[v4,03/14] dmaengine: tegra-apb: Prevent race conditions on channel's freeing
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Message ID 20200112173006.29863-4-digetx@gmail.com
State Changes Requested
Headers show
Series
  • NVIDIA Tegra APB DMA driver fixes and improvements
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Commit Message

Dmitry Osipenko Jan. 12, 2020, 5:29 p.m. UTC
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(-)

Comments

Jon Hunter Jan. 14, 2020, 3:16 p.m. UTC | #1
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

Patch
diff mbox series

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);