Re: [PATCH v6 2/6] ACPI: Add _OST support for sysfs eject

[Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>]

Hi Toshi,

2012/06/27 5:42, Toshi Kani wrote:
> Changed acpi_bus_hot_remove_device() to support _OST. This function is
> also changed to global so that it can be called from hotplug notify
> handlers to perform hot-remove operation.
> 
> Changed acpi_eject_store(), which is the sysfs eject handler. It checks
> eject_pending to see if the request was originated from ACPI eject
> notification. If not, it calls _OST(0x103,84,) per Figure 6-37 in ACPI
> 5.0 spec.
> 
> Added eject_pending bit to acpi_device_flags. This bit is set when the
> kernel has received an ACPI eject notification, but does not initiate
> its hot-remove operation by itself.
> 
> Added struct acpi_eject_event. This structure is used to pass extended
> information to acpi_bus_hot_remove_device(), which has a single argument
> to support asynchronous call
> 
> Signed-off-by: Toshi Kani <toshi.kani@hp.com>
> ---
>   drivers/acpi/scan.c     |   57 +++++++++++++++++++++++++++++++++++++++-------
>   include/acpi/acpi_bus.h |    9 ++++++-
>   2 files changed, 56 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index c8a1f3b..dbdb9fc 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -83,19 +83,29 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
>   }
>   static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
>   
> -static void acpi_bus_hot_remove_device(void *context)
> +/**
> + * acpi_bus_hot_remove_device: hot-remove a device and its children
> + * @context: struct acpi_eject_event pointer (freed in this func)
> + *
> + * Hot-remove a device and its children. This function frees up the
> + * memory space passed by arg context, so that the caller may call
> + * this function asynchronously through acpi_os_hotplug_execute().
> + */
> +void acpi_bus_hot_remove_device(void *context)
>   {
> +	struct acpi_eject_event *ej_event = (struct acpi_eject_event *) context;
>   	struct acpi_device *device;
> -	acpi_handle handle = context;
> +	acpi_handle handle = ej_event->handle;
>   	struct acpi_object_list arg_list;
>   	union acpi_object arg;
>   	acpi_status status = AE_OK;
> +	u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
>   
>   	if (acpi_bus_get_device(handle, &device))
> -		return;
> +		goto err_out;
>   
>   	if (!device)
> -		return;
> +		goto err_out;
>   
>   	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>   		"Hot-removing device %s...\n", dev_name(&device->dev)));
> @@ -103,7 +113,7 @@ static void acpi_bus_hot_remove_device(void *context)
>   	if (acpi_bus_trim(device, 1)) {
>   		printk(KERN_ERR PREFIX
>   				"Removing device failed\n");
> -		return;
> +		goto err_out;
>   	}
>   
>   	/* power off device */
> @@ -129,10 +139,20 @@ static void acpi_bus_hot_remove_device(void *context)
>   	 * TBD: _EJD support.
>   	 */
>   	status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
> -	if (ACPI_FAILURE(status))
> -		printk(KERN_WARNING PREFIX
> -				"Eject device failed\n");
> +	if (ACPI_FAILURE(status)) {
> +		if (status != AE_NOT_FOUND)
> +			pr_warn(PREFIX "Eject device failed\n");
> +		goto err_out;
> +	}
> +
> +	kfree(context);
> +	return;
>   
> +err_out:
> +	/* Inform firmware the hot-remove operation has completed w/ error */
> +	(void) acpi_evaluate_hotplug_ost(handle,
> +				ej_event->event, ost_code, NULL);
> +	kfree(context);
>   	return;
>   }

When I read your patch named [PATCH] ACPI: Add ACPI CPU hot-remove support,
a question about this patch appeared.

The question is :
Why does not acpi_bus_hot_remove_device() inform firmware of
ACPI_OST_SC_SUCCESS, when it succeeded? Are thre any reasons?

If you have already discussed my question, please let me know the log.

Thanks,
Yasuaki Ishimatsu


>   
> @@ -144,6 +164,7 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
>   	acpi_status status;
>   	acpi_object_type type = 0;
>   	struct acpi_device *acpi_device = to_acpi_device(d);
> +	struct acpi_eject_event *ej_event;
>   
>   	if ((!count) || (buf[0] != '1')) {
>   		return -EINVAL;
> @@ -160,7 +181,25 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
>   		goto err;
>   	}
>   
> -	acpi_os_hotplug_execute(acpi_bus_hot_remove_device, acpi_device->handle);
> +	ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
> +	if (!ej_event) {
> +		ret = -ENOMEM;
> +		goto err;
> +	}
> +
> +	ej_event->handle = acpi_device->handle;
> +	if (acpi_device->flags.eject_pending) {
> +		/* event originated from ACPI eject notification */
> +		ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
> +		acpi_device->flags.eject_pending = 0;
> +	} else {
> +		/* event originated from user */
> +		ej_event->event = ACPI_OST_EC_OSPM_EJECT;
> +		(void) acpi_evaluate_hotplug_ost(ej_event->handle,
> +			ej_event->event, ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
> +	}
> +
> +	acpi_os_hotplug_execute(acpi_bus_hot_remove_device, (void *)ej_event);
>   err:
>   	return ret;
>   }
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index 1d9e432..b22b774 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -182,7 +182,8 @@ struct acpi_device_flags {
>   	u32 suprise_removal_ok:1;
>   	u32 power_manageable:1;
>   	u32 performance_manageable:1;
> -	u32 reserved:24;
> +	u32 eject_pending:1;
> +	u32 reserved:23;
>   };
>   
>   /* File System */
> @@ -334,6 +335,11 @@ struct acpi_bus_event {
>   	u32 data;
>   };
>   
> +struct acpi_eject_event {
> +	acpi_handle	handle;
> +	u32		event;
> +};
> +
>   extern struct kobject *acpi_kobj;
>   extern int acpi_bus_generate_netlink_event(const char*, const char*, u8, int);
>   void acpi_bus_private_data_handler(acpi_handle, void *);
> @@ -371,6 +377,7 @@ int acpi_bus_register_driver(struct acpi_driver *driver);
>   void acpi_bus_unregister_driver(struct acpi_driver *driver);
>   int acpi_bus_add(struct acpi_device **child, struct acpi_device *parent,
>   		 acpi_handle handle, int type);
> +void acpi_bus_hot_remove_device(void *context);
>   int acpi_bus_trim(struct acpi_device *start, int rmdevice);
>   int acpi_bus_start(struct acpi_device *device);
>   acpi_status acpi_bus_get_ejd(acpi_handle handle, acpi_handle * ejd);
>