cpuset: Clean up cpuset_node_allowed

Commit 002f2906 ("cpuset: use static key better and convert to new API")
has used __cpuset_node_allowed() instead of cpuset_node_allowed() to check
whether we can allocate on a memory node. Now this function isn't used by
anyone, so we can do the follow things to clean up it.

1. remove unused codes
2. rename __cpuset_node_allowed() to cpuset_node_allowed()
3. update comments in mm/page_alloc.c
Suggested-by: Waiman Long <longman@redhat.com>
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

include/linux/cpuset.h

@@ -80,18 +80,11 @@ extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
 void cpuset_init_current_mems_allowed(void);
 int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
 
-extern bool __cpuset_node_allowed(int node, gfp_t gfp_mask);
-
-static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
-{
-	if (cpusets_enabled())
-		return __cpuset_node_allowed(node, gfp_mask);
-	return true;
-}
+extern bool cpuset_node_allowed(int node, gfp_t gfp_mask);
 
 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
 {
-	return __cpuset_node_allowed(zone_to_nid(z), gfp_mask);
+	return cpuset_node_allowed(zone_to_nid(z), gfp_mask);
 }
 
 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
@@ -223,11 +216,6 @@ static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
 	return 1;
 }
 
-static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
-{
-	return true;
-}
-
 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
 {
 	return true;

kernel/cgroup/cpuset.c

@@ -3831,7 +3831,7 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
 }
 
 /*
- * __cpuset_node_allowed - Can we allocate on a memory node?
+ * cpuset_node_allowed - Can we allocate on a memory node?
  * @node: is this an allowed node?
  * @gfp_mask: memory allocation flags
  *
@@ -3870,7 +3870,7 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
  *	GFP_KERNEL   - any node in enclosing hardwalled cpuset ok
  *	GFP_USER     - only nodes in current tasks mems allowed ok.
  */
-bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
+bool cpuset_node_allowed(int node, gfp_t gfp_mask)
 {
 	struct cpuset *cs;		/* current cpuset ancestors */
 	bool allowed;			/* is allocation in zone z allowed? */

mm/page_alloc.c

@@ -4217,7 +4217,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
 retry:
 	/*
 	 * Scan zonelist, looking for a zone with enough free.
-	 * See also __cpuset_node_allowed() comment in kernel/cgroup/cpuset.c.
+	 * See also cpuset_node_allowed() comment in kernel/cgroup/cpuset.c.
 	 */
 	no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
 	z = ac->preferred_zoneref;
@@ -4891,7 +4891,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order)
 		/*
 		 * Ignore cpuset mems for non-blocking __GFP_HIGH (probably
 		 * GFP_ATOMIC) rather than fail, see the comment for
-		 * __cpuset_node_allowed().
+		 * cpuset_node_allowed().
 		 */
 		if (alloc_flags & ALLOC_MIN_RESERVE)
 			alloc_flags &= ~ALLOC_CPUSET;