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Commit da009f39 authored by Ben Dooks's avatar Ben Dooks Committed by Greg Kroah-Hartman
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sysdev: detect multiple driver registrations 



I've just found how easy it is to accidentally register a sysdev_driver for
two different classes.  When this happens, bad things happen as the
sysdev_driver structure keeps has the list entry for the driver
registration.

The following patch makes a WARN_ON() if this happens, although I think
BUG_ON or returning -EAGAIN could also be valid responses to this.

Signed-off-by: default avatarBen Dooks <ben@fluff.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 6c847402

drivers/base/sys.c

+16 −0
Original line number Diff line number Diff line
@@ -167,6 +167,22 @@ int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv) 
{

	int err = 0;



	if (!cls) {

		printk(KERN_WARNING "sysdev: invalid class passed to "

			"sysdev_driver_register!\n");

		WARN_ON(1);

		return -EINVAL;

	}



	/* Check whether this driver has already been added to a class. */

	if ((drv->entry.next != drv->entry.prev) ||

	    (drv->entry.next != NULL)) {

		printk(KERN_WARNING "sysdev: class %s: driver (%p) has already"

			" been registered to a class, something is wrong, but "

			"will forge on!\n", cls->name, drv);

		WARN_ON(1);

	}



	mutex_lock(&sysdev_drivers_lock);

	if (cls && kset_get(&cls->kset)) {

		list_add_tail(&drv->entry, &cls->drivers);