[qemu-xen stable-4.13] libvhost-user: fix SLAVE_SEND_FD handling

[patchbot@xxxxxxx]

commit 28a9a3558a427493049723fff390add7026653eb
Author:     Johannes Berg <johannes.berg@xxxxxxxxx>
AuthorDate: Tue Sep 3 23:04:22 2019 +0300
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun Oct 27 23:59:27 2019 -0500

    libvhost-user: fix SLAVE_SEND_FD handling
    
    It doesn't look like this could possibly work properly since
    VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD is defined to 10, but the
    dev->protocol_features has a bitmap. I suppose the peer this
    was tested with also supported VHOST_USER_PROTOCOL_F_LOG_SHMFD,
    in which case the test would always be false, but nevertheless
    the code seems wrong.
    
    Use has_feature() to fix this.
    
    Fixes: d84599f56c82 ("libvhost-user: support host notifier")
    Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
    Message-Id: <20190903200422.11693-1-johannes@xxxxxxxxxxxxxxxx>
    Reviewed-by: Tiwei Bie <tiwei.bie@xxxxxxxxx>
    Reviewed-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    (cherry picked from commit 8726b70b449896f1211f869ec4f608904f027207)
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 contrib/libvhost-user/libvhost-user.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/contrib/libvhost-user/libvhost-user.c 
b/contrib/libvhost-user/libvhost-user.c
index 4b36e35a82..cb5f5770e4 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -1097,7 +1097,8 @@ bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, 
int fd,
 
     vmsg.fd_num = fd_num;
 
-    if ((dev->protocol_features & VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD) == 0) {
+    if (!has_feature(dev->protocol_features,
+                     VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD)) {
         return false;
     }
 
--
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