Date: Sun, 20 Oct 2019 22:55:47 +0000 (UTC) From: Kyle Evans <kevans@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r353786 - head/sys/net Message-ID: <201910202255.x9KMtlki086927@repo.freebsd.org>
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Author: kevans Date: Sun Oct 20 22:55:47 2019 New Revision: 353786 URL: https://svnweb.freebsd.org/changeset/base/353786 Log: tuntap(4): use cdevpriv w/ dtor for last close instead of d_close cdevpriv dtors will be called when the reference count on the associated struct file drops to 0, while d_close can be unreliable for cleaning up state at "last close" for a number of reasons. As far as tunclose/tundtor is concerned the difference is minimal, so make the switch. Modified: head/sys/net/if_tuntap.c Modified: head/sys/net/if_tuntap.c ============================================================================== --- head/sys/net/if_tuntap.c Sun Oct 20 22:39:40 2019 (r353785) +++ head/sys/net/if_tuntap.c Sun Oct 20 22:55:47 2019 (r353786) @@ -220,6 +220,7 @@ static int tuntap_name2info(const char *name, int *uni static void tunclone(void *arg, struct ucred *cred, char *name, int namelen, struct cdev **dev); static void tuncreate(struct cdev *dev); +static void tundtor(void *data); static void tunrename(void *arg, struct ifnet *ifp); static int tunifioctl(struct ifnet *, u_long, caddr_t); static void tuninit(struct ifnet *); @@ -238,7 +239,6 @@ static int tun_clone_destroy(struct if_clone *, struct static void tun_vnethdr_set(struct ifnet *ifp, int vhdrlen); static d_open_t tunopen; -static d_close_t tunclose; static d_read_t tunread; static d_write_t tunwrite; static d_ioctl_t tunioctl; @@ -278,7 +278,6 @@ static struct tuntap_driver { .d_version = D_VERSION, .d_flags = D_NEEDMINOR, .d_open = tunopen, - .d_close = tunclose, .d_read = tunread, .d_write = tunwrite, .d_ioctl = tunioctl, @@ -296,7 +295,6 @@ static struct tuntap_driver { .d_version = D_VERSION, .d_flags = D_NEEDMINOR, .d_open = tunopen, - .d_close = tunclose, .d_read = tunread, .d_write = tunwrite, .d_ioctl = tunioctl, @@ -314,7 +312,6 @@ static struct tuntap_driver { .d_version = D_VERSION, .d_flags = D_NEEDMINOR, .d_open = tunopen, - .d_close = tunclose, .d_read = tunread, .d_write = tunwrite, .d_ioctl = tunioctl, @@ -1100,24 +1097,33 @@ tunopen(struct cdev *dev, int flag, int mode, struct t if_link_state_change(ifp, LINK_STATE_UP); TUNDEBUG(ifp, "open\n"); TUN_UNLOCK(tp); + + /* + * This can fail with either ENOENT or EBUSY. This is in the middle of + * d_open, so ENOENT should not be possible. EBUSY is possible, but + * the only cdevpriv dtor being set will be tundtor and the softc being + * passed is constant for a given cdev. We ignore the possible error + * because of this as either "unlikely" or "not actually a problem." + */ + (void)devfs_set_cdevpriv(tp, tundtor); CURVNET_RESTORE(); return (0); } /* - * tunclose - close the device - mark i/f down & delete + * tundtor - tear down the device - mark i/f down & delete * routing info */ -static int -tunclose(struct cdev *dev, int foo, int bar, struct thread *td) +static void +tundtor(void *data) { struct proc *p; struct tuntap_softc *tp; struct ifnet *ifp; bool l2tun; - p = td->td_proc; - tp = dev->si_drv1; + tp = data; + p = curproc; ifp = TUN2IFP(tp); TUN_LOCK(tp); @@ -1133,7 +1139,7 @@ tunclose(struct cdev *dev, int foo, int bar, struct th if (p->p_pid != tp->tun_pid) { log(LOG_INFO, "pid %d (%s), %s: tun/tap protocol violation, non-controlling process closed last.\n", - p->p_pid, p->p_comm, dev->si_name); + p->p_pid, p->p_comm, tp->tun_dev->si_name); } /* @@ -1193,7 +1199,6 @@ out: tun_unbusy_locked(tp); TUN_UNLOCK(tp); - return (0); } static void
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