Message-ID: <4AE1E060.5000903@hp.com>
Date: Fri, 23 Oct 2009 12:57:04 -0400
From: Vlad Yasevich <vladislav.yasevich@hp.com>
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To: Sam Ravnborg <sam@ravnborg.org>
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
References: <20091015082849.4605.48311.sendpatchset@localhost.localdomain> <4AE0C64A.9080400@hp.com> <20091022214439.GA2635@merkur.ravnborg.org> <4AE1D2AA.8060200@hp.com> <20091023163938.GA3858@merkur.ravnborg.org>
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Sam Ravnborg wrote:
> 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.

Yep, but this is just socket option definitions.  The enum type is not even used
anywhere, so no help from sparse.  I think it's here just for sequential numbering.

Thanks
-vlad
> 
> 	Sam
> 
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