mm/slab, docs: switch mm-api docs generation from slab.c to slub.c

The SLAB implementation is going to be removed, and mm-api.rst currently
uses mm/slab.c to obtain kerneldocs for some API functions. Switch it to
mm/slub.c and move the relevant kerneldocs of exported functions from
one to the other. The rest of kerneldocs in slab.c is for static SLAB
implementation-specific functions that don't have counterparts in slub.c
and thus can be simply removed with the implementation.

Acked-by: David Rientjes <[e-mail]>
Tested-by: David Rientjes <[e-mail]>
Reviewed-by: Hyeonggon Yoo <[e-mail]>
Tested-by: Hyeonggon Yoo <[e-mail]>
Signed-off-by: Vlastimil Babka <[e-mail]>

Documentation/core-api/mm-api.rst

···
 .. kernel-doc:: include/linux/slab.h
    :internal:
 
-.. kernel-doc:: mm/slab.c
+.. kernel-doc:: mm/slub.c
    :export:
 
 .. kernel-doc:: mm/slab_common.c

mm/slab.c

···
 }
 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
 
-/**
- * kmem_cache_alloc_node - Allocate an object on the specified node
- * @cachep: The cache to allocate from.
- * @flags: See kmalloc().
- * @nodeid: node number of the target node.
- *
- * Identical to kmem_cache_alloc but it will allocate memory on the given
- * node, which can improve the performance for cpu bound structures.
- *
- * Fallback to other node is possible if __GFP_THISNODE is not set.
- *
- * Return: pointer to the new object or %NULL in case of error
- */
 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
 {
 	void *ret = slab_alloc_node(cachep, NULL, flags, nodeid, cachep->object_size, _RET_IP_);
···
 	__do_kmem_cache_free(cachep, objp, caller);
 }
 
-/**
- * kmem_cache_free - Deallocate an object
- * @cachep: The cache the allocation was from.
- * @objp: The previously allocated object.
- *
- * Free an object which was previously allocated from this
- * cache.
- */
 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
 {
 	cachep = cache_from_obj(cachep, objp);

mm/slub.c

···
 			       caller, orig_size);
 }
 
+/**
+ * kmem_cache_alloc_node - Allocate an object on the specified node
+ * @s: The cache to allocate from.
+ * @gfpflags: See kmalloc().
+ * @node: node number of the target node.
+ *
+ * Identical to kmem_cache_alloc but it will allocate memory on the given
+ * node, which can improve the performance for cpu bound structures.
+ *
+ * Fallback to other node is possible if __GFP_THISNODE is not set.
+ *
+ * Return: pointer to the new object or %NULL in case of error
+ */
 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
 {
 	void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
···
 	slab_free(s, virt_to_slab(x), x, NULL, &x, 1, caller);
 }
 
+/**
+ * kmem_cache_free - Deallocate an object
+ * @s: The cache the allocation was from.
+ * @x: The previously allocated object.
+ *
+ * Free an object which was previously allocated from this
+ * cache.
+ */
 void kmem_cache_free(struct kmem_cache *s, void *x)
 {
 	s = cache_from_obj(s, x);