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Date: Tue, 19 Feb 2013 16:10:15 +0900
From: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To: "Rafael J. Wysocki" <rjw@...k.pl>
CC: ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
LKML <linux-kernel@...r.kernel.org>,
Yinghai Lu <yinghai@...nel.org>,
Toshi Kani <toshi.kani@...com>, Jiang Liu <liuj97@...il.com>
Subject: Re: [PATCH 2/7] ACPI / scan: Introduce common code for ACPI-based
device hotplug
2013/02/19 15:43, Yasuaki Ishimatsu wrote:
> Hi Rafael,
>
> I have comments. Please see below.
>
> 2013/02/18 0:21, Rafael J. Wysocki wrote:
>> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>>
>> Multiple drivers handling hotplug-capable ACPI device nodes install
>> notify handlers covering the same types of events in a very similar
>> way. Moreover, those handlers are installed in separate namespace
>> walks, although that really should be done during namespace scans
>> carried out by acpi_bus_scan(). This leads to substantial code
>> duplication, unnecessary overhead and behavior that is hard to
>> follow.
>>
>> For this reason, introduce common code in drivers/acpi/scan.c for
>> handling hotplug-related notification and carrying out device
>> insertion and eject operations in a generic fashion, such that it
>> may be used by all of the relevant drivers in the future. To cover
>> the existing differences between those drivers introduce struct
>> acpi_hotplug_profile for representing collections of hotplug
>> settings associated with different ACPI scan handlers that can be
>> used by the drivers to make the common code reflect their current
>> behavior.
>>
>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> ---
>> drivers/acpi/scan.c | 271 +++++++++++++++++++++++++++++++++++++-----------
>> include/acpi/acpi_bus.h | 7 +
>> 2 files changed, 220 insertions(+), 58 deletions(-)
>>
>> Index: test/include/acpi/acpi_bus.h
>> ===================================================================
>> --- test.orig/include/acpi/acpi_bus.h
>> +++ test/include/acpi/acpi_bus.h
>> @@ -88,11 +88,18 @@ struct acpi_device;
>> * -----------------
>> */
>>
>> +struct acpi_hotplug_profile {
>> + bool enabled:1;
>> + bool uevents:1;
>> + bool autoeject:1;
>> +};
>> +
>> struct acpi_scan_handler {
>> const struct acpi_device_id *ids;
>> struct list_head list_node;
>> int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);
>> void (*detach)(struct acpi_device *dev);
>> + struct acpi_hotplug_profile hotplug;
>> };
>>
>> /*
>> Index: test/drivers/acpi/scan.c
>> ===================================================================
>> --- test.orig/drivers/acpi/scan.c
>> +++ test/drivers/acpi/scan.c
>> @@ -107,32 +107,19 @@ acpi_device_modalias_show(struct device
>> }
>> static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
>>
>> -/**
>> - * 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)
>> +static int acpi_scan_hot_remove(struct acpi_device *device)
>> {
>> - struct acpi_eject_event *ej_event = context;
>> - struct acpi_device *device = ej_event->device;
>> acpi_handle handle = device->handle;
>> - acpi_handle temp;
>> + acpi_handle not_used;
>> 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 */
>> -
>> - mutex_lock(&acpi_scan_lock);
>> + acpi_status status;
>>
>> /* If there is no handle, the device node has been unregistered. */
>> - if (!device->handle) {
>> + if (!handle) {
>> dev_dbg(&device->dev, "ACPI handle missing\n");
>> put_device(&device->dev);
>> - goto out;
>> + return -EINVAL;
>> }
>>
>> ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>> @@ -143,7 +130,7 @@ void acpi_bus_hot_remove_device(void *co
>> put_device(&device->dev);
>> device = NULL;
>>
>> - if (ACPI_SUCCESS(acpi_get_handle(handle, "_LCK", &temp))) {
>> + if (ACPI_SUCCESS(acpi_get_handle(handle, "_LCK", ¬_used))) {
>> arg_list.count = 1;
>> arg_list.pointer = &arg;
>> arg.type = ACPI_TYPE_INTEGER;
>> @@ -161,18 +148,162 @@ void acpi_bus_hot_remove_device(void *co
>> */
>> status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
>> if (ACPI_FAILURE(status)) {
>> - if (status != AE_NOT_FOUND)
>> + if (status == AE_NOT_FOUND) {
>> + return -ENODEV;
>> + } else {
>> acpi_handle_warn(handle, "Eject failed\n");
>> + return -EIO;
>> + }
>> + }
>> + return 0;
>> +}
>> +
>> +static void acpi_bus_device_eject(void *context)
>> +{
>> + acpi_handle handle = context;
>> + struct acpi_device *device = NULL;
>> + struct acpi_scan_handler *handler;
>> + u32 ost_source = ACPI_NOTIFY_EJECT_REQUEST;
>> + u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
>> +
>> + mutex_lock(&acpi_scan_lock);
>>
>> - /* Tell the firmware the hot-remove operation has failed. */
>> - acpi_evaluate_hotplug_ost(handle, ej_event->event,
>> - ost_code, NULL);
>> + acpi_bus_get_device(handle, &device);
>> + if (!device)
>> + goto out;
>> +
>> + handler = device->handler;
>> + if (!handler || !handler->hotplug.enabled) {
>> + ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
>> + goto out;
>> }
>> + acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
>> + ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
>
>> + if (handler->hotplug.uevents)
>> + kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
>> +
>> + if (handler->hotplug.autoeject) {
>> + int error;
>> +
>> + ost_source = ACPI_OST_EC_OSPM_EJECT;
>> + get_device(&device->dev);
>> + error = acpi_scan_hot_remove(device);
>> + if (!error)
>> + ost_code = ACPI_OST_SC_SUCCESS;
>> + } else {
>> + device->flags.eject_pending = true;
>> + goto out_unlock;
>> + }
>
> I want you to change the order of uevents and autoeject.
