xen-netback: support frontends without feature-rx-notify again

[cascardo/linux.git] / drivers / net / xen-netback / xenbus.c

diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index d44cd19..efbaf2a 100644 (file)
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -887,9 +887,15 @@ static int read_xenbus_vif_flags(struct backend_info *be)
                return -EOPNOTSUPP;
 
        if (xenbus_scanf(XBT_NIL, dev->otherend,
-                        "feature-rx-notify", "%d", &val) < 0 || val == 0) {
-               xenbus_dev_fatal(dev, -EINVAL, "feature-rx-notify is mandatory");
-               return -EINVAL;
+                        "feature-rx-notify", "%d", &val) < 0)
+               val = 0;
+       if (!val) {
+               /* - Reduce drain timeout to poll more frequently for
+                *   Rx requests.
+                * - Disable Rx stall detection.
+                */
+               be->vif->drain_timeout = msecs_to_jiffies(30);
+               be->vif->stall_timeout = 0;
        }
 
        if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",