[PATCH] Fix cpu iterator on empty bitmask

[Rusty Russell]

Name: Fix cpumask iterator over empty cpu set
Status: Trivial

Can't use _ffs() without first checking for zero, and if bits beyond
NR_CPUS set it'll give bogus results.  Use find_first_bit

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .26180-linux-2.6.6-rc2-bk5/include/asm-generic/cpumask_arith.h .26180-linux-2.6.6-rc2-bk5.updated/include/asm-generic/cpumask_arith.h
--- .26180-linux-2.6.6-rc2-bk5/include/asm-generic/cpumask_arith.h	2004-01-10 13:59:33.000000000 +1100
+++ .26180-linux-2.6.6-rc2-bk5.updated/include/asm-generic/cpumask_arith.h	2004-04-28 09:50:23.000000000 +1000
@@ -43,7 +43,7 @@
 #define cpus_promote(map)		({ map; })
 #define cpumask_of_cpu(cpu)		({ ((cpumask_t)1) << (cpu); })
 
-#define first_cpu(map)			__ffs(map)
+#define first_cpu(map)			find_first_bit(&(map), NR_CPUS)
 #define next_cpu(cpu, map)		find_next_bit(&(map), NR_CPUS, cpu + 1)
 
 #endif /* __ASM_GENERIC_CPUMASK_ARITH_H */
-- 
Anyone who quotes me in their signature is an idiot -- Rusty Russell

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