cpufreq: use work_on_cpu in acpi-cpufreq.c for drv_read and drv_write

Impact: use new work_on_cpu function to reduce stack usage

Replace the saving of current->cpus_allowed and set_cpus_allowed_ptr() with
a work_on_cpu function for drv_read() and drv_write().

Basically converts do_drv_{read,write} into "work_on_cpu" functions that
are now called by drv_read and drv_write.

Note: This patch basically reverts 50c668d6 which reverted 7503bfba, now
that the work_on_cpu() function is more stable.

Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Dieter Ries <clip2@gmx.de>
Tested-by: Maciej Rutecki <maciej.rutecki@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: <cpufreq@vger.kernel.org>

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 9 insertions, 13 deletions

diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
index 8f3c95c7e61f..5bf2c834a236 100644
--- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -150,8 +150,9 @@ struct drv_cmd {
         u32 val;
 };
 
-static void do_drv_read(struct drv_cmd *cmd)
+static long do_drv_read(void *_cmd)
 {
+        struct drv_cmd *cmd = _cmd;
         u32 h;
 
         switch (cmd->type) {
@@ -166,10 +167,12 @@ static void do_drv_read(struct drv_cmd *cmd)
         default:
                 break;
         }
+        return 0;
 }
 
-static void do_drv_write(struct drv_cmd *cmd)
+static long do_drv_write(void *_cmd)
 {
+        struct drv_cmd *cmd = _cmd;
         u32 lo, hi;
 
         switch (cmd->type) {
@@ -186,30 +189,23 @@ static void do_drv_write(struct drv_cmd *cmd)
         default:
                 break;
         }
+        return 0;
 }
 
 static void drv_read(struct drv_cmd *cmd)
 {
-        cpumask_t saved_mask = current->cpus_allowed;
         cmd->val = 0;
 
-        set_cpus_allowed_ptr(current, cmd->mask);
-        do_drv_read(cmd);
-        set_cpus_allowed_ptr(current, &saved_mask);
+        work_on_cpu(cpumask_any(cmd->mask), do_drv_read, cmd);
 }
 
 static void drv_write(struct drv_cmd *cmd)
 {
-        cpumask_t saved_mask = current->cpus_allowed;
         unsigned int i;
 
         for_each_cpu(i, cmd->mask) {
-                set_cpus_allowed_ptr(current, cpumask_of(i));
-                do_drv_write(cmd);
+                work_on_cpu(i, do_drv_write, cmd);
         }
-
-        set_cpus_allowed_ptr(current, &saved_mask);
-        return;
 }
 
 static u32 get_cur_val(const struct cpumask *mask)
@@ -366,7 +362,7 @@ static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
         return freq;
 }
 
-static unsigned int check_freqs(const cpumask_t *mask, unsigned int freq,
+static unsigned int check_freqs(const struct cpumask *mask, unsigned int freq,
                                 struct acpi_cpufreq_data *data)
 {
         unsigned int cur_freq;