linux-kernel - Re: [PATCH 6/6] dma: qcom: hidma: no need to check return value of debugfs

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Message-ID: <78da53a1-1363-fad8-16fa-4dfc6555f4e4@kernel.org>
Date:   Wed, 12 Jun 2019 12:17:31 -0400
From:   Sinan Kaya <Okaya@...nel.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     dan.j.williams@...el.com, vkoul@...nel.org,
        Andy Gross <agross@...nel.org>,
        David Brown <david.brown@...aro.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/6] dma: qcom: hidma: no need to check return value of
 debugfs_create functions

On 6/12/2019 11:39 AM, Greg Kroah-Hartman wrote:
>> Interesting. Wouldn't debugfs_create_file() blow up if dir is NULL
>> for some reason?
> It will create a file in the root of debugfs.  But how will that happen?
> debugfs_create_dir() can not return NULL.

I see.

> 
>> +		debugfs_create_file("stats", S_IRUGO, dir, chan,
>> +				    &hidma_chan_fops);
>>
>> Note that code ignores the return value of hidma_debug_init();
>> It was just trying to do clean up on debugfs failure by calling
>>
>> 	debugfs_remove_recursive(dmadev->debugfs);
> Is that a problem?

I just wanted to double check. You probably want to remove the return
value on debugfs_create_file() to prevent others from doing the same
thing.

Acked-by: Sinan Kaya <okaya@...nel.org>