mm, sl[aou]b: Extract common fields from struct kmem_cache

Define a struct that describes common fields used in all slab allocators.
A slab allocator either uses the common definition (like SLOB) or is
required to provide members of kmem_cache with the definition given.

After that it will be possible to share code that
only operates on those fields of kmem_cache.

The patch basically takes the slob definition of kmem cache and
uses the field namees for the other allocators.

It also standardizes the names used for basic object lengths in
allocators:

object_size	Struct size specified at kmem_cache_create. Basically
		the payload expected to be used by the subsystem.

size		The size of memory allocator for each object. This size
		is larger than object_size and includes padding, alignment
		and extra metadata for each object (f.e. for debugging
		and rcu).

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

1 files changed, 1 insertions, 8 deletions

diff --git a/mm/slob.c b/mm/slob.c
index c85265d22e0..95d1c7dd88e 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -506,13 +506,6 @@ size_t ksize(const void *block)
 }
 EXPORT_SYMBOL(ksize);
 
-struct kmem_cache {
-	unsigned int size, align;
-	unsigned long flags;
-	const char *name;
-	void (*ctor)(void *);
-};
-
 struct kmem_cache *kmem_cache_create(const char *name, size_t size,
 	size_t align, unsigned long flags, void (*ctor)(void *))
 {
@@ -523,7 +516,7 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
 
 	if (c) {
 		c->name = name;
-		c->size = size;
+		c->size = c->object_size;
 		if (flags & SLAB_DESTROY_BY_RCU) {
 			/* leave room for rcu footer at the end of object */
 			c->size += sizeof(struct slob_rcu);