xen/blkfront: correct setting for xen_blkif_max_ring_order

According to this piece code:
"
     pr_info("Invalid max_ring_order (%d), will use default max: %d.\n",
              xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER);
"
if xen_blkif_max_ring_order is bigger that XENBUS_MAX_RING_GRANT_ORDER,
need to set xen_blkif_max_ring_order using XENBUS_MAX_RING_GRANT_ORDER,
but not 0.

Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
(cherry picked from commit 45fc82642e54018740a25444d1165901501b601b)
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index f53dfe825a0e44c35a80684b1e342db5c0a3a822..92c49778dd31d5079c3e81de43495d026aad7ff5 100644 (file)
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -2445,7 +2445,7 @@ static int __init xlblk_init(void)
        if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) {
                pr_info("Invalid max_ring_order (%d), will use default max: %d.\n",
                        xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER);
-               xen_blkif_max_ring_order = 0;
+               xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER;
        }
 
        if (xen_blkif_max_queues > nr_cpus) {