Merge tag 'for-linus-5.10b-rc1c-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull more xen updates from Juergen Gross:

 - a series for the Xen pv block drivers adding module parameters for
   better control of resource usge

 - a cleanup series for the Xen event driver

* tag 'for-linus-5.10b-rc1c-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  Documentation: add xen.fifo_events kernel parameter description
  xen/events: unmask a fifo event channel only if it was masked
  xen/events: only register debug interrupt for 2-level events
  xen/events: make struct irq_info private to events_base.c
  xen: remove no longer used functions
  xen-blkfront: Apply changed parameter name to the document
  xen-blkfront: add a parameter for disabling of persistent grants
  xen-blkback: add a parameter for disabling of persistent grants

1 files changed, 16 insertions, 6 deletions

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 5e7c36d73dc6..f5705569e2a7 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -473,6 +473,12 @@ static void xen_vbd_free(struct xen_vbd *vbd)
 	vbd->bdev = NULL;
 }
 
+/* Enable the persistent grants feature. */
+static bool feature_persistent = true;
+module_param(feature_persistent, bool, 0644);
+MODULE_PARM_DESC(feature_persistent,
+		"Enables the persistent grants feature");
+
 static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 			  unsigned major, unsigned minor, int readonly,
 			  int cdrom)
@@ -518,6 +524,8 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 	if (q && blk_queue_secure_erase(q))
 		vbd->discard_secure = true;
 
+	vbd->feature_gnt_persistent = feature_persistent;
+
 	pr_debug("Successful creation of handle=%04x (dom=%u)\n",
 		handle, blkif->domid);
 	return 0;
@@ -905,7 +913,8 @@ again:
 
 	xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
 
-	err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1);
+	err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u",
+			be->blkif->vbd.feature_gnt_persistent);
 	if (err) {
 		xenbus_dev_fatal(dev, err, "writing %s/feature-persistent",
 				 dev->nodename);
@@ -1066,7 +1075,6 @@ static int connect_ring(struct backend_info *be)
 {
 	struct xenbus_device *dev = be->dev;
 	struct xen_blkif *blkif = be->blkif;
-	unsigned int pers_grants;
 	char protocol[64] = "";
 	int err, i;
 	char *xspath;
@@ -1092,9 +1100,11 @@ static int connect_ring(struct backend_info *be)
 		xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
 		return -ENOSYS;
 	}
-	pers_grants = xenbus_read_unsigned(dev->otherend, "feature-persistent",
-					   0);
-	blkif->vbd.feature_gnt_persistent = pers_grants;
+	if (blkif->vbd.feature_gnt_persistent)
+		blkif->vbd.feature_gnt_persistent =
+			xenbus_read_unsigned(dev->otherend,
+					"feature-persistent", 0);
+
 	blkif->vbd.overflow_max_grants = 0;
 
 	/*
@@ -1117,7 +1127,7 @@ static int connect_ring(struct backend_info *be)
 
 	pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename,
 		 blkif->nr_rings, blkif->blk_protocol, protocol,
-		 pers_grants ? "persistent grants" : "");
+		 blkif->vbd.feature_gnt_persistent ? "persistent grants" : "");
 
 	ring_page_order = xenbus_read_unsigned(dev->otherend,
 					       "ring-page-order", 0);