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

[Thomas Huth <thuth@redhat.com>]

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?

 Thomas