linux-kernel - Re: [PATCH v2 10/16] dmaengine: bcm-sba-raid: Alloc resources before registering DMA device

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Date:   Thu, 17 Aug 2017 12:08:12 +0530
From:   Vinod Koul <vinod.koul@...el.com>
To:     Anup Patel <anup.patel@...adcom.com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Dan Williams <dan.j.williams@...el.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Scott Branden <sbranden@...adcom.com>,
        Ray Jui <rjui@...adcom.com>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        dmaengine@...r.kernel.org, bcm-kernel-feedback-list@...adcom.com
Subject: Re: [PATCH v2 10/16] dmaengine: bcm-sba-raid: Alloc resources before
 registering DMA device

On Tue, Aug 01, 2017 at 04:07:54PM +0530, Anup Patel wrote:
> We should allocate DMA channel resources before registering the
> DMA device in sba_probe() because we can get DMA request soon
> after registering the DMA device. If DMA channel resources are
> not allocated before first DMA request then SBA-RAID driver will
> crash.
> 
> Signed-off-by: Anup Patel <anup.patel@...adcom.com>
> ---
>  drivers/dma/bcm-sba-raid.c | 30 +++++++++++++++---------------
>  1 file changed, 15 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/dma/bcm-sba-raid.c b/drivers/dma/bcm-sba-raid.c
> index f6616da..f14ed0a 100644
> --- a/drivers/dma/bcm-sba-raid.c
> +++ b/drivers/dma/bcm-sba-raid.c
> @@ -1478,13 +1478,13 @@ static int sba_prealloc_channel_resources(struct sba_device *sba)
>  	int i, j, ret = 0;
>  	struct sba_request *req = NULL;
>  
> -	sba->resp_base = dma_alloc_coherent(sba->dma_dev.dev,
> +	sba->resp_base = dma_alloc_coherent(sba->mbox_dev,

how does this qualify as move before registering, you seem to be using
different device now

>  					    sba->max_resp_pool_size,
>  					    &sba->resp_dma_base, GFP_KERNEL);
>  	if (!sba->resp_base)
>  		return -ENOMEM;
>  
> -	sba->cmds_base = dma_alloc_coherent(sba->dma_dev.dev,
> +	sba->cmds_base = dma_alloc_coherent(sba->mbox_dev,
>  					    sba->max_cmds_pool_size,
>  					    &sba->cmds_dma_base, GFP_KERNEL);
>  	if (!sba->cmds_base) {
> @@ -1534,11 +1534,11 @@ static int sba_prealloc_channel_resources(struct sba_device *sba)
>  	return 0;
>  
>  fail_free_cmds_pool:
> -	dma_free_coherent(sba->dma_dev.dev,
> +	dma_free_coherent(sba->mbox_dev,
>  			  sba->max_cmds_pool_size,
>  			  sba->cmds_base, sba->cmds_dma_base);
>  fail_free_resp_pool:
> -	dma_free_coherent(sba->dma_dev.dev,
> +	dma_free_coherent(sba->mbox_dev,
>  			  sba->max_resp_pool_size,
>  			  sba->resp_base, sba->resp_dma_base);
>  	return ret;
> @@ -1547,9 +1547,9 @@ static int sba_prealloc_channel_resources(struct sba_device *sba)
>  static void sba_freeup_channel_resources(struct sba_device *sba)
>  {
>  	dmaengine_terminate_all(&sba->dma_chan);
> -	dma_free_coherent(sba->dma_dev.dev, sba->max_cmds_pool_size,
> +	dma_free_coherent(sba->mbox_dev, sba->max_cmds_pool_size,
>  			  sba->cmds_base, sba->cmds_dma_base);
> -	dma_free_coherent(sba->dma_dev.dev, sba->max_resp_pool_size,
> +	dma_free_coherent(sba->mbox_dev, sba->max_resp_pool_size,
>  			  sba->resp_base, sba->resp_dma_base);
>  	sba->resp_base = NULL;
>  	sba->resp_dma_base = 0;
> @@ -1737,15 +1737,15 @@ static int sba_probe(struct platform_device *pdev)
>  		}
>  	}
>  
> -	/* Register DMA device with linux async framework */
> -	ret = sba_async_register(sba);
> +	/* Prealloc channel resource */
> +	ret = sba_prealloc_channel_resources(sba);
>  	if (ret)
>  		goto fail_free_mchans;
>  
> -	/* Prealloc channel resource */
> -	ret = sba_prealloc_channel_resources(sba);
> +	/* Register DMA device with Linux async framework */
> +	ret = sba_async_register(sba);
>  	if (ret)
> -		goto fail_async_dev_unreg;
> +		goto fail_free_resources;
>  
>  	/* Print device info */
>  	dev_info(sba->dev, "%s using SBAv%d and %d mailbox channels",
> @@ -1754,8 +1754,8 @@ static int sba_probe(struct platform_device *pdev)
>  
>  	return 0;
>  
> -fail_async_dev_unreg:
> -	dma_async_device_unregister(&sba->dma_dev);
> +fail_free_resources:
> +	sba_freeup_channel_resources(sba);
>  fail_free_mchans:
>  	for (i = 0; i < sba->mchans_count; i++)
>  		mbox_free_channel(sba->mchans[i]);
> @@ -1767,10 +1767,10 @@ static int sba_remove(struct platform_device *pdev)
>  	int i;
>  	struct sba_device *sba = platform_get_drvdata(pdev);
>  
> -	sba_freeup_channel_resources(sba);
> -
>  	dma_async_device_unregister(&sba->dma_dev);
>  
> +	sba_freeup_channel_resources(sba);
> +
>  	for (i = 0; i < sba->mchans_count; i++)
>  		mbox_free_channel(sba->mchans[i]);
>  
> -- 
> 2.7.4
> 

-- 
~Vinod