On 09/09/25 at 06:15下午, Jakub Kicinski wrote:

Date: Tue, 9 Sep 2025 18:15:47 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: 李克斯 <redacted>
Cc: vkoul@kernel.org, davem@davemloft.net, wens@csie.org,
 mripard@kernel.org, netdev@vger.kernel.org, dmaengine@vger.kernel.org,
 linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: ethernet: sun4i-emac: free dma descriptor

On Tue, 9 Sep 2025 14:36:42 +0800 李克斯 wrote:

quoted

Thank you for the suggestion. I've reviewed the documentation, and
setting the reuse flag while reusing descriptors might be a good
optimization. I'll make the changes and run some tests. If everything
works well, I'll submit a new patch.

To be clear if you're saying the driver is buggy and can crash right
now we need to fix it first and then optimize it later, as separate
commits. So that LTS kernels can backport the fix.

The questions I'm asking are because I don't understand whether the
upstream kernel is buggy and how exactly..

After carefully reviewing the documentation and how other drivers use
dmaengine, I think that if the reuse flag is not set for the descriptor,
manual release is unnecessary. Therefore, the current driver implementation
does not contain a bug. This fix patch was a mistake.

Thank you for your thorough review.