1 files changed, 37 insertions, 0 deletions
diff --git a/mm/mempool.c b/mm/mempool.c
index 103dc4770cfb..cb7b4b56cec1 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -457,6 +457,43 @@ repeat_alloc:
 EXPORT_SYMBOL(mempool_alloc);
 
 /**
+ * mempool_alloc_preallocated - allocate an element from preallocated elements
+ *                              belonging to a specific memory pool
+ * @pool:      pointer to the memory pool which was allocated via
+ *             mempool_create().
+ *
+ * This function is similar to mempool_alloc, but it only attempts allocating
+ * an element from the preallocated elements. It does not sleep and immediately
+ * returns if no preallocated elements are available.
+ *
+ * Return: pointer to the allocated element or %NULL if no elements are
+ * available.
+ */
+void *mempool_alloc_preallocated(mempool_t *pool)
+{
+	void *element;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pool->lock, flags);
+	if (likely(pool->curr_nr)) {
+		element = remove_element(pool);
+		spin_unlock_irqrestore(&pool->lock, flags);
+		/* paired with rmb in mempool_free(), read comment there */
+		smp_wmb();
+		/*
+		 * Update the allocation stack trace as this is more useful
+		 * for debugging.
+		 */
+		kmemleak_update_trace(element);
+		return element;
+	}
+	spin_unlock_irqrestore(&pool->lock, flags);
+
+	return NULL;
+}
+EXPORT_SYMBOL(mempool_alloc_preallocated);
+
+/**
  * mempool_free - return an element to the pool.
  * @element:   pool element pointer.
  * @pool:      pointer to the memory pool which was allocated via