vers/nvdimm/virtio_pmem.h b/drivers/nvdimm/virtio_pmem.h
index 0dddefe594c46..f72cf17f9518f 100644
--- a/drivers/nvdimm/virtio_pmem.h
+++ b/drivers/nvdimm/virtio_pmem.h
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <uapi/linux/virtio_pmem.h>
 #include <linux/libnvdimm.h>
+#include <linux/mutex.h>
 #include <linux/spinlock.h>
 
 struct virtio_pmem_request {
@@ -35,6 +36,9 @@ struct virtio_pmem {
 	/* Virtio pmem request queue */
 	struct virtqueue *req_vq;
 
+	/* Serialize flush requests to the device. */
+	struct mutex flush_lock;
+
 	/* nvdimm bus registers virtio pmem device */
 	struct nvdimm_bus *nvdimm_bus;
 	struct nvdimm_bus_descriptor nd_desc;
-- 
2.51.0[PATCH 6.19 501/781] nvdimm: virtio_pmem: serialize flush requestsGreg Kroah-Hartman <gregkh@linuxfoundation.org> undefinedstable@vger.kernel.org undefined undefined undefined undefined undefined undefined undefined˜}†˜=