On 25.06.2021 13:36, Andrew Cooper wrote:
> On 25/06/2021 11:59, Ian Jackson wrote:
>> Jan Beulich writes ("Re: [PATCH] libxencall: Bump SONAME following new
>> functionality"):
>>> On 25.06.2021 11:17, Andrew Cooper wrote:
>>>> On 25/06/2021 07:31, Jan Beulich wrote:
>>>>> On 24.06.2021 19:55, Andrew Cooper wrote:
>>>>>> Fixes: bef64f2c00 ("libxencall: introduce variant of xencall2()
>>>>>> returning long")
>>>>> Is this strictly necessary, i.e. is a Fixes: tag here warranted?
>>>> Yes - very much so.
>>>>
>>>> andrewcoop@andrewcoop:/local/xen.git/xen$ readelf -Wa
>>>> ../tools/libs/call/libxencall.so.1.2 | grep 1\\.3
>>>> 33: 0000000000001496 59 FUNC GLOBAL DEFAULT 13
>>>> xencall2L@@VERS_1.3
>>>> 39: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS VERS_1.3
>>>> 76: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS VERS_1.3
>>>> 020: 4 (VERS_1.2) 5 (VERS_1.3) 2 (VERS_1.0) 3
>>>> (VERS_1.1)
>>>> 024: 3 (VERS_1.1) 2 (VERS_1.0) 4 (VERS_1.2) 5
>>>> (VERS_1.3)
>>>> 0x0080: Rev: 1 Flags: none Index: 5 Cnt: 2 Name: VERS_1.3
>>>>
>>>> Without this, you create a library called .so.1.2 with 1.3's ABI in.
>>> I'm aware of the change to file contents as well as the disagreement
>>> of file name / SONAME vs enumerated versions. So telling me this is
>>> not really an answer to my question. It may be by convention that
>>> the two should match up, but I don't see any functional issue (yet)
>>> if they don't. Plus of course you leave open altogether the
>>> backporting aspect of my question.
>> The patch, including the Fixes tag,
>>
>> Reviewed-by: Ian Jackson <i...@xenproject.org>
>
> Thanks.
>
>> Changing minor version in the filename as well as the .so is not an
>> impediment to backporting. The actual soname remains the same so
>> there is no compatibility problem and the change is still suitable for
>> including in eg distro stsable releases.
>
> Correct, although backporting in general however is problematic.
>
> Until Xen 4.16 is released (or, we explicitly decide to make an explicit
> library release early), the 1.3 ABI isn't set in stone.
>
> Backports to older stable-* branches must sit on a boundary already set
> in stone in staging, or we'll end up with different versions of Xen
> having different ideas of what VERS_1.3 mean.
Which effectively means we'd have to open 1.4 despite being in the
same release cycle if this change got backported. Or did I not
understand correctly what you were trying to say?
Jan
