mm/slab_common: move declaration of __ksize() to mm/slab.h

__ksize() is only called by KASAN. Remove export symbol and move
declaration to mm/slab.h as we don't want to grow its callers.
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

include/linux/slab.h

@@ -187,7 +187,6 @@ int kmem_cache_shrink(struct kmem_cache *s);
 void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __alloc_size(2);
 void kfree(const void *objp);
 void kfree_sensitive(const void *objp);
-size_t __ksize(const void *objp);
 size_t ksize(const void *objp);
 #ifdef CONFIG_PRINTK
 bool kmem_valid_obj(void *object);

mm/slab.h

@@ -668,6 +668,8 @@ void free_large_kmalloc(struct folio *folio, void *object);
 
 #endif /* CONFIG_SLOB */
 
+size_t __ksize(const void *objp);
+
 static inline size_t slab_ksize(const struct kmem_cache *s)
 {
 #ifndef CONFIG_SLUB

mm/slab_common.c

@@ -974,15 +974,7 @@ void kfree(const void *object)
 }
 EXPORT_SYMBOL(kfree);
 
-/**
- * __ksize -- Uninstrumented ksize.
- * @object: pointer to the object
- *
- * Unlike ksize(), __ksize() is uninstrumented, and does not provide the same
- * safety checks as ksize() with KASAN instrumentation enabled.
- *
- * Return: size of the actual memory used by @object in bytes
- */
+/* Uninstrumented ksize. Only called by KASAN. */
 size_t __ksize(const void *object)
 {
 	struct folio *folio;
@@ -997,7 +989,6 @@ size_t __ksize(const void *object)
 
 	return slab_ksize(folio_slab(folio)->slab_cache);
 }
-EXPORT_SYMBOL(__ksize);
 
 #ifdef CONFIG_TRACING
 void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)

mm/slob.c

@@ -584,7 +584,6 @@ size_t __ksize(const void *block)
 	m = (unsigned int *)(block - align);
 	return SLOB_UNITS(*m) * SLOB_UNIT;
 }
-EXPORT_SYMBOL(__ksize);
 
 int __kmem_cache_create(struct kmem_cache *c, slab_flags_t flags)
 {