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>

2 files changed, 2 insertions, 2 deletions

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 29b7a648cc6e..e1a90bbb4747 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2911,7 +2911,7 @@ static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev)
         if (!disk->queue)
                 goto out_mem2;
 
-        pd->pkt_dev = MKDEV(disk->major, disk->first_minor);
+        pd->pkt_dev = MKDEV(pktdev_major, idx);
         ret = pkt_new_dev(pd, dev);
         if (ret)
                 goto out_new_dev;
diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index 4b0d6c7f4c66..936466f62afd 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);