slab: move struct kmem_cache to headers

Move the SLAB struct kmem_cache definition to <linux/slab_def.h> like
with SLUB so kmemcheck can access ->ctor and ->flags.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index 713f841..850d057 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -16,6 +16,87 @@
 #include <linux/compiler.h>
 #include <linux/kmemtrace.h>
 
+/*
+ * struct kmem_cache
+ *
+ * manages a cache.
+ */
+
+struct kmem_cache {
+/* 1) per-cpu data, touched during every alloc/free */
+	struct array_cache *array[NR_CPUS];
+/* 2) Cache tunables. Protected by cache_chain_mutex */
+	unsigned int batchcount;
+	unsigned int limit;
+	unsigned int shared;
+
+	unsigned int buffer_size;
+	u32 reciprocal_buffer_size;
+/* 3) touched by every alloc & free from the backend */
+
+	unsigned int flags;		/* constant flags */
+	unsigned int num;		/* # of objs per slab */
+
+/* 4) cache_grow/shrink */
+	/* order of pgs per slab (2^n) */
+	unsigned int gfporder;
+
+	/* force GFP flags, e.g. GFP_DMA */
+	gfp_t gfpflags;
+
+	size_t colour;			/* cache colouring range */
+	unsigned int colour_off;	/* colour offset */
+	struct kmem_cache *slabp_cache;
+	unsigned int slab_size;
+	unsigned int dflags;		/* dynamic flags */
+
+	/* constructor func */
+	void (*ctor)(void *obj);
+
+/* 5) cache creation/removal */
+	const char *name;
+	struct list_head next;
+
+/* 6) statistics */
+#ifdef CONFIG_DEBUG_SLAB
+	unsigned long num_active;
+	unsigned long num_allocations;
+	unsigned long high_mark;
+	unsigned long grown;
+	unsigned long reaped;
+	unsigned long errors;
+	unsigned long max_freeable;
+	unsigned long node_allocs;
+	unsigned long node_frees;
+	unsigned long node_overflow;
+	atomic_t allochit;
+	atomic_t allocmiss;
+	atomic_t freehit;
+	atomic_t freemiss;
+
+	/*
+	 * If debugging is enabled, then the allocator can add additional
+	 * fields and/or padding to every object. buffer_size contains the total
+	 * object size including these internal fields, the following two
+	 * variables contain the offset to the user object and its size.
+	 */
+	int obj_offset;
+	int obj_size;
+#endif /* CONFIG_DEBUG_SLAB */
+
+	/*
+	 * We put nodelists[] at the end of kmem_cache, because we want to size
+	 * this array to nr_node_ids slots instead of MAX_NUMNODES
+	 * (see kmem_cache_init())
+	 * We still use [MAX_NUMNODES] and not [1] or [0] because cache_cache
+	 * is statically defined, so we reserve the max number of nodes.
+	 */
+	struct kmem_list3 *nodelists[MAX_NUMNODES];
+	/*
+	 * Do not add fields after nodelists[]
+	 */
+};
+
 /* Size description struct for general caches. */
 struct cache_sizes {
 	size_t		 	cs_size;