1 files changed, 47 insertions, 2 deletions

diff --git a/mm/slub.c b/mm/slub.c
index 3ca89ef9b7b0..30e7dedec664 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2750,16 +2750,61 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 }
 EXPORT_SYMBOL(kmem_cache_free);
 
+/* Note that interrupts must be enabled when calling this function. */
 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
 {
 	__kmem_cache_free_bulk(s, size, p);
 }
 EXPORT_SYMBOL(kmem_cache_free_bulk);
 
+/* Note that interrupts must be enabled when calling this function. */
 bool kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
-								void **p)
+			   void **p)
 {
-	return __kmem_cache_alloc_bulk(s, flags, size, p);
+	struct kmem_cache_cpu *c;
+	int i;
+
+	/* Debugging fallback to generic bulk */
+	if (kmem_cache_debug(s))
+		return __kmem_cache_alloc_bulk(s, flags, size, p);
+
+	/*
+	 * Drain objects in the per cpu slab, while disabling local
+	 * IRQs, which protects against PREEMPT and interrupts
+	 * handlers invoking normal fastpath.
+	 */
+	local_irq_disable();
+	c = this_cpu_ptr(s->cpu_slab);
+
+	for (i = 0; i < size; i++) {
+		void *object = c->freelist;
+
+		if (!object)
+			break;
+
+		c->freelist = get_freepointer(s, object);
+		p[i] = object;
+	}
+	c->tid = next_tid(c->tid);
+	local_irq_enable();
+
+	/* Clear memory outside IRQ disabled fastpath loop */
+	if (unlikely(flags & __GFP_ZERO)) {
+		int j;
+
+		for (j = 0; j < i; j++)
+			memset(p[j], 0, s->object_size);
+	}
+
+	/* Fallback to single elem alloc */
+	for (; i < size; i++) {
+		void *x = p[i] = kmem_cache_alloc(s, flags);
+		if (unlikely(!x)) {
+			__kmem_cache_free_bulk(s, i, p);
+			return false;
+		}
+	}
+	return true;
 }
 EXPORT_SYMBOL(kmem_cache_alloc_bulk);