Re: [PATCH][2.6] first/next_cpu returns values > NR_CPUS

[William Lee Irwin III <wli@holomorphy.com>]

On Sun, Aug 01, 2004 at 06:36:32AM -0700, Paul Jackson wrote:
> You mean, in Zwane's example, we'd see a return from any_online_cpu() of
> 32 or 64, not 3 (his NR_CPUS), and not just on i386, but on a majority
> of arch's.  That's what you're saying, right?
> Ok ... that favors your preference, teaching the users of find_next_bit
> to be more tolerant.
> Darn.  Your min(nbits, ...) patch looks good, but more is needed.
> And could you make it:
> +	return min(nbits, find_next_bit(srcp->bits, nbits, n+1));
> rather than:
> +	return min(NR_CPUS, find_next_bit(srcp->bits, nbits, n+1));
> for consistency of presentation?  All the cpu and node mask macros of
> this form (#define wrapped static inline) use the inline's parameter
> names in the body of the inline, not what the define passed as those
> params, including another 'nbits' in this very line of code.

No problem.


Index: hotplug-2.6.8-rc2/include/linux/cpumask.h
===================================================================
--- hotplug-2.6.8-rc2.orig/include/linux/cpumask.h	2004-07-29 04:44:59.000000000 -0700
+++ hotplug-2.6.8-rc2/include/linux/cpumask.h	2004-08-01 06:32:31.615472016 -0700
@@ -207,13 +207,13 @@
 #define first_cpu(src) __first_cpu(&(src), NR_CPUS)
 static inline int __first_cpu(const cpumask_t *srcp, int nbits)
 {
-	return find_first_bit(srcp->bits, nbits);
+	return min_t(int, nbits, find_first_bit(srcp->bits, nbits));
 }
 
 #define next_cpu(n, src) __next_cpu((n), &(src), NR_CPUS)
 static inline int __next_cpu(int n, const cpumask_t *srcp, int nbits)
 {
-	return find_next_bit(srcp->bits, nbits, n+1);
+	return min_t(int, nbits, find_next_bit(srcp->bits, nbits, n+1));
 }
 
 #define cpumask_of_cpu(cpu)						\