Remove destructor support from slab allocators

Index: linux-2.6.21-mm2/arch/sh/mm/pmb.c
===================================================================
@@ -3,7 +3,7 @@
  *
  * Privileged Space Mapping Buffer (PMB) Support.
  *
- * Copyright (C) 2005, 2006 Paul Mundt
+ * Copyright (C) 2005, 2006, 2007 Paul Mundt
  *
  * P1/P2 Section mapping definitions from map32.h, which was:
  *

@@ -68,6 +68,32 @@ static inline unsigned long mk_pmb_data(
 	return mk_pmb_entry(entry) | PMB_DATA;
 }
 
+static DEFINE_SPINLOCK(pmb_list_lock);
+static struct pmb_entry *pmb_list;
+
+static inline void pmb_list_add(struct pmb_entry *pmbe)
+{
+	struct pmb_entry **p, *tmp;
+
+	p = &pmb_list;
+	while ((tmp = *p) != NULL)
+		p = &tmp->next;
+
+	pmbe->next = tmp;
+	*p = pmbe;
+}
+
+static inline void pmb_list_del(struct pmb_entry *pmbe)
+{
+	struct pmb_entry **p, *tmp;
+
+	for (p = &pmb_list; (tmp = *p); p = &tmp->next)
+		if (tmp == pmbe) {
+			*p = tmp->next;
+			return;
+		}
+}
+
 struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
 			    unsigned long flags)
 {

@@ -81,11 +107,19 @@ struct pmb_entry *pmb_alloc(unsigned lon
 	pmbe->ppn	= ppn;
 	pmbe->flags	= flags;
 
+	spin_lock_irq(&pmb_list_lock);
+	pmb_list_add(pmbe);
+	spin_unlock_irq(&pmb_list_lock);
+
 	return pmbe;
 }
 
 void pmb_free(struct pmb_entry *pmbe)
 {
+	spin_lock_irq(&pmb_list_lock);
+	pmb_list_del(pmbe);
+	spin_unlock_irq(&pmb_list_lock);
+
 	kmem_cache_free(pmb_cache, pmbe);
 }
 

@@ -167,31 +201,6 @@ void clear_pmb_entry(struct pmb_entry *p
 	clear_bit(entry, &pmb_map);
 }
 
-static DEFINE_SPINLOCK(pmb_list_lock);
-static struct pmb_entry *pmb_list;
-
-static inline void pmb_list_add(struct pmb_entry *pmbe)
-{
-	struct pmb_entry **p, *tmp;
-
-	p = &pmb_list;
-	while ((tmp = *p) != NULL)
-		p = &tmp->next;
-
-	pmbe->next = tmp;
-	*p = pmbe;
-}
-
-static inline void pmb_list_del(struct pmb_entry *pmbe)
-{
-	struct pmb_entry **p, *tmp;
-
-	for (p = &pmb_list; (tmp = *p); p = &tmp->next)
-		if (tmp == pmbe) {
-			*p = tmp->next;
-			return;
-		}
-}
 
 static struct {
 	unsigned long size;

@@ -283,25 +292,14 @@ void pmb_unmap(unsigned long addr)
 	} while (pmbe);
 }
 
-static void pmb_cache_ctor(void *pmb, struct kmem_cache *cachep, unsigned long flags)
+static void pmb_cache_ctor(void *pmb, struct kmem_cache *cachep,
+			   unsigned long flags)
 {
 	struct pmb_entry *pmbe = pmb;
 
 	memset(pmb, 0, sizeof(struct pmb_entry));
 
-	spin_lock_irq(&pmb_list_lock);
-
 	pmbe->entry = PMB_NO_ENTRY;
-	pmb_list_add(pmbe);
-
-	spin_unlock_irq(&pmb_list_lock);
-}
-
-static void pmb_cache_dtor(void *pmb, struct kmem_cache *cachep, unsigned long flags)
-{
-	spin_lock_irq(&pmb_list_lock);
-	pmb_list_del(pmb);
-	spin_unlock_irq(&pmb_list_lock);
 }
 
 static int __init pmb_init(void)

@@ -312,8 +310,7 @@ static int __init pmb_init(void)
 	BUG_ON(unlikely(nr_entries >= NR_PMB_ENTRIES));
 
 	pmb_cache = kmem_cache_create("pmb", sizeof(struct pmb_entry), 0,
-				      SLAB_PANIC, pmb_cache_ctor,
-				      pmb_cache_dtor);
+				      SLAB_PANIC, pmb_cache_ctor, NULL);
 
 	jump_to_P2();
 

Index: linux-2.6.21-mm2/include/linux/slub_def.h
===================================================================
@@ -40,7 +40,6 @@ struct kmem_cache {
 	int objects;		/* Number of objects in slab */
 	int refcount;		/* Refcount for slab cache destroy */
 	void (*ctor)(void *, struct kmem_cache *, unsigned long);
-	void (*dtor)(void *, struct kmem_cache *, unsigned long);
 	int inuse;		/* Offset to metadata */
 	int align;		/* Alignment */
 	const char *name;	/* Name (only for display!) */

