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[src/trunk]: src/sys/net Replace ifnet_lock with if_get and if_put
details: https://anonhg.NetBSD.org/src/rev/7ea6c31c4040
branches: trunk
changeset: 815413:7ea6c31c4040
user: ozaki-r <ozaki-r%NetBSD.org@localhost>
date: Mon May 16 01:16:24 2016 +0000
description:
Replace ifnet_lock with if_get and if_put
ifnet_lock is a dedicated method to safely destroy an interface over running
ioctl operations. Replace it with a more generic mechanism using psref(9).
diffstat:
sys/net/if.c | 201 +++++++++++++++++-----------------------------------------
sys/net/if.h | 25 +------
2 files changed, 62 insertions(+), 164 deletions(-)
diffs (truncated from 423 to 300 lines):
diff -r b92b8d623d8c -r 7ea6c31c4040 sys/net/if.c
--- a/sys/net/if.c Mon May 16 01:06:31 2016 +0000
+++ b/sys/net/if.c Mon May 16 01:16:24 2016 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: if.c,v 1.335 2016/05/16 01:06:31 ozaki-r Exp $ */
+/* $NetBSD: if.c,v 1.336 2016/05/16 01:16:24 ozaki-r Exp $ */
/*-
* Copyright (c) 1999, 2000, 2001, 2008 The NetBSD Foundation, Inc.
@@ -90,7 +90,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if.c,v 1.335 2016/05/16 01:06:31 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if.c,v 1.336 2016/05/16 01:16:24 ozaki-r Exp $");
#if defined(_KERNEL_OPT)
#include "opt_inet.h"
@@ -192,10 +192,6 @@
static kauth_listener_t if_listener;
static int doifioctl(struct socket *, u_long, void *, struct lwp *);
-static int ifioctl_attach(struct ifnet *);
-static void ifioctl_detach(struct ifnet *);
-static void ifnet_lock_enter(struct ifnet_lock *);
-static void ifnet_lock_exit(struct ifnet_lock *);
static void if_detach_queues(struct ifnet *, struct ifqueue *);
static void sysctl_sndq_setup(struct sysctllog **, const char *,
struct ifaltq *);
@@ -348,10 +344,6 @@
if_nullioctl(struct ifnet *ifp, u_long cmd, void *data)
{
- /* Wake ifioctl_detach(), who may wait for all threads to
- * quit the critical section.
- */
- cv_signal(&ifp->if_ioctl_lock->il_emptied);
return ENXIO;
}
@@ -653,6 +645,7 @@
PSLIST_ENTRY_INIT(ifp, if_pslist_entry);
psref_target_init(&ifp->if_psref, ifnet_psref_class);
+ ifp->if_ioctl_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
IFNET_LOCK();
if_getindex(ifp);
@@ -665,8 +658,12 @@
void
if_register(ifnet_t *ifp)
{
- if (ifioctl_attach(ifp) != 0)
- panic("%s: ifioctl_attach() failed", __func__);
+ /*
+ * If the driver has not supplied its own if_ioctl, then
+ * supply the default.
+ */
+ if (ifp->if_ioctl == NULL)
+ ifp->if_ioctl = ifioctl_common;
sysctl_sndq_setup(&ifp->if_sysctl_log, ifp->if_xname, &ifp->if_snd);
@@ -1047,6 +1044,9 @@
s = splnet();
sysctl_teardown(&ifp->if_sysctl_log);
+ mutex_enter(ifp->if_ioctl_lock);
+ ifp->if_ioctl = if_nullioctl;
+ mutex_exit(ifp->if_ioctl_lock);
IFNET_LOCK();
ifindex2ifnet[ifp->if_index] = NULL;
@@ -1059,6 +1059,9 @@
psref_target_destroy(&ifp->if_psref, ifnet_psref_class);
PSLIST_ENTRY_DESTROY(ifp, if_pslist_entry);
+ mutex_obj_free(ifp->if_ioctl_lock);
+ ifp->if_ioctl_lock = NULL;
+
if (ifp->if_slowtimo != NULL) {
ifp->if_slowtimo = NULL;
callout_halt(ifp->if_slowtimo_ch, NULL);
@@ -1191,8 +1194,6 @@
/* Announce that the interface is gone. */
rt_ifannouncemsg(ifp, IFAN_DEPARTURE);
- ifioctl_detach(ifp);
-
IF_AFDATA_LOCK_DESTROY(ifp);
softint_disestablish(ifp->if_link_si);
@@ -1300,13 +1301,18 @@
{
struct if_clone *ifc;
int unit;
+ struct ifnet *ifp;
+ struct psref psref;
ifc = if_clone_lookup(name, &unit);
if (ifc == NULL)
return EINVAL;
- if (ifunit(name) != NULL)
+ ifp = if_get(name, &psref);
+ if (ifp != NULL) {
+ if_put(ifp, &psref);
return EEXIST;
+ }
return (*ifc->ifc_create)(ifc, unit);
}
@@ -1319,17 +1325,29 @@
{
struct if_clone *ifc;
struct ifnet *ifp;
+ struct psref psref;
ifc = if_clone_lookup(name, NULL);
if (ifc == NULL)
return EINVAL;
- ifp = ifunit(name);
+ if (ifc->ifc_destroy == NULL)
+ return EOPNOTSUPP;
+
+ ifp = if_get(name, &psref);
if (ifp == NULL)
return ENXIO;
- if (ifc->ifc_destroy == NULL)
- return EOPNOTSUPP;
+ /* We have to disable ioctls here */
+ mutex_enter(ifp->if_ioctl_lock);
+ ifp->if_ioctl = if_nullioctl;
+ mutex_exit(ifp->if_ioctl_lock);
+
+ /*
+ * We cannot call ifc_destroy with holding ifp.
+ * Releasing ifp here is safe thanks to if_clone_mtx.
+ */
+ if_put(ifp, &psref);
return (*ifc->ifc_destroy)(ifp);
}
@@ -2421,32 +2439,6 @@
}
}
-static void
-ifnet_lock_enter(struct ifnet_lock *il)
-{
- uint64_t *nenter;
-
- /* Before trying to acquire the mutex, increase the count of threads
- * who have entered or who wait to enter the critical section.
- * Avoid one costly locked memory transaction by keeping a count for
- * each CPU.
- */
- nenter = percpu_getref(il->il_nenter);
- (*nenter)++;
- percpu_putref(il->il_nenter);
- mutex_enter(&il->il_lock);
-}
-
-static void
-ifnet_lock_exit(struct ifnet_lock *il)
-{
- /* Increase the count of threads who have exited the critical
- * section. Increase while we still hold the lock.
- */
- il->il_nexit++;
- mutex_exit(&il->il_lock);
-}
-
/*
* Interface ioctls.
*/
@@ -2465,6 +2457,8 @@
struct oifreq *oifr = NULL;
#endif
int r;
+ struct psref psref;
+ int bound = curlwp->l_pflag & LP_BOUND;
switch (cmd) {
#ifdef COMPAT_OIFREQ
@@ -2493,24 +2487,29 @@
#endif
ifr = data;
- ifp = ifunit(ifr->ifr_name);
-
switch (cmd) {
case SIOCIFCREATE:
case SIOCIFDESTROY:
+ curlwp->l_pflag |= LP_BOUND;
if (l != NULL) {
+ ifp = if_get(ifr->ifr_name, &psref);
error = kauth_authorize_network(l->l_cred,
KAUTH_NETWORK_INTERFACE,
KAUTH_REQ_NETWORK_INTERFACE_SETPRIV, ifp,
(void *)cmd, NULL);
- if (error != 0)
+ if (ifp != NULL)
+ if_put(ifp, &psref);
+ if (error != 0) {
+ curlwp->l_pflag ^= bound ^ LP_BOUND;
return error;
+ }
}
mutex_enter(&if_clone_mtx);
r = (cmd == SIOCIFCREATE) ?
if_clone_create(ifr->ifr_name) :
if_clone_destroy(ifr->ifr_name);
mutex_exit(&if_clone_mtx);
+ curlwp->l_pflag ^= bound ^ LP_BOUND;
return r;
case SIOCIFGCLONERS:
@@ -2521,8 +2520,12 @@
}
}
- if (ifp == NULL)
+ curlwp->l_pflag |= LP_BOUND;
+ ifp = if_get(ifr->ifr_name, &psref);
+ if (ifp == NULL) {
+ curlwp->l_pflag ^= bound ^ LP_BOUND;
return ENXIO;
+ }
switch (cmd) {
case SIOCALIFADDR:
@@ -2557,13 +2560,14 @@
KAUTH_REQ_NETWORK_INTERFACE_SETPRIV, ifp,
(void *)cmd, NULL);
if (error != 0)
- return error;
+ goto out;
}
}
oif_flags = ifp->if_flags;
- ifnet_lock_enter(ifp->if_ioctl_lock);
+ mutex_enter(ifp->if_ioctl_lock);
+
error = (*ifp->if_ioctl)(ifp, cmd, data);
if (error != ENOTTY)
;
@@ -2590,100 +2594,13 @@
ifreqn2o(oifr, ifr);
#endif
- ifnet_lock_exit(ifp->if_ioctl_lock);
+ mutex_exit(ifp->if_ioctl_lock);
+out:
+ if_put(ifp, &psref);
+ curlwp->l_pflag ^= bound ^ LP_BOUND;
return error;
}
-/* This callback adds to the sum in `arg' the number of
- * threads on `ci' who have entered or who wait to enter the
- * critical section.
- */
-static void
-ifnet_lock_sum(void *p, void *arg, struct cpu_info *ci)
-{
- uint64_t *sum = arg, *nenter = p;
-
- *sum += *nenter;
-}
-
-/* Return the number of threads who have entered or who wait
- * to enter the critical section on all CPUs.
- */
-static uint64_t
-ifnet_lock_entrances(struct ifnet_lock *il)
-{
- uint64_t sum = 0;
-
- percpu_foreach(il->il_nenter, ifnet_lock_sum, &sum);
-
- return sum;
-}
-
-static int
-ifioctl_attach(struct ifnet *ifp)
-{
- struct ifnet_lock *il;
-
- /* If the driver has not supplied its own if_ioctl, then
- * supply the default.
- */
- if (ifp->if_ioctl == NULL)
- ifp->if_ioctl = ifioctl_common;
-
- /* Create an ifnet_lock for synchronizing ifioctls. */
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