Messages in this thread | | | Date | Tue, 18 Dec 2012 23:45:43 -0800 | From | Andrew Morton <> | Subject | Re: [rtc-linux] [PATCH] rtc: recycle id when unloading a rtc driver |
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On Wed, 19 Dec 2012 08:37:07 +0100 Alexander Holler <holler@ahsoftware.de> wrote:
> Am 19.12.2012 01:46, schrieb Andrew Morton: > > On Thu, 2 Aug 2012 16:53:25 -0700 > > Vincent Palatin <vpalatin@chromium.org> wrote: > > > >> When calling rtc_device_unregister, we are not freeing the id used by the > >> driver. > >> So when doing a unload/load cycle for a RTC driver (e.g. rmmod rtc_cmos > >> && modprobe rtc_cmos), its id is incremented by one. As a consequence, > >> we no longer have neither an rtc0 driver nor a /proc/driver/rtc (as it > >> only exists for the first driver). > >> > >> Signed-off-by: Vincent Palatin <vpalatin@chromium.org> > >> --- > >> drivers/rtc/class.c | 1 + > >> 1 files changed, 1 insertions(+), 0 deletions(-) > >> > >> diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c > >> index dc4c274..37b1d82 100644 > >> --- a/drivers/rtc/class.c > >> +++ b/drivers/rtc/class.c > >> @@ -238,6 +238,7 @@ void rtc_device_unregister(struct rtc_device *rtc) > >> rtc_proc_del_device(rtc); > >> device_unregister(&rtc->dev); > >> rtc->ops = NULL; > >> + ida_simple_remove(&rtc_ida, rtc->id); > >> mutex_unlock(&rtc->ops_lock); > >> put_device(&rtc->dev); > >> } > > > > Now I think about it, this shouldn't have been needed? > > > > That put_device() should call rtc_device_release(), which does the > > ida_simple_remove(). Isn't that working? > > It is, see the mini-thread, patch and my comment here: > > https://lkml.org/lkml/2012/12/6/152 > > Maybe it would be better to move the ida_simple_remove from the > rtc_device_release to rt_device_unregister as I've hinted in the above > comment. That would make it easier to spot the ida_simple_remove().
I'm all confused.
Lothar's patch simply reverts Vincent's patch. And that appears to be the correct thing to so, as the ida_simple_remove() in rtc_device_release() should be sufficient.
But apparently that doesn't work, because Vincent was seeing the RTC ID's increment rather than getting reused.
Is it the case that rtc_device_release() is not being called sometimes? If so, under what circumstances?
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