linux-kernel - Re: [PATCH] ccp: ccp_dmaengine_unregister release dma channels

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Message-ID: <Yh6LLFAf+f48BBFa@dell9853host>
Date:   Tue, 1 Mar 2022 15:07:56 -0600
From:   John Allen <john.allen@....com>
To:     Dāvis Mosāns <davispuh@...il.com>
Cc:     linux-kernel@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>,
        linux-crypto@...r.kernel.org, dmaengine@...r.kernel.org
Subject: Re: [PATCH] ccp: ccp_dmaengine_unregister release dma channels

On Mon, Feb 28, 2022 at 05:15:45AM +0200, Dāvis Mosāns wrote:
> ccp_dmaengine_register adds dma_chan->device_node to dma_dev->channels list
> but ccp_dmaengine_unregister didn't remove them.
> That can cause crashes in various dmaengine methods that tries to use dma_dev->channels
> 
> Signed-off-by: Dāvis Mosāns <davispuh@...il.com>

Acked-by: John Allen <john.allen@....com>

> ---
>  drivers/crypto/ccp/ccp-dmaengine.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/crypto/ccp/ccp-dmaengine.c b/drivers/crypto/ccp/ccp-dmaengine.c
> index d718db224be42..7d4b4ad1db1f3 100644
> --- a/drivers/crypto/ccp/ccp-dmaengine.c
> +++ b/drivers/crypto/ccp/ccp-dmaengine.c
> @@ -632,6 +632,20 @@ static int ccp_terminate_all(struct dma_chan *dma_chan)
>  	return 0;
>  }
>  
> +static void ccp_dma_release(struct ccp_device *ccp)
> +{
> +	struct ccp_dma_chan *chan;
> +	struct dma_chan *dma_chan;
> +	unsigned int i;
> +
> +	for (i = 0; i < ccp->cmd_q_count; i++) {
> +		chan = ccp->ccp_dma_chan + i;
> +		dma_chan = &chan->dma_chan;
> +		tasklet_kill(&chan->cleanup_tasklet);
> +		list_del_rcu(&dma_chan->device_node);
> +	}
> +}
> +
>  int ccp_dmaengine_register(struct ccp_device *ccp)
>  {
>  	struct ccp_dma_chan *chan;
> @@ -736,6 +750,7 @@ int ccp_dmaengine_register(struct ccp_device *ccp)
>  	return 0;
>  
>  err_reg:
> +	ccp_dma_release(ccp);
>  	kmem_cache_destroy(ccp->dma_desc_cache);
>  
>  err_cache:
> @@ -752,6 +767,7 @@ void ccp_dmaengine_unregister(struct ccp_device *ccp)
>  		return;
>  
>  	dma_async_device_unregister(dma_dev);
> +	ccp_dma_release(ccp);
>  
>  	kmem_cache_destroy(ccp->dma_desc_cache);
>  	kmem_cache_destroy(ccp->dma_cmd_cache);
> -- 
> 2.35.1
>