Re: liblockdep soname versioning

[Sasha Levin <sasha.levin@oracle.com>]

On 04/01/2014 09:35 AM, Sasha Levin wrote:
> On 04/01/2014 09:28 AM, Josh Boyer wrote:
>> On Tue, Apr 1, 2014 at 9:19 AM, Sasha Levin <sasha.levin@oracle.com> wrote:
>>> On 04/01/2014 08:56 AM, Josh Boyer wrote:
>>>>
>>>> Hi Sasha,
>>>>
>>>> We've had a request [1] to package up liblockdep in Fedora.  Looking
>>>> things over, I noticed the library isn't actually versioned at all and
>>>> instead just builds a plain .so file.  That's likely fine during
>>>> development of it, but if distros are to ship it for broader use then
>>>> it would be a good idea to specify the soname and use a versioned .so.
>>>>
>>>> The makefile already has LIBLOCKDEP_VERSION defined.  Would it be
>>>> possible to use this as the soname and version number?  Then
>>>> liblockdep.so could be the normal symlink to the versioned .so
>>>> (liblockdep.so.0.0.1 in this case).
>>>>
>>>> Thanks.
>>>>
>>>> josh
>>>>
>>>> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1082763
>>>>
>>>
>>> Sure! I never expected it to live outside the kernel tree as a separate
>>> package, but I'm happy to accommodate for that.
>>>
>>> I think that I'll just match the version number with the kernel version
>>> since what mostly matters is what you have in kernel/lockdep.c, so for
>>> example, right now we'll have 'liblockdep.so.3.15.0'. Sounds good?
>>
>> The only concern I would have is that it would require applications
>> linking to it to rebuild with every kernel release even if nothing
>> else changed.  Maybe nothing changing is going to be rare enough that
>> in practice people will need to rebuild anyway.  Either way, it's
>> better to be explicit rather than break users silently, so it sounds
>> good to me.
>
> I don't think we ever had a kernel version without changes to lockdep :)
>
> Since lockdep isn't an ABI either, no one promises me it'll work the same
> way between versions either, so I'm kinda happy about just forcing rebuilds.

Hi Josh,

Could you please confirm that the below is what you'd expect it to be:

sasha@lappy:~/linux/tools/lib/lockdep$ make
   CC FPIC            common.o
   CC FPIC            lockdep.o
   CC FPIC            preload.o
   CC FPIC            rbtree.o
   BUILD STATIC LIB   liblockdep.a
   BUILD SHARED LIB   liblockdep.so.3.14.0

sasha@lappy:~/linux/tools/lib/lockdep$ ls -al liblockdep.so
lrwxrwxrwx 1 sasha sasha 20 Apr  1 11:31 liblockdep.so -> liblockdep.so.3.14.0

sasha@lappy:~/linux/tools/lib/lockdep$ readelf -d liblockdep.so  | grep SONAME
  0x000000000000000e (SONAME)             Library soname: ["liblockdep.so.3.14.0"]

Thanks,
Sasha