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From: Jesper Dangaard Brouer <jbrouer@redhat.com>
To: Yunsheng Lin <linyunsheng@huawei.com>,
	davem@davemloft.net, kuba@kernel.org
Cc: brouer@redhat.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, linuxarm@openeuler.org,
	hawk@kernel.org, ilias.apalodimas@linaro.org,
	jonathan.lemon@gmail.com, alobakin@pm.me, willemb@google.com,
	cong.wang@bytedance.com, pabeni@redhat.com, haokexin@gmail.com,
	nogikh@google.com, elver@google.com, memxor@gmail.com,
	edumazet@google.com, alexander.duyck@gmail.com,
	dsahern@gmail.com
Subject: Re: [PATCH net-next 1/7] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
Date: Thu, 23 Sep 2021 11:33:27 +0200	[thread overview]
Message-ID: <0ffa15a1-742d-a05d-3ea6-04ff25be6a29@redhat.com> (raw)
In-Reply-To: <20210922094131.15625-2-linyunsheng@huawei.com>


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


  parent reply	other threads:[~2021-09-23  9:33 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-22  9:41 [PATCH net-next 0/7] some optimization for page pool Yunsheng Lin
2021-09-22  9:41 ` [PATCH net-next 1/7] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA Yunsheng Lin
2021-09-23  9:10   ` Ilias Apalodimas
2021-09-23  9:33   ` Jesper Dangaard Brouer [this message]
2021-09-23 10:02     ` Ilias Apalodimas
2021-09-23 11:13       ` Yunsheng Lin
2021-09-23 13:07         ` Ilias Apalodimas
2021-09-24  7:04           ` Yunsheng Lin
2021-09-24  7:25             ` Ilias Apalodimas
2021-09-24  8:01               ` Yunsheng Lin
2021-09-22  9:41 ` [PATCH net-next 2/7] page_pool: support non-split page with PP_FLAG_PAGE_FRAG Yunsheng Lin
2021-09-23 12:08   ` Jesper Dangaard Brouer
2021-09-24  7:23     ` Yunsheng Lin
2021-09-30  7:28       ` [Linuxarm] " Yunsheng Lin
2021-09-22  9:41 ` [PATCH net-next 3/7] pool_pool: avoid calling compound_head() for skb frag page Yunsheng Lin
2021-09-23  8:33   ` Ilias Apalodimas
2021-09-23 11:24     ` Yunsheng Lin
2021-09-23 11:47       ` Ilias Apalodimas
2021-09-24  7:33         ` Yunsheng Lin
2021-09-24  7:44           ` Ilias Apalodimas
2021-09-22  9:41 ` [PATCH net-next 4/7] page_pool: change BIAS_MAX to support incrementing Yunsheng Lin
2021-09-22  9:41 ` [PATCH net-next 5/7] skbuff: keep track of pp page when __skb_frag_ref() is called Yunsheng Lin
2021-09-22  9:41 ` [PATCH net-next 6/7] skbuff: only use pp_magic identifier for a skb' head page Yunsheng Lin
2021-09-22  9:41 ` [PATCH net-next 7/7] skbuff: remove unused skb->pp_recycle Yunsheng Lin
2021-09-23  7:07 ` [PATCH net-next 0/7] some optimization for page pool Ilias Apalodimas
2021-09-23 11:12   ` Yunsheng Lin

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