Re: [PATCH v7 10/22] dma-direct: use __DMA_ATTR_ALLOC_CC_SHARED in alloc/free paths

[Jason Gunthorpe]

On Wed, Jul 01, 2026 at 11:19:14AM +0530, Aneesh Kumar K.V (Arm) wrote:
> Propagate force_dma_unencrypted() into __DMA_ATTR_ALLOC_CC_SHARED in the
> dma-direct allocation path and use the attribute to drive the related
> decisions.
> 
> This updates dma_direct_alloc(), dma_direct_free(), and
> dma_direct_alloc_pages() to fold the forced unencrypted case into attrs.
> 
> Tested-by: Jiri Pirko <jiri@xxxxxxxxxx>
> Tested-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
> Tested-by: Mostafa Saleh <smostafa@xxxxxxxxxx>
> Reviewed-by: Petr Tesarik <ptesarik@xxxxxxxx>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>
> ---
>  kernel/dma/direct.c  | 42 +++++++++++++++++++++++++++++++++---------
>  kernel/dma/mapping.c |  9 +++++++++
>  2 files changed, 42 insertions(+), 9 deletions(-)
> 
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 0cbf2b0835c4..98e47e0b332d 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -192,16 +192,22 @@ void *dma_direct_alloc(struct device *dev, size_t size,
>  		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
>  {
>  	bool remap = false, set_uncached = false;
> -	bool mark_mem_decrypt = true;
> +	bool mark_mem_decrypt = false;
>  	struct page *page;
>  	void *ret;
>  
> +	if (force_dma_unencrypted(dev))
> +		attrs |= __DMA_ATTR_ALLOC_CC_SHARED;

After going through what was left of force_dma_unencrypted() once the
series was fully applied you might consider something like

  dma_update_attrs(dev, &attrs);

To remove the frequently duplicated code

It is fine like this too

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

Jason