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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: Ben Dooks <ben@fluff.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Ben Dooks 2008-03-04 15:09:06 -08:00 committed by Greg Kroah-Hartman
parent 6c847402e1
commit da009f39f8
1 changed files with 16 additions and 0 deletions
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16
drivers/base/sys.c
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@ -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);