[PATCH V3] crypto: ccp - Release dma channels before dmaengine unrgister

[PATCH V3] crypto: ccp - Release dma channels before dmaengine unrgister

[Koba Ko]

A warning is shown during shutdown,

__dma_async_device_channel_unregister called while 2 clients hold a reference
WARNING: CPU: 15 PID: 1 at drivers/dma/dmaengine.c:1110 __dma_async_device_channel_unregister+0xb7/0xc0

Call dma_release_channel for occupied channles before dma_async_device_unregister.

Fixes: 54cce8ecb925 ("crypto: ccp - ccp_dmaengine_unregister release dma channels")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Koba Ko <koba.ko@canonical.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>

---
V2: Fix the unused warning
V3: Fix the Fixes: tag.
---
 drivers/crypto/ccp/ccp-dmaengine.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/ccp/ccp-dmaengine.c b/drivers/crypto/ccp/ccp-dmaengine.c
index 7d4b4ad1db1f3..9f753cb4f5f18 100644
--- a/drivers/crypto/ccp/ccp-dmaengine.c
+++ b/drivers/crypto/ccp/ccp-dmaengine.c
@@ -641,6 +641,10 @@ static void ccp_dma_release(struct ccp_device *ccp)
 	for (i = 0; i < ccp->cmd_q_count; i++) {
 		chan = ccp->ccp_dma_chan + i;
 		dma_chan = &chan->dma_chan;
+
+		if (dma_chan->client_count)
+			dma_release_channel(dma_chan);
+
 		tasklet_kill(&chan->cleanup_tasklet);
 		list_del_rcu(&dma_chan->device_node);
 	}
@@ -766,8 +770,8 @@ void ccp_dmaengine_unregister(struct ccp_device *ccp)
 	if (!dmaengine)
 		return;
 
-	dma_async_device_unregister(dma_dev);
 	ccp_dma_release(ccp);
+	dma_async_device_unregister(dma_dev);
 
 	kmem_cache_destroy(ccp->dma_desc_cache);
 	kmem_cache_destroy(ccp->dma_cmd_cache);
-- 
2.25.1

Re: [PATCH V3] crypto: ccp - Release dma channels before dmaengine unrgister

[Herbert Xu]

On Thu, Sep 01, 2022 at 10:47:12PM +0800, Koba Ko wrote:
> A warning is shown during shutdown,
> 
> __dma_async_device_channel_unregister called while 2 clients hold a reference
> WARNING: CPU: 15 PID: 1 at drivers/dma/dmaengine.c:1110 __dma_async_device_channel_unregister+0xb7/0xc0
> 
> Call dma_release_channel for occupied channles before dma_async_device_unregister.
> 
> Fixes: 54cce8ecb925 ("crypto: ccp - ccp_dmaengine_unregister release dma channels")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Koba Ko <koba.ko@canonical.com>
> Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
> 
> ---
> V2: Fix the unused warning
> V3: Fix the Fixes: tag.
> ---
>  drivers/crypto/ccp/ccp-dmaengine.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

Patch applied.  Thanks. 
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt