Re: [PATCH v2 1/2] mm/vmalloc: drop VM_DMA_COHERENT from remap_vmalloc_range_partial

["Jose A. Perez de Azpillaga" <azpijr@gmail.com>]

On 10/29/26 10:19 AM, Ye Liu wrote:
> From: Ye Liu <liuye@kylinos.cn>
> 
> No caller maps a VM_DMA_COHERENT area through this path: such areas
> come from dma_alloc_coherent() internals and are freed via vunmap(),
> never through remap_vmalloc_range[_partial](); all 13 callers pass
> vmalloc_user()/vmalloc()-backed addresses.
> 
> The flag was added in commit fe9041c245196 ("vmalloc: lift the arm
> flag for coherent mappings to common code") as a mechanical
> translation of ARM's VM_ARM_DMA_CONSISTENT.
> 
> Drop it so DMA-coherent areas can never enter the path.
> 
> Signed-off-by: Ye Liu <liuye@kylinos.cn>
> ---
>  mm/vmalloc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index db669103dc66..a888eca016a8 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -4894,7 +4894,7 @@ int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr,
>  	if (!area)
>  		return -EINVAL;
>  
> -	if (!(area->flags & (VM_USERMAP | VM_DMA_COHERENT)))
> +	if (!(area->flags & VM_USERMAP))
>  		return -EINVAL;
>  
>  	if (check_add_overflow(size, off, &end_index) ||
> 

Reviewed-by: Jose A. Perez de Azpillaga <azpijr@gmail.com>

-- 
cheers,
jose a. p-a