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Date:   Thu, 7 Nov 2019 08:02:29 +0100
From:   "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
To:     Peng Fan <peng.fan@nxp.com>
Cc:     "jslaby@suse.com" <jslaby@suse.com>,
        "shawnguo@kernel.org" <shawnguo@kernel.org>,
        "festevam@gmail.com" <festevam@gmail.com>,
        dl-linux-imx <linux-imx@nxp.com>,
        "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Andy Duan <fugang.duan@nxp.com>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH V2] tty: serial: fsl_lpuart: use the sg count from
 dma_map_sg
Message-ID: <20191107070229.GA1114824@kroah.com>
References: <1573094911-448-1-git-send-email-peng.fan@nxp.com>
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On Thu, Nov 07, 2019 at 02:50:11AM +0000, Peng Fan wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> The dmaengine_prep_slave_sg needs to use sg count returned
> by dma_map_sg, not use sport->dma_tx_nents, because the return
> value of dma_map_sg is not always same with "nents".
> 
> When enabling iommu for lpuart + edma, iommu framework may concatenate
> two sgs into one.
> 
> Fixes: 6250cc30c4c4e ("tty: serial: fsl_lpuart: Use scatter/gather DMA for Tx")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
> 
> V2:
>  Assign ret to sport->dma_tx_nents, then we no need to fix dma_unmap_sg
>  Hi Greg,
>   I saw v1 patch merged to tty-next, please help to replace with V2 if this
>   is ok for you, or you need I have a follow up fix for v1.

I can not "replace" anything, my tree does not rebase, sorry.  Please
send fix-up patches on top of it if there is any changes that need to
happen.

thanks,

greg k-h