Merge branches 'for-4.11/upstream-fixes', 'for-4.12/accutouch', 'for-4.12/cp2112...

[mirror_ubuntu-artful-kernel.git] / block / genhd.c

diff --git a/block/genhd.c b/block/genhd.c
index f2f22d0e8e1432142d282bb21fa3ad6b864c714e..3631cd4802955247d27316c10b172744700e6340 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -572,6 +572,20 @@ exit:
        disk_part_iter_exit(&piter);
 }
 
+void put_disk_devt(struct disk_devt *disk_devt)
+{
+       if (disk_devt && atomic_dec_and_test(&disk_devt->count))
+               disk_devt->release(disk_devt);
+}
+EXPORT_SYMBOL(put_disk_devt);
+
+void get_disk_devt(struct disk_devt *disk_devt)
+{
+       if (disk_devt)
+               atomic_inc(&disk_devt->count);
+}
+EXPORT_SYMBOL(get_disk_devt);
+
 /**
  * device_add_disk - add partitioning information to kernel list
  * @parent: parent device for the disk
@@ -612,8 +626,15 @@ void device_add_disk(struct device *parent, struct gendisk *disk)
 
        disk_alloc_events(disk);
 
+       /*
+        * Take a reference on the devt and assign it to queue since it
+        * must not be reallocated while the bdi is registered
+        */
+       disk->queue->disk_devt = disk->disk_devt;
+       get_disk_devt(disk->disk_devt);
+
        /* Register BDI before referencing it from bdev */
-       bdi = &disk->queue->backing_dev_info;
+       bdi = disk->queue->backing_dev_info;
        bdi_register_owner(bdi, disk_to_dev(disk));
 
        blk_register_region(disk_devt(disk), disk->minors, NULL,