mtd: blktrans: Hotplug fixes

* Add locking where it was missing.

* Don't do a get_mtd_device in blktrans_open because it would lead to a
  deadlock; instead do that in add_mtd_blktrans_dev.

* Only free the mtd_blktrans_dev structure when the last user exits.

* Flush request queue on device removal.

* Track users, and call tr->release in del_mtd_blktrans_dev
  Due to that ->open and release aren't called more that once.

Now it is safe to call del_mtd_blktrans_dev while the device is still in use.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/mtd/blktrans.h b/include/linux/mtd/blktrans.h
index a4b392868b5..d89b8fbba4c 100644
--- a/include/linux/mtd/blktrans.h
+++ b/include/linux/mtd/blktrans.h
@@ -9,6 +9,7 @@
 #define __MTD_TRANS_H__
 
 #include <linux/mutex.h>
+#include <linux/kref.h>
 
 struct hd_geometry;
 struct mtd_info;
@@ -24,6 +25,8 @@ struct mtd_blktrans_dev {
         int devnum;
         unsigned long size;
         int readonly;
+        int open;
+        struct kref ref;
         struct gendisk *disk;
         struct task_struct *thread;
         struct request_queue *rq;