linux-kernel - Re: [PATCH] mmc: wbsd: safer check if dma

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Message-ID: <CAPDyKFow-fa_tePQ7VO9SsapgMj_TQqc-v7XNOnGNtPXr7TRtg@mail.gmail.com>
Date:   Thu, 19 Jan 2017 12:23:19 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Alexey Khoroshilov <khoroshilov@...ras.ru>
Cc:     Pierre Ossman <pierre@...man.eu>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        ldv-project@...uxtesting.org
Subject: Re: [PATCH] mmc: wbsd: safer check if dma_addr is valid DMA address

On 13 January 2017 at 23:52, Alexey Khoroshilov <khoroshilov@...ras.ru> wrote:
> host->dma_addr can store a value that is not returned by the DMA API,
> so it is safer to check if is a valid DMA address indirectly.
>
> Signed-off-by: Alexey Khoroshilov <khoroshilov@...ras.ru>

Thanks, applied for next!

Kind regards
Uffe

> ---
>  drivers/mmc/host/wbsd.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/wbsd.c b/drivers/mmc/host/wbsd.c
> index 80a3b11f3217..bd04e8bae010 100644
> --- a/drivers/mmc/host/wbsd.c
> +++ b/drivers/mmc/host/wbsd.c
> @@ -1437,11 +1437,14 @@ static void wbsd_request_dma(struct wbsd_host *host, int dma)
>
>  static void wbsd_release_dma(struct wbsd_host *host)
>  {
> -       if (!dma_mapping_error(mmc_dev(host->mmc), host->dma_addr)) {
> +       /*
> +        * host->dma_addr is valid here iff host->dma_buffer is not NULL.
> +        */
> +       if (host->dma_buffer) {
>                 dma_unmap_single(mmc_dev(host->mmc), host->dma_addr,
>                         WBSD_DMA_SIZE, DMA_BIDIRECTIONAL);
> +               kfree(host->dma_buffer);
>         }
> -       kfree(host->dma_buffer);
>         if (host->dma >= 0)
>                 free_dma(host->dma);
>
> --
> 2.7.4
>