zio-core: export zio_alloc/free_control()

zio_free_control is needed by external buffers.

zio_alloc_control will be needed by external triggers that don't rely
on zio_fire_trigger(). It will also be needed by in-kernel sources
of output data.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Federico Vaga <federico.vaga@gmail.com>

zio-core.c

@@ -30,11 +30,13 @@ struct zio_control *zio_alloc_control(gfp_t gfp)
 		ctrl->flags |= ZIO_CONTROL_LITTLE_ENDIAN;
 	return ctrl;
 }
+EXPORT_SYMBOL(zio_alloc_control); /* used by buffers */
 
 void zio_free_control(struct zio_control *ctrl)
 {
 	kmem_cache_free(zio_ctrl_slab, ctrl);
 }
+EXPORT_SYMBOL(zio_free_control); /* used by buffers */
 
 int __init zio_slab_init(void)
 {