[PATCH xenvif] Don't allow a frontend to go from Closed to Initialising...

[Paul Durrant <paul@xxxxxxx>]

From: Paul Durrant <pdurrant@xxxxxxxxxx>

... if the backend is offline.

It's possible for the enumeration thread to spot a device that is in the
process of being removed. In this case the 'online' node in the backend
XenStore area will be 0 and devices in this state should remain Closed.

Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
---
 src/xenvif/frontend.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/xenvif/frontend.c b/src/xenvif/frontend.c
index 7ea66cf73610..dab0ebbec0e4 100644
--- a/src/xenvif/frontend.c
+++ b/src/xenvif/frontend.c
@@ -1548,8 +1548,12 @@ FrontendPrepare(
             break;
 
         case XenbusStateClosed:
-            FrontendSetXenbusState(Frontend,
-                                   XenbusStateInitialising);
+            if (FrontendIsBackendOnline(Frontend))
+                FrontendSetXenbusState(Frontend,
+                                       XenbusStateInitialising);
+            else
+                FrontendSetOffline(Frontend);
+
             break;
 
         case XenbusStateConnected:
-- 
2.17.1