block: don't depend on consecutive minor space

* Implement disk_devt() and part_devt() and use them to directly
  access devt instead of computing it from ->major and ->first_minor.

  Note that all references to ->major and ->first_minor outside of
  block layer is used to determine devt of the disk (the part0) and as
  ->major and ->first_minor will continue to represent devt for the
  disk, converting these users aren't strictly necessary.  However,
  convert them for consistency.

* Implement disk_max_parts() to avoid directly deferencing
  genhd->minors.

* Update bdget_disk() such that it doesn't assume consecutive minor
  space.

* Move devt computation from register_disk() to add_disk() and make it
  the only one (all other usages use the initially determined value).

These changes clean up the code and will help disk->part dereference
fix and extended block device numbers.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index 4b0d6c7..936466f 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -541,7 +541,7 @@ static int ps3disk_remove(struct ps3_system_bus_device *_dev)
 	struct ps3disk_private *priv = dev->sbd.core.driver_data;
 
 	mutex_lock(&ps3disk_mask_mutex);
-	__clear_bit(priv->gendisk->first_minor / PS3DISK_MINORS,
+	__clear_bit(MINOR(disk_devt(priv->gendisk)) / PS3DISK_MINORS,
 		    &ps3disk_mask);
 	mutex_unlock(&ps3disk_mask_mutex);
 	del_gendisk(priv->gendisk);