2012-10-19 04:09:12

by Rafael J. Wysocki

Subject: Re: [PATCH 1/2] acpi : cpu hot-remove returns error when cpu_down() fails

On Friday 28 of September 2012 19:36:02 Yasuaki Ishimatsu wrote:
> Even if cpu_down() fails, acpi_processor_remove() continues to remove the cpu.
> But in this case, it should return error number since some process may run on
> the cpu. If the cpu has a running process and the cpu is turned the power off,
> the system may not work well.
>
> Reviewed-by: Srivatsa S. Bhat <[email protected]>
> Reviewed-by: Toshi Kani <[email protected]>
> Signed-off-by: Yasuaki Ishimatsu <[email protected]>
>
> ---
> drivers/acpi/processor_driver.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> Index: linux-3.6-rc7/drivers/acpi/processor_driver.c
> ===================================================================
> --- linux-3.6-rc7.orig/drivers/acpi/processor_driver.c 2012-09-24 10:10:57.000000000 +0900
> +++ linux-3.6-rc7/drivers/acpi/processor_driver.c 2012-09-28 19:16:33.207858261 +0900
> @@ -605,7 +605,7 @@ err_free_pr:
> static int acpi_processor_remove(struct acpi_device *device, int type)
> {
> struct acpi_processor *pr = NULL;
> -
> + int ret;
>
> if (!device || !acpi_driver_data(device))
> return -EINVAL;
> @@ -616,8 +616,9 @@ static int acpi_processor_remove(struct
> goto free;
>
> if (type == ACPI_BUS_REMOVAL_EJECT) {
> - if (acpi_processor_handle_eject(pr))
> - return -EINVAL;
> + ret = acpi_processor_handle_eject(pr);
> + if (ret)
> + return ret;
> }
>
> acpi_processor_power_exit(pr, device);
> @@ -848,12 +849,17 @@ static acpi_status acpi_processor_hotadd
>
> static int acpi_processor_handle_eject(struct acpi_processor *pr)
> {
> - if (cpu_online(pr->id))
> - cpu_down(pr->id);
> + int ret = 0;
> +
> + if (cpu_online(pr->id)) {
> + ret = cpu_down(pr->id);

If you defined ret here ...

> + if (ret)
> + return ret;
> + }
>
> arch_unregister_cpu(pr->id);
> acpi_unmap_lsapic(pr->id);
> - return (0);
> + return ret;

... this line wouldn't need to be changed.

> }
> #else
> static acpi_status acpi_processor_hotadd_init(struct acpi_processor *pr)

Thanks,
Rafael


--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

2012-10-19 04:40:49

by Yasuaki Ishimatsu

Subject: Re: [PATCH 1/2] acpi : cpu hot-remove returns error when cpu_down() fails

Hi Rafael,

2012/10/19 10:06, Rafael J. Wysocki wrote:
> On Friday 28 of September 2012 19:36:02 Yasuaki Ishimatsu wrote:
>> Even if cpu_down() fails, acpi_processor_remove() continues to remove the cpu.
>> But in this case, it should return error number since some process may run on
>> the cpu. If the cpu has a running process and the cpu is turned the power off,
>> the system may not work well.
>>
>> Reviewed-by: Srivatsa S. Bhat <[email protected]>
>> Reviewed-by: Toshi Kani <[email protected]>
>> Signed-off-by: Yasuaki Ishimatsu <[email protected]>
>>
>> ---
>> drivers/acpi/processor_driver.c | 18 ++++++++++++------
>> 1 file changed, 12 insertions(+), 6 deletions(-)
>>
>> Index: linux-3.6-rc7/drivers/acpi/processor_driver.c
>> ===================================================================
>> --- linux-3.6-rc7.orig/drivers/acpi/processor_driver.c 2012-09-24 10:10:57.000000000 +0900
>> +++ linux-3.6-rc7/drivers/acpi/processor_driver.c 2012-09-28 19:16:33.207858261 +0900
>> @@ -605,7 +605,7 @@ err_free_pr:
>> static int acpi_processor_remove(struct acpi_device *device, int type)
>> {
>> struct acpi_processor *pr = NULL;
>> -
>> + int ret;
>>
>> if (!device || !acpi_driver_data(device))
>> return -EINVAL;
>> @@ -616,8 +616,9 @@ static int acpi_processor_remove(struct
>> goto free;
>>
>> if (type == ACPI_BUS_REMOVAL_EJECT) {
>> - if (acpi_processor_handle_eject(pr))
>> - return -EINVAL;
>> + ret = acpi_processor_handle_eject(pr);
>> + if (ret)
>> + return ret;
>> }
>>
>> acpi_processor_power_exit(pr, device);
>> @@ -848,12 +849,17 @@ static acpi_status acpi_processor_hotadd
>>
>> static int acpi_processor_handle_eject(struct acpi_processor *pr)
>> {
>> - if (cpu_online(pr->id))
>> - cpu_down(pr->id);
>> + int ret = 0;
>> +
>> + if (cpu_online(pr->id)) {
>> + ret = cpu_down(pr->id);
>
> If you defined ret here ...
>
>> + if (ret)
>> + return ret;
>> + }
>>

