From d5ed9177f64fe95d9de79e6504d41612d9127e8a Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Fri, 17 Mar 2017 12:48:21 -0600 Subject: 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: Logan Gunthorpe Acked-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/class.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'drivers/rtc/class.c') diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 74fd9746aeca..5fb439897fe1 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -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); -- cgit v1.2.3