[Linuxarm] Re: [PATCH net-next 1/7] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA

On 22/09/2021 11.41, Yunsheng Lin wrote:

diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 1a6978427d6c..a65bd7972e37 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -49,6 +49,12 @@ static int page_pool_init(struct page_pool *pool, * which is the XDP_TX use-case. */ if (pool->p.flags & PP_FLAG_DMA_MAP) {

• /* DMA-mapping is not supported on 32-bit systems with
  

•  * 64-bit DMA mapping.
  

•  */
  

• if (sizeof(dma_addr_t) > sizeof(unsigned long))
  

• 	return -EINVAL;
  

As I said before, can we please use another error than EINVAL. We should give drivers a chance/ability to detect this error, and e.g. fallback to doing DMA mappings inside driver instead.

I suggest using EOPNOTSUPP 95 (Operation not supported).

-Jesper