Re: [PATCH-for-5.2 v3] configure: Check vhost-user is available for vhost-user-blk-server

[Thomas Huth]

On 09/11/2020 20.15, Philippe Mathieu-Daudé wrote:
> On 11/9/20 7:52 PM, Philippe Mathieu-Daudé wrote:
>> On 11/9/20 7:44 PM, Thomas Huth wrote:
>>> On 09/11/2020 19.41, Philippe Mathieu-Daudé wrote:
>>>> On Mon, Nov 9, 2020 at 6:22 PM Thomas Huth <thuth@redhat.com> wrote:
>>>>> On 09/11/2020 15.07, Philippe Mathieu-Daudé wrote:
>>>>>> Check vhost-user is available when building vhost-user-blk-server.
>>>>>>
>>>>>> This fixes:
>>>>>>
>>>>>>  $ ../configure \
>>>>>>       --disable-vhost-user --enable-vhost-user-blk-server && \
>>>>>>    make qemu-nbd
>>>>>>  ...
>>>>>>  [505/505] Linking target qemu-nbd
>>>>>>  FAILED: qemu-nbd
>>>>>>  cc  -o qemu-nbd qemu-nbd.p/qemu-nbd.c.o -Wl,--as-needed 
>>>>>> -Wl,--no-undefined -pie -Wl,--whole-archive libblockdev.fa libblock.fa 
>>>>>> libcrypto.fa libauthz.fa libqom.fa libio.fa -Wl,--no-whole-archive 
>>>>>> -Wl,--warn-common -Wl,-z,relro -Wl,-z,now -m64 -fstack-protector-strong 
>>>>>> -Wl,--start-group libqemuutil.a libblockdev.fa libblock.fa libcrypto.fa 
>>>>>> libauthz.fa libqom.fa libio.fa @block.syms -lgio-2.0 -lgobject-2.0 
>>>>>> -lglib-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 -pthread -lgnutls -lutil 
>>>>>> -lm -lgthread-2.0 -lglib-2.0 -lbz2 -lgthread-2.0 -lglib-2.0 -lssh -lrbd 
>>>>>> -lrados -lcurl -lxml2 -lzstd -lacl -lgfapi -lglusterfs -lgfrpc -lgfxdr 
>>>>>> -luuid -laio /usr/lib64/libz.so -L/usr/lib64/iscsi -liscsi -lnettle 
>>>>>> -lgnutls -lpam -Wl,--end-group
>>>>>>  /usr/bin/ld: libblockdev.fa(block_export_vhost-user-blk-server.c.o): in 
>>>>>> function `vu_blk_process_vq':
>>>>>>  block/export/vhost-user-blk-server.c:203: undefined reference to 
>>>>>> `vu_get_queue'
>>>>>>  /usr/bin/ld: block/export/vhost-user-blk-server.c:208: undefined 
>>>>>> reference to `vu_queue_pop'
>>>>>>  /usr/bin/ld: libblockdev.fa(block_export_vhost-user-blk-server.c.o): in 
>>>>>> function `vu_blk_queue_set_started':
>>>>>>  block/export/vhost-user-blk-server.c:228: undefined reference to 
>>>>>> `vu_get_queue'
>>>>>>  /usr/bin/ld: libblockdev.fa(block_export_vhost-user-blk-server.c.o): in 
>>>>>> function `vu_blk_req_complete':
>>>>>>  block/export/vhost-user-blk-server.c:55: undefined reference to 
>>>>>> `vu_queue_push'
>>>>>>  /usr/bin/ld: block/export/vhost-user-blk-server.c:56: undefined 
>>>>>> reference to `vu_queue_notify'
>>>>>>  /usr/bin/ld: libblockdev.fa(block_export_vhost-user-blk-server.c.o): in 
>>>>>> function `vu_blk_queue_set_started':
>>>>>>  block/export/vhost-user-blk-server.c:229: undefined reference to 
>>>>>> `vu_set_queue_handler'
>>>>>>  /usr/bin/ld: libqemuutil.a(util_vhost-user-server.c.o): in function 
>>>>>> `vu_client_trip':
>>>>>>  util/vhost-user-server.c:176: undefined reference to `vu_dispatch'
