linux-kernel - Re: [PATCH V2] crypto: ccp - Release dma channels before dmaengine unrgister

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Message-ID: <a15ab3e6-249d-af48-b4d5-25840b72a933@amd.com>
Date:   Thu, 1 Sep 2022 08:42:31 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Koba Ko <koba.ko@...onical.com>, John Allen <john.allen@....com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2] crypto: ccp - Release dma channels before dmaengine
 unrgister

On 8/31/22 21:16, 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: 4cbe9bc34ed0 ("crypto: ccp - ccp_dmaengine_unregister release dma channels")

I can't find this Fixes: tag. I did find:

54cce8ecb925 ("crypto: ccp - ccp_dmaengine_unregister release dma channels")

Not sure if Herbert can take care of that or if you'll need a v3.

With the change to the Fixes: tag

Acked-by: Tom Lendacky <thomas.lendacky@....com>

> Reported-by: kernel test robot <lkp@...el.com>
> Signed-off-by: Koba Ko <koba.ko@...onical.com>
> ---
> V2: Fix the unused warning
> ---
>   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);