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

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

On Sat, Jul 31, 2004 at 04:52:18PM -0400, Zwane Mwaikambo wrote:
> The following caused some fireworks whilst merging i386 cpu hotplug.
> any_online_cpu(0x2) returns 32 on i386 if we're forced to continue past
> the only set bit due to the additional find_first_bit in the
> find_next_bit i386 implementation. Not wanting to change current
> behaviour in the bitops primitives and since the NR_CPUS thing is a
> cpumask issue, i've opted to fix next_cpu() and first_cpu() instead.
> Signed-off-by: Zwane Mwaikambo <zwane@fsmlabs.com>

This might save a couple of lines of code.


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	2004-07-31 13:49:15.647650104 -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(NR_CPUS, 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(NR_CPUS, find_next_bit(srcp->bits, nbits, n+1));
 }
 
 #define cpumask_of_cpu(cpu)						\