From mboxrd@z Thu Jan  1 00:00:00 1970
From: Panu Matilainen <pmatilai@redhat.com>
Subject: Re: [PATCH 1/4] vhost: handle VHOST_USER_SET_LOG_BASE
 request
Date: Mon, 7 Dec 2015 08:29:46 +0200
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Cc: dev@dpdk.org, Victor Kaplansky <vkaplans@redhat.com>,
 "Michael S. Tsirkin" <mst@redhat.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>,
 Yuanhan Liu <yuanhan.liu@linux.intel.com>
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On 12/07/2015 01:07 AM, Thomas Monjalon wrote:
> 2015-12-02 15:53, Panu Matilainen:
>> This (and other changes in patch 2 breaks the librte_vhost ABI again, so
>> you'd need to at least add a deprecation note to 2.2 to be able to do it
>> in 2.3 at all according to the ABI policy.
>>
>> Perhaps a better option would be adding some padding to the structs now
>> for 2.2 since the vhost ABI is broken there anyway. That would at least
>> give a chance to keep it compatible from 2.2 to 2.3.
>
> Please could you point where the vhost ABI is broken in 2.2?
>

The vhost ABI break was announced for DPDK 2.2 in commit 
3c848bd7b1c6f4f681b833322a748fdefbb5fb2d:

> commit 3c848bd7b1c6f4f681b833322a748fdefbb5fb2d
> Author: Ouyang Changchun <changchun.ouyang@intel.com>
> Date:   Tue Jun 16 09:38:43 2015 +0800
>
>     doc: announce ABI changes for vhost-user multiple queues
>
>     It announces the planned ABI changes for vhost-user multiple
>     queues feature on v2.2.
>
>     Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
>     Acked-by: Neil Horman <nhorman@tuxdriver.com>

So the ABI process was properly followed, except for actually bumping 
LIBABIVER. Bumping LIBABIVER is mentioned in 
doc/guides/contributing/versioning.rst but it doesn't specify *when* 
this should be done, eg should the first patch breaking the ABI bump it 
or should it done be shortly before the next stable release, or 
something else. As it is, it seems a bit too easy to simply forget.

	- Panu -