Re: [PATCH] fix BUG using smp_processor_id() in touch_nmi_watchdogand touch_softlockup_watchdog

[Don Zickus]

On Wed, Aug 18, 2010 at 01:01:56PM -0700, Andrew Morton wrote:
> The surprise new requirement that touch_nmi_watchdog() be called from
> non-preemptible code does seem to make sense IMO.  It's hard to see why
> anyone would be touching the watchdog unless he's spinning in irqs-off
> code.  Except, of course, when we have a utility function which can be
> called from wither irqs-on or irqs-off: acpi_os_stall().
> 
> That being said, it's not good to introduce new API requirements by
> accident!  An audit of all callers should first be performed, at least.
> 
> 
> The surprise new requirement that touch_softlockup_watchdog() be called
> from non-preemptible code doesn't make sense IMO.  If I have a piece of
> code in the kernel which I expect to sit in TASK_UNINTERRUPTIBLE state
> for three minutes waiting for my egg to boil, I should be able to do
> that and I should be able to touch the softlockup detector without
> needing to go non-preemptible.

Ok, so here is my patch that syncs the touch_*_watchdog back in line with
the old semantics.  Hopefully this will undo any harm I caused.

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