[RFC v2 2/2] pmem: device flush over VIRTIO

[Pankaj Gupta <pagupta-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

This patch adds functionality to perform 
flush from guest to hosy over VIRTIO 
when 'ND_REGION_VIRTIO'flag is set on 
nd_negion. Flag is set by 'virtio-pmem'
driver.

Signed-off-by: Pankaj Gupta <pagupta-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 drivers/nvdimm/region_devs.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index a612be6..6c6454e 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -20,6 +20,7 @@
 #include <linux/nd.h>
 #include "nd-core.h"
 #include "nd.h"
+#include <linux/virtio_pmem.h>
 
 /*
  * For readq() and writeq() on 32-bit builds, the hi-lo, lo-hi order is
@@ -1074,6 +1075,12 @@ void nvdimm_flush(struct nd_region *nd_region)
 	struct nd_region_data *ndrd = dev_get_drvdata(&nd_region->dev);
 	int i, idx;
 
+       /* call PV device flush */
+	if (test_bit(ND_REGION_VIRTIO, &nd_region->flags)) {
+		virtio_pmem_flush(&nd_region->dev);
+		return;
+	}
+
 	/*
 	 * Try to encourage some diversity in flush hint addresses
 	 * across cpus assuming a limited number of flush hints.
-- 
2.9.3