[PATCH V9 4/8] dax: Save the kva from memremap

["John Groves" <john@jagalactic.com>]

From: John Groves <john@groves.net>

Save the kva from memremap because we need it for iomap rw support.

Prior to famfs, there were no iomap users of /dev/dax - so the virtual
address from memremap was not needed.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: John Groves <john@groves.net>
---
 drivers/dax/dax-private.h | 2 ++
 drivers/dax/fsdev.c       | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
index c6ae27c982f4..7a3727d76a68 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -69,6 +69,7 @@ struct dev_dax_range {
  * data while the device is activated in the driver.
  * @region: parent region
  * @dax_dev: core dax functionality
+ * @virt_addr: kva from memremap; used by fsdev_dax
  * @align: alignment of this instance
  * @target_node: effective numa node if dev_dax memory range is onlined
  * @dyn_id: is this a dynamic or statically created instance
@@ -83,6 +84,7 @@ struct dev_dax_range {
 struct dev_dax {
 	struct dax_region *region;
 	struct dax_device *dax_dev;
+	void *virt_addr;
 	unsigned int align;
 	int target_node;
 	bool dyn_id;
diff --git a/drivers/dax/fsdev.c b/drivers/dax/fsdev.c
index 8b5c6976ad17..c75478d3d548 100644
--- a/drivers/dax/fsdev.c
+++ b/drivers/dax/fsdev.c
@@ -121,6 +121,7 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
 	struct device *dev = &dev_dax->dev;
 	struct dev_pagemap *pgmap;
 	struct inode *inode;
+	u64 data_offset = 0;
 	struct cdev *cdev;
 	void *addr;
 	int rc, i;
@@ -196,7 +197,6 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
 	if (pgmap->range.start != dev_dax->ranges[0].range.start) {
 		u64 phys = dev_dax->ranges[0].range.start;
 		u64 pgmap_phys = dev_dax->pgmap[0].range.start;
-		u64 data_offset = 0;
 
 		if (!WARN_ON(pgmap_phys > phys))
 			data_offset = phys - pgmap_phys;
@@ -204,6 +204,7 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
 		pr_debug("%s: offset detected phys=%llx pgmap_phys=%llx offset=%llx\n",
 		       __func__, phys, pgmap_phys, data_offset);
 	}
+	dev_dax->virt_addr = addr + data_offset;
 
 	inode = dax_inode(dax_dev);
 	cdev = inode->i_cdev;
-- 
2.53.0