bna: make pointers to read-only inputs const

[cascardo/linux.git] / lib / cpumask.c

diff --git a/lib/cpumask.c b/lib/cpumask.c
index 830dd5d..5f62708 100644 (file)
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -139,64 +139,42 @@ void __init free_bootmem_cpumask_var(cpumask_var_t mask)
 #endif
 
 /**
- * cpumask_set_cpu_local_first - set i'th cpu with local numa cpu's first
- *
+ * cpumask_local_spread - select the i'th cpu with local numa cpu's first
  * @i: index number
- * @numa_node: local numa_node
- * @dstp: cpumask with the relevant cpu bit set according to the policy
+ * @node: local numa_node
  *
- * This function sets the cpumask according to a numa aware policy.
- * cpumask could be used as an affinity hint for the IRQ related to a
- * queue. When the policy is to spread queues across cores - local cores
- * first.
+ * This function selects an online CPU according to a numa aware policy;
+ * local cpus are returned first, followed by non-local ones, then it
+ * wraps around.
  *
- * Returns 0 on success, -ENOMEM for no memory, and -EAGAIN when failed to set
- * the cpu bit and need to re-call the function.
+ * It's not very efficient, but useful for setup.
  */
-int cpumask_set_cpu_local_first(int i, int numa_node, cpumask_t *dstp)
+unsigned int cpumask_local_spread(unsigned int i, int node)
 {
-       cpumask_var_t mask;
        int cpu;
-       int ret = 0;
-
-       if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
-               return -ENOMEM;
 
+       /* Wrap: we always want a cpu. */
        i %= num_online_cpus();
 
-       if (numa_node == -1 || !cpumask_of_node(numa_node)) {
-               /* Use all online cpu's for non numa aware system */
-               cpumask_copy(mask, cpu_online_mask);
+       if (node == -1) {
+               for_each_cpu(cpu, cpu_online_mask)
+                       if (i-- == 0)
+                               return cpu;
        } else {
-               int n;
-
-               cpumask_and(mask,
-                           cpumask_of_node(numa_node), cpu_online_mask);
-
-               n = cpumask_weight(mask);
-               if (i >= n) {
-                       i -= n;
-
-                       /* If index > number of local cpu's, mask out local
-                        * cpu's
-                        */
-                       cpumask_andnot(mask, cpu_online_mask, mask);
+               /* NUMA first. */
+               for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask)
+                       if (i-- == 0)
+                               return cpu;
+
+               for_each_cpu(cpu, cpu_online_mask) {
+                       /* Skip NUMA nodes, done above. */
+                       if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
+                               continue;
+
+                       if (i-- == 0)
+                               return cpu;
                }
        }
-
-       for_each_cpu(cpu, mask) {
-               if (--i < 0)
-                       goto out;
-       }
-
-       ret = -EAGAIN;
-
-out:
-       free_cpumask_var(mask);
-
-       if (!ret)
-               cpumask_set_cpu(cpu, dstp);
-
-       return ret;
+       BUG();
 }
-EXPORT_SYMBOL(cpumask_set_cpu_local_first);
+EXPORT_SYMBOL(cpumask_local_spread);