>> arch_unregister_cpu(pr->id);
>> acpi_unmap_lsapic(pr->id);
>> - return (0);
>> + return ret;
>
> ... this line wouldn't need to be changed.

Thank you for your review.
O.K. I'll put the return code back.

Thanks,
Yasuaki Ishimatsu

>
>> }
>> #else
>> static acpi_status acpi_processor_hotadd_init(struct acpi_processor *pr)
>
> Thanks,
> Rafael
>
>

2012-10-26 09:26:22

by Yasuaki Ishimatsu

Subject: [PATCH v2 1/2] acpi : cpu hot-remove returns error when cpu_down() fails

v1 -> v2
- update Rafael's comment.

>> static int acpi_processor_handle_eject(struct acpi_processor *pr)
>> {
>> - if (cpu_online(pr->id))
>> - cpu_down(pr->id);
>> + int ret = 0;
>> +
>> + if (cpu_online(pr->id)) {
>> + ret = cpu_down(pr->id);
>
> If you defined ret here ...
>
>> + if (ret)
>> + return ret;
>> + }
>>

>> arch_unregister_cpu(pr->id);
>> acpi_unmap_lsapic(pr->id);
>> - return (0);
>> + return ret;
>
> ... this line wouldn't need to be changed.

---
Even if cpu_down() fails, acpi_processor_remove() continues to remove the cpu.
But in this case, it should return error number since some process may run on
the cpu. If the cpu has a running process and the cpu is turned the power off,
the system may not work well.

Reviewed-by: Srivatsa S. Bhat <[email protected]>
Reviewed-by: Toshi Kani <[email protected]>
Signed-off-by: Yasuaki Ishimatsu <[email protected]>

---
drivers/acpi/processor_driver.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)

Index: linux-3.7-rc2/drivers/acpi/processor_driver.c
===================================================================
--- linux-3.7-rc2.orig/drivers/acpi/processor_driver.c 2012-10-21 04:11:32.000000000 +0900
+++ linux-3.7-rc2/drivers/acpi/processor_driver.c 2012-10-26 18:15:43.721665836 +0900
@@ -605,7 +605,7 @@ err_free_pr:
static int acpi_processor_remove(struct acpi_device *device, int type)
{
struct acpi_processor *pr = NULL;
-
+ int ret;

if (!device || !acpi_driver_data(device))
return -EINVAL;
@@ -616,8 +616,9 @@ static int acpi_processor_remove(struct
goto free;

if (type == ACPI_BUS_REMOVAL_EJECT) {
- if (acpi_processor_handle_eject(pr))
- return -EINVAL;
+ ret = acpi_processor_handle_eject(pr);
+ if (ret)
+ return ret;
}

acpi_processor_power_exit(pr);
@@ -848,8 +849,13 @@ static acpi_status acpi_processor_hotadd

static int acpi_processor_handle_eject(struct acpi_processor *pr)
{
- if (cpu_online(pr->id))
- cpu_down(pr->id);
+ int ret = 0;
+
+ if (cpu_online(pr->id)) {
+ ret = cpu_down(pr->id);
+ if (ret)
+ return ret;
+ }

arch_unregister_cpu(pr->id);
acpi_unmap_lsapic(pr->id);