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Subject[RFC 02/13] cpumask: add for_each_online_cpu_mask_nr function
  * Add for_each_online_cpu_mask_nr() function to eliminate need for
a common use of a temporary cpumask_t variable. When the following
procedure is being used:

funcproto(cpumask_t *mask, ...)
cpumask_t temp;

cpus_and(temp, *mask, cpu_online_map);
for_each_cpu_mask_nr(cpu, temp)
...

If then becomes:

for_each_online_cpu_mask_nr(cpu, *mask)
...

* Note the generic __next_cpu_and (and __next_cpu_and_nr) functions
allowing AND'ing with any cpumask_t variable, not just the cpu_online_map.


Applies to linux-2.6.tip/master.

Signed-off-by: Mike Travis <travis@sgi.com>
---
include/linux/cpumask.h | 26 +++++++++++++++++++++++---
lib/cpumask.c | 26 ++++++++++++++++++++++++++
2 files changed, 49 insertions(+), 3 deletions(-)

--- linux-2.6.tip.orig/include/linux/cpumask.h
+++ linux-2.6.tip/include/linux/cpumask.h
@@ -404,23 +404,32 @@ static inline void __cpus_fold(cpumask_t
#define first_cpu(src) ({ (void)(src); 0; })
#define next_cpu(n, src) ({ (void)(src); 1; })
#define any_online_cpu(mask) 0
-#define for_each_cpu_mask(cpu, mask) \
+
+#define for_each_cpu_mask(cpu, mask) \
for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
+#define for_each_online_cpu_mask(cpu, mask) \
+ for_each_cpu_mask(cpu, mask)

#else /* NR_CPUS > 1 */

extern int nr_cpu_ids;
int __first_cpu(const cpumask_t *srcp);
int __next_cpu(int n, const cpumask_t *srcp);
+int __next_cpu_and(int n, const cpumask_t *srcp, const cpumask_t *andp);
int __any_online_cpu(const cpumask_t *mask);

#define first_cpu(src) __first_cpu(&(src))
#define next_cpu(n, src) __next_cpu((n), &(src))
#define any_online_cpu(mask) __any_online_cpu(&(mask))
+
#define for_each_cpu_mask(cpu, mask) \
for ((cpu) = -1; \
(cpu) = next_cpu((cpu), (mask)), \
(cpu) < NR_CPUS; )
+#define for_each_online_cpu_mask(cpu, mask) \
+ for ((cpu) = -1; \
+ (cpu) = __next_cpu_and((cpu), &(mask), &(cpu_online_map)), \
+ (cpu) < NR_CPUS; )
#endif

#if NR_CPUS <= 64
@@ -428,17 +437,28 @@ int __any_online_cpu(const cpumask_t *ma
#define next_cpu_nr(n, src) next_cpu(n, src)
#define cpus_weight_nr(cpumask) cpus_weight(cpumask)
#define for_each_cpu_mask_nr(cpu, mask) for_each_cpu_mask(cpu, mask)
+#define for_each_online_cpu_mask_nr(cpu, mask) \
+ for_each_online_cpu_mask(cpu, mask)

#else /* NR_CPUS > 64 */

int __next_cpu_nr(int n, const cpumask_t *srcp);
-#define next_cpu_nr(n, src) __next_cpu_nr((n), &(src))
-#define cpus_weight_nr(cpumask) __cpus_weight(&(cpumask), nr_cpu_ids)
+int __next_cpu_and_nr(int n, const cpumask_t *srcp, const cpumask_t *andp);
+
+#define next_cpu_nr(n, src) __next_cpu_nr((n), &(src))
+#define next_cpu_and_nr(n, src, and) __next_cpu_and_nr((n), &(src), &(and))
+#define cpus_weight_nr(cpumask) __cpus_weight(&(cpumask), nr_cpu_ids)
+
#define for_each_cpu_mask_nr(cpu, mask) \
for ((cpu) = -1; \
(cpu) = next_cpu_nr((cpu), (mask)), \
(cpu) < nr_cpu_ids; )

+#define for_each_online_cpu_mask_nr(cpu, mask) \
+ for ((cpu) = -1; \
+ (cpu) = next_cpu_and_nr((cpu), (mask), (cpu_online_map)), \
+ (cpu) < nr_cpu_ids; )
+
#endif /* NR_CPUS > 64 */

/*
--- linux-2.6.tip.orig/lib/cpumask.c
+++ linux-2.6.tip/lib/cpumask.c
@@ -14,6 +14,19 @@ int __next_cpu(int n, const cpumask_t *s
return min_t(int, NR_CPUS, find_next_bit(srcp->bits, NR_CPUS, n+1));
}
EXPORT_SYMBOL(__next_cpu);
+int __next_cpu_and(int n, const cpumask_t *srcp, const cpumask_t *andp)
+{
+ int cpu;
+
+ for (cpu = n + 1; cpu < NR_CPUS; cpu++) {
+ cpu = find_next_bit(srcp->bits, NR_CPUS, cpu);
+
+ if (cpu < NR_CPUS && cpu_isset(cpu, *andp))
+ return cpu;
+ }
+ return NR_CPUS;
+}
+EXPORT_SYMBOL(__next_cpu_and);

#if NR_CPUS > 64
int __next_cpu_nr(int n, const cpumask_t *srcp)
@@ -22,6 +35,19 @@ int __next_cpu_nr(int n, const cpumask_t
find_next_bit(srcp->bits, nr_cpu_ids, n+1));
}
EXPORT_SYMBOL(__next_cpu_nr);
+int __next_cpu_and_nr(int n, const cpumask_t *srcp, const cpumask_t *andp)
+{
+ int cpu;
+
+ for (cpu = n + 1; cpu < nr_cpu_ids; cpu++) {
+ cpu = find_next_bit(srcp->bits, nr_cpu_ids, cpu);
+
+ if (cpu < nr_cpu_ids && cpu_isset(cpu, *andp))
+ return cpu;
+ }
+ return nr_cpu_ids;
+}
+EXPORT_SYMBOL(__next_cpu_and_nr);
#endif

int __any_online_cpu(const cpumask_t *mask)
--


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