netdev - Re: [PATCH net-next] net: ethernet: mtk_wed: get rid of queue lock for rx queue

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Message-ID: <20230109193721.7d05d24b@kernel.org>
Date:   Mon, 9 Jan 2023 19:37:21 -0800
From:   Jakub Kicinski <kuba@...nel.org>
To:     Lorenzo Bianconi <lorenzo@...nel.org>
Cc:     Alexander H Duyck <alexander.duyck@...il.com>,
        netdev@...r.kernel.org, davem@...emloft.net, edumazet@...gle.com,
        pabeni@...hat.com, lorenzo.bianconi@...hat.com, nbd@....name,
        john@...ozen.org, sean.wang@...iatek.com, Mark-MC.Lee@...iatek.com,
        sujuan.chen@...iatek.com, daniel@...rotopia.org
Subject: Re: [PATCH net-next] net: ethernet: mtk_wed: get rid of queue lock
 for rx queue

On Mon, 09 Jan 2023 16:50:55 -0800 Alexander H Duyck wrote:
> On Sat, 2023-01-07 at 15:41 +0100, Lorenzo Bianconi wrote:
> > mtk_wed_wo_queue_rx_clean and mtk_wed_wo_queue_refill routines can't run
> > concurrently so get rid of spinlock for rx queues.

You say "for rx queues" but mtk_wed_wo_queue_refill() is also called
for tx queues.

> My understanding is that mtk_wed_wo_queue_refill will only be called
> during init and by the tasklet. The mtk_wed_wo_queue_rx_clean function
> is only called during deinit and only after the tasklet has been
> disabled. That is the reason they cannot run at the same time correct?
> 
> It would be nice if you explained why they couldn't run concurrently
> rather than just stating it is so in the patch description. It makes it
> easier to verify assumptions that way. Otherwise the patch itself looks
> good to me.

Agreed, please respin with a better commit message.