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Date: Sun, 09 Jun 2013 09:54:49 +0800
From: Aaron Lu <aaron.lu@...el.com>
To: "Rafael J. Wysocki" <rjw@...k.pl>
CC: ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI / scan: Simplify ACPI driver probing
On 06/09/2013 09:19 AM, Aaron Lu wrote:
> On 06/09/2013 06:28 AM, Rafael J. Wysocki wrote:
>> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>>
>> There is no particular reason why acpi_bus_driver_init() needs to be
>> a separate function and its location with respect to its only caller,
>> acpi_device_probe(), makes the code a bit difficult to follow.
>>
>> Besides, it doesn't really make sense to check if 'device' is not
>> NULL in acpi_bus_driver_init(), because we've already dereferenced
>> dev->driver in acpi_device_probe() at that point, so that check has
>> to be moved to acpi_device_probe() anyway.
>>
>> For these reasons, drop acpi_bus_driver_init() altogether and move
>> the code from it directly into acpi_device_probe().
>>
>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> ---
>>
>> Should apply on top of the bleeding-edge branch of the linux-pm.git tree.
>>
>> Thanks,
>> Rafael
>>
>> ---
>> drivers/acpi/scan.c | 88 +++++++++++++++++++---------------------------------
>> 1 file changed, 33 insertions(+), 55 deletions(-)
>>
>> Index: linux-pm/drivers/acpi/scan.c
>> ===================================================================
>> --- linux-pm.orig/drivers/acpi/scan.c
>> +++ linux-pm/drivers/acpi/scan.c
>> @@ -933,32 +933,45 @@ static void acpi_device_remove_notify_ha
>> acpi_device_notify);
>> }
>>
>> -static int acpi_bus_driver_init(struct acpi_device *, struct acpi_driver *);
>> static int acpi_device_probe(struct device * dev)
>> {
>> - struct acpi_device *acpi_dev = to_acpi_device(dev);
>> - struct acpi_driver *acpi_drv = to_acpi_driver(dev->driver);
>> + struct acpi_device *acpi_dev;
>> + struct acpi_driver *acpi_drv;
>> int ret;
>>
>> - ret = acpi_bus_driver_init(acpi_dev, acpi_drv);
>> - if (!ret) {
>> - if (acpi_drv->ops.notify) {
>> - ret = acpi_device_install_notify_handler(acpi_dev);
>> - if (ret) {
>> - if (acpi_drv->ops.remove)
>> - acpi_drv->ops.remove(acpi_dev);
>> - acpi_dev->driver = NULL;
>> - acpi_dev->driver_data = NULL;
>> - return ret;
>> - }
>> - }
>> + if (!dev || !dev->driver)
>> + return -EINVAL;
>
> Just out of curiosity, will dev ever be NULL in this function?
> This function is called in really_probe by dev->bus->probe after
> assigning dev->driver, so does the above check make any sense?
BTW, I also tested the patch on a desktop and two laptops, no problems
found. Feel free to add my tested-by tag.
Thanks,
Aaron
>
> Thanks,
> Aaron
>
>> +
>> + acpi_dev = to_acpi_device(dev);
>> + acpi_drv = to_acpi_driver(dev->driver);
>> + if (!acpi_drv->ops.add)
>> + return -ENOSYS;
>> +
>> + ret = acpi_drv->ops.add(acpi_dev);
>> + if (ret)
>> + return ret;
>> +
>> + acpi_dev->driver = acpi_drv;
>> + ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>> + "Driver [%s] successfully bound to device [%s]\n",
>> + acpi_drv->name, acpi_dev->pnp.bus_id));
>>
>> - ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>> - "Found driver [%s] for device [%s]\n",
>> - acpi_drv->name, acpi_dev->pnp.bus_id));
>> - get_device(dev);
>> + if (acpi_drv->ops.notify) {
>> + ret = acpi_device_install_notify_handler(acpi_dev);
>> + if (ret) {
>> + if (acpi_drv->ops.remove)
>> + acpi_drv->ops.remove(acpi_dev);
>> +
>> + acpi_dev->driver = NULL;
>> + acpi_dev->driver_data = NULL;
>> + return ret;
>> + }
>> }
>> - return ret;
>> +
>> + ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found driver [%s] for device [%s]\n",
>> + acpi_drv->name, acpi_dev->pnp.bus_id));
>> + get_device(dev);
>> + return 0;
>> }
>>
>> static int acpi_device_remove(struct device * dev)
>> @@ -1114,41 +1127,6 @@ static void acpi_device_unregister(struc
>> Driver Management
>> -------------------------------------------------------------------------- */
>> /**
>> - * acpi_bus_driver_init - add a device to a driver
>> - * @device: the device to add and initialize
>> - * @driver: driver for the device
>> - *
>> - * Used to initialize a device via its device driver. Called whenever a
>> - * driver is bound to a device. Invokes the driver's add() ops.
>> - */
>> -static int
>> -acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
>> -{
>> - int result = 0;
>> -
>> - if (!device || !driver)
>> - return -EINVAL;
>> -
>> - if (!driver->ops.add)
>> - return -ENOSYS;
>> -
>> - result = driver->ops.add(device);
>> - if (result)
>> - return result;
>> -
>> - device->driver = driver;
>> -
>> - /*
>> - * TBD - Configuration Management: Assign resources to device based
>> - * upon possible configuration and currently allocated resources.
>> - */
>> -
>> - ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>> - "Driver successfully bound to device\n"));
>> - return 0;
>> -}
>> -
>> -/**
>> * acpi_bus_register_driver - register a driver with the ACPI bus
>> * @driver: driver being registered
>> *
>>
>
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