[PATCH v15 07/10] mm/demotion: Drop memtier from memtype

["Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>]

Now that we track node-specific memtier in pg_data_t, we can drop
memtier from memtype.

Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
---
 include/linux/memory-tiers.h |  1 -
 mm/memory-tiers.c            | 16 +++++++++-------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index 548e69f23727..108083d74557 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -28,7 +28,6 @@ struct memory_dev_type {
 	/* Nodes of same abstract distance */
 	nodemask_t nodes;
 	struct kref kref;
-	struct memory_tier *memtier;
 };
 
 #ifdef CONFIG_NUMA
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 2b7e91b45a75..455c104fab5d 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -100,17 +100,22 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
 
 	lockdep_assert_held_once(&memory_tier_lock);
 
+	adistance = round_down(adistance, memtier_adistance_chunk_size);
 	/*
 	 * If the memtype is already part of a memory tier,
 	 * just return that.
 	 */
-	if (memtype->memtier)
-		return memtype->memtier;
+	if (!list_empty(&memtype->tier_sibiling)) {
+		list_for_each_entry(memtier, &memory_tiers, list) {
+			if (adistance == memtier->adistance_start)
+				return memtier;
+		}
+		WARN_ON(1);
+		return ERR_PTR(-EINVAL);
+	}
 
-	adistance = round_down(adistance, memtier_adistance_chunk_size);
 	list_for_each_entry(memtier, &memory_tiers, list) {
 		if (adistance == memtier->adistance_start) {
-			memtype->memtier = memtier;
 			list_add(&memtype->tier_sibiling, &memtier->memory_types);
 			return memtier;
 		} else if (adistance < memtier->adistance_start) {
@@ -130,7 +135,6 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
 		list_add_tail(&new_memtier->list, &memtier->list);
 	else
 		list_add_tail(&new_memtier->list, &memory_tiers);
-	memtype->memtier = new_memtier;
 	list_add(&memtype->tier_sibiling, &new_memtier->memory_types);
 	return new_memtier;
 }
@@ -357,7 +361,6 @@ static bool clear_node_memory_tier(int node)
 		node_clear(node, memtype->nodes);
 		if (nodes_empty(memtype->nodes)) {
 			list_del(&memtype->tier_sibiling);
-			memtype->memtier = NULL;
 			if (list_empty(&memtier->memory_types))
 				destroy_memory_tier(memtier);
 		}
@@ -385,7 +388,6 @@ struct memory_dev_type *alloc_memory_type(int adistance)
 	memtype->adistance = adistance;
 	INIT_LIST_HEAD(&memtype->tier_sibiling);
 	memtype->nodes  = NODE_MASK_NONE;
-	memtype->memtier = NULL;
 	kref_init(&memtype->kref);
 	return memtype;
 }
-- 
2.37.2