Don't enforce unique device minor number policy anymore.

Except for the case where we use the cloner library (clone_create() and
friends), there is no reason to enforce a unique device minor number
policy. There are various drivers in the source tree that allocate unr
pools and such to provide minor numbers, without using them themselves.

Because we still need to support unique device minor numbers for the
cloner library, introduce a new flag called D_NEEDMINOR. All cdevsw's
that are used in combination with the cloner library should be marked
with this flag to make the cloning work.

This means drivers can now freely use si_drv0 to store their own flags
and state, making it effectively the same as si_drv1 and si_drv2. We
still keep the minor() and dev2unit() routines around to make drivers
happy.

The NTFS code also used the minor number in its hash table. We should
not do this anymore. If the si_drv0 field would be changed, it would no
longer end up in the same list.

Approved by:	philip (mentor)

sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c

@@ -16445,6 +16445,7 @@ void dtrace_invop_uninit(void);
 
 static struct cdevsw dtrace_cdevsw = {
 	.d_version	= D_VERSION,
+	.d_flags	= D_NEEDMINOR,
 	.d_close	= dtrace_close,
 	.d_ioctl	= dtrace_ioctl,
 	.d_open		= dtrace_open,

sys/dev/nmdm/nmdm.c

@@ -68,7 +68,7 @@ static struct cdevsw nmdm_cdevsw = {
 	.d_open =	nmdmopen,
 	.d_close =	nmdmclose,
 	.d_name =	"nmdn",
-	.d_flags =	D_TTY | D_PSEUDO | D_NEEDGIANT,
+	.d_flags =	D_TTY | D_PSEUDO | D_NEEDGIANT | D_NEEDMINOR,
 };
 
 #define BUFSIZ 		100		/* Chunk size iomoved to/from user */

sys/dev/snp/snp.c

@@ -44,7 +44,7 @@ static	d_poll_t	snppoll;
 
 static struct cdevsw snp_cdevsw = {
 	.d_version =	D_VERSION,
-	.d_flags =	D_PSEUDO | D_NEEDGIANT,
+	.d_flags =	D_PSEUDO | D_NEEDGIANT | D_NEEDMINOR,
 	.d_open =	snpopen,
 	.d_close =	snpclose,
 	.d_read =	snpread,

sys/dev/vkbd/vkbd.c

@@ -158,7 +158,7 @@ static int		vkbd_data_read(vkbd_state_t *, int);
 
 static struct cdevsw	vkbd_dev_cdevsw = {
 	.d_version =	D_VERSION,
-	.d_flags =	D_PSEUDO | D_NEEDGIANT,
+	.d_flags =	D_PSEUDO | D_NEEDGIANT | D_NEEDMINOR,
 	.d_open =	vkbd_dev_open,
 	.d_close =	vkbd_dev_close,
 	.d_read =	vkbd_dev_read,

sys/fs/ntfs/ntfs_ihash.c

@@ -52,7 +52,7 @@ MALLOC_DEFINE(M_NTFSNTHASH, "ntfs_nthash", "NTFS ntnode hash tables");
  */
 static LIST_HEAD(nthashhead, ntnode) *ntfs_nthashtbl;
 static u_long	ntfs_nthash;		/* size of hash table - 1 */
-#define	NTNOHASH(device, inum)	(&ntfs_nthashtbl[(minor(device) + (inum)) & ntfs_nthash])
+#define	NTNOHASH(inum)	(&ntfs_nthashtbl[(inum) & ntfs_nthash])
 static struct mtx ntfs_nthash_mtx;
 struct lock ntfs_hashlock;
 
@@ -90,7 +90,7 @@ ntfs_nthashlookup(dev, inum)
 	struct ntnode *ip;
 
 	mtx_lock(&ntfs_nthash_mtx);
-	LIST_FOREACH(ip, NTNOHASH(dev, inum), i_hash)
+	LIST_FOREACH(ip, NTNOHASH(inum), i_hash)
 		if (inum == ip->i_number && dev == ip->i_dev)
 			break;
 	mtx_unlock(&ntfs_nthash_mtx);
@@ -108,7 +108,7 @@ ntfs_nthashins(ip)
 	struct nthashhead *ipp;
 
