Re: [PATCH v2 1/2] mm: fix mmap errno value when MAP_DROPPABLE is not supported

[Vlastimil Babka (SUSE)]

On 4/3/26 01:59, Anthony Yznaga wrote:
> On configs where MAP_DROPPABLE is not supported (currently any 32-bit
> config except for PPC32), mmap fails with errno set to ENOTSUPP.
> However, ENOTSUPP is not a standard error value that userspace knows
> about. The acceptable userspace-visible errno to use is EOPNOTSUPP.
> checkpatch.pl has a warning to this effect.
> 
> Fixes: 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always lazily freeable mappings")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>

Acked-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>


> ---
>  mm/mmap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 5754d1c36462..2311ae7c2ff4 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -504,7 +504,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
>  			break;
>  		case MAP_DROPPABLE:
>  			if (VM_DROPPABLE == VM_NONE)
> -				return -ENOTSUPP;
> +				return -EOPNOTSUPP;
>  			/*
>  			 * A locked or stack area makes no sense to be droppable.
>  			 *