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Date:   Sat, 18 Apr 2020 08:49:09 -0500
From:   Corey Minyard <minyard@acm.org>
To:     Tang Bin <tangbin@cmss.chinamobile.com>
Cc:     arnd@arndb.de, gregkh@linuxfoundation.org,
        openipmi-developer@lists.sourceforge.net,
        linux-kernel@vger.kernel.org,
        Shengju Zhang <zhangshengju@cmss.chinamobile.com>
Subject: Re: [PATCH v2] ipmi:bt-bmc: Fix error handling and status check
Message-ID: <20200418134909.GF6246@minyard.net>
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References: <20200418080228.19028-1-tangbin@cmss.chinamobile.com>
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On Sat, Apr 18, 2020 at 04:02:29PM +0800, Tang Bin wrote:
> If the function platform_get_irq() failed, the negative
> value returned will not be detected here. So fix error
> handling in bt_bmc_config_irq(). And if devm_request_irq()
> failed, 'bt_bmc->irq' is assigned to zero maybe redundant,
> it may be more suitable for using the correct negative values
> to make the status check in the function bt_bmc_remove().

You need to mention changing platform_get_irq to
platform_get_irq_optional in the header.

Another comment inline below.

Otherwise, this looks good.

> 
> Signed-off-by: Shengju Zhang <zhangshengju@cmss.chinamobile.com>
> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
> ---
> Changes from v1
>  - fix the code of status check
> ---
>  drivers/char/ipmi/bt-bmc.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
> index cd0349bff..33d3a5d50 100644
> --- a/drivers/char/ipmi/bt-bmc.c
> +++ b/drivers/char/ipmi/bt-bmc.c
> @@ -399,15 +399,14 @@ static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
>  	struct device *dev = &pdev->dev;
>  	int rc;
>  
> -	bt_bmc->irq = platform_get_irq(pdev, 0);
> -	if (!bt_bmc->irq)
> -		return -ENODEV;
> +	bt_bmc->irq = platform_get_irq_optional(pdev, 0);
> +	if (bt_bmc->irq < 0)
> +		return bt_bmc->irq;
>  
>  	rc = devm_request_irq(dev, bt_bmc->irq, bt_bmc_irq, IRQF_SHARED,
>  			      DEVICE_NAME, bt_bmc);
>  	if (rc < 0) {
>  		dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq);
> -		bt_bmc->irq = 0;

You need to set this to rc.  Otherwise it will remain the interrupt
number assigned by platform_get_irq_optional().

-corey

>  		return rc;
>  	}
>  
> @@ -474,7 +473,7 @@ static int bt_bmc_probe(struct platform_device *pdev)
>  
>  	bt_bmc_config_irq(bt_bmc, pdev);
>  
> -	if (bt_bmc->irq) {
> +	if (bt_bmc->irq >= 0) {
>  		dev_info(dev, "Using IRQ %d\n", bt_bmc->irq);
>  	} else {
>  		dev_info(dev, "No IRQ; using timer\n");
> @@ -500,7 +499,7 @@ static int bt_bmc_remove(struct platform_device *pdev)
>  	struct bt_bmc *bt_bmc = dev_get_drvdata(&pdev->dev);
>  
>  	misc_deregister(&bt_bmc->miscdev);
> -	if (!bt_bmc->irq)
> +	if (bt_bmc->irq < 0)
>  		del_timer_sync(&bt_bmc->poll_timer);
>  	return 0;
>  }
> -- 
> 2.20.1.windows.1
> 
> 
>