device_schedule_callback() needs a module reference

This patch (as896b) fixes an oversight in the design of
device_schedule_callback().  It is necessary to acquire a reference to the
module owning the callback routine, to prevent the module from being
unloaded before the callback can run.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Satyam Sharma <satyam.sharma@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern
2007-04-26 00:12:04 -07:00
committed by Greg Kroah-Hartman
parent fa1a8c23eb
commit 523ded71de
4 changed files with 29 additions and 13 deletions
+10 -6
View File
@@ -480,9 +480,10 @@ void device_remove_bin_file(struct device *dev, struct bin_attribute *attr)
EXPORT_SYMBOL_GPL(device_remove_bin_file);
/**
* device_schedule_callback - helper to schedule a callback for a device
* device_schedule_callback_owner - helper to schedule a callback for a device
* @dev: device.
* @func: callback function to invoke later.
* @owner: module owning the callback routine
*
* Attribute methods must not unregister themselves or their parent device
* (which would amount to the same thing). Attempts to do so will deadlock,
@@ -493,20 +494,23 @@ EXPORT_SYMBOL_GPL(device_remove_bin_file);
* argument in the workqueue's process context. @dev will be pinned until
* @func returns.
*
* This routine is usually called via the inline device_schedule_callback(),
* which automatically sets @owner to THIS_MODULE.
*
* Returns 0 if the request was submitted, -ENOMEM if storage could not
* be allocated.
* be allocated, -ENODEV if a reference to @owner isn't available.
*
* NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
* underlying sysfs routine (since it is intended for use by attribute
* methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
*/
int device_schedule_callback(struct device *dev,
void (*func)(struct device *))
int device_schedule_callback_owner(struct device *dev,
void (*func)(struct device *), struct module *owner)
{
return sysfs_schedule_callback(&dev->kobj,
(void (*)(void *)) func, dev);
(void (*)(void *)) func, dev, owner);
}
EXPORT_SYMBOL_GPL(device_schedule_callback);
EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
static void klist_children_get(struct klist_node *n)
{