[win-pv-devel] [PATCH] Fix locking and teardown bugs in controller frontend

[Paul Durrant <pdurrant@xxxxxxxxx>]

If the backend does not implement the control ring then the frontend will
eventually deadlock. Also, by inspection, the teardown code does not
release interfaces if the control ring was not present.

This patch fixes both issues.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
 src/xenvif/controller.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/xenvif/controller.c b/src/xenvif/controller.c
index e54c9fc..a90397a 100644
--- a/src/xenvif/controller.c
+++ b/src/xenvif/controller.c
@@ -797,8 +797,10 @@ ControllerDisconnect(
 
     __ControllerAcquireLock(Controller);
 
-    if (!Controller->Connected)
+    if (!Controller->Connected) {
+        __ControllerReleaseLock(Controller);
         goto done;
+    }
 
     Controller->Connected = FALSE;
 
@@ -837,6 +839,7 @@ ControllerDisconnect(
                   Controller->GnttabCache);
     Controller->GnttabCache = NULL;
 
+done:
     XENBUS_GNTTAB(Release, &Controller->GnttabInterface);
 
     XENBUS_EVTCHN(Release, &Controller->EvtchnInterface);
@@ -845,7 +848,6 @@ ControllerDisconnect(
 
     XENBUS_DEBUG(Release, &Controller->DebugInterface);
 
-done:
     Trace("<====\n");
 }
 
-- 
2.1.1


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