linux-kernel - Re: [PATCH v2] net: arc/emac: Move arc_emac_tx_clean() into arc_emac

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Date:	Sun, 08 May 2016 23:42:56 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	wxt@...k-chips.com
Cc:	heiko@...ech.de, linux-rockchip@...ts.infradead.org,
	sy.w@...look.com, al.kochet@...il.com, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] net: arc/emac: Move arc_emac_tx_clean() into
 arc_emac_tx() and disable tx interrut

From: Caesar Wang <wxt@...k-chips.com>
Date: Fri,  6 May 2016 20:19:16 +0800

> Doing tx_clean() inside poll() may scramble the tx ring buffer if
> tx() is running. This will cause tx to stop working, which can be
> reproduced by simultaneously downloading two large files at high speed.
> 
> Moving tx_clean() into tx() will prevent this. And tx interrupt is no
> longer needed now.

TX completion work is always recommended to be done in the ->poll()
handler.

Fix the race or whatever bug there is rather than working around it,
and regressing the driver, by handling TX completion in the interrupt
handler.

Thanks.