Re: [PATCH v4 03/14] dmaengine: tegra-apb: Prevent race conditions on channel's freeing

Jon Hunter
2020-01-14T15:16:50Z

On 12/01/2020 17:29, Dmitry Osipenko wrote:
> It's incorrect to check the channel's "busy" state without taking a lock.
> That shouldn't cause any real troubles, nevertheless it's always better
> not to have any race conditions in the code.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/dma/tegra20-apb-dma.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 664e9c5df3ba..24ad3a5a04e3 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -1294,8 +1294,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
>
> dev_dbg(tdc2dev(tdc), "Freeing channel %d\n", tdc->id);
>
> - if (tdc->busy)
> - tegra_dma_terminate_all(dc);
> + tegra_dma_terminate_all(dc);
>
> spin_lock_irqsave(&tdc->lock, flags);
> list_splice_init(&tdc->pending_sg_req, &sg_req_list);

Acked-by: Jon Hunter <jonathanh@nvidia.com>

Cheers
Jon

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