Slab allocators: Drop support for destructors

There is no user of destructors left.  There is no reason why we should keep
checking for destructors calls in the slab allocators.

The RFC for this patch was discussed at
http://marc.info/?l=linux-kernel&m=117882364330705&w=2

Destructors were mainly used for list management which required them to take a
spinlock.  Taking a spinlock in a destructor is a bit risky since the slab
allocators may run the destructors anytime they decide a slab is no longer
needed.

Patch drops destructor support.  Any attempt to use a destructor will BUG().

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 1 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!) */