Re: [PATCH] gpiolib: fix device_create() result check

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 20 Oct 2009 20:35:23 +0400
Sergei Shtylyov <sshtylyov@ru.mvista.com> wrote:

> In case of failure, device_create() returns not NULL but the error code.
> The current code checks for non-NULL though which causes kernel oops in
> sysfs_create_group() when device_create() fails.  Check for error using
> IS_ERR() and propagate the error value using PTR_ERR() instead of fixed
> -ENODEV code returned now...

Does anyone notice any missing information here?

/**
 * device_create - creates a device and registers it with sysfs
 * @class: pointer to the struct class that this device should be registered to
 * @parent: pointer to the parent struct device of this new device, if any
 * @devt: the dev_t for the char device to be added
 * @drvdata: the data to be added to the device for callbacks
 * @fmt: string for the device's name
 *
 * This function can be used by char device classes.  A struct device
 * will be created in sysfs, registered to the specified class.
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
 * If a pointer to a parent struct device is passed in, the newly created
 * struct device will be a child of that device in sysfs.
 * The pointer to the struct device will be returned from the call.
 * Any further sysfs files that might be required can be created using this
 * pointer.
 *
 * Note: the struct class passed to this function must have previously
 * been created with a call to class_create().
 */


Why do we do this to ourselves?