@@ -232,6 +232,23 @@ unsigned int cpumask_local_spread(unsigned int i, int node);
(cpu) = cpumask_next_zero((cpu), (mask)), \
(cpu) < nr_cpu_ids;)
+extern int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap);
+
+/**
+ * for_each_cpu_wrap - iterate over every cpu in a mask, starting at a specified location
+ * @cpu: the (optionally unsigned) integer iterator
+ * @mask: the cpumask poiter
+ * @start: the start location
+ *
+ * The implementation does not assume any bit in @mask is set (including @start).
+ *
+ * After the loop, cpu is >= nr_cpu_ids.
+ */
+#define for_each_cpu_wrap(cpu, mask, start) \
+ for ((cpu) = cpumask_next_wrap((start)-1, (mask), (start), false); \
+ (cpu) < nr_cpumask_bits; \
+ (cpu) = cpumask_next_wrap((cpu), (mask), (start), true))
+
/**
* for_each_cpu_and - iterate over every cpu in both masks
* @cpu: the (optionally unsigned) integer iterator
@@ -42,6 +42,38 @@ int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
return i;
}
+/**
+ * cpumask_next_wrap - helper to implement for_each_cpu_wrap
+ * @n: the cpu prior to the place to search
+ * @mask: the cpumask pointer
+ * @start: the start point of the iteration
+ * @wrap: assume @n crossing @start terminates the iteration
+ *
+ * Returns >= nr_cpu_ids on completion
+ *
+ * Note: the @wrap argument is required for the start condition when
+ * we cannot assume @start is set in @mask.
+ */
+int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap)
+{
+ int next;
+
+again:
+ next = cpumask_next(n, mask);
+
+ if (wrap && n < start && next >= start) {
+ return nr_cpumask_bits;
+
+ } else if (next >= nr_cpumask_bits) {
+ wrap = true;
+ n = -1;
+ goto again;
+ }
+
+ return next;
+}
+EXPORT_SYMBOL(cpumask_next_wrap);
+
/* These are not inline because of header tangles. */
#ifdef CONFIG_CPUMASK_OFFSTACK
/**