[RFC PATCH 8/8] sched: drop for_each_numa_hop_mask()

[Yury Norov]

Now that we have for_each_numa_cpu(), for_each_numa_hop_mask()
and all related code is a deadcode. Drop it.

Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
---
This is RFC because despite that the code below is unused, there may be
new users, particularly Intel, and I don't want to cut people on the fly.
Those interested in for_each_numa_hop_mask(), please send NAKs.

 include/linux/topology.h | 25 -------------------------
 kernel/sched/topology.c  | 32 --------------------------------
 lib/test_bitmap.c        | 13 -------------
 3 files changed, 70 deletions(-)

diff --git a/include/linux/topology.h b/include/linux/topology.h
index 3d8d486c817d..d2defd59b2d0 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -255,7 +255,6 @@ static inline const struct cpumask *cpu_cpu_mask(int cpu)
 #ifdef CONFIG_NUMA
 int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node);
 int sched_numa_find_next_cpu(const struct cpumask *cpus, int cpu, int node, unsigned int *hop);
-extern const struct cpumask *sched_numa_hop_mask(unsigned int node, unsigned int hops);
 #else
 static __always_inline int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node)
 {
@@ -267,32 +266,8 @@ int sched_numa_find_next_cpu(const struct cpumask *cpus, int cpu, int node, unsi
 {
 	return cpumask_next(cpu, cpus);
 }
-
-static inline const struct cpumask *
-sched_numa_hop_mask(unsigned int node, unsigned int hops)
-{
-	return ERR_PTR(-EOPNOTSUPP);
-}
 #endif	/* CONFIG_NUMA */
 
-/**
- * for_each_numa_hop_mask - iterate over cpumasks of increasing NUMA distance
- *                          from a given node.
- * @mask: the iteration variable.
- * @node: the NUMA node to start the search from.
- *
- * Requires rcu_lock to be held.
- *
- * Yields cpu_online_mask for @node == NUMA_NO_NODE.
- */
-#define for_each_numa_hop_mask(mask, node)				       \
-	for (unsigned int __hops = 0;					       \
-	     mask = (node != NUMA_NO_NODE || __hops) ?			       \
-		     sched_numa_hop_mask(node, __hops) :		       \
-		     cpu_online_mask,					       \
-	     !IS_ERR_OR_NULL(mask);					       \
-	     __hops++)
-
 /**
  * for_each_numa_cpu - iterate over cpus in increasing order taking into account
  *		       NUMA distances from a given node.
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 5f5f994a56da..2842a4d10624 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -2171,38 +2171,6 @@ int sched_numa_find_next_cpu(const struct cpumask *cpus, int cpu, int node, unsi
 }
 EXPORT_SYMBOL_GPL(sched_numa_find_next_cpu);
 
-/**
- * sched_numa_hop_mask() - Get the cpumask of CPUs at most @hops hops away from
- *                         @node
- * @node: The node to count hops from.
- * @hops: Include CPUs up to that many hops away. 0 means local node.
- *
- * Return: On success, a pointer to a cpumask of CPUs at most @hops away from
- * @node, an error value otherwise.
- *
- * Requires rcu_lock to be held. Returned cpumask is only valid within that
- * read-side section, copy it if required beyond that.
- *
- * Note that not all hops are equal in distance; see sched_init_numa() for how
- * distances and masks are handled.
- * Also note that this is a reflection of sched_domains_numa_masks, which may change
- * during the lifetime of the system (offline nodes are taken out of the masks).
- */
-const struct cpumask *sched_numa_hop_mask(unsigned int node, unsigned int hops)
-{
-	struct cpumask ***masks;
-
-	if (node >= nr_node_ids || hops >= sched_domains_numa_levels)
-		return ERR_PTR(-EINVAL);
-
-	masks = rcu_dereference(sched_domains_numa_masks);
-	if (!masks)
-		return ERR_PTR(-EBUSY);
-
-	return masks[hops][node];
-}
-EXPORT_SYMBOL_GPL(sched_numa_hop_mask);
-
 #endif /* CONFIG_NUMA */
 
 static int __sdt_alloc(const struct cpumask *cpu_map)
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 1b5f805f6879..6becb044a66f 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -756,19 +756,6 @@ static void __init test_for_each_numa(void)
 {
 	unsigned int cpu, node;
 
-	for (node = 0; node < sched_domains_numa_levels; node++) {
-		const struct cpumask *m, *p = cpu_none_mask;
-		unsigned int c = 0;
-
-		rcu_read_lock();
-		for_each_numa_hop_mask(m, node) {
-			for_each_cpu_andnot(cpu, m, p)
-				expect_eq_uint(cpumask_local_spread(c++, node), cpu);
-			p = m;
-		}
-		rcu_read_unlock();
-	}
-
 	for (node = 0; node < sched_domains_numa_levels; node++) {
 		unsigned int hop, c = 0;
 
-- 
2.34.1