xen-blkback: advertise indirect segment support earlier

There's no reason to defer this until the connect phase, and in fact
there are frontend implementations expecting this to be available
earlier. Move it into the probe function.
Acked-by: NRoger Pau Monné <roger.pau@citrix.com>
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Cc: Bob Liu <bob.liu@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/block/xen-blkback/xenbus.c

@@ -618,6 +618,14 @@ static int xen_blkbk_probe(struct xenbus_device *dev,
 		goto fail;
 	}
 
+	err = xenbus_printf(XBT_NIL, dev->nodename,
+			    "feature-max-indirect-segments", "%u",
+			    MAX_INDIRECT_SEGMENTS);
+	if (err)
+		dev_warn(&dev->dev,
+			 "writing %s/feature-max-indirect-segments (%d)",
+			 dev->nodename, err);
+
 	/* Multi-queue: advertise how many queues are supported by us.*/
 	err = xenbus_printf(XBT_NIL, dev->nodename,
 			    "multi-queue-max-queues", "%u", xenblk_max_queues);
@@ -849,11 +857,6 @@ static void connect(struct backend_info *be)
 				 dev->nodename);
 		goto abort;
 	}
-	err = xenbus_printf(xbt, dev->nodename, "feature-max-indirect-segments", "%u",
-			    MAX_INDIRECT_SEGMENTS);
-	if (err)
-		dev_warn(&dev->dev, "writing %s/feature-max-indirect-segments (%d)",
-			 dev->nodename, err);
 
 	err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
 			    (unsigned long long)vbd_sz(&be->blkif->vbd));