Date: Fri, 23 Oct 2009 18:39:38 +0200
From: Sam Ravnborg <sam@ravnborg.org>
To: Vlad Yasevich <vladislav.yasevich@hp.com>
Cc: Amerigo Wang <amwang@redhat.com>, linux-kernel@vger.kernel.org,
       netdev@vger.kernel.org, akpm@linux-foundation.org
Subject: Re: [Patch] sctp: remove deprecated SCTP_GET_*_OLD stuffs
Message-ID: <20091023163938.GA3858@merkur.ravnborg.org>
References: <20091015082849.4605.48311.sendpatchset@localhost.localdomain> <4AE0C64A.9080400@hp.com> <20091022214439.GA2635@merkur.ravnborg.org> <4AE1D2AA.8060200@hp.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4AE1D2AA.8060200@hp.com>
User-Agent: Mutt/1.5.18 (2008-05-17)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 2511
Lines: 53

On Fri, Oct 23, 2009 at 11:58:34AM -0400, Vlad Yasevich wrote:
> 
> 
> Sam Ravnborg wrote:
> > On Thu, Oct 22, 2009 at 04:53:30PM -0400, Vlad Yasevich wrote:
> >>> diff --git a/include/net/sctp/user.h b/include/net/sctp/user.h
> >>> index be2334a..0991f1b 100644
> >>> --- a/include/net/sctp/user.h
> >>> +++ b/include/net/sctp/user.h
> >>> @@ -131,14 +131,6 @@ enum sctp_optname {
> >>>  #define SCTP_SOCKOPT_BINDX_REM	SCTP_SOCKOPT_BINDX_REM
> >>>  	SCTP_SOCKOPT_PEELOFF, 	/* peel off association. */
> >>>  #define SCTP_SOCKOPT_PEELOFF	SCTP_SOCKOPT_PEELOFF
> >>> -	SCTP_GET_PEER_ADDRS_NUM_OLD, 	/* Get number of peer addresss. */
> >>> -#define SCTP_GET_PEER_ADDRS_NUM_OLD	SCTP_GET_PEER_ADDRS_NUM_OLD
> >>> -	SCTP_GET_PEER_ADDRS_OLD, 	/* Get all peer addresss. */
> >>> -#define SCTP_GET_PEER_ADDRS_OLD	SCTP_GET_PEER_ADDRS_OLD
> >>> -	SCTP_GET_LOCAL_ADDRS_NUM_OLD, 	/* Get number of local addresss. */
> >>> -#define SCTP_GET_LOCAL_ADDRS_NUM_OLD	SCTP_GET_LOCAL_ADDRS_NUM_OLD
> >>> -	SCTP_GET_LOCAL_ADDRS_OLD, 	/* Get all local addresss. */
> >>> -#define SCTP_GET_LOCAL_ADDRS_OLD	SCTP_GET_LOCAL_ADDRS_OLD
> >>>  	SCTP_SOCKOPT_CONNECTX_OLD, /* CONNECTX old requests. */
> >> After running the regression suite against this patch I find that we can't
> >> remove the enum values.  Removing the enums changes the value for the remainder
> >> of the definitions and breaks binary compatibility for applications that use
> >> those trailing options.
> >>
> >> You should be ok with removing the #defines and actual code that uses them,
> >> but not the enums.  You can even rename the enums, but we must preserve
> >> numeric ordering.
> > 
> > If we really depend on the actual value of an enum as in this case,
> > then e should assign them direct to better document this.
> > 
> > 	Sam
> > 
> 
> I agree.  I have a patch that converts the enum to just a #define section that
> I'll apply on top of this removal patch and document the deletion.

If you keep the enum then you will have a have extras:
- a debugger will understand the symbols and display the correct value
- sparse may trigger a warning if you try to assign a non-valid value
  (a value which is not included in the enum)

But that may not matter much in this case - just wanted to highligt it.

	Sam
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/