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[src/trunk]: src/sys/net wg: Fix detach logic.
details: https://anonhg.NetBSD.org/src/rev/8d8123c3ec8c
branches: trunk
changeset: 943943:8d8123c3ec8c
user: riastradh <riastradh%NetBSD.org@localhost>
date: Sun Sep 13 17:18:54 2020 +0000
description:
wg: Fix detach logic.
Not tested but this should be less of a rake to step on if anyone
made an unloadable wg module.
diffstat:
sys/net/if_wg.c | 83 ++++++++++++++++++++++++++++++++------------------------
1 files changed, 48 insertions(+), 35 deletions(-)
diffs (167 lines):
diff -r f860fbc6ff8f -r 8d8123c3ec8c sys/net/if_wg.c
--- a/sys/net/if_wg.c Sun Sep 13 17:18:13 2020 +0000
+++ b/sys/net/if_wg.c Sun Sep 13 17:18:54 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: if_wg.c,v 1.58 2020/09/13 17:18:13 riastradh Exp $ */
+/* $NetBSD: if_wg.c,v 1.59 2020/09/13 17:18:54 riastradh Exp $ */
/*
* Copyright (C) Ryota Ozaki <ozaki.ryota%gmail.com@localhost>
@@ -41,7 +41,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_wg.c,v 1.58 2020/09/13 17:18:13 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_wg.c,v 1.59 2020/09/13 17:18:54 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_inet.h"
@@ -144,8 +144,6 @@
* - Data messages are always sent via a stable session
*
* Locking notes:
- * - wg interfaces (struct wg_softc, wg) is listed in wg_softcs.list and
- * protected by wg_softcs.lock
* - Each wg has a mutex(9) wg_lock, and a rwlock(9) wg_rwlock
* - Changes to the peer list are serialized by wg_lock
* - The peer list may be read with pserialize(9) and psref(9)
@@ -780,11 +778,7 @@
/*
* Global variables
*/
-LIST_HEAD(wg_sclist, wg_softc);
-static struct {
- struct wg_sclist list;
- kmutex_t lock;
-} wg_softcs __cacheline_aligned;
+static volatile unsigned wg_count __cacheline_aligned;
struct psref_class *wg_psref_class __read_mostly;
@@ -811,9 +805,6 @@
wg_psref_class = psref_class_create("wg", IPL_SOFTNET);
- mutex_init(&wg_softcs.lock, MUTEX_DEFAULT, IPL_NONE);
- LIST_INIT(&wg_softcs.list);
-
if_clone_attach(&wg_cloner);
}
@@ -848,23 +839,49 @@
}
static int
+wg_count_inc(void)
+{
+ unsigned o, n;
+
+ do {
+ o = atomic_load_relaxed(&wg_count);
+ if (o == UINT_MAX)
+ return ENFILE;
+ n = o + 1;
+ } while (atomic_cas_uint(&wg_count, o, n) != o);
+
+ return 0;
+}
+
+static void
+wg_count_dec(void)
+{
+ unsigned c __diagused;
+
+ c = atomic_dec_uint_nv(&wg_count);
+ KASSERT(c != UINT_MAX);
+}
+
+static int
wgdetach(void)
{
- int error = 0;
-
- mutex_enter(&wg_softcs.lock);
- if (!LIST_EMPTY(&wg_softcs.list)) {
- mutex_exit(&wg_softcs.lock);
- error = EBUSY;
+
+ /* Prevent new interface creation. */
+ if_clone_detach(&wg_cloner);
+
+ /* Check whether there are any existing interfaces. */
+ if (atomic_load_relaxed(&wg_count)) {
+ /* Back out -- reattach the cloner. */
+ if_clone_attach(&wg_cloner);
+ return EBUSY;
}
- if (error == 0) {
- psref_class_destroy(wg_psref_class);
-
- if_clone_detach(&wg_cloner);
- }
-
- return error;
+ /* No interfaces left. Nuke it. */
+ workqueue_destroy(wg_wq);
+ pktq_destroy(wg_pktq);
+ psref_class_destroy(wg_psref_class);
+
+ return 0;
}
static void
@@ -3555,6 +3572,10 @@
wg_guarantee_initialized();
+ error = wg_count_inc();
+ if (error)
+ return error;
+
wg = kmem_zalloc(sizeof(*wg), KM_SLEEP);
if_initname(&wg->wg_if, ifc->ifc_name, unit);
@@ -3593,16 +3614,9 @@
if (error)
goto fail3;
- mutex_enter(&wg_softcs.lock);
- LIST_INSERT_HEAD(&wg_softcs.list, wg, wg_list);
- mutex_exit(&wg_softcs.lock);
-
return 0;
fail4: __unused
- mutex_enter(&wg_softcs.lock);
- LIST_REMOVE(wg, wg_list);
- mutex_exit(&wg_softcs.lock);
wg_if_detach(wg);
fail3: wg_destroy_all_peers(wg);
#ifdef INET6
@@ -3640,6 +3654,7 @@
thmap_destroy(wg->wg_peers_bypubkey);
PSLIST_DESTROY(&wg->wg_peers);
kmem_free(wg, sizeof(*wg));
+ wg_count_dec();
return error;
}
@@ -3655,9 +3670,6 @@
}
#endif
- mutex_enter(&wg_softcs.lock);
- LIST_REMOVE(wg, wg_list);
- mutex_exit(&wg_softcs.lock);
wg_if_detach(wg);
wg_destroy_all_peers(wg);
#ifdef INET6
@@ -3693,6 +3705,7 @@
thmap_destroy(wg->wg_peers_bypubkey);
PSLIST_DESTROY(&wg->wg_peers);
kmem_free(wg, sizeof(*wg));
+ wg_count_dec();
return 0;
}
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