linux-kernel - Re: [Cluster-devel] [PATCH] dlm: remove unnecessary error check

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Message-ID: <5577AAB4.20700@suse.com>
Date:	Wed, 10 Jun 2015 11:10:44 +0800
From:	Guoqing Jiang <gqJiang@...e.com>
To:	Bob Peterson <rpeterso@...hat.com>
CC:	ccaulfie@...hat.com, teigland@...hat.com, cluster-devel@...hat.com,
	linux-kernel@...r.kernel.org
Subject: Re: [Cluster-devel] [PATCH] dlm: remove unnecessary error check

Bob Peterson wrote:
> ----- Original Message -----
>   
>> Hi Bob,
>>
>> Bob Peterson wrote:
>>     
>>> ----- Original Message -----
>>>   
>>>       
>>>> We don't need the redundant logic since send_message always returns 0.
>>>>
>>>> Signed-off-by: Guoqing Jiang <gqjiang@...e.com>
>>>> ---
>>>>  fs/dlm/lock.c | 10 ++--------
>>>>  1 file changed, 2 insertions(+), 8 deletions(-)
>>>>
>>>> diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
>>>> index 35502d4..6fc3de9 100644
>>>> --- a/fs/dlm/lock.c
>>>> +++ b/fs/dlm/lock.c
>>>> @@ -3656,10 +3656,7 @@ static int send_common(struct dlm_rsb *r, struct
>>>> dlm_lkb *lkb, int mstype)
>>>>  
>>>>  	send_args(r, lkb, ms);
>>>>  
>>>> -	error = send_message(mh, ms);
>>>> -	if (error)
>>>> -		goto fail;
>>>> -	return 0;
>>>> +	return send_message(mh, ms);
>>>>  
>>>>   fail:
>>>>  	remove_from_waiters(lkb, msg_reply_type(mstype));
>>>> @@ -3763,10 +3760,7 @@ static int send_lookup(struct dlm_rsb *r, struct
>>>> dlm_lkb *lkb)
>>>>  
>>>>  	send_args(r, lkb, ms);
>>>>  
>>>> -	error = send_message(mh, ms);
>>>> -	if (error)
>>>> -		goto fail;
>>>> -	return 0;
>>>> +	return send_message(mh, ms);
>>>>  
>>>>   fail:
>>>>  	remove_from_waiters(lkb, DLM_MSG_LOOKUP_REPLY);
>>>> --
>>>> 1.7.12.4
>>>>     
>>>>         
>>> Hi,
>>>
>>> The patch looks okay, but if remove_from_waiters() always returns 0,
>>> wouldn't it be better to change the function from int to void and
>>> return 0 here? The advantage is that code spelunkers wouldn't need
>>> to back-track one more level (not to mention the instruction or two
>>> it might save).
>>>
>>>   
>>>       
>> Seems remove_from_waiters is not always returns 0, the return value
>> could  be -1 or 0 which depends on _remove_from_waiters.
>>
>> BTW, I found that there are no big difference between send_common
>> and send_lookup, since the send_common can also be use to send
>> lookup message, I guess send_lookup can be removed as well.
>>
>> Thanks,
>> Guoqing
>>     
>
> Hi Guoqing,
>
> If remove_from_waiters can return -1, then the patch would prevent the
> code from calling remove_from_waiters. So the patch still doesn't look
> right to me.
>
>   
Hi Bob,

The remove_from_waiters could  only be invoked after failed to
create_message, right?
Since send_message always returns 0, this patch doesn't touch anything
about the failure
path, and it also doesn't change the original semantic.

Thanks,
Guoqing
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