Merge branch 'slab/for-6.15/kfree_rcu_tiny' into slab/for-next

Merge the slab feature branch kfree_rcu_tiny for 6.15:

- Move the TINY_RCU kvfree_rcu() implementation from RCU to SLAB
  subsystem and cleanup its integration.

mm/slab_common.c

@@ -1277,6 +1277,29 @@ EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
 EXPORT_TRACEPOINT_SYMBOL(kfree);
 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
 
+#ifndef CONFIG_KVFREE_RCU_BATCHED
+
+void kvfree_call_rcu(struct rcu_head *head, void *ptr)
+{
+	if (head) {
+		kasan_record_aux_stack(ptr);
+		call_rcu(head, kvfree_rcu_cb);
+		return;
+	}
+
+	// kvfree_rcu(one_arg) call.
+	might_sleep();
+	synchronize_rcu();
+	kvfree(ptr);
+}
+EXPORT_SYMBOL_GPL(kvfree_call_rcu);
+
+void __init kvfree_rcu_init(void)
+{
+}
+
+#else /* CONFIG_KVFREE_RCU_BATCHED */
+
 /*
  * This rcu parameter is runtime-read-only. It reflects
  * a minimum allowed number of objects which can be cached
@@ -1527,8 +1550,7 @@ kvfree_rcu_list(struct rcu_head *head)
 		rcu_lock_acquire(&rcu_callback_map);
 		trace_rcu_invoke_kvfree_callback("slab", head, offset);
 
-		if (!WARN_ON_ONCE(!__is_kvfree_rcu_offset(offset)))
-			kvfree(ptr);
+		kvfree(ptr);
 
 		rcu_lock_release(&rcu_callback_map);
 		cond_resched_tasks_rcu_qs();
@@ -1856,8 +1878,6 @@ add_ptr_to_bulk_krc_lock(struct kfree_rcu_cpu **krcp,
 	return true;
 }
 
-#if !defined(CONFIG_TINY_RCU)
-
 static enum hrtimer_restart
 schedule_page_work_fn(struct hrtimer *t)
 {
@@ -2066,8 +2086,6 @@ void kvfree_rcu_barrier(void)
 }
 EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
 
-#endif /* #if !defined(CONFIG_TINY_RCU) */
-
 static unsigned long
 kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 {
@@ -2161,3 +2179,6 @@ void __init kvfree_rcu_init(void)
 
 	shrinker_register(kfree_rcu_shrinker);
 }
+
+#endif /* CONFIG_KVFREE_RCU_BATCHED */
+