Re: [PATCH] fix RTC_CLASS regression with PARISC

Andrew Morton
2008-09-10T21:05:29Z

On Mon, 08 Sep 2008 19:52:35 -0700 (PDT)
David Miller <davem@davemloft.net> wrote:

> From: David Brownell <david-b@pacbell.net>
> Date: Mon, 8 Sep 2008 17:55:25 -0700
>
> > On Monday 08 September 2008, David Miller wrote:
> > > From: David Brownell <david-b@pacbell.net>
> > > Date: Mon, 8 Sep 2008 16:29:20 -0700
> > >
> > > > That said, there's a bit of unresolved stuff around NTP hooks
> > > > in the kernel. Some patches are pending to let thtem work with
> > > > the RTC framework -- where writing an RTC may need to sleep,
> > > > for example because the RTC is on an I2C or SPI bus. And
> > > > then there's the discussion of whether that shouldn't all be
> > > > handled by NTPD anyway, no special kernel support desired.
> > > > Alessandro has opinions there. ;)
> > >
> > > My update_persistent_clock() on sparc64 is:
> > >
> > > int update_persistent_clock(struct timespec now)
> > > {
> > > struct rtc_device *rtc = rtc_class_open("rtc0");
> >
> > I'd be tempted to cache that ... notice how you never
> > close it, too. That will goof lots of refcounts...
>
> Well if I cache it then we'll hold it forever and that's not
> so nice right?
>
> I'm going to put the missing rtc_close() in there for now to
> fix the leak.
>
> I'm happy to cache this if you think it's warranted, but then
> this is like saying that the refcount doesn't matter :-)
>
> > =============== CUT ON THE DOTTED LINE ==================
> > Subject: ntp: let update_persistent_clock() sleep
> > From: "Maciej W. Rozycki" <macro@linux-mips.org>
>
> I see, as Paul mentioned this is needed for stuff like RTCs
> behind I2C.
>
> This change isn't in Linus's tree yet.

Should it be?

Its current status is: stuck in -mm. I've sent it to Thomas a couple
of times marked "for 2.6.27?" and he might have applied it now (I'm a
few days behind, waiting for linux-next to start up again).

It was not included in Thomas's recent mainline pull request:

From: Thomas Gleixner <tglx@tglx.de>
Subject: [GIT pull] timer updates for 2.6.27
Date: Tue, 9 Sep 2008 22:32:39 +0200 (CEST)