Create a general facility for making dev_t's depend on another

dev_t.  The dev_depends(dev_t, dev_t) function is for tying them
to each other.

When destroy_dev() is called on a dev_t, all dev_t's depending
on it will also be destroyed (depth first order).

Rewrite the make_dev_alias() to use this dependency facility.

kern/subr_disk.c:
Make the disk mini-layer use dependencies to make sure all
relevant dev_t's are removed when the disk disappears.

Make the disk mini-layer precreate some magic sub devices
which the disk/slice/label code expects to be there.

kern/subr_disklabel.c:
Remove some now unneeded variables.

kern/subr_diskmbr.c:
Remove some ancient, commented out code.

kern/subr_diskslice.c:
Minor cleanup.  Use name from dev_t instead of dsname()

1 files changed, 0 insertions, 2 deletions

diff --git a/sys/kern/subr_disklabel.c b/sys/kern/subr_disklabel.c
index 3a9ad24..5498bf2 100644
--- a/sys/kern/subr_disklabel.c
+++ b/sys/kern/subr_disklabel.c
@@ -352,8 +352,6 @@ diskerr(bp, what, blkdone, lp)
 	int blkdone;
 	register struct disklabel *lp;
 {
-	int unit = dkunit(bp->bio_dev);
-	int slice = dkslice(bp->bio_dev);
 	int part = dkpart(bp->bio_dev);
 	char partname[2];
 	char *sname;