powerpc: Make sysfs code use smp_call_function_single
Impact: performance improvement
This fixes 'powerpc: avoid cpumask games in arch/powerpc/kernel/sysfs.c'
which talked about using smp_call_function_single, but actually used
work_on_cpu (an older version of the patch).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 4a2ee08..e6cd6c9 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -134,36 +134,16 @@
}
EXPORT_SYMBOL(ppc_enable_pmcs);
-#if defined(CONFIG_6xx) || defined(CONFIG_PPC64)
-/* XXX convert to rusty's on_one_cpu */
-static unsigned long run_on_cpu(unsigned long cpu,
- unsigned long (*func)(unsigned long),
- unsigned long arg)
-{
- cpumask_t old_affinity = current->cpus_allowed;
- unsigned long ret;
-
- /* should return -EINVAL to userspace */
- if (set_cpus_allowed(current, cpumask_of_cpu(cpu)))
- return 0;
-
- ret = func(arg);
-
- set_cpus_allowed(current, old_affinity);
-
- return ret;
-}
-#endif
#define SYSFS_PMCSETUP(NAME, ADDRESS) \
-static unsigned long read_##NAME(unsigned long junk) \
+static void read_##NAME(void *val) \
{ \
- return mfspr(ADDRESS); \
+ mtspr(ADDRESS, *(unsigned long *)val); \
} \
static unsigned long write_##NAME(unsigned long val) \
{ \
ppc_enable_pmcs(); \
- mtspr(ADDRESS, val); \
+ mtspr(ADDRESS, *(unsigned long *)val); \
return 0; \
} \
static ssize_t show_##NAME(struct sys_device *dev, \
@@ -171,7 +151,8 @@
char *buf) \
{ \
struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
- unsigned long val = run_on_cpu(cpu->sysdev.id, read_##NAME, 0); \
+ unsigned long val; \
+ smp_call_function_single(cpu->sysdev.id, read_##NAME, &val, 1); \
return sprintf(buf, "%lx\n", val); \
} \
static ssize_t __used \
@@ -183,7 +164,7 @@
int ret = sscanf(buf, "%lx", &val); \
if (ret != 1) \
return -EINVAL; \
- run_on_cpu(cpu->sysdev.id, write_##NAME, val); \
+ smp_call_function_single(cpu->sysdev.id, write_##NAME, &val, 1); \
return count; \
}