[PATCH 3/3] cpufreq: use work_on_cpu in acpi-cpufreq.c for drv_read and drv_write

From: Mike Travis
Date: Fri Jan 16 2009 - 14:12:56 EST


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@xxxxxxx>
Acked-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Tested-by: Dieter Ries <clip2@xxxxxx>
Tested-by: Maciej Rutecki <maciej.rutecki@xxxxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxx>
Cc: <cpufreq@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 22 +++++++++-------------
1 file changed, 9 insertions(+), 13 deletions(-)

--- linux-2.6-for-ingo.orig/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ linux-2.6-for-ingo/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 *
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
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)
@@ -367,7 +363,7 @@ static unsigned int get_cur_freq_on_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;

--
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