slab, slub, slob: Unify alignment definition

Every slab has its on alignment definition in include/linux/sl?b_def.h. Extract those
and define a common set in include/linux/slab.h.

SLOB: As notes sometimes we need double word alignment on 32 bit. This gives all
structures allocated by SLOB a unsigned long long alignment like the others do.

SLAB: If ARCH_SLAB_MINALIGN is not set SLAB would set ARCH_SLAB_MINALIGN to
zero meaning no alignment at all. Give it the default unsigned long long alignment.

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

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/slab.h b/include/linux/slab.h
index ad4dd1c8d30a..646a639a4aae 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -133,6 +133,16 @@ unsigned int kmem_cache_size(struct kmem_cache *);
 #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_HIGH)
 #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
 
+#ifdef ARCH_DMA_MINALIGN
+#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
+#else
+#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
+#endif
+
+#ifndef ARCH_SLAB_MINALIGN
+#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
+#endif
+
 /*
  * Common kmalloc functions provided by all allocators
  */