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

[Thomas Huth]

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.

 Thomas