On 25/02/2017 at 23:38:15 -0700, Logan Gunthorpe wrote: > 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. > > Signed-off-by: Logan Gunthorpe <log...@deltatee.com> Acked-by: Alexandre Belloni <alexandre.bell...@free-electrons.com>
> --- > drivers/rtc/class.c | 14 ++++++++++---- > drivers/rtc/rtc-dev.c | 17 ----------------- > 2 files changed, 10 insertions(+), 21 deletions(-) > > diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c > index 74fd974..5fb4398 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); > diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c > index a6d9434..fdd071f 100644 > --- a/drivers/rtc/rtc-dev.c > +++ b/drivers/rtc/rtc-dev.c > @@ -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) > -- > 2.1.4 > -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm