpu_entry->states[cx->index].eax = cx->address;
+ percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
+ }
return retval;
}
EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);