[PATCH] dlm: remove unnecessary error check

[PATCH] dlm: remove unnecessary error check

[Guoqing Jiang]

We don't need the redundant logic since send_message always returns 0.

Signed-off-by: Guoqing Jiang <gqjiang@suse.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

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

[Bob Peterson]

----- Original Message -----
> We don't need the redundant logic since send_message always returns 0.
> 
> Signed-off-by: Guoqing Jiang <gqjiang@suse.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).

Regards,

Bob Peterson
Red Hat File Systems

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

[Guoqing Jiang]

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@suse.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

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

[Bob Peterson]

----- 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@suse.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.

Regards,

Bob Peterson
Red Hat File Systems

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

[Guoqing Jiang]

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@suse.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

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

[Bob Peterson]

----- Original Message -----
> 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@suse.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);

Hi Guoqing,

Sorry, I was momentarily confused. I think you misunderstood what I was saying.
What I meant was: Instead of doing:

+	return send_message(mh, ms);
...where send_message returns 0, it might be better to have:

static void send_message(struct dlm_mhandle *mh, struct dlm_message *ms)
{
	dlm_message_out(ms);
	dlm_lowcomms_commit_buffer(mh);
}

...And in send_common, do (in both places):
+	send_message(mh, ms);
+	return 0;

Since it's so short, it might even be better to code send_message as a macro,
or at least an "inline" function.

Regards,

Bob Peterson
Red Hat File Systems

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

[David Teigland]

On Wed, Jun 10, 2015 at 11:10:44AM +0800, Guoqing Jiang wrote:
> 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.

I'm not inclined to take any patches unless there's a problem identified.

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

[Guoqing Jiang]

Bob Peterson wrote:
>
>>>>     
>>>>         
>>>>> ----- Original Message -----
>>>>>   
>>>>>       
>>>>>           
>>>>>> We don't need the redundant logic since send_message always returns 0.
>>>>>>
>>>>>> Signed-off-by: Guoqing Jiang <gqjiang@suse.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);
>>>>>>             
>
> Hi Guoqing,
>
> Sorry, I was momentarily confused. I think you misunderstood what I was saying.
> What I meant was: Instead of doing:
>
> +	return send_message(mh, ms);
> ...where send_message returns 0, it might be better to have:
>
> static void send_message(struct dlm_mhandle *mh, struct dlm_message *ms)
> {
> 	dlm_message_out(ms);
> 	dlm_lowcomms_commit_buffer(mh);
> }
>
> ...And in send_common, do (in both places):
> +	send_message(mh, ms);
> +	return 0;
>
> Since it's so short, it might even be better to code send_message as a macro,
> or at least an "inline" function.
>
>   
Hi Bob,

Got it, thanks. It is a better solution but it is not a bug fix or
similar thing, so maybe just leave it as it is.

Regards,
Guoqing

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

[Guoqing Jiang]

Hi David,

David Teigland wrote:
> On Wed, Jun 10, 2015 at 11:10:44AM +0800, Guoqing Jiang wrote:
>   
>> 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.
>>     
>
> I'm not inclined to take any patches unless there's a problem identified.
>
> .  
>   
Do you consider take the following clean up? If yes, I will send a
formal patch,
otherwise pls ignore it.

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 35502d4..7c822f7 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -3747,30 +3747,7 @@ static int send_bast(struct dlm_rsb *r, struct
dlm_lkb *lkb, int mode)
 
 static int send_lookup(struct dlm_rsb *r, struct dlm_lkb *lkb)
 {
-       struct dlm_message *ms;
-       struct dlm_mhandle *mh;
-       int to_nodeid, error;
-
-       to_nodeid = dlm_dir_nodeid(r);
-
-       error = add_to_waiters(lkb, DLM_MSG_LOOKUP, to_nodeid);
-       if (error)
-               return error;
-
-       error = create_message(r, NULL, to_nodeid, DLM_MSG_LOOKUP, &ms,
&mh);
-       if (error)
-               goto fail;
-
-       send_args(r, lkb, ms);
-
-       error = send_message(mh, ms);
-       if (error)
-               goto fail;
-       return 0;
-
- fail:
-       remove_from_waiters(lkb, DLM_MSG_LOOKUP_REPLY);
-       return error;
+       return send_common(r, lkb, DLM_MSG_LOOKUP);
 }

Thanks,
Guoqing

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

[David Teigland]

On Thu, Jun 11, 2015 at 05:47:28PM +0800, Guoqing Jiang wrote:
> Do you consider take the following clean up? If yes, I will send a
> formal patch, otherwise pls ignore it.

On first glance, the old and new code do not appear to do the same thing,
so let's leave it as it is.

> -       to_nodeid = dlm_dir_nodeid(r);

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

[Guoqing Jiang]

Hi David,

David Teigland wrote:
> On Thu, Jun 11, 2015 at 05:47:28PM +0800, Guoqing Jiang wrote:
>   
>> Do you consider take the following clean up? If yes, I will send a
>> formal patch, otherwise pls ignore it.
>>     
>
> On first glance, the old and new code do not appear to do the same thing,
> so let's leave it as it is.
>
>   
>> -       to_nodeid = dlm_dir_nodeid(r);
>>     
Sorry, seems it is the only different thing, if combines previous change
with below modification, then the behavior is same.

@@ -3644,7 +3644,10 @@ static int send_common(struct dlm_rsb *r, struct
dlm_lkb *lkb, int mstype)
        struct dlm_mhandle *mh;
        int to_nodeid, error;
 
-       to_nodeid = r->res_nodeid;
+       if (mstype == DLM_MSG_LOOKUP)
+               to_nodeid = dlm_dir_nodeid(r);
+       else
+               to_nodeid = r->res_nodeid;

And for create_message, the second parameter (lkb) is not effective to
create three type msgs (REQUEST/LOOKUP/REMOVE).

Thanks,
Guoqing