Re: [PATCH net 1/2] sctp: remove redundant assignment when call sctp_get_port_local

From: maowenan <maowenan@huawei.com>
To: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
	Dan Carpenter <dan.carpenter@oracle.com>
Cc: <vyasevich@gmail.com>, <nhorman@tuxdriver.com>,
	<davem@davemloft.net>, <linux-sctp@vger.kernel.org>,
	<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<kernel-janitors@vger.kernel.org>
Subject: Re: [PATCH net 1/2] sctp: remove redundant assignment when call sctp_get_port_local
Date: Thu, 12 Sep 2019 10:05:45 +0800	[thread overview]
Message-ID: <7a450679-40ca-8a84-4cba-7a16f22ea3c0@huawei.com> (raw)
In-Reply-To: <20190911143923.GE3499@localhost.localdomain>


On 2019/9/11 22:39, Marcelo Ricardo Leitner wrote:
> On Wed, Sep 11, 2019 at 11:30:08AM -0300, Marcelo Ricardo Leitner wrote:
>> On Wed, Sep 11, 2019 at 11:30:38AM +0300, Dan Carpenter wrote:
>>> On Wed, Sep 11, 2019 at 09:30:47AM +0800, maowenan wrote:
>>>>
>>>>
>>>> On 2019/9/11 3:22, Dan Carpenter wrote:
>>>>> On Tue, Sep 10, 2019 at 09:57:10PM +0300, Dan Carpenter wrote:
>>>>>> On Tue, Sep 10, 2019 at 03:13:42PM +0800, Mao Wenan wrote:
>>>>>>> There are more parentheses in if clause when call sctp_get_port_local
>>>>>>> in sctp_do_bind, and redundant assignment to 'ret'. This patch is to
>>>>>>> do cleanup.
>>>>>>>
>>>>>>> Signed-off-by: Mao Wenan <maowenan@huawei.com>
>>>>>>> ---
>>>>>>>  net/sctp/socket.c | 3 +--
>>>>>>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>>>>>>
>>>>>>> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
>>>>>>> index 9d1f83b10c0a..766b68b55ebe 100644
>>>>>>> --- a/net/sctp/socket.c
>>>>>>> +++ b/net/sctp/socket.c
>>>>>>> @@ -399,9 +399,8 @@ static int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
>>>>>>>  	 * detection.
>>>>>>>  	 */
>>>>>>>  	addr->v4.sin_port = htons(snum);
>>>>>>> -	if ((ret = sctp_get_port_local(sk, addr))) {
>>>>>>> +	if (sctp_get_port_local(sk, addr))
>>>>>>>  		return -EADDRINUSE;
>>>>>>
>>>>>> sctp_get_port_local() returns a long which is either 0,1 or a pointer
>>>>>> casted to long.  It's not documented what it means and neither of the
>>>>>> callers use the return since commit 62208f12451f ("net: sctp: simplify
>>>>>> sctp_get_port").
>>>>>
>>>>> Actually it was commit 4e54064e0a13 ("sctp: Allow only 1 listening
>>>>> socket with SO_REUSEADDR") from 11 years ago.  That patch fixed a bug,
>>>>> because before the code assumed that a pointer casted to an int was the
>>>>> same as a pointer casted to a long.
>>>>
>>>> commit 4e54064e0a13 treated non-zero return value as unexpected, so the current
>>>> cleanup is ok?
>>>
>>> Yeah.  It's fine, I was just confused why we weren't preserving the
>>> error code and then I saw that we didn't return errors at all and got
>>> confused.
>>
>> But please lets seize the moment and do the change Dean suggested.
> 
> *Dan*, sorry.
> 
>> This was the last place saving this return value somewhere. It makes
>> sense to cleanup sctp_get_port_local() now and remove that masked
>> pointer return.
>>
>> Then you may also cleanup:
>> socket.c:       return !!sctp_get_port_local(sk, &addr);
>> as it will be a direct map.

Thanks Marcelo, shall I post a new individual patch for cleanup as your suggest?
>>
>>   Marcelo
>>
> 
> .
>