[PATCHv5 for-next 10/19] block/rnbd-srv: Remove force_close file after holding a lock

[Gioh Kim <gi-oh.kim@xxxxxxxxx>]

From: Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxx>

We changed the rnbd_srv_sess_dev_force_close to use try-lock
because rnbd_srv_sess_dev_force_close and process_msg_close
can generate a deadlock.

Now rnbd_srv_sess_dev_force_close would do nothing
if it fails to get the lock. So removing the force_close
file should be moved to after the lock. Or the force_close
file is removed but the others are not removed.

Signed-off-by: Gioh Kim <gi-oh.kim@xxxxxxxxx>
Signed-off-by: Md Haris Iqbal <haris.iqbal@xxxxxxxxx>
Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxx>
---
 drivers/block/rnbd/rnbd-srv-sysfs.c | 5 +----
 drivers/block/rnbd/rnbd-srv.c       | 5 ++++-
 drivers/block/rnbd/rnbd-srv.h       | 3 ++-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/block/rnbd/rnbd-srv-sysfs.c b/drivers/block/rnbd/rnbd-srv-sysfs.c
index 05ffe488ddc6..acf5fced11ef 100644
--- a/drivers/block/rnbd/rnbd-srv-sysfs.c
+++ b/drivers/block/rnbd/rnbd-srv-sysfs.c
@@ -147,10 +147,7 @@ static ssize_t rnbd_srv_dev_session_force_close_store(struct kobject *kobj,
 	}
 
 	rnbd_srv_info(sess_dev, "force close requested\n");
-
-	/* first remove sysfs itself to avoid deadlock */
-	sysfs_remove_file_self(&sess_dev->kobj, &attr->attr);
-	rnbd_srv_sess_dev_force_close(sess_dev);
+	rnbd_srv_sess_dev_force_close(sess_dev, attr);
 
 	return count;
 }
diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index 1549a6361630..a9bb414f7442 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -329,7 +329,8 @@ static int rnbd_srv_link_ev(struct rtrs_srv *rtrs,
 	}
 }
 
-void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev)
+void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev,
+				   struct kobj_attribute *attr)
 {
 	struct rnbd_srv_session	*sess = sess_dev->sess;
 
@@ -337,6 +338,8 @@ void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev)
 	/* It is already started to close by client's close message. */
 	if (!mutex_trylock(&sess->lock))
 		return;
+	/* first remove sysfs itself to avoid deadlock */
+	sysfs_remove_file_self(&sess_dev->kobj, &attr->attr);
 	rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 	mutex_unlock(&sess->lock);
 }
diff --git a/drivers/block/rnbd/rnbd-srv.h b/drivers/block/rnbd/rnbd-srv.h
index b157371c25ed..98ddc31eb408 100644
--- a/drivers/block/rnbd/rnbd-srv.h
+++ b/drivers/block/rnbd/rnbd-srv.h
@@ -64,7 +64,8 @@ struct rnbd_srv_sess_dev {
 	enum rnbd_access_mode		access_mode;
 };
 
-void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev);
+void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev,
+				   struct kobj_attribute *attr);
 /* rnbd-srv-sysfs.c */
 
 int rnbd_srv_create_dev_sysfs(struct rnbd_srv_dev *dev,
-- 
2.25.1