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 <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
This commit is contained in:
Tejun Heo 2008-08-25 19:56:17 +09:00 • committed by Jens Axboe
commit 3e1a7ff8a0
5 changed files with 82 additions and 23 deletions

View file

@ -478,14 +478,37 @@ static int exact_lock(dev_t devt, void *data)
*
* This function registers the partitioning information in @disk
* with the kernel.
*
* FIXME: error handling
*/
void add_disk(struct gendisk *disk)
{
struct backing_dev_info *bdi;
dev_t devt;
int retval;
/* minors == 0 indicates to use ext devt from part0 and should
* be accompanied with EXT_DEVT flag. Make sure all
* parameters make sense.
*/
WARN_ON(disk->minors && !(disk->major || disk->first_minor));
WARN_ON(!disk->minors && !(disk->flags & GENHD_FL_EXT_DEVT));
disk->flags |= GENHD_FL_UP;
disk_to_dev(disk)->devt = MKDEV(disk->major, disk->first_minor);
retval = blk_alloc_devt(&disk->part0, &devt);
if (retval) {
WARN_ON(1);
return;
}
disk_to_dev(disk)->devt = devt;
/* ->major and ->first_minor aren't supposed to be
* dereferenced from here on, but set them just in case.
*/
disk->major = MAJOR(devt);
disk->first_minor = MINOR(devt);
blk_register_region(disk_devt(disk), disk->minors, NULL,
exact_match, exact_lock, disk);
register_disk(disk);