 	mtx_lock(&ntfs_nthash_mtx);
-	ipp = NTNOHASH(ip->i_dev, ip->i_number);
+	ipp = NTNOHASH(ip->i_number);
 	LIST_INSERT_HEAD(ipp, ip, i_hash);
 	ip->i_flag |= IN_HASHED;
 	mtx_unlock(&ntfs_nthash_mtx);

sys/i386/acpica/acpi_machdep.c

@@ -84,7 +84,7 @@ static struct filterops	apm_readfiltops =
 
 static struct cdevsw apm_cdevsw = {
 	.d_version =	D_VERSION,
-	.d_flags =	D_TRACKCLOSE,
+	.d_flags =	D_TRACKCLOSE | D_NEEDMINOR,
 	.d_open =	apmopen,
 	.d_close =	apmclose,
 	.d_write =	apmwrite,

sys/kern/kern_conf.c

@@ -566,10 +566,13 @@ newdev(struct cdevsw *csw, int y, struct cdev *si)
 
 	mtx_assert(&devmtx, MA_OWNED);
 	udev = y;
-	LIST_FOREACH(si2, &csw->d_devs, si_list) {
-		if (si2->si_drv0 == udev) {
-			dev_free_devlocked(si);
-			return (si2);
+	if (csw->d_flags & D_NEEDMINOR) {
+		/* We may want to return an existing device */
+		LIST_FOREACH(si2, &csw->d_devs, si_list) {
+			if (si2->si_drv0 == udev) {
+				dev_free_devlocked(si);
+				return (si2);
+			}
 		}
 	}
 	si->si_drv0 = udev;
@@ -1016,6 +1019,8 @@ clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **
 	    ("Illegal extra bits (0x%x) in clone_create", extra));
 	KASSERT(*up <= CLONE_UNITMASK,
 	    ("Too high unit (0x%x) in clone_create", *up));
+	KASSERT(csw->d_flags & D_NEEDMINOR,
+	    ("clone_create() on cdevsw without minor numbers"));
 
 
 	/*

sys/net/if_tap.c

@@ -132,7 +132,7 @@ static struct filterops	tap_write_filterops = {
 
 static struct cdevsw	tap_cdevsw = {
 	.d_version =	D_VERSION,
-	.d_flags =	D_PSEUDO | D_NEEDGIANT,
+	.d_flags =	D_PSEUDO | D_NEEDGIANT | D_NEEDMINOR,
 	.d_open =	tapopen,
 	.d_close =	tapclose,
 	.d_read =	tapread,

sys/net/if_tun.c

@@ -162,7 +162,7 @@ static struct filterops tun_write_filterops = {
 
 static struct cdevsw tun_cdevsw = {
 	.d_version =	D_VERSION,
-	.d_flags =	D_PSEUDO | D_NEEDGIANT,
+	.d_flags =	D_PSEUDO | D_NEEDGIANT | D_NEEDMINOR,
 	.d_open =	tunopen,
 	.d_close =	tunclose,
 	.d_read =	tunread,

sys/security/audit/audit_pipe.c

@@ -177,7 +177,7 @@ static d_kqfilter_t	audit_pipe_kqfilter;
 
 static struct cdevsw	audit_pipe_cdevsw = {
 	.d_version =	D_VERSION,
-	.d_flags =	D_PSEUDO | D_NEEDGIANT,
+	.d_flags =	D_PSEUDO | D_NEEDGIANT | D_NEEDMINOR,
 	.d_open =	audit_pipe_open,
 	.d_close =	audit_pipe_close,
 	.d_read =	audit_pipe_read,

sys/sys/conf.h

@@ -71,7 +71,7 @@ struct cdev {
 	gid_t		si_gid;
 	mode_t		si_mode;
 	struct ucred	*si_cred;	/* cached clone-time credential */
-	u_int		si_drv0;
+	int		si_drv0;
 	int		si_refcount;
 	LIST_ENTRY(cdev)	si_list;
 	LIST_ENTRY(cdev)	si_clone;
@@ -171,6 +171,7 @@ typedef int dumper_t(
 #define D_MMAP_ANON	0x00100000	/* special treatment in vm_mmap.c */
 #define D_PSEUDO	0x00200000	/* make_dev() can return NULL */
 #define D_NEEDGIANT	0x00400000	/* driver want Giant */
+#define	D_NEEDMINOR	0x00800000	/* driver uses clone_create() */
 
 /*
  * Version numbers.