[PATCH-for-5.2 v2 3/4] vhost-user-blk-server: depend on CONFIG_VHOST_USER

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

From: Stefan Hajnoczi <stefanha@redhat.com>

I interpreted CONFIG_VHOST_USER as controlling only QEMU's vhost-user
device frontends. However, virtiofsd and contrib/ vhost-user device
backends are also controlled by CONFIG_VHOST_USER. Make the
vhost-user-blk server depend on CONFIG_VHOST_USER for consistency.

Now the following error is printed when the vhost-user-blk server is
enabled without CONFIG_VHOST_USER:

  $ ./configure --disable-vhost-user --enable-vhost-user-blk ...
  ../meson.build:761:8: ERROR: Problem encountered: vhost_user_blk_server requires vhost-user support

Suggested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Suggested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20201110171121.1265142-3-stefanha@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 meson.build | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/meson.build b/meson.build
index 4fc58eb2c3d..b978e89ec70 100644
--- a/meson.build
+++ b/meson.build
@@ -755,11 +755,14 @@
     error('vhost-user does not make sense without system or tools support enabled')
 endif
 
-have_vhost_user_blk_server = (targetos == 'linux')
+have_vhost_user_blk_server = (targetos == 'linux' and
+    'CONFIG_VHOST_USER' in config_host)
 
 if get_option('vhost_user_blk_server').enabled()
     if targetos != 'linux'
         error('vhost_user_blk_server requires linux')
+    elif 'CONFIG_VHOST_USER' not in config_host
+        error('vhost_user_blk_server requires vhost-user support')
     endif
 elif get_option('vhost_user_blk_server').disabled() or not have_system
     have_vhost_user_blk_server = false
-- 
2.26.2