Commit d5ed9177 authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Greg Kroah-Hartman
Browse files

rtc: utilize new cdev_device_add helper function 



Mostly straightforward, but we had to remove the rtc_dev_add/del_device
functions as they split up the cdev_add and the device_add.

Doing this also revealed that there was likely another subtle bug:
seeing cdev_add was done after device_register, the cdev probably
was not ready before device_add when the uevent occurs. This would
race with userspace, if it tried to use the device directly after
the uevent. This is fixed just by using the new helper function.

Another weird thing is this driver would, in some error cases, call
cdev_add() without calling cdev_init. This patchset corrects this
by avoiding calling cdev_add if the devt is not set.

Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Acked-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent dbef390d

drivers/rtc/class.c

+10 −4
Original line number Diff line number Diff line
@@ -195,6 +195,8 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, 
		goto exit_ida;

	}



	device_initialize(&rtc->dev);



	rtc->id = id;

	rtc->ops = ops;

	rtc->owner = owner;
@@ -233,14 +235,19 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, 


	rtc_dev_prepare(rtc);



	err = device_register(&rtc->dev);

	err = cdev_device_add(&rtc->char_dev, &rtc->dev);

	if (err) {

		dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n",

			 rtc->name, MAJOR(rtc->dev.devt), rtc->id);



		/* This will free both memory and the ID */

		put_device(&rtc->dev);

		goto exit;

	} else {

		dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", rtc->name,

			MAJOR(rtc->dev.devt), rtc->id);

	}



	rtc_dev_add_device(rtc);

	rtc_proc_add_device(rtc);



	dev_info(dev, "rtc core: registered %s as %s\n",
@@ -271,9 +278,8 @@ void rtc_device_unregister(struct rtc_device *rtc) 
	 * Remove innards of this RTC, then disable it, before

	 * letting any rtc_class_open() users access it again

	 */

	rtc_dev_del_device(rtc);

	rtc_proc_del_device(rtc);

	device_del(&rtc->dev);

	cdev_device_del(&rtc->char_dev, &rtc->dev);

	rtc->ops = NULL;

	mutex_unlock(&rtc->ops_lock);

	put_device(&rtc->dev);

drivers/rtc/rtc-core.h

+0 −10
Original line number Diff line number Diff line
@@ -3,8 +3,6 @@ 
extern void __init rtc_dev_init(void);

extern void __exit rtc_dev_exit(void);

extern void rtc_dev_prepare(struct rtc_device *rtc);

extern void rtc_dev_add_device(struct rtc_device *rtc);

extern void rtc_dev_del_device(struct rtc_device *rtc);



#else
@@ -20,14 +18,6 @@ static inline void rtc_dev_prepare(struct rtc_device *rtc) 
{

}



static inline void rtc_dev_add_device(struct rtc_device *rtc)

{

}



static inline void rtc_dev_del_device(struct rtc_device *rtc)

{

}



#endif



#ifdef CONFIG_RTC_INTF_PROC

drivers/rtc/rtc-dev.c

+0 −17
Original line number Diff line number Diff line
@@ -477,23 +477,6 @@ void rtc_dev_prepare(struct rtc_device *rtc) 


	cdev_init(&rtc->char_dev, &rtc_dev_fops);

	rtc->char_dev.owner = rtc->owner;

	rtc->char_dev.kobj.parent = &rtc->dev.kobj;

}



void rtc_dev_add_device(struct rtc_device *rtc)

{

	if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))

		dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n",

			rtc->name, MAJOR(rtc_devt), rtc->id);

	else

		dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", rtc->name,

			MAJOR(rtc_devt), rtc->id);

}



void rtc_dev_del_device(struct rtc_device *rtc)

{

	if (rtc->dev.devt)

		cdev_del(&rtc->char_dev);

}



void __init rtc_dev_init(void)

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