Re: [PATCH V1] Revert "accel/amdxdna: Support read-only user-pointer BO mappings"

[Christian König <christian.koenig@amd.com>]

On 5/21/26 18:29, Lizhi Hou wrote:
> This reverts commit f649e63d4a6423eda8eb208638849fd6396aedd7.
> 
> The read-only feature requires further consideration.
> 
> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>

Acked-by: Christian König <christian.koenig@amd.com>

> ---
>  drivers/accel/amdxdna/amdxdna_ubuf.c | 29 ++--------------------------
>  1 file changed, 2 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/accel/amdxdna/amdxdna_ubuf.c b/drivers/accel/amdxdna/amdxdna_ubuf.c
> index 3769210c55cc..4c0647057759 100644
> --- a/drivers/accel/amdxdna/amdxdna_ubuf.c
> +++ b/drivers/accel/amdxdna/amdxdna_ubuf.c
> @@ -125,26 +125,6 @@ static const struct dma_buf_ops amdxdna_ubuf_dmabuf_ops = {
>  	.vunmap = amdxdna_ubuf_vunmap,
>  };
>  
> -static int readonly_va_entry(struct amdxdna_drm_va_entry *va_ent)
> -{
> -	struct mm_struct *mm = current->mm;
> -	struct vm_area_struct *vma;
> -	int ret;
> -
> -	mmap_read_lock(mm);
> -
> -	vma = find_vma(mm, va_ent->vaddr);
> -	if (!vma ||
> -	    vma->vm_start > va_ent->vaddr ||
> -	    vma->vm_end - va_ent->vaddr < va_ent->len)
> -		ret = -ENOENT;
> -	else
> -		ret = vma->vm_flags & VM_WRITE ? 0 : 1;
> -
> -	mmap_read_unlock(mm);
> -	return ret;
> -}
> -
>  struct dma_buf *amdxdna_get_ubuf(struct drm_device *dev,
>  				 u32 num_entries, void __user *va_entries)
>  {
> @@ -154,7 +134,6 @@ struct dma_buf *amdxdna_get_ubuf(struct drm_device *dev,
>  	struct amdxdna_ubuf_priv *ubuf;
>  	u32 npages, start = 0;
>  	struct dma_buf *dbuf;
> -	bool readonly = true;
>  	int i, ret;
>  	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
>  
> @@ -193,10 +172,6 @@ struct dma_buf *amdxdna_get_ubuf(struct drm_device *dev,
>  			ret = -EINVAL;
>  			goto free_ent;
>  		}
> -
> -		/* Pin pages as writable as long as not all entries are read-only. */
> -		if (readonly && readonly_va_entry(&va_ent[i]) != 1)
> -			readonly = false;
>  	}
>  
>  	ubuf->nr_pages = exp_info.size >> PAGE_SHIFT;
> @@ -219,7 +194,7 @@ struct dma_buf *amdxdna_get_ubuf(struct drm_device *dev,
>  		npages = va_ent[i].len >> PAGE_SHIFT;
>  
>  		ret = pin_user_pages_fast(va_ent[i].vaddr, npages,
> -					  (readonly ? 0 : FOLL_WRITE) | FOLL_LONGTERM,
> +					  FOLL_WRITE | FOLL_LONGTERM,
>  					  &ubuf->pages[start]);
>  		if (ret >= 0) {
>  			start += ret;
> @@ -236,7 +211,7 @@ struct dma_buf *amdxdna_get_ubuf(struct drm_device *dev,
>  
>  	exp_info.ops = &amdxdna_ubuf_dmabuf_ops;
>  	exp_info.priv = ubuf;
> -	exp_info.flags = (readonly ? O_RDONLY : O_RDWR) | O_CLOEXEC;
> +	exp_info.flags = O_RDWR | O_CLOEXEC;
>  
>  	dbuf = dma_buf_export(&exp_info);
>  	if (IS_ERR(dbuf)) {