Re: [PATCH] crypto: hisilicon - check if debugfs opened

From: tanghui20 <tanghui20@huawei.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: <herbert@gondor.apana.org.au>, <davem@davemloft.net>,
	<linux-crypto@vger.kernel.org>, <xuzaibo@huawei.com>,
	<wangzhou1@hisilicon.com>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] crypto: hisilicon - check if debugfs opened
Date: Tue, 30 Mar 2021 20:09:46 +0800	[thread overview]
Message-ID: <17d627e8-b89a-bbb8-f5d7-11210b859ac7@huawei.com> (raw)
In-Reply-To: <YGCcQnFHXEMW9Jz/@kroah.com>

On 2021/3/28 23:09, Greg KH wrote:
> On Sat, Mar 27, 2021 at 04:33:00PM +0800, Hui Tang wrote:
>> 'xx_debugfs_init' check if debugfs opened.
>>
>> Signed-off-by: Hui Tang <tanghui20@huawei.com>
>> ---
>>  drivers/crypto/hisilicon/hpre/hpre_main.c | 5 ++++-
>>  drivers/crypto/hisilicon/qm.c             | 3 +++
>>  drivers/crypto/hisilicon/sec2/sec_main.c  | 5 ++++-
>>  drivers/crypto/hisilicon/zip/zip_main.c   | 3 +++
>>  4 files changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/crypto/hisilicon/hpre/hpre_main.c b/drivers/crypto/hisilicon/hpre/hpre_main.c
>> index c7ab06d..f2605c4 100644
>> --- a/drivers/crypto/hisilicon/hpre/hpre_main.c
>> +++ b/drivers/crypto/hisilicon/hpre/hpre_main.c
>> @@ -779,6 +779,9 @@ static int hpre_debugfs_init(struct hisi_qm *qm)
>>  	struct device *dev = &qm->pdev->dev;
>>  	int ret;
>>
>> +	if (!debugfs_initialized())
>> +		return -ENOENT;
>
> Why?  What does this help with?  Why does the code care if debugfs is
> running or not?
>
When !CONFIG_DEBUG_FS, there is no problem if debugfs is not checked,
but if checking debugfs, a series of stub functions of debugfs can be
skipped and 'xx_debugfs_init' will be return immediately.

Thanks.