Re: [PATCH v3 1/3] acpi : cpu hot-remove returns error whencpu_down() fails

From: Toshi Kani
Date: Thu Jul 12 2012 - 12:52:36 EST


On Thu, 2012-07-12 at 20:22 +0900, 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.
>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
>
> ---
> drivers/acpi/processor_driver.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> Index: linux-3.5-rc4/drivers/acpi/processor_driver.c
> ===================================================================
> --- linux-3.5-rc4.orig/drivers/acpi/processor_driver.c 2012-06-25 04:53:04.000000000 +0900
> +++ linux-3.5-rc4/drivers/acpi/processor_driver.c 2012-07-05 21:02:58.711285382 +0900
> @@ -610,7 +610,7 @@ 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;
> @@ -621,8 +621,9 @@ 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);
> @@ -841,12 +842,17 @@ 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;
> +
> + if (cpu_online(pr->id)) {
> + ret = cpu_down(pr->id);
> + if (ret)
> + return ret;
> + }
>
> arch_unregister_cpu(pr->id);
> acpi_unmap_lsapic(pr->id);
> - return (0);
> + return ret;

ret is uninitialized when !cpu_online().

Thanks,
-Toshi

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