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

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Date:	Tue, 9 Jun 2015 22:50:43 -0400 (EDT)
From:	Bob Peterson <rpeterso@...hat.com>
To:	Guoqing Jiang <gqJiang@...e.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

----- 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.

Regards,

Bob Peterson
Red Hat File Systems
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