From: Dan Williams <dan.j.williams@intel.com>
Date: Tue, 27 Jun 2017 17:59:28 -0700
Subject: dax: convert to bitmask for flags
Patch-mainline: v4.13-rc1
Git-commit: 9a60c3ef577beb0376704808949f2c1f8fb0672c
References: FATE#323717

In preparation for adding more flags, convert the existing flag to a
bit-flag.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/dax/super.c |   17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -116,13 +116,18 @@ int __bdev_dax_supported(struct super_bl
 EXPORT_SYMBOL_GPL(__bdev_dax_supported);
 #endif
 
+enum dax_device_flags {
+	/* !alive + rcu grace period == no new operations / mappings */
+	DAXDEV_ALIVE,
+};
+
 /**
  * struct dax_device - anchor object for dax services
  * @inode: core vfs
  * @cdev: optional character interface for "device dax"
  * @host: optional name for lookups where the device path is not available
  * @private: dax driver private data
- * @alive: !alive + rcu grace period == no new operations / mappings
+ * @flags: state and boolean properties
  */
 struct dax_device {
 	struct hlist_node list;
@@ -130,7 +135,7 @@ struct dax_device {
 	struct cdev cdev;
 	const char *host;
 	void *private;
-	bool alive;
+	unsigned long flags;
 	const struct dax_operations *ops;
 };
 
@@ -199,7 +204,7 @@ EXPORT_SYMBOL_GPL(dax_flush);
 bool dax_alive(struct dax_device *dax_dev)
 {
 	lockdep_assert_held(&dax_srcu);
-	return dax_dev->alive;
+	return test_bit(DAXDEV_ALIVE, &dax_dev->flags);
 }
 EXPORT_SYMBOL_GPL(dax_alive);
 
@@ -219,7 +224,7 @@ void kill_dax(struct dax_device *dax_dev
 	if (!dax_dev)
 		return;
 
-	dax_dev->alive = false;
+	clear_bit(DAXDEV_ALIVE, &dax_dev->flags);
 
 	synchronize_srcu(&dax_srcu);
 
@@ -263,7 +268,7 @@ static void dax_destroy_inode(struct ino
 {
 	struct dax_device *dax_dev = to_dax_dev(inode);
 
-	WARN_ONCE(dax_dev->alive,
+	WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags),
 			"kill_dax() must be called before final iput()\n");
 	call_rcu(&inode->i_rcu, dax_i_callback);
 }
@@ -315,7 +320,7 @@ static struct dax_device *dax_dev_get(de
 
 	dax_dev = to_dax_dev(inode);
 	if (inode->i_state & I_NEW) {
-		dax_dev->alive = true;
+		set_bit(DAXDEV_ALIVE, &dax_dev->flags);
 		inode->i_cdev = &dax_dev->cdev;
 		inode->i_mode = S_IFCHR;
 		inode->i_flags = S_DAX;