Messages in this thread | | | Date | Mon, 15 Nov 2010 09:24:04 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH 2.6.36 1/1 RESEND] kernel SPIN_LOCK_UNLOCKED changed to __SPIN_LOCK_UNLOCKED() |
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On Sun, Nov 14, 2010 at 12:01:06AM +0530, Atul Sowani wrote: > There are still some files containing .lock = SPIN_LOCK_UNLOCKED type > assignments which should be converted to __SPIN_LOCK_UNLOCKED(). > Corrected spacing between __SPIN_LOCK_UNLOCKED and ( for ARM.
Thinking about the ARM bit, I'll have to NAK this patch.
> diff -uprN a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > --- a/arch/arm/kernel/smp.c 2010-10-21 02:00:22.000000000 +0530 > +++ b/arch/arm/kernel/smp.c 2010-11-07 00:47:32.000000000 +0530 > @@ -56,7 +56,7 @@ struct ipi_data { > }; > > static DEFINE_PER_CPU(struct ipi_data, ipi_data) = { > - .lock = SPIN_LOCK_UNLOCKED, > + .lock = __SPIN_LOCK_UNLOCKED(ipi_data.lock), > };
This lock is in the percpu data area. This means that when other CPUs are brought online, and therefore other percpu areas are instantiated, this lock will be mis-initialized (the pointers et.al. will be pointing at the original percpu instance.)
So NAK, this will break.
We can either go back to a static array for this, initialize the lock manually (though this could be problematical), or we require to go to per-ipi type interrupts for all SMP architectures.
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