Hi Jesper, On Thu, 23 Sept 2021 at 12:33, Jesper Dangaard Brouer <jbrouer@redhat.com> wrote:
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).
I am fine with both. In any case though the aforementioned driver can just remove PP_FLAG_DMA_MAP and do it's own mappings. Regards /Ilias
-Jesper