Revert "scsi, block: fix duplicate bdi name registration crashes"

This reverts commit 0dba1314d4f81115dce711292ec7981d17231064. It causes
leaking of device numbers for SCSI when SCSI registers multiple gendisks
for one request_queue in succession. It can be easily reproduced using
Omar's script [1] on kernel with CONFIG_DEBUG_TEST_DRIVER_REMOVE.
Furthermore the protection provided by this commit is not needed anymore
as the problem it was fixing got also fixed by commit 165a5e22fafb
"block: Move bdi_unregister() to del_gendisk()".

[1]: http://marc.info/?l=linux-block&m=148554717109098&w=2

Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 0 insertions, 21 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 94f323842b52..a9c516a8b37d 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -572,20 +572,6 @@ 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
@@ -626,13 +612,6 @@ 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_register_owner(bdi, disk_to_dev(disk));