block: allow disk to have extended device number

Now that disk and partition handlings are mostly unified, it's easy to
allow disk to have extended device number.  This patch makes
add_disk() use extended device number if disk->minors is zero.  Both
sd and ide-disk are updated to use this.

* sd_format_disk_name() is implemented which can generically determine
  the drive name.  This removes disk number restriction stemming from
  limited device names.

* If sd index goes over SD_MAX_DISKS (which can be increased now BTW),
  sd simply doesn't initialize minors letting block layer choose
  extended device number.

* If CONFIG_DEBUG_EXT_DEVT is set, both sd and ide-disk always set
  minors to 0 and use extended 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/ide/ide-disk.c b/drivers/ide/ide-disk.c
index 29c8ae752683..33ea8c048717 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -44,7 +44,7 @@
 #if !defined(CONFIG_DEBUG_BLOCK_EXT_DEVT)
 #define IDE_DISK_MINORS         (1 << PARTN_BITS)
 #else
-#define IDE_DISK_MINORS         1
+#define IDE_DISK_MINORS         0
 #endif
 
 struct ide_disk_obj {