linux-kernel - Re: [PATCH v2 1/6] serial: imx: only set DMA rx-ing when DMA starts

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Date:   Thu, 6 Jul 2017 10:31:38 +0200
From:   Romain Perier <romain.perier@...labora.com>
To:     Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-serial@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Nandor Han <nandor.han@...com>
Subject: Re: [PATCH v2 1/6] serial: imx: only set DMA rx-ing when DMA starts

Hello,


Le 05/07/2017 à 15:29, Uwe Kleine-König a écrit :
> Hello,
>
> On Wed, Jul 05, 2017 at 03:07:01PM +0200, Romain Perier wrote:
>> From: Nandor Han <nandor.han@...com>
>>
>> Avoid the situation when `dma_is_rxing` could incorrectly signal that
>> DMA RX channel is receiving data in case DMA preparation or sg mapping
>> fails.
>>
>> This commit fixes the issues by moving the assignment of dma_is_rxing
>> out of imx_disable_rx_int(), then the variable is set to 1 from
>> start_rx_dma() only when the preparation is correctly done.
> I'd write:
>
> 	There are a few issues with setting dma_is_rxing to 1 in
> 	imx_disable_rx_int:
>
> 	 - Currently always after imx_disable_rx_int() the function
> 	   start_rx_dma() is called. This dependency isn't obvious though.
> 	 - start_rx_dma() does error checking and might exit without enabling
> 	   DMA but keeping dma_is_rxing 1.
>
> 	So the more natural place for setting dma_is_rxing to 1 is in
> 	start_rx_dma after all errors are checked.
>
> If you use this, there is nothing left of Nandor Han's patch and you can
> drop his authorship.
>
> Best regards
> Uwe
>
Ok, will do. No other feedback for the rest of the series ? (just to
know if I send a v3 or If I wait a bit...)

Thanks,
Romain