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Date: Fri, 9 Sep 2016 17:23:05 +0530
From: Vinod Koul <vinod.koul@...el.com>
To: Hsin-Yu Chao <hychao@...omium.org>
Cc: smbarber@...omium.org, groeck@...omium.org,
Dan Williams <dan.j.williams@...el.com>,
"open list:DMA GENERIC OFFLOAD ENGINE SUBSYSTEM"
<dmaengine@...r.kernel.org>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] dmaengine: pl330: Acquire dmac's spinlock in
pl330_tx_status
On Tue, Aug 23, 2016 at 05:16:55PM +0800, Hsin-Yu Chao wrote:
> There is a racing when accessing dmac thread in pl330_tx_status that
> the pl330_update is handling active request at the same time and
> changing the status of descriptors. This could cause an invalid
> transferred count from BUSY descriptor added up to the residual number.
> Fix the bug by using the dmac's spinlock in pl330_tx_status to protect
> thread resources from changing.
> Note that the nested order of holding dmac's and dma_chan's spinlock is
> consistent with the rest of the driver: dma_chan first and then dmac,
> so it is safe from deadlock scenario.
Applied, thanks
--
~Vinod
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