Re: [PATCH] x86, efi: Don't recursively acquire rtc_lock

From: Matt Fleming
Date: Thu Aug 04 2011 - 05:34:50 EST


On Thu, 2011-08-04 at 03:53 +0100, Jan Beulich wrote:
>
> Seems the wrong approach to me: The call happening with the lock held
> is the wrong part imo, and hence the fix ought to be to drop the lock
> there.

But what about other platforms that provide a get_wallclock()
implementation such as the kvm or xen code? If we called get_wallclock()
without rtc_lock held we'd be requiring everyone to lock it in their
clock code, which is unnecessary work and increases the amount of code
that touches rtc_lock (not to mention spreading it across several
files).

I think it's much better to do the locking as high up the callstack as
possible and preferably in as few places as possible.

--
Matt Fleming, Intel Open Source Technology Center

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