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authorBen Dooks <ben@fluff.org>2008-03-04 15:09:06 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2008-04-19 19:10:24 -0700
commitda009f39f85a3ee9deeb10f0f05ddd4efdd67020 (patch)
treeba04c23e0d5a831705f0f9bfe1a9be10aff99a78 /drivers/base/sys.c
parent6c847402e1c69c1cfe2bddeadc8391bacbb3d0a5 (diff)
downloadlinux-da009f39f85a3ee9deeb10f0f05ddd4efdd67020.tar.bz2
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>
Diffstat (limited to 'drivers/base/sys.c')
-rw-r--r--drivers/base/sys.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/base/sys.c b/drivers/base/sys.c
index 8e13fd942163..1a06c2393719 100644
--- a/drivers/base/sys.c
+++ b/drivers/base/sys.c
@@ -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);