2022-05-30 14:03:45

by Nam Cao

Subject: [PATCH v2] dmaengine: altera-msgdma: correct mutex locking order

The order of spin_unlock and spin_lock seems wrong. Correct it.

Signed-off-by: Nam Cao <[email protected]>
---
Changes in v2:
- Get rid of dirty index problem due to the patch being manually editted.

drivers/dma/altera-msgdma.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
index 6f56dfd375e3..e35096c12abc 100644
--- a/drivers/dma/altera-msgdma.c
+++ b/drivers/dma/altera-msgdma.c
@@ -591,9 +591,9 @@ static void msgdma_chan_desc_cleanup(struct msgdma_device *mdev)

dmaengine_desc_get_callback(&desc->async_tx, &cb);
if (dmaengine_desc_callback_valid(&cb)) {
- spin_unlock(&mdev->lock);
- dmaengine_desc_callback_invoke(&cb, NULL);
spin_lock(&mdev->lock);
+ dmaengine_desc_callback_invoke(&cb, NULL);
+ spin_unlock(&mdev->lock);
}

/* Run any dependencies, then free the descriptor */
--
2.25.1

2022-06-01 12:35:28

by Olivier Dautricourt

Subject: Re: [PATCH v2] dmaengine: altera-msgdma: correct mutex locking order

On Sun, May 29, 2022 at 08:23:06PM +0200, Nam Cao wrote:
> The order of spin_unlock and spin_lock seems wrong. Correct it.
>
> Signed-off-by: Nam Cao <[email protected]>
> ---
> Changes in v2:
> - Get rid of dirty index problem due to the patch being manually editted.
>
> drivers/dma/altera-msgdma.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
> index 6f56dfd375e3..e35096c12abc 100644
> --- a/drivers/dma/altera-msgdma.c
> +++ b/drivers/dma/altera-msgdma.c
> @@ -591,9 +591,9 @@ static void msgdma_chan_desc_cleanup(struct msgdma_device *mdev)
>
> dmaengine_desc_get_callback(&desc->async_tx, &cb);
> if (dmaengine_desc_callback_valid(&cb)) {
> - spin_unlock(&mdev->lock);
> - dmaengine_desc_callback_invoke(&cb, NULL);
> spin_lock(&mdev->lock);
> + dmaengine_desc_callback_invoke(&cb, NULL);
> + spin_unlock(&mdev->lock);
> }
>
> /* Run any dependencies, then free the descriptor */
> --
> 2.25.1
>
Hello,

the lock is first grabbed in msgdma_tasklet.

Kr,

Olivier