Subject: [PATCH v5 15/20] dma-direct: return struct page from dma_direct_alloc_from_pool()

From: "Aneesh Kumar K.V (Arm)" <[email-masked]>
Date: Fri, 22 May 2026 09:58:10 +0530

Commit 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool
helper") changed dma_direct_alloc_from_pool() to return the CPU address
from dma_alloc_from_pool(). That fits dma_direct_alloc(), but
dma_direct_alloc_pages() also uses the helper and expects a struct page *.

Fix this by making dma_direct_alloc_from_pool() return the struct page *
again, and pass the CPU address back through an out-parameter for the
dma_direct_alloc() caller.

Fixes: 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool helper")
Cc: [email-masked]

Signed-off-by: Aneesh Kumar K.V (Arm) <[email-masked]>
---
 kernel/dma/direct.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 6b00c7f4a78b..907c6084c616 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -157,24 +157,24 @@ static bool dma_direct_use_pool(struct device *dev, gfp_t gfp)
 	return !gfpflags_allow_blocking(gfp) && !is_swiotlb_for_alloc(dev);
 }
 
-static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
-		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
+static struct page *dma_direct_alloc_from_pool(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, void **cpu_addr, gfp_t gfp,
+		unsigned long attrs)
 {
 	struct page *page;
 	u64 phys_limit;
-	void *ret;
 
 	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)))
 		return NULL;
 
 	gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit);
-	page = dma_alloc_from_pool(dev, size, &ret, gfp, attrs,
+	page = dma_alloc_from_pool(dev, size, cpu_addr, gfp, attrs,
 				   dma_coherent_ok);
 	if (!page)
 		return NULL;
 	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page),
 					 !!(attrs & DMA_ATTR_CC_SHARED));
-	return ret;
+	return page;
 }
 
 static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
@@ -270,9 +270,12 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 	 * the atomic pools instead if we aren't allowed block.
 	 */
 	if ((remap || (attrs & DMA_ATTR_CC_SHARED)) &&
-	    dma_direct_use_pool(dev, gfp))
-		return dma_direct_alloc_from_pool(dev, size, dma_handle,
-						  gfp, attrs);
+	    dma_direct_use_pool(dev, gfp)) {
+		page = dma_direct_alloc_from_pool(dev, size,
+					dma_handle, &cpu_addr,
+					gfp, attrs);
+		return page ? cpu_addr : NULL;
+	}
 
 	if (is_swiotlb_for_alloc(dev)) {
 		page = dma_direct_alloc_swiotlb(dev, size, attrs);
@@ -445,7 +448,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 
 	if ((attrs & DMA_ATTR_CC_SHARED) && dma_direct_use_pool(dev, gfp))
 		return dma_direct_alloc_from_pool(dev, size, dma_handle,
-						  gfp, attrs);
+						  &cpu_addr, gfp, attrs);
 
 	if (is_swiotlb_for_alloc(dev)) {
 		page = dma_direct_alloc_swiotlb(dev, size, attrs);
-- 
2.43.0