4 files changed, 16 insertions, 62 deletions

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index c6c1f4a120e3..5e2e7297dfaa 100644
--- a/include/linux/slub_def.h
+++ b/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!) */
diff --git a/mm/slab.c b/mm/slab.c
index 944b20581f8c..12344432e201 100644
--- a/mm/slab.c
+++ b/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 kmem_cache *cachep, struct slab *slabp)
                                 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_cache *cachep)
  * @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, size_t size, size_t align,
          * 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, size_t size, size_t align,
         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, size_t size, size_t align,
                 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(struct kmem_cache *cachep, void *objp,
         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
diff --git a/mm/slob.c b/mm/slob.c
index 57bb72ed0d46..79164a4f54ad 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -280,7 +280,6 @@ struct kmem_cache {
         unsigned long flags;
         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,
@@ -296,13 +295,11 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
                 c->name = name;
                 c->size = size;
                 if (flags & SLAB_DESTROY_BY_RCU) {
-                        BUG_ON(dtor);
                         /* leave room for rcu footer at the end of object */
                         c->size += sizeof(struct slob_rcu);
                 }
                 c->flags = flags;
                 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)
@@ -371,8 +368,6 @@ void kmem_cache_free(struct kmem_cache *c, void *b)
                 slob_rcu->size = c->size;
                 call_rcu(&slob_rcu->head, kmem_rcu_free);
         } else {
-                if (c->dtor)
-                        c->dtor(b, c, 0);
                 __kmem_cache_free(b, c->size);
         }
 }
diff --git a/mm/slub.c b/mm/slub.c
index 5e3e8bc9838f..022c1b4d74d4 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -891,13 +891,13 @@ static void kmem_cache_open_debug_check(struct kmem_cache *s)
          * On 32 bit platforms the limit is 256k. On 64bit platforms
          * the limit is 512k.
          *
-         * Debugging or ctor/dtors may create a need to move the free
+         * Debugging or ctor may create a need to move the free
          * pointer. Fail if this happens.
          */
         if (s->size >= 65535 * sizeof(void *)) {
                 BUG_ON(s->flags & (SLAB_RED_ZONE | SLAB_POISON |
                                 SLAB_STORE_USER | SLAB_DESTROY_BY_RCU));
-                BUG_ON(s->ctor || s->dtor);
+                BUG_ON(s->ctor);
         }
         else
                 /*
@@ -1030,15 +1030,12 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
 {
         int pages = 1 << s->order;
 
-        if (unlikely(SlabDebug(page) || s->dtor)) {
+        if (unlikely(SlabDebug(page))) {
                 void *p;
 
                 slab_pad_check(s, page);
-                for_each_object(p, s, page_address(page)) {
-                        if (s->dtor)
-                                s->dtor(p, s, 0);
+                for_each_object(p, s, page_address(page))
                         check_object(s, page, p, 0);
-                }
         }
 
         mod_zone_page_state(page_zone(page),
@@ -1871,7 +1868,7 @@ static int calculate_sizes(struct kmem_cache *s)
          * then we should never poison the object itself.
          */
         if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
-                        !s->ctor && !s->dtor)
+                        !s->ctor)
                 s->flags |= __OBJECT_POISON;
         else
                 s->flags &= ~__OBJECT_POISON;
@@ -1901,7 +1898,7 @@ static int calculate_sizes(struct kmem_cache *s)
 
 #ifdef CONFIG_SLUB_DEBUG
         if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
-                s->ctor || s->dtor)) {
+                s->ctor)) {
                 /*
                  * Relocate free pointer after the object if it is not
                  * permitted to overwrite the first word of the object on
@@ -1970,13 +1967,11 @@ static int calculate_sizes(struct kmem_cache *s)
 static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
                 const char *name, size_t size,
                 size_t align, unsigned long flags,
-                void (*ctor)(void *, struct kmem_cache *, unsigned long),
-                void (*dtor)(void *, struct kmem_cache *, unsigned long))
+                void (*ctor)(void *, struct kmem_cache *, unsigned long))
 {
         memset(s, 0, kmem_size);
         s->name = name;
         s->ctor = ctor;
-        s->dtor = dtor;
         s->objsize = size;
         s->flags = flags;
         s->align = align;
@@ -2161,7 +2156,7 @@ static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
 
         down_write(&slub_lock);
         if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
-                        flags, NULL, NULL))
+                        flags, NULL))
                 goto panic;
 
         list_add(&s->list, &slab_caches);
@@ -2463,7 +2458,7 @@ static int slab_unmergeable(struct kmem_cache *s)
         if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
                 return 1;
 
-        if (s->ctor || s->dtor)
+        if (s->ctor)
                 return 1;
 
         return 0;
@@ -2471,15 +2466,14 @@ static int slab_unmergeable(struct kmem_cache *s)
 
 static struct kmem_cache *find_mergeable(size_t size,
                 size_t align, unsigned long flags,
-                void (*ctor)(void *, struct kmem_cache *, unsigned long),
-                void (*dtor)(void *, struct kmem_cache *, unsigned long))
+                void (*ctor)(void *, struct kmem_cache *, unsigned long))
 {
         struct list_head *h;
 
         if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
                 return NULL;
 
-        if (ctor || dtor)
+        if (ctor)
                 return NULL;
 
         size = ALIGN(size, sizeof(void *));
@@ -2521,8 +2515,9 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
 {
         struct kmem_cache *s;
 
+        BUG_ON(dtor);
         down_write(&slub_lock);
-        s = find_mergeable(size, align, flags, ctor, dtor);
+        s = find_mergeable(size, align, flags, ctor);
         if (s) {
                 s->refcount++;
                 /*
@@ -2536,7 +2531,7 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
         } else {
                 s = kmalloc(kmem_size, GFP_KERNEL);
                 if (s && kmem_cache_open(s, GFP_KERNEL, name,
-                                size, align, flags, ctor, dtor)) {
+                                size, align, flags, ctor)) {
                         if (sysfs_slab_add(s)) {
                                 kfree(s);
                                 goto err;
@@ -3177,17 +3172,6 @@ static ssize_t ctor_show(struct kmem_cache *s, char *buf)
 }
 SLAB_ATTR_RO(ctor);
 
-static ssize_t dtor_show(struct kmem_cache *s, char *buf)
-{
-        if (s->dtor) {
-                int n = sprint_symbol(buf, (unsigned long)s->dtor);
-
-                return n + sprintf(buf + n, "\n");
-        }
-        return 0;
-}
-SLAB_ATTR_RO(dtor);
-
 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
 {
         return sprintf(buf, "%d\n", s->refcount - 1);
@@ -3419,7 +3403,6 @@ static struct attribute * slab_attrs[] = {
         &partial_attr.attr,
         &cpu_slabs_attr.attr,
         &ctor_attr.attr,
-        &dtor_attr.attr,
         &aliases_attr.attr,
         &align_attr.attr,
         &sanity_checks_attr.attr,