path: root/block/genhd.c
diff options
authorJan Kara <>2017-02-08 08:05:56 +0100
committerJens Axboe <>2017-03-02 16:08:35 -0700
commit165a5e22fafb127ecb5914e12e8c32a1f0d3f820 (patch)
tree844b4541dcc7edd35feac79dfda0c25312d51ade /block/genhd.c
parent113285b473824922498d07d7f82459507b9792eb (diff)
block: Move bdi_unregister() to del_gendisk()
Commit 6cd18e711dd8 "block: destroy bdi before blockdev is unregistered." moved bdi unregistration (at that time through bdi_destroy()) from blk_release_queue() to blk_cleanup_queue() because it needs to happen before blk_unregister_region() call in del_gendisk() for MD. SCSI though will free up the device number from sd_remove() called through a maze of callbacks from device_del() in __scsi_remove_device() before blk_cleanup_queue() and thus similar races as described in 6cd18e711dd8 can happen for SCSI as well as reported by Omar [1]. Moving bdi_unregister() to del_gendisk() works for MD and fixes the problem for SCSI since del_gendisk() gets called from sd_remove() before freeing the device number. This also makes device_add_disk() (calling bdi_register_owner()) more symmetric with del_gendisk(). [1] Tested-by: Lekshmi Pillai <> Acked-by: Tejun Heo <> Signed-off-by: Jan Kara <> Tested-by: Omar Sandoval <> Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block/genhd.c')
1 files changed, 5 insertions, 0 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 2f444b8..b26a5ea 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -681,6 +681,11 @@ void del_gendisk(struct gendisk *disk)
disk->flags &= ~GENHD_FL_UP;
sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
+ /*
+ * Unregister bdi before releasing device numbers (as they can get
+ * reused and we'd get clashes in sysfs).
+ */
+ bdi_unregister(disk->queue->backing_dev_info);
blk_unregister_region(disk_devt(disk), disk->minors);