dax: define a unified inode/address_space for device-dax mappings

In support of enabling resize / truncate of device-dax instances, define
a pseudo-fs to provide a unified inode/address space for vm operations.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 6edd825231c5..44a240c4bb65 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -406,6 +406,7 @@ void cd_forget(struct inode *inode)
         spin_lock(&cdev_lock);
         list_del_init(&inode->i_devices);
         inode->i_cdev = NULL;
+        inode->i_mapping = &inode->i_data;
         spin_unlock(&cdev_lock);
 }