From: Matthew Dobson <colpatch@us.ibm.com>
nodemask.h is more or less a "s/cpu/node/g" on cpumask.h. That being the
case, the bug Zwane found where first/next_cpu() returns values > NR_CPUS when
NR_CPUS < 32, exists for first/next_node() which similarly returns values >
MAX_NUMNODES when MAX_NUMNODES < 32. As the thread demonstrated, most arch's
version of find_next_bit() only look at whole unsigned longs, and thus if the
mask you pass find_next_bit() is empty, it will return 32 (on 32 bit arches)
even if you only wanted it to search the first 3 bits. This change ensures
that first/next_node() calls return the smaller of either the requested search
length (MAX_NUMNODES in this case) or the first set bit it found.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/include/linux/nodemask.h | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff -puN include/linux/nodemask.h~some-random-nodemask-fix include/linux/nodemask.h
--- 25/include/linux/nodemask.h~some-random-nodemask-fix Mon Aug 2 16:30:38 2004
+++ 25-akpm/include/linux/nodemask.h Mon Aug 2 16:30:38 2004
@@ -216,13 +216,13 @@ static inline void __nodes_shift_left(no
#define first_node(src) __first_node(&(src), MAX_NUMNODES)
static inline int __first_node(const nodemask_t *srcp, int nbits)
{
- return find_first_bit(srcp->bits, nbits);
+ return min_t(int, nbits, find_first_bit(srcp->bits, nbits));
}
#define next_node(n, src) __next_node((n), &(src), MAX_NUMNODES)
static inline int __next_node(int n, const nodemask_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 nodemask_of_node(node) \
_