dma-direct: fix type mismatch in dma_direct_alloc_pages

[PATCH] dma-direct: fix type mismatch in dma_direct_alloc_pages

Posted by yangge1116@126.com 1 week, 4 days ago

From: Ge Yang <yangge1116@126.com>

The pool allocation path directly returned the void* cpu virtual
address from dma_direct_alloc_from_pool(), which is type‑mismatched
against struct page *. Convert the dma_handle to page via
dma_direct_to_page() instead.

Fixes: 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool helper")
Signed-off-by: Ge Yang <yangge1116@126.com>
Cc: stable@vger.kernel.org
---
 kernel/dma/direct.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 4391b79..f496568 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -356,8 +356,12 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 	struct page *page;
 	void *ret;
 
-	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
-		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp)) {
+		ret = dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+		if (!ret)
+			return NULL;
+		return dma_direct_to_page(dev, *dma_handle);
+	}
 
 	page = __dma_direct_alloc_pages(dev, size, gfp, false);
 	if (!page)
-- 
2.7.4

Re: [PATCH] dma-direct: fix type mismatch in dma_direct_alloc_pages

Posted by Marek Szyprowski 1 week, 4 days ago

On 14.08.2026 08:30, yangge1116@126.com wrote:
> From: Ge Yang <yangge1116@126.com>
>
> The pool allocation path directly returned the void* cpu virtual
> address from dma_direct_alloc_from_pool(), which is type‑mismatched
> against struct page *. Convert the dma_handle to page via
> dma_direct_to_page() instead.
>
> Fixes: 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool helper")
> Signed-off-by: Ge Yang <yangge1116@126.com>
> Cc: stable@vger.kernel.org

This is a duplicate of the patch already applied to dma-mapping-for-next, see

https://lore.kernel.org/r/20260717180442.110954-2-aneesh.kumar@kernel.org

> ---
>  kernel/dma/direct.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 4391b79..f496568 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -356,8 +356,12 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
>  	struct page *page;
>  	void *ret;
>  
> -	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
> -		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
> +	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp)) {
> +		ret = dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
> +		if (!ret)
> +			return NULL;
> +		return dma_direct_to_page(dev, *dma_handle);
> +	}
>  
>  	page = __dma_direct_alloc_pages(dev, size, gfp, false);
>  	if (!page)

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland