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Date:      Sun, 28 Feb 2010 16:25:49 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r204464 - head/sys/net
Message-ID:  <201002281625.o1SGPnh1030127@svn.freebsd.org>
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Author: kib
Date: Sun Feb 28 16:25:49 2010
New Revision: 204464
URL: http://svn.freebsd.org/changeset/base/204464

Log:
  In both if_tun and if_tap:
  
  Do not do additional dev_ref() on the newly created interface in the
  if_clone create method [1]. This reference is not needed and never
  removed, causing struct cdevpriv leakage. Remove the setting of
  SI_CHEAPCLONE flag as well, since it is unused.
  
  For dev_clone handlers, create cdevs with the call make_dev_credf(MAKEDEV_REF)
  instead of calling make_dev() and then dev_ref(), to avoid a race.
  
  Call drain_dev_clone_events() at the module unload time after dev_clone
  handler is deinstalled.
  
  Submitted by:	Mikolaj Golub <to.my.trociny gmail com> [1]
  MFC after:	1 week

Modified:
  head/sys/net/if_tap.c
  head/sys/net/if_tun.c

Modified: head/sys/net/if_tap.c
==============================================================================
--- head/sys/net/if_tap.c	Sun Feb 28 16:14:34 2010	(r204463)
+++ head/sys/net/if_tap.c	Sun Feb 28 16:25:49 2010	(r204464)
@@ -192,10 +192,6 @@ tap_clone_create(struct if_clone *ifc, i
 	if (i) {
 		dev = make_dev(&tap_cdevsw, unit | extra,
 		     UID_ROOT, GID_WHEEL, 0600, "%s%d", ifc->ifc_name, unit);
-		if (dev != NULL) {
-			dev_ref(dev);
-			dev->si_flags |= SI_CHEAPCLONE;
-		}
 	}
 
 	tapcreate(dev);
@@ -300,6 +296,7 @@ tapmodevent(module_t mod, int type, void
 		EVENTHANDLER_DEREGISTER(dev_clone, eh_tag);
 		if_clone_detach(&tap_cloner);
 		if_clone_detach(&vmnet_cloner);
+		drain_dev_clone_events();
 
 		mtx_lock(&tapmtx);
 		while ((tp = SLIST_FIRST(&taphead)) != NULL) {
@@ -381,12 +378,8 @@ tapclone(void *arg, struct ucred *cred, 
 			name = devname;
 		}
 
-		*dev = make_dev(&tap_cdevsw, unit | extra,
-		     UID_ROOT, GID_WHEEL, 0600, "%s", name);
-		if (*dev != NULL) {
-			dev_ref(*dev);
-			(*dev)->si_flags |= SI_CHEAPCLONE;
-		}
+		*dev = make_dev_credf(MAKEDEV_REF, &tap_cdevsw, unit | extra,
+		     cred, UID_ROOT, GID_WHEEL, 0600, "%s", name);
 	}
 
 	if_clone_create(name, namelen, NULL);

Modified: head/sys/net/if_tun.c
==============================================================================
--- head/sys/net/if_tun.c	Sun Feb 28 16:14:34 2010	(r204463)
+++ head/sys/net/if_tun.c	Sun Feb 28 16:25:49 2010	(r204464)
@@ -188,10 +188,6 @@ tun_clone_create(struct if_clone *ifc, i
 		/* No preexisting struct cdev *, create one */
 		dev = make_dev(&tun_cdevsw, unit,
 		    UID_UUCP, GID_DIALER, 0600, "%s%d", ifc->ifc_name, unit);
-		if (dev != NULL) {
-			dev_ref(dev);
-			dev->si_flags |= SI_CHEAPCLONE;
-		}
 	}
 	tuncreate(ifc->ifc_name, dev);
 
@@ -237,12 +233,8 @@ tunclone(void *arg, struct ucred *cred, 
 			name = devname;
 		}
 		/* No preexisting struct cdev *, create one */
-		*dev = make_dev(&tun_cdevsw, u,
+		*dev = make_dev_credf(MAKEDEV_REF, &tun_cdevsw, u, cred,
 		    UID_UUCP, GID_DIALER, 0600, "%s", name);
-		if (*dev != NULL) {
-			dev_ref(*dev);
-			(*dev)->si_flags |= SI_CHEAPCLONE;
-		}
 	}
 
 	if_clone_create(name, namelen, NULL);
@@ -303,6 +295,7 @@ tunmodevent(module_t mod, int type, void
 	case MOD_UNLOAD:
 		if_clone_detach(&tun_cloner);
 		EVENTHANDLER_DEREGISTER(dev_clone, tag);
+		drain_dev_clone_events();
 
 		mtx_lock(&tunmtx);
 		while ((tp = TAILQ_FIRST(&tunhead)) != NULL) {

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