 @@ -1,14 +1,14 @@
-/*	$NetBSD: md.c,v 1.61 2009/10/22 20:15:45 snj Exp $	*/
+/*	$NetBSD: md.c,v 1.62 2010/01/21 02:14:42 dyoung Exp $	*/
 /*
  * Copyright (c) 1995 Gordon W. Ross, Leo Weppelman.
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
 @@ -30,27 +30,27 @@
  * See md.h for notes on the config types.
+ *
  * Note that this driver provides the same functionality
  * as the MFS filesystem hack, but this is better because
  * you can use this for any filesystem type you'd like!
+ *
  * Credit for most of the kmem ramdisk code goes to:
  *   Leo Weppelman (atari) and Phil Nelson (pc532)
  * Credit for the ideas behind the "user space memory" code goes
  * to the authors of the MFS implementation.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: md.c,v 1.61 2009/10/22 20:15:45 snj Exp $");
+__KERNEL_RCSID(0, "$NetBSD: md.c,v 1.62 2010/01/21 02:14:42 dyoung Exp $");
 #include "opt_md.h"
 #include "opt_tftproot.h"
 #include <sys/param.h>
 #include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/systm.h>
 #include <sys/buf.h>
 #include <sys/bufq.h>
 #include <sys/device.h>
 #include <sys/disk.h>
 #include <sys/stat.h>
 @@ -314,59 +314,59 @@ mdclose(dev_t dev, int flag, int fmt, st
 	dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
 	mutex_exit(&dk->dk_openlock);
 	return 0;
+}
 static int
 mdread(dev_t dev, struct uio *uio, int flags)
+{
 	struct md_softc *sc;
 	sc = device_lookup_private(&md_cd, MD_UNIT(dev));
-	if (sc->sc_type == MD_UNCONFIGURED)
+	if (sc == NULL || sc->sc_type == MD_UNCONFIGURED)
 		return ENXIO;
 	return (physio(mdstrategy, NULL, dev, B_READ, minphys, uio));
+}
 static int
 mdwrite(dev_t dev, struct uio *uio, int flags)
+{
 	struct md_softc *sc;
 	sc = device_lookup_private(&md_cd, MD_UNIT(dev));
-	if (sc->sc_type == MD_UNCONFIGURED)
+	if (sc == NULL || sc->sc_type == MD_UNCONFIGURED)
 		return ENXIO;
 	return (physio(mdstrategy, NULL, dev, B_WRITE, minphys, uio));
+}
 /*
  * Handle I/O requests, either directly, or
  * by passing them to the server process.
  */
 static void
 mdstrategy(struct buf *bp)
+{
 	struct md_softc	*sc;
 	void *	addr;
 	size_t off, xfer;
 	sc = device_lookup_private(&md_cd, MD_UNIT(bp->b_dev));
-	if (sc->sc_type == MD_UNCONFIGURED) {
+	if (sc == NULL || sc->sc_type == MD_UNCONFIGURED) {
 		bp->b_error = ENXIO;
 		goto done;
+	}
 	switch (sc->sc_type) {
 #if MEMORY_DISK_SERVER
 	case MD_UMEM_SERVER:
 		/* Just add this job to the server's queue. */
 		bufq_put(sc->sc_buflist, bp);
 		wakeup((void *)sc);
 		/* see md_server_loop() */
 		/* no biodone in this case */
 		return;
 @@ -399,27 +399,28 @@ mdstrategy(struct buf *bp)
 		bp->b_error = EIO;
 		break;
+	}
  done:
 	biodone(bp);
+}
 static int
 mdioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
+{
 	struct md_softc *sc;
 	struct md_conf *umd;
-	sc = device_lookup_private(&md_cd, MD_UNIT(dev));
+	if ((sc = device_lookup_private(&md_cd, MD_UNIT(dev))) == NULL)
 		return ENXIO;
 	/* If this is not the raw partition, punt! */
 	if (DISKPART(dev) != RAW_PART)
 		return ENOTTY;
 	umd = (struct md_conf *)data;
 	switch (cmd) {
 	case MD_GETCONF:
 		*umd = sc->sc_md;
 		return 0;
 	case MD_SETCONF:
 		/* Can only set it once. */