On Tue, Mar 3, 2026 at 4:25 PM Linus Walleij linusw@kernel.org wrote:

As of commit 62a9f5a85b98 "mm: introduce clear_pages() and clear_user_pages()" we can clear a range of pages with a potentially assembly-optimized call.

Instead of using a memset, use this helper to clear the whole range of pages from the CMA allocation.

Signed-off-by: Linus Walleij linusw@kernel.org

drivers/dma-buf/heaps/cma_heap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma-buf/heaps/cma_heap.c

b/drivers/dma-buf/heaps/cma_heap.c

index bd3370b9a3f6..f0bacf25ed9d 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -343,7 +343,7 @@ static struct dma_buf *cma_heap_allocate(struct

dma_heap *heap,

                    nr_clear_pages--;
            }
    } else {

•           memset(page_address(cma_pages), 0, size);
  

•           clear_pages(page_address(cma_pages), pagecount);
    }
  
    buffer->pages = kmalloc_objs(*buffer->pages, pagecount);
  
  

---

base-commit: 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f change-id: 20260303-cma-heap-clear-pages-540f3ac9f734

Best regards,

Linus Walleij linusw@kernel.org

Hi Linus,

I think we can also use clear_highpage (singular) instead of memset in the while loop above here to be a little more concise.

Thanks, T.J.