Let Clang verify lock and unlock calls. Enable lock context analysis in the
Makefile.

Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/block/xen-blkback/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/block/xen-blkback/Makefile b/drivers/block/xen-blkback/Makefile
index b0ea5ab5b9a1..864ef423226c 100644
--- a/drivers/block/xen-blkback/Makefile
+++ b/drivers/block/xen-blkback/Makefile
@@ -1,4 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
+
+CONTEXT_ANALYSIS := y
+
 obj-$(CONFIG_XEN_BLKDEV_BACKEND) := xen-blkback.o
 
 xen-blkback-y	:= blkback.o xenbus.o