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, 3 insertions, 3 deletions

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 7ce1ac4baa6d..6af435b89867 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -661,10 +661,10 @@ void add_disk_randomness(struct gendisk *disk)
         if (!disk || !disk->random)
                 return;
         /* first major is 1, so we get >= 0x200 here */
-        DEBUG_ENT("disk event %d:%d\n", disk->major, disk->first_minor);
+        DEBUG_ENT("disk event %d:%d\n",
+                  MAJOR(disk_devt(disk)), MINOR(disk_devt(disk)));
 
-        add_timer_randomness(disk->random,
-                             0x100 + MKDEV(disk->major, disk->first_minor));
+        add_timer_randomness(disk->random, 0x100 + disk_devt(disk));
 }
 #endif