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authorDavid Brownell <david-b@pacbell.net>2007-02-28 20:12:40 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-03-01 14:53:37 -0800
commite109ebd1eed2b91e3c9bb3b42cc27961f0dc22b3 (patch)
tree402ca61d265c59d35282b0786363dfbe32659564 /drivers/rtc/class.c
parent0478e62e8a04154b7bdc0dfd33ffbcabc5446e9c (diff)
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[PATCH] rtc_cmos oops fix
Fix an oops on the rtc_device_unregister() path by waiting until the last moment before nulling the rtc->ops vector. Fix some potential oopses by having the rtc_class_open()/rtc_class_close() interface increase the RTC's reference count while an RTC handle is available outside the RTC framework. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/rtc/class.c')
-rw-r--r--drivers/rtc/class.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 7a0d8ee2de9c..04aaa6347234 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -113,10 +113,16 @@ EXPORT_SYMBOL_GPL(rtc_device_register);
*/
void rtc_device_unregister(struct rtc_device *rtc)
{
- mutex_lock(&rtc->ops_lock);
- rtc->ops = NULL;
- mutex_unlock(&rtc->ops_lock);
- class_device_unregister(&rtc->class_dev);
+ if (class_device_get(&rtc->class_dev) != NULL) {
+ mutex_lock(&rtc->ops_lock);
+ /* remove innards of this RTC, then disable it, before
+ * letting any rtc_class_open() users access it again
+ */
+ class_device_unregister(&rtc->class_dev);
+ rtc->ops = NULL;
+ mutex_unlock(&rtc->ops_lock);
+ class_device_put(&rtc->class_dev);
+ }
}
EXPORT_SYMBOL_GPL(rtc_device_unregister);