> When user caught OFFLINE event, user thinks devices were removed.
> But it is not guaranteed in this code since acpi_scan_hot_remove() may
> be running.
>
>> +
>> + out:
>> + acpi_evaluate_hotplug_ost(handle, ost_source, ost_code, NULL);
>> +
>> + out_unlock:
>> + mutex_unlock(&acpi_scan_lock);
>> +}
>> +
>> +static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source)
>> +{
>> + struct acpi_device *device = NULL;
>> + u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
>> + int error;
>> +
>> + mutex_lock(&acpi_scan_lock);
>> +
>> + acpi_bus_get_device(handle, &device);
>> + if (device) {
>> + dev_warn(&device->dev, "Attempt to re-insert\n");
>> + goto out;
>> + }
>> + acpi_evaluate_hotplug_ost(handle, ost_source,
>> + ACPI_OST_SC_INSERT_IN_PROGRESS, NULL);
>> + ost_source = ACPI_OST_EC_OSPM_INSERTION;
>> + error = acpi_bus_scan(handle);
>> + if (error) {
>> + acpi_handle_warn(handle, "Namespace scan failure\n");
>> + goto out;
>> + }
>> + error = acpi_bus_get_device(handle, &device);
>> + if (error) {
>> + acpi_handle_warn(handle, "Missing device node object\n");
>> + goto out;
>> + }
>> + ost_code = ACPI_OST_SC_SUCCESS;
>> + if (device->handler && device->handler->hotplug.uevents)
>> + kobject_uevent(&device->dev.kobj, KOBJ_ONLINE);
>>
>> out:
>> + acpi_evaluate_hotplug_ost(handle, ost_source, ost_code, NULL);
>> + mutex_unlock(&acpi_scan_lock);
>> +}
Why don't you check _STA method in acpi_scan_bus_device_check()?
When hot adding new device, we must check _STA method of the device.
Thanks,
Yasuaki Ishimatsu
>> +
>> +static void acpi_scan_bus_check(void *context)
>> +{
>> + acpi_scan_bus_device_check((acpi_handle)context,
>> + ACPI_NOTIFY_BUS_CHECK);
>> +}
>> +
>> +static void acpi_scan_device_check(void *context)
>> +{
>> + acpi_scan_bus_device_check((acpi_handle)context,
>> + ACPI_NOTIFY_DEVICE_CHECK);
>> +}
>> +
>> +static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *not_used)
>> +{
>> + acpi_osd_exec_callback callback;
>> + acpi_status status;
>> +
>> + switch (type) {
>> + case ACPI_NOTIFY_BUS_CHECK:
>> + acpi_handle_debug(handle, "ACPI_NOTIFY_BUS_CHECK event\n");
>> + callback = acpi_scan_bus_check;
>> + break;
>> + case ACPI_NOTIFY_DEVICE_CHECK:
>> + acpi_handle_debug(handle, "ACPI_NOTIFY_DEVICE_CHECK event\n");
>> + callback = acpi_scan_device_check;
>> + break;
>> + case ACPI_NOTIFY_EJECT_REQUEST:
>> + acpi_handle_debug(handle, "ACPI_NOTIFY_EJECT_REQUEST event\n");
>> + callback = acpi_bus_device_eject;
>> + break;
>> + default:
>> + /* non-hotplug event; possibly handled by other handler */
>> + return;
>> + }
>> + status = acpi_os_hotplug_execute(callback, handle);
>> + if (ACPI_FAILURE(status))
>> + acpi_evaluate_hotplug_ost(handle, type,
>> + ACPI_OST_SC_NON_SPECIFIC_FAILURE,
>> + NULL);
>> +}
>> +
>> +/**
>> + * 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 = context;
>> + struct acpi_device *device = ej_event->device;
>> + acpi_handle handle = device->handle;
>> + u32 ost_code = ACPI_OST_SC_SUCCESS;
>> + int error;
>> +
>> + mutex_lock(&acpi_scan_lock);
>> +
>> + error = acpi_scan_hot_remove(device);
>> + if (error)
>> + ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
>> +
>> + acpi_evaluate_hotplug_ost(handle, ej_event->event, ost_code, NULL);
>> +
>> mutex_unlock(&acpi_scan_lock);
>> kfree(context);
>> - return;
>> }
>> EXPORT_SYMBOL(acpi_bus_hot_remove_device);
>>
>> @@ -206,50 +337,48 @@ static ssize_t
>> acpi_eject_store(struct device *d, struct device_attribute *attr,
>> const char *buf, size_t count)
>> {
>> - int ret = count;
>> - acpi_status status;
>> - acpi_object_type type = 0;
