famfs needs to look up a dax_device by dev_t when resolving fmap
entries that reference character dax devices.

Signed-off-by: John Groves <john@groves.net>
---
 drivers/dax/super.c | 3 ++-
 include/linux/dax.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 68c45b918cff..c14b07be6a4e 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -511,7 +511,7 @@ static int dax_set(struct inode *inode, void *data)
 	return 0;
 }
 
-static struct dax_device *dax_dev_get(dev_t devt)
+struct dax_device *dax_dev_get(dev_t devt)
 {
 	struct dax_device *dax_dev;
 	struct inode *inode;
@@ -534,6 +534,7 @@ static struct dax_device *dax_dev_get(dev_t devt)
 
 	return dax_dev;
 }
+EXPORT_SYMBOL_GPL(dax_dev_get);
 
 struct dax_device *alloc_dax(void *private, const struct dax_operations *ops)
 {
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 76f2a75f3144..2a04c3535806 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -56,6 +56,7 @@ struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
 int fs_dax_get(struct dax_device *dax_dev, void *holder, const struct dax_holder_operations *hops);
 struct dax_device *inode_dax(struct inode *inode);
 #endif
+struct dax_device *dax_dev_get(dev_t devt);
 void *dax_holder(struct dax_device *dax_dev);
 void put_dax(struct dax_device *dax_dev);
 void kill_dax(struct dax_device *dax_dev);
-- 
2.49.0