mm: Move ARCH_SLAB_MINALIGN and ARCH_KMALLOC_MINALIGN to <linux/slab_def.h>

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index ca6b2b317991..1812dac8c496 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -16,6 +16,30 @@
 #include <linux/compiler.h>
 #include <linux/kmemtrace.h>
 
+#ifndef ARCH_KMALLOC_MINALIGN
+/*
+ * Enforce a minimum alignment for the kmalloc caches.
+ * Usually, the kmalloc caches are cache_line_size() aligned, except when
+ * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
+ * Some archs want to perform DMA into kmalloc caches and need a guaranteed
+ * alignment larger than the alignment of a 64-bit integer.
+ * ARCH_KMALLOC_MINALIGN allows that.
+ * Note that increasing this value may disable some debug features.
+ */
+#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
+#endif
+
+#ifndef ARCH_SLAB_MINALIGN
+/*
+ * Enforce a minimum alignment for all caches.
+ * Intended for archs that get misalignment faults even for BYTES_PER_WORD
+ * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
+ * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
+ * some debug features.
+ */
+#define ARCH_SLAB_MINALIGN 0
+#endif
+
 /*
  * struct kmem_cache
  *