Now a dev_t is a pointer to struct specinfo which is shared by all specdev

vnodes referencing this device.

Details:
        cdevsw->d_parms has been removed, the specinfo is available
        now (== dev_t) and the driver should modify it directly
        when applicable, and the only driver doing so, does so:
        vn.c.  I am not sure the logic in checking for "<" was right
        before, and it looks even less so now.

        An intial pool of 50 struct specinfo are depleted during
        early boot, after that malloc had better work.  It is
        likely that fewer than 50 would do.

        Hashing is done from udev_t to dev_t with a prime number
        remainder hash, experiments show no better hash available
        for decent cost (MD5 is only marginally better)  The prime
        number used should not be close to a power of two, we use
        83 for now.

        Add new checkalias2() to get around the loss of info from
        dev2udev() in bdevvp();

        The aliased vnodes are hung on a list straight of the dev_t,
        and speclisth[SPECSZ] is unused.  The sharing of struct
        specinfo means that the v_specnext moves into the vnode
        which grows by 4 bytes.

        Don't use a VBLK dev_t which doesn't make sense in MFS, now
        we hang a dummy cdevsw on B/Cmaj 253 so that things look sane.

	Storage overhead from all of this is O(50k).

        Bump __FreeBSD_version to 400009

The next step will add the stuff needed so device-drivers can start to
hang things from struct specinfo

1 files changed, 26 insertions, 3 deletions

diff --git a/sys/ufs/mfs/mfs_vfsops.c b/sys/ufs/mfs/mfs_vfsops.c
index 47e4676..7569f74 100644
--- a/sys/ufs/mfs/mfs_vfsops.c
+++ b/sys/ufs/mfs/mfs_vfsops.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)mfs_vfsops.c	8.11 (Berkeley) 6/19/95
- * $Id: mfs_vfsops.c,v 1.64 1999/05/24 00:27:12 jb Exp $
+ * $Id: mfs_vfsops.c,v 1.65 1999/07/17 18:43:49 phk Exp $
  */
 
 
@@ -79,6 +79,28 @@ static int	mfs_statfs __P((struct mount *mp, struct statfs *sbp,
 			struct proc *p));
 static int	mfs_init __P((struct vfsconf *));
 
+static struct cdevsw mfs_cdevsw = {
+	/* open */      noopen,
+	/* close */     noclose,
+	/* read */      physread,
+	/* write */     physwrite,
+	/* ioctl */     noioctl,
+	/* stop */      nostop,
+	/* reset */     noreset,
+	/* devtotty */  nodevtotty,
+	/* poll */      nopoll,
+	/* mmap */      nommap,
+	/* strategy */  nostrategy,
+	/* name */      "MFS",
+	/* parms */     noparms,
+	/* maj */       253,
+	/* dump */      nodump,
+	/* psize */     nopsize,
+	/* flags */     D_DISK,
+	/* maxio */     0,
+	/* bmaj */      253,
+};
+
 /*
  * mfs vfs operations.
  */
@@ -308,7 +330,7 @@ mfs_mount(mp, path, data, ndp, p)
 		goto error_1;
 	}
 	devvp->v_type = VBLK;
-	if (checkalias(devvp, makeudev(255, mfs_minor++), (struct mount *)0))
+	if (checkalias(devvp, makeudev(253, mfs_minor++), (struct mount *)0))
 		panic("mfs_mount: dup dev");
 	devvp->v_data = mfsp;
 	mfsp->mfs_baseoff = args.base;
@@ -459,12 +481,13 @@ static int
 mfs_init(vfsp)
 	struct vfsconf *vfsp;
 {
+	cdevsw_add(&mfs_cdevsw);
 #ifdef MFS_ROOT
 	if (bootverbose)
 		printf("Considering MFS root f/s.\n");
 	if (mfs_getimage()) {
 		mountrootfsname = "mfs";
-		rootdev = makedev(255, mfs_minor++);
+		rootdev = makedev(253, mfs_minor++);
 	} else if (bootverbose)
 		printf("No MFS image available as root f/s.\n");
 #endif