Merge branch 'stable/for-jens-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus

Pull a xen_blkfront fix from Konrad:

"It has one simple fix for the multi-queue support not showing up after
a block device was detached/re-attached."

* 'stable/for-jens-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen-blkfront: move negotiate_mq to cover all cases of new VBDs

drivers/block/xen-blkfront.c

···
 
 static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo);
 static void blkfront_gather_backend_features(struct blkfront_info *info);
+static int negotiate_mq(struct blkfront_info *info);
 
 static int get_id_from_freelist(struct blkfront_ring_info *rinfo)
 {
···
 	unsigned int i, max_page_order;
 	unsigned int ring_page_order;
 
+	if (!info)
+		return -ENODEV;
+
 	max_page_order = xenbus_read_unsigned(info->xbdev->otherend,
 					      "max-ring-page-order", 0);
 	ring_page_order = min(xen_blkif_max_ring_order, max_page_order);
 	info->nr_ring_pages = 1 << ring_page_order;
+
+	err = negotiate_mq(info);
+	if (err)
+		goto destroy_blkring;
 
 	for (i = 0; i < info->nr_rings; i++) {
 		struct blkfront_ring_info *rinfo = &info->rinfo[i];
···
 	}
 
 	info->xbdev = dev;
-	err = negotiate_mq(info);
-	if (err) {
-		kfree(info);
-		return err;
-	}
 
 	mutex_init(&info->mutex);
 	info->vdevice = vdevice;
···
 	}
 
 	blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
-
-	err = negotiate_mq(info);
-	if (err)
-		return err;
 
 	err = talk_to_blkback(dev, info);
 	if (!err)