Divorce "dev_t" from the "major|minor" bitmap, which is now called

udev_t in the kernel but still called dev_t in userland.

Provide functions to manipulate both types:
        major()         umajor()
        minor()         uminor()
        makedev()       umakedev()
        dev2udev()      udev2dev()

For now they're functions, they will become in-line functions
after one of the next two steps in this process.

Return major/minor/makedev to macro-hood for userland.

Register a name in cdevsw[] for the "filedescriptor" driver.

In the kernel the udev_t appears in places where we have the
major/minor number combination, (ie: a potential device: we
may not have the driver nor the device), like in inodes, vattr,
cdevsw registration and so on, whereas the dev_t appears where
we carry around a reference to a actual device.

In the future the cdevsw and the aliased-from vnode will be hung
directly from the dev_t, along with up to two softc pointers for
the device driver and a few houskeeping bits.  This will essentially
replace the current "alias" check code (same buck, bigger bang).

A little stunt has been provided to try to catch places where the
wrong type is being used (dev_t vs udev_t), if you see something
not working, #undef DEVT_FASCIST in kern/kern_conf.c and see if
it makes a difference.  If it does, please try to track it down
(many hands make light work) or at least try to reproduce it
as simply as possible, and describe how to do that.

Without DEVT_FASCIST I belive this patch is a no-op.

Stylistic/posixoid comments about the userland view of the <sys/*.h>
files welcome now, from userland they now contain the end result.

Next planned step: make all dev_t's refer to the same devsw[] which
means convert BLK's to CHR's at the perimeter of the vnodes and
other places where they enter the game (bootdev, mknod, sysctl).

1 files changed, 13 insertions, 10 deletions

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index ff42b06..bce703f 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
- * $Id: vfs_subr.c,v 1.192 1999/05/08 06:39:48 phk Exp $
+ * $Id: vfs_subr.c,v 1.193 1999/05/08 07:02:38 phk Exp $
  */
 
 /*
@@ -1188,7 +1188,7 @@ bdevvp(dev, vpp)
 	}
 	vp = nvp;
 	vp->v_type = VBLK;
-	if ((nvp = checkalias(vp, dev, (struct mount *)0)) != NULL) {
+	if ((nvp = checkalias(vp, dev2udev(dev), (struct mount *)0)) != NULL) {
 		vput(vp);
 		vp = nvp;
 	}
@@ -1207,22 +1207,25 @@ bdevvp(dev, vpp)
 struct vnode *
 checkalias(nvp, nvp_rdev, mp)
 	register struct vnode *nvp;
-	dev_t nvp_rdev;
+	udev_t nvp_rdev;
 	struct mount *mp;
 {
 	struct proc *p = curproc;	/* XXX */
 	struct vnode *vp;
 	struct vnode **vpp;
-	int rmaj = major(nvp_rdev);
+	int rmaj = umajor(nvp_rdev);
+	dev_t	dev;
 
 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
 		return (NULLVP);
 
+	dev = udev2dev(nvp_rdev, 2);
+
 	vpp = &speclisth[SPECHASH(nvp_rdev)];
 loop:
 	simple_lock(&spechash_slock);
 	for (vp = *vpp; vp; vp = vp->v_specnext) {
-		if (nvp_rdev != vp->v_rdev || nvp->v_type != vp->v_type)
+		if (dev != vp->v_rdev || nvp->v_type != vp->v_type)
 			continue;
 		/*
 		 * Alias, but not in use, so flush it out.
@@ -1262,7 +1265,7 @@ loop:
 		    sizeof(struct specinfo), M_VNODE, M_WAITOK);
 		bzero(sinfo, sizeof(struct specinfo));
 		nvp->v_specinfo = sinfo;
-		sinfo->si_rdev = nvp_rdev;
+		sinfo->si_rdev = dev;
 		sinfo->si_hashchain = vpp;
 		sinfo->si_specnext = *vpp;
 		sinfo->si_bsize_phys = DEV_BSIZE;
@@ -1275,12 +1278,12 @@ loop:
 		 */
 
 		if (nvp->v_type == VBLK && rmaj < nblkdev) {
-			if (bdevsw(nvp_rdev) && bdevsw(nvp_rdev)->d_parms)
+			if (bdevsw(dev) && bdevsw(dev)->d_parms)
 				
-				(*bdevsw(nvp_rdev)->d_parms)(nvp_rdev, sinfo, DPARM_GET);
+				(*bdevsw(dev)->d_parms)(dev, sinfo, DPARM_GET);
 		} else if (nvp->v_type == VCHR && rmaj < nchrdev) {
-			if (devsw(nvp_rdev) && devsw(nvp_rdev)->d_parms)
-				(*devsw(nvp_rdev)->d_parms)(nvp_rdev, sinfo, DPARM_GET);
+			if (devsw(dev) && devsw(dev)->d_parms)
+				(*devsw(dev)->d_parms)(dev, sinfo, DPARM_GET);
 		}
 
 		simple_unlock(&spechash_slock);