[PATCH 4.19 091/267] xen/pvcalls-back: test for errors when calling backend_connect()

[Greg Kroah-Hartman]

From: Juergen Gross <jgross@xxxxxxxx>

commit c8d70a29d6bbc956013f3401f92a4431a9385a3c upstream.

backend_connect() can fail, so switch the device to connected only if
no error occurred.

Fixes: 0a9c75c2c7258f2 ("xen/pvcalls: xenbus state handling")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Link: https://lore.kernel.org/r/20200511074231.19794-1-jgross@xxxxxxxx
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/xen/pvcalls-back.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -1096,7 +1096,8 @@ static void set_backend_state(struct xen
 		case XenbusStateInitialised:
 			switch (state) {
 			case XenbusStateConnected:
-				backend_connect(dev);
+				if (backend_connect(dev))
+					return;
 				xenbus_switch_state(dev, XenbusStateConnected);
 				break;
 			case XenbusStateClosing: