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path: root/drivers/block/xen-blkback/xenbus.c
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Diffstat (limited to 'drivers/block/xen-blkback/xenbus.c')
-rw-r--r--drivers/block/xen-blkback/xenbus.c23
1 files changed, 21 insertions, 2 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index f58434c2617c..63980722db41 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -117,6 +117,7 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
atomic_set(&blkif->drain, 0);
blkif->st_print = jiffies;
init_waitqueue_head(&blkif->waiting_to_free);
+ blkif->persistent_gnts.rb_node = NULL;
return blkif;
}
@@ -672,6 +673,13 @@ again:
xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
+ err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1);
+ if (err) {
+ xenbus_dev_fatal(dev, err, "writing %s/feature-persistent",
+ dev->nodename);
+ goto abort;
+ }
+
err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
(unsigned long long)vbd_sz(&be->blkif->vbd));
if (err) {
@@ -720,6 +728,7 @@ static int connect_ring(struct backend_info *be)
struct xenbus_device *dev = be->dev;
unsigned long ring_ref;
unsigned int evtchn;
+ unsigned int pers_grants;
char protocol[64] = "";
int err;
@@ -749,8 +758,18 @@ static int connect_ring(struct backend_info *be)
xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
return -1;
}
- pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s)\n",
- ring_ref, evtchn, be->blkif->blk_protocol, protocol);
+ err = xenbus_gather(XBT_NIL, dev->otherend,
+ "feature-persistent", "%u",
+ &pers_grants, NULL);
+ if (err)
+ pers_grants = 0;
+
+ be->blkif->vbd.feature_gnt_persistent = pers_grants;
+ be->blkif->vbd.overflow_max_grants = 0;
+
+ pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s) %s\n",
+ ring_ref, evtchn, be->blkif->blk_protocol, protocol,
+ pers_grants ? "persistent grants" : "");
/* Map the shared frame, irq etc. */
err = xen_blkif_map(be->blkif, ring_ref, evtchn);