>> struct acpi_device *acpi_device = to_acpi_device(d);
>> - struct acpi_eject_event *ej_event;
>> + acpi_object_type not_used;
>> + acpi_status status;
>> + u32 ost_source;
>> + u32 ost_code;
>> + int ret;
>>
>> - if ((!count) || (buf[0] != '1')) {
>> + if (!count || buf[0] != '1')
>> return -EINVAL;
>> - }
>> - if (!acpi_device->driver && !acpi_device->handler) {
>> - ret = -ENODEV;
>> - goto err;
>> - }
>> - status = acpi_get_type(acpi_device->handle, &type);
>> - if (ACPI_FAILURE(status) || (!acpi_device->flags.ejectable)) {
>> - ret = -ENODEV;
>> - goto err;
>> - }
>>
>> - ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
>> - if (!ej_event) {
>> - ret = -ENOMEM;
>> - goto err;
>> - }
>> + if ((!acpi_device->handler || !acpi_device->handler->hotplug.enabled)
>> + && !acpi_device->driver)
>> + return -ENODEV;
>> +
>> + status = acpi_get_type(acpi_device->handle, ¬_used);
>> + if (ACPI_FAILURE(status) || !acpi_device->flags.ejectable)
>> + return -ENODEV;
>> +
>> + mutex_lock(&acpi_scan_lock);
>>
>> - get_device(&acpi_device->dev);
>> - ej_event->device = acpi_device;
>> if (acpi_device->flags.eject_pending) {
>> - /* event originated from ACPI eject notification */
>> - ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
>> + /* ACPI eject notification event. */
>> + ost_source = 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(acpi_device->handle,
>> - ej_event->event, ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
>> + /* Eject initiated by user space. */
>> + ost_source = ACPI_OST_EC_OSPM_EJECT;
>> }
>> -
>
>> - status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
>> - if (ACPI_FAILURE(status)) {
>> - put_device(&acpi_device->dev);
>> - kfree(ej_event);
>> + acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
>> + ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
>> + get_device(&acpi_device->dev);
>> + ret = acpi_scan_hot_remove(acpi_device);
>
> Why don't you use acpi_os_hotplug_execute()? Do you have some reason?
>
> Thanks,
> Yasuaki Ishimatsu
>
>> + if (ret) {
>> + ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
>> + } else {
>> + ost_code = ACPI_OST_SC_SUCCESS;
>> + ret = count;
>> }
>> -err:
>> + acpi_evaluate_hotplug_ost(acpi_device->handle, ACPI_OST_EC_OSPM_EJECT,
>> + ost_code, NULL);
>> +
>> + mutex_unlock(&acpi_scan_lock);
>> return ret;
>> }
>>
>> @@ -1548,6 +1677,30 @@ static struct acpi_scan_handler *acpi_sc
>> return NULL;
>> }
>>
>> +static void acpi_scan_init_hotplug(acpi_handle handle)
>> +{
>> + struct acpi_device_info *info;
>> + struct acpi_scan_handler *handler;
>> +
>> + if (ACPI_FAILURE(acpi_get_object_info(handle, &info)))
>> + return;
>> +
>> + if (!(info->valid & ACPI_VALID_HID)) {
>> + kfree(info);
>> + return;
>> + }
>> +
>> + /*
>> + * This relies on the fact that acpi_install_notify_handler() will not
>> + * install the same notify handler routine twice for the same handle.
>> + */
>> + handler = acpi_scan_match_handler(info->hardware_id.string, NULL);
>> + kfree(info);
>> + if (handler && handler->hotplug.enabled)
>> + acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
>> + acpi_hotplug_notify_cb, NULL);
>> +}
>> +
>> static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
>> void *not_used, void **return_value)
>> {
>> @@ -1570,6 +1723,8 @@ static acpi_status acpi_bus_check_add(ac
>> return AE_OK;
>> }
>>
>> + acpi_scan_init_hotplug(handle);
>> +
>> if (!(sta & ACPI_STA_DEVICE_PRESENT) &&
>> !(sta & ACPI_STA_DEVICE_FUNCTIONING)) {
>> struct acpi_device_wakeup wakeup;
>>
>
>
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