Device megapatch 2/6:

This commit adds a couple of functions for pseudodrivers to use for
implementing cloning in a manner we will be able to lock down (shortly).

Basically what happens is that pseudo drivers get a way to ask for
"give me the dev_t with this unit number" or alternatively "give
me a dev_t with the lowest guaranteed free unit number" (there is
unfortunately a lot of non-POLA in the exact numeric value of this
number, just live with it for now)

Managing the unit number space this way removes the need to use
rman(9) to do so in the drivers this greatly simplifies the code in
the drivers because even using rman(9) they still needed to manage
their dev_t's anyway.

I have taken the if_tun, if_tap, snp and nmdm drivers through the
mill, partly because they (ab)used makedev(), but mostly because
together they represent three different problems for device-cloning:

if_tun and snp is the plain case: just give me a device.

if_tap has two kinds of devices, with a flag for device type.

nmdm has paired devices (ala pty) can you can clone either of them.

1 files changed, 35 insertions, 129 deletions

diff --git a/sys/net/if_tap.c b/sys/net/if_tap.c
index 82ae3b9..f83243b 100644
--- a/sys/net/if_tap.c
+++ b/sys/net/if_tap.c
@@ -54,8 +54,6 @@
 #include <sys/ttycom.h>
 #include <sys/uio.h>
 #include <sys/vnode.h>
-#include <machine/bus.h>	/* XXX: Shouldn't really be required! */
-#include <sys/rman.h>
 #include <sys/queue.h>
 
 #include <net/bpf.h>
@@ -71,14 +69,12 @@
 
 
 #define CDEV_NAME	"tap"
-#define CDEV_MAJOR	149
 #define TAPDEBUG	if (tapdebug) printf
 
 #define TAP		"tap"
 #define VMNET		"vmnet"
 #define TAPMAXUNIT	0x7fff
-#define VMNET_DEV_MASK	0x00800000
-		/*	0x007f00ff	*/
+#define VMNET_DEV_MASK	CLONE_FLAG0
 
 /* module */
 static int		tapmodevent(module_t, int, void *);
@@ -108,15 +104,12 @@ static struct cdevsw	tap_cdevsw = {
 	.d_ioctl =	tapioctl,
 	.d_poll =	tappoll,
 	.d_name =	CDEV_NAME,
-	.d_maj =	CDEV_MAJOR,
+	.d_flags =	D_PSEUDO,
 };
 
 static int			tapdebug = 0;        /* debug flag   */
 static SLIST_HEAD(, tap_softc)	taphead;             /* first device */
-static udev_t			tapbasedev = NOUDEV; /* base device  */
-static struct rman		tapdevunits[2];      /* device units */
-#define		tapunits	tapdevunits
-#define		vmnetunits	(tapdevunits + 1)
+static struct clonedevs 	*tapclones;
 
 MALLOC_DECLARE(M_TAP);
 MALLOC_DEFINE(M_TAP, CDEV_NAME, "Ethernet tunnel interface");
@@ -137,63 +130,27 @@ tapmodevent(mod, type, data)
 	static eventhandler_tag	 eh_tag = NULL;
 	struct tap_softc	*tp = NULL;
 	struct ifnet		*ifp = NULL;
-	int			 error, s;
+	int			 s;
 
 	switch (type) {
 	case MOD_LOAD:
-		/* initialize resources */
-		tapunits->rm_type = RMAN_ARRAY;
-		tapunits->rm_descr = "open tap units";
-		vmnetunits->rm_type = RMAN_ARRAY;
-		vmnetunits->rm_descr = "open vmnet units";
-
-		error = rman_init(tapunits);
-		if (error != 0)
-			goto bail;
-
-		error = rman_init(vmnetunits);
-		if (error != 0)
-			goto bail1;
-
-		error = rman_manage_region(tapunits, 0, TAPMAXUNIT);
-		if (error != 0)
-			goto bail2;
-
-		error = rman_manage_region(vmnetunits, 0, TAPMAXUNIT);
-		if (error != 0)
-			goto bail2;
 
 		/* intitialize device */
 
 		SLIST_INIT(&taphead);
 
 		eh_tag = EVENTHANDLER_REGISTER(dev_clone, tapclone, 0, 1000);
-		if (eh_tag == NULL) {
-			error = ENOMEM;
-			goto bail2;
-		}
-
-
+		if (eh_tag == NULL)
+			return (ENOMEM);
 		return (0);
-bail2:
-		rman_fini(vmnetunits);
-bail1:
-		rman_fini(tapunits);
-bail:
-		return (error);
 
 	case MOD_UNLOAD:
 		SLIST_FOREACH(tp, &taphead, tap_next)
-			if (tp->tap_unit != NULL)
+			if (tp->tap_flags & TAP_OPEN)
 				return (EBUSY);
 
 		EVENTHANDLER_DEREGISTER(dev_clone, eh_tag);
 
-		error = rman_fini(tapunits);
-		KASSERT((error == 0), ("Could not fini tap units"));
-		error = rman_fini(vmnetunits);
-		KASSERT((error == 0), ("Could not fini vmnet units"));
-
 		while ((tp = SLIST_FIRST(&taphead)) != NULL) {
 			SLIST_REMOVE_HEAD(&taphead, tap_next);
 
@@ -204,18 +161,14 @@ bail:
 			KASSERT(!(tp->tap_flags & TAP_OPEN), 
 				("%s flags is out of sync", ifp->if_xname));
 
-			/* XXX makedev check? nah.. not right now :) */
-
+			destroy_dev(tp->tap_dev);
 			s = splimp();
 			ether_ifdetach(ifp);
 			splx(s);
 
 			free(tp, M_TAP);
 		}
-
-		if (tapbasedev != NOUDEV)
-			destroy_dev(udev2dev(tapbasedev, 0));
-
+		clone_cleanup(&tapclones);
 
 		break;
 
@@ -239,65 +192,35 @@ tapclone(arg, name, namelen, dev)
 	int	 namelen;
 	dev_t	*dev;
 {
-	int		 unit, minor = 0 /* XXX avoid warning */ , error;
+	u_int		extra;
+	int		i, unit;
 	char		*device_name = name;
-	struct resource	*r = NULL;
 
 	if (*dev != NODEV)
 		return;
 
-	if (strcmp(device_name, TAP) == 0) {
-		/* get first free tap unit */
-		r = rman_reserve_resource(tapunits, 0, TAPMAXUNIT, 1,
-			RF_ALLOCATED | RF_ACTIVE, NULL);
-		unit = rman_get_start(r);
-		minor = unit2minor(unit);
-	}
-	else if (strcmp(device_name, VMNET) == 0) {
-		/* get first free vmnet unit */
-		r = rman_reserve_resource(vmnetunits, 0, TAPMAXUNIT, 1,
-			RF_ALLOCATED | RF_ACTIVE, NULL);
-		unit = rman_get_start(r);
-		minor = unit2minor(unit) | VMNET_DEV_MASK;
+	device_name = TAP;
+	extra = 0;
+	if (strcmp(name, TAP) == 0) {
+		unit = -1;
+	} else if (strcmp(name, VMNET) == 0) {
+		device_name = VMNET;
+		extra = VMNET_DEV_MASK;
+		unit = -1;
+	} else if (dev_stdclone(name, NULL, device_name, &unit) != 1) {
+		device_name = VMNET;
+		extra = VMNET_DEV_MASK;
+		if (dev_stdclone(name, NULL, device_name, &unit) != 1)
+			return;
 	}
 
