On Sat, Jan 26, 2013 at 2:41 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> There is no guarantee that acpi_bus_scan() and acpi_bus_trim() will
> not be run in parallel for the same scope of the ACPI namespace,
> which may lead to a great deal of confusion, so introduce a new mutex
> to prevent that from happening.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Steven,
Can you apply this one to for-pci-res-alloc to check if racing with
docking hotplug/eject
still happen?
or wait one or two days after i rebase that branch.
Thanks
Yinghai
> ---
> drivers/acpi/scan.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -52,6 +52,7 @@ static const struct acpi_device_id acpi_
>
> static LIST_HEAD(acpi_device_list);
> static LIST_HEAD(acpi_bus_id_list);
> +static DEFINE_MUTEX(acpi_scan_lock);
> DEFINE_MUTEX(acpi_device_lock);
> LIST_HEAD(acpi_wakeup_device_list);
>
> @@ -1612,19 +1613,22 @@ static acpi_status acpi_bus_device_attac
> int acpi_bus_scan(acpi_handle handle)
> {
> void *device = NULL;
> + int error = 0;
> +
> + mutex_lock(&acpi_scan_lock);
>
> if (ACPI_SUCCESS(acpi_bus_check_add(handle, 0, NULL, &device)))
> acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
> acpi_bus_check_add, NULL, NULL, &device);
>
> if (!device)
> - return -ENODEV;
> -
> - if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL)))
> + error = -ENODEV;
> + else if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL)))
> acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
> acpi_bus_device_attach, NULL, NULL, NULL);
>
> - return 0;
> + mutex_unlock(&acpi_scan_lock);
> + return error;
> }
> EXPORT_SYMBOL(acpi_bus_scan);
>
> @@ -1653,6 +1657,8 @@ static acpi_status acpi_bus_remove(acpi_
>
> void acpi_bus_trim(struct acpi_device *start)
> {
> + mutex_lock(&acpi_scan_lock);
> +
> /*
> * Execute acpi_bus_device_detach() as a post-order callback to detach
> * all ACPI drivers from the device nodes being removed.
> @@ -1667,6 +1673,8 @@ void acpi_bus_trim(struct acpi_device *s
> acpi_walk_namespace(ACPI_TYPE_ANY, start->handle, ACPI_UINT32_MAX, NULL,
> acpi_bus_remove, NULL, NULL);
> acpi_bus_remove(start->handle, 0, NULL, NULL);
> +
> + mutex_unlock(&acpi_scan_lock);
> }
> EXPORT_SYMBOL_GPL(acpi_bus_trim);
>
>
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