From d3f661d69a486db0e0e6343b452f45d91b4b3656 Mon Sep 17 00:00:00 2001
From: Christoph Lameter <cl@linux.com>
Date: Fri, 25 Feb 2011 11:38:52 -0600
Subject: slub: Get rid of slab_free_hook_irq()

The following patch will make the fastpaths lockless and will no longer
require interrupts to be disabled. Calling the free hook with irq disabled
will no longer be possible.

Move the slab_free_hook_irq() logic into slab_free_hook. Only disable
interrupts if the features are selected that require callbacks with
interrupts off and reenable after calls have been made.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/mm/slub.c b/mm/slub.c
index e15aa7f..bae7a5c 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -807,14 +807,24 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void
 static inline void slab_free_hook(struct kmem_cache *s, void *x)
 {
 	kmemleak_free_recursive(x, s->flags);
-}
 
-static inline void slab_free_hook_irq(struct kmem_cache *s, void *object)
-{
-	kmemcheck_slab_free(s, object, s->objsize);
-	debug_check_no_locks_freed(object, s->objsize);
-	if (!(s->flags & SLAB_DEBUG_OBJECTS))
-		debug_check_no_obj_freed(object, s->objsize);
+	/*
+	 * Trouble is that we may no longer disable interupts in the fast path
+	 * So in order to make the debug calls that expect irqs to be
+	 * disabled we need to disable interrupts temporarily.
+	 */
+#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
+	{
+		unsigned long flags;
+
+		local_irq_save(flags);
+		kmemcheck_slab_free(s, x, s->objsize);
+		debug_check_no_locks_freed(x, s->objsize);
+		if (!(s->flags & SLAB_DEBUG_OBJECTS))
+			debug_check_no_obj_freed(x, s->objsize);
+		local_irq_restore(flags);
+	}
+#endif
 }
 
 /*
@@ -1101,9 +1111,6 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
 
 static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
 
-static inline void slab_free_hook_irq(struct kmem_cache *s,
-		void *object) {}
-
 #endif /* CONFIG_SLUB_DEBUG */
 
 /*
@@ -1909,8 +1916,6 @@ static __always_inline void slab_free(struct kmem_cache *s,
 	local_irq_save(flags);
 	c = __this_cpu_ptr(s->cpu_slab);
 
-	slab_free_hook_irq(s, x);
-
 	if (likely(page == c->page && c->node != NUMA_NO_NODE)) {
 		set_freepointer(s, object, c->freelist);
 		c->freelist = object;
-- 
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