>>>>>>  /usr/bin/ld: util/vhost-user-server.c:180: undefined reference to 
>>>>>> `vu_deinit'
>>>>>>  /usr/bin/ld: libqemuutil.a(util_vhost-user-server.c.o): in function 
>>>>>> `vu_accept':
>>>>>>  util/vhost-user-server.c:291: undefined reference to `vu_init'
>>>>>>  collect2: error: ld returned 1 exit status
>>>>>>  ninja: build stopped: subcommand failed.
>>>>>>  make: *** [Makefile:171: run-ninja] Error 1
>>>>>>
>>>>>> Now we get:
>>>>>>
>>>>>>  $ ../configure \
>>>>>>       --disable-vhost-user --enable-vhost-user-blk-server && \
>>>>>>  ERROR: --enable-vhost-user-blk-server requires --enable-vhost-user
>>>>>>
>>>>>> Fixes: bc15e44cb21 ("configure: introduce 
>>>>>> --enable-vhost-user-blk-server")
>>>>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>>>>> ---
>>>>>> Since v1:
>>>>>> - Addressed Thomas review comments
>>>>>> https://lists.gnu.org/archive/html/qemu-devel/2020-11/msg02188.html
>>>>>> ---
>>>>>>  configure | 4 ++++
>>>>>>  1 file changed, 4 insertions(+)
>>>>>>
>>>>>> diff --git a/configure b/configure
>>>>>> index 805f7791503..3124be82da1 100755
>>>>>> --- a/configure
>>>>>> +++ b/configure
>>>>>> @@ -2375,6 +2375,10 @@ test "$vhost_user_fs" = "" && 
>>>>>> vhost_user_fs=$vhost_user
>>>>>>  if test "$vhost_user_fs" = "yes" && test "$vhost_user" = "no"; then
>>>>>>    error_exit "--enable-vhost-user-fs requires --enable-vhost-user"
>>>>>>  fi
>>>>>> +test "$vhost_user_blk_server" = "" && vhost_user_blk_server=$vhost_user
>>>>>> +if test "$vhost_user_blk_server" = "yes" && test "$vhost_user" = "no"; 
>>>>>> then
>>>>>> +  error_exit "--enable-vhost-user-blk-server requires 
>>>>>> --enable-vhost-user"
>>>>>> +fi
>>>>>
>>>>> A little bit later in this file, we've got :
>>>>>
>>>>> # libvhost-user is Linux-only
>>>>> test "$vhost_user_blk_server" = "" && vhost_user_blk_server=$linux
>>>>> if test "$vhost_user_blk_server" = "yes" && test "$linux" = "no"; then
>>>>>   error_exit "--enable-vhost-user-blk-server is only available on Linux"
>>>>> fi
>>>>>
>>>>> I think it would be better to add the new code there instead.
>>>>> Also maybe better do something like:
>>>>>
>>>>> test "$vhost_user_blk_server" = "" && test "$vhost_user" = "yes" \
>>>>>  &&  vhost_user_blk_server=$linux
>>>>>
>>>>> instead?
>>>>
>>>> I understood this option is similar to the other vhost-user related ones
>>>> and should be treated the same way.
>>>
>>> But the second check does not make much sense anymore after your change,
>>> since "$vhost_user_blk_server" is certainly not empty anymore. So the two
>>> checks IMHO have to be combined.
>>
>> Ah now I see it... You are right, thanks for the review :)
> 
> So we are back to v2:
> https://lists.gnu.org/archive/html/qemu-devel/2020-11/msg02333.html

That looks wrong to me, too, since the default value is now $vhost_user and
not $linux ... so it could get enabled by default on non-Linux systems, too.

 Thomas