On Tue, Aug 30, 2022 at 05:32:07PM +0800, Koba Ko wrote:
> If the passed client_count is 0,
> it would be incremented by balance_ref_count first
> then increment one more.
> This would cause client_count to 2.
>
> cat /sys/class/dma/dma0chan*/in_use
> 2
> 2
> 2
>
> Fixes: d2f4f99db3e9 ("dmaengine: Rework dma_chan_get")
> Signed-off-by: Koba Ko <koba.ko@xxxxxxxxxxxxx>
> ---
> drivers/dma/dmaengine.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 2cfa8458b51be..78f8a9f3ad825 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -451,7 +451,8 @@ static int dma_chan_get(struct dma_chan *chan)
> /* The channel is already in use, update client count */
> if (chan->client_count) {
> __module_get(owner);
> - goto out;
> + chan->client_count++;
> + return 0;
> }
>
> if (!try_module_get(owner))
> @@ -470,11 +471,11 @@ static int dma_chan_get(struct dma_chan *chan)
> goto err_out;
> }
>
> + chan->client_count++;
> +
> if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
> balance_ref_count(chan);
>
> -out:
> - chan->client_count++;
> return 0;
>
> err_out:
> --
> 2.25.1
>
Hi Vinod,
Any thoughts on this patch? We recently came across this issue as well.
Thanks,
Jerry