-	if (r != NULL) { /* need cloning */
-		TAPDEBUG("%s%d is available. minor = %#x\n",
-			device_name, unit, minor);
-
-		error = rman_release_resource(r);
-		KASSERT((error == 0), ("Could not release tap/vmnet unit"));
-
-		/* check if device for the unit has been created */
-		*dev = makedev(CDEV_MAJOR, minor);
-		if ((*dev)->si_flags & SI_NAMED) {
-			TAPDEBUG("%s%d device exists. minor = %#x\n",
-				device_name, unit, minor);
-			return; /* device has been created */
-		}
-	} else { /* try to match name/unit, first try tap then vmnet */
-		device_name = TAP;
-		if (dev_stdclone(name, NULL, device_name, &unit) != 1) {
-			device_name = VMNET;
-
-			if (dev_stdclone(name, NULL, device_name, &unit) != 1)
-				return;
-
-			minor = unit2minor(unit) | VMNET_DEV_MASK;
-		} else
-			minor = unit2minor(unit);
-	}
-
-	TAPDEBUG("make_dev(%s%d). minor = %#x\n", device_name, unit, minor);
-
-	*dev = make_dev(&tap_cdevsw, minor, UID_ROOT, GID_WHEEL, 0600, "%s%d",
-			device_name, unit);
-
-	if (tapbasedev == NOUDEV)
-		tapbasedev = (*dev)->si_udev;
-	else {
-		(*dev)->si_flags |= SI_CHEAPCLONE;
-		dev_depends(udev2dev(tapbasedev, 0), *dev);
+	/* find any existing device, or allocate new unit number */
+	i = clone_create(&tapclones, &tap_cdevsw, &unit, dev, extra);
+	if (i) {
+		*dev = make_dev(&tap_cdevsw, unit2minor(unit) | extra,
+		     UID_ROOT, GID_WHEEL, 0600, "%s%d", device_name, unit);
+		if (*dev != NULL)
+			(*dev)->si_flags |= SI_CHEAPCLONE;
 	}
 } /* tapclone */
 
@@ -317,6 +240,8 @@ tapcreate(dev)
 	int			 unit, s;
 	char			*name = NULL;
 
+	dev->si_flags &= ~SI_CHEAPCLONE;
+
 	/* allocate driver storage and create device */
 	MALLOC(tp, struct tap_softc *, sizeof(*tp), M_TAP, M_WAITOK | M_ZERO);
 	SLIST_INSERT_HEAD(&taphead, tp, tap_next);
@@ -354,6 +279,7 @@ tapcreate(dev)
 	ifp->if_snd.ifq_maxlen = ifqmaxlen;
 
 	dev->si_drv1 = tp;
+	tp->tap_dev = dev;
 
 	s = splimp();
 	ether_ifattach(ifp, tp->arpcom.ac_enaddr);
@@ -380,24 +306,12 @@ tapopen(dev, flag, mode, td)
 {
 	struct tap_softc	*tp = NULL;
 	int			 unit, error;
-	struct resource		*r = NULL;
 
 	if ((error = suser(td)) != 0)
 		return (error);
 
 	unit = dev2unit(dev) & TAPMAXUNIT;
 
-	if (minor(dev) & VMNET_DEV_MASK)
-		r = rman_reserve_resource(vmnetunits, unit, unit, 1,
-			RF_ALLOCATED | RF_ACTIVE, NULL);
-	else
-		r = rman_reserve_resource(tapunits, unit, unit, 1,
-			RF_ALLOCATED | RF_ACTIVE, NULL);
-
-	if (r == NULL)
-		return (EBUSY);
-
-	dev->si_flags &= ~SI_CHEAPCLONE;
 
 	tp = dev->si_drv1;
 	if (tp == NULL) {
@@ -410,7 +324,6 @@ tapopen(dev, flag, mode, td)
 
 	bcopy(tp->arpcom.ac_enaddr, tp->ether_addr, sizeof(tp->ether_addr));
 
-	tp->tap_unit = r;
 	tp->tap_pid = td->td_proc->p_pid;
 	tp->tap_flags |= TAP_OPEN;
 
@@ -433,12 +346,9 @@ tapclose(dev, foo, bar, td)
 	int		 bar;
 	struct thread	*td;
 {
-	int			 s, error;
 	struct tap_softc	*tp = dev->si_drv1;
 	struct ifnet		*ifp = &tp->tap_if;
-
-	KASSERT((tp->tap_unit != NULL),
-		("%s is not open", ifp->if_xname));
+	int			s;
 
 	/* junk all pending output */
 	IF_DRAIN(&ifp->if_snd);
@@ -479,10 +389,6 @@ tapclose(dev, foo, bar, td)
 
 	tp->tap_flags &= ~TAP_OPEN;
 	tp->tap_pid = 0;
-	error = rman_release_resource(tp->tap_unit);
-	KASSERT((error == 0), 
-		("%s could not release unit", ifp->if_xname)); 
-	tp->tap_unit = NULL;
 
 	TAPDEBUG("%s is closed. minor = %#x\n", 
 		ifp->if_xname, minor(dev));