Index: linux-2.6.21-mm2/mm/slab.c
===================================================================
@@ -409,9 +409,6 @@ struct kmem_cache {
 	/* constructor func */
 	void (*ctor) (void *, struct kmem_cache *, unsigned long);
 
-	/* de-constructor func */
-	void (*dtor) (void *, struct kmem_cache *, unsigned long);
-
 /* 5) cache creation/removal */
 	const char *name;
 	struct list_head next;

@@ -1911,20 +1908,11 @@ static void slab_destroy_objs(struct kme
 				slab_error(cachep, "end of a freed object "
 					   "was overwritten");
 		}
-		if (cachep->dtor && !(cachep->flags & SLAB_POISON))
-			(cachep->dtor) (objp + obj_offset(cachep), cachep, 0);
 	}
 }
 #else
 static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp)
 {
-	if (cachep->dtor) {
-		int i;
-		for (i = 0; i < cachep->num; i++) {
-			void *objp = index_to_obj(cachep, slabp, i);
-			(cachep->dtor) (objp, cachep, 0);
-		}
-	}
 }
 #endif
 

@@ -2124,7 +2112,7 @@ static int setup_cpu_cache(struct kmem_c
  * @align: The required alignment for the objects.
  * @flags: SLAB flags
  * @ctor: A constructor for the objects.
- * @dtor: A destructor for the objects.
+ * @dtor: A destructor for the objects (not implemented anymore).
  *
  * Returns a ptr to the cache on success, NULL on failure.
  * Cannot be called within a int, but can be interrupted.

@@ -2159,7 +2147,7 @@ kmem_cache_create (const char *name, siz
 	 * Sanity checks... these are all serious usage bugs.
 	 */
 	if (!name || in_interrupt() || (size < BYTES_PER_WORD) ||
-	    (size > (1 << MAX_OBJ_ORDER) * PAGE_SIZE) || (dtor && !ctor)) {
+	    (size > (1 << MAX_OBJ_ORDER) * PAGE_SIZE) || dtor) {
 		printk(KERN_ERR "%s: Early error in slab %s\n", __FUNCTION__,
 				name);
 		BUG();

@@ -2213,9 +2201,6 @@ kmem_cache_create (const char *name, siz
 	if (flags & SLAB_DESTROY_BY_RCU)
 		BUG_ON(flags & SLAB_POISON);
 #endif
-	if (flags & SLAB_DESTROY_BY_RCU)
-		BUG_ON(dtor);
-
 	/*
 	 * Always checks flags, a caller might be expecting debug support which
 	 * isn't available.

@@ -2370,7 +2355,6 @@ kmem_cache_create (const char *name, siz
 		BUG_ON(!cachep->slabp_cache);
 	}
 	cachep->ctor = ctor;
-	cachep->dtor = dtor;
 	cachep->name = name;
 
 	if (setup_cpu_cache(cachep)) {

@@ -2835,7 +2819,6 @@ failed:
  * Perform extra freeing checks:
  * - detect bad pointers.
  * - POISON/RED_ZONE checking
- * - destructor calls, for caches with POISON+dtor
  */
 static void kfree_debugcheck(const void *objp)
 {

@@ -2894,12 +2877,6 @@ static void *cache_free_debugcheck(struc
 	BUG_ON(objnr >= cachep->num);
 	BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
 
-	if (cachep->flags & SLAB_POISON && cachep->dtor) {
-		/* we want to cache poison the object,
-		 * call the destruction callback
-		 */
-		cachep->dtor(objp + obj_offset(cachep), cachep, 0);
-	}
 #ifdef CONFIG_DEBUG_SLAB_LEAK
 	slab_bufctl(slabp)[objnr] = BUFCTL_FREE;
 #endif

Index: linux-2.6.21-mm2/mm/slob.c
===================================================================
@@ -268,7 +268,6 @@ struct kmem_cache {
 	unsigned int size, align;
 	const char *name;
 	void (*ctor)(void *, struct kmem_cache *, unsigned long);
-	void (*dtor)(void *, struct kmem_cache *, unsigned long);
 };
 
 struct kmem_cache *kmem_cache_create(const char *name, size_t size,

@@ -278,13 +277,13 @@ struct kmem_cache *kmem_cache_create(con
 {
 	struct kmem_cache *c;
 
+	BUG_ON(dtor);
 	c = slob_alloc(sizeof(struct kmem_cache), flags, 0);
 
 	if (c) {
 		c->name = name;
 		c->size = size;
 		c->ctor = ctor;
-		c->dtor = dtor;
 		/* ignore alignment unless it's forced */
 		c->align = (flags & SLAB_HWCACHE_ALIGN) ? SLOB_ALIGN : 0;
 		if (c->align < align)

@@ -330,9 +329,6 @@ EXPORT_SYMBOL(kmem_cache_zalloc);
 
 void kmem_cache_free(struct kmem_cache *c, void *b)
 {
-	if (c->dtor)
-		c->dtor(b, c, 0);
-
 	if (c->size < PAGE_SIZE)
 		slob_free(b, c->size);
 	else

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