Re: [PATCH 01/15] mm: various small mmap_prepare cleanups

[Andrew Morton]

On Thu, 12 Mar 2026 20:27:16 +0000 "Lorenzo Stoakes (Oracle)" <l...@kernel.org> 
wrote:

> +int mmap_action_prepare(struct vm_area_desc *desc,
> +                     struct mmap_action *action)
> +
>  {
>       switch (action->type) {
>       case MMAP_NOTHING:
> -             break;
> +             return 0;
>       case MMAP_REMAP_PFN:
> -             remap_pfn_range_prepare(desc, action->remap.start_pfn);
> -             break;
> +             return remap_pfn_range_prepare(desc, action);
>       case MMAP_IO_REMAP_PFN:
> -             io_remap_pfn_range_prepare(desc, action->remap.start_pfn,
> -                                        action->remap.size);
> -             break;
> +             return io_remap_pfn_range_prepare(desc, action);
>       }
>  }
>  EXPORT_SYMBOL(mmap_action_prepare);

hm, was this the correct version?

mm/util.c: In function 'mmap_action_prepare':
mm/util.c:1451:1: error: control reaches end of non-void function 
[-Werror=return-type]
 1451 | }

--- a/mm/util.c~mm-various-small-mmap_prepare-cleanups-fix
+++ a/mm/util.c
@@ -1356,6 +1356,8 @@ int mmap_action_prepare(struct vm_area_d
                return remap_pfn_range_prepare(desc, action);
        case MMAP_IO_REMAP_PFN:
                return io_remap_pfn_range_prepare(desc, action);
+       default:
+               BUG();
        }
 }
 EXPORT_SYMBOL(mmap_action_prepare);
_