[src/trunk]: src/sys/net Switch if_l2tp to atomic_load/store_*.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ee07fcae8c8d
branches:  trunk
changeset: 744415:ee07fcae8c8d
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Feb 01 02:58:05 2020 +0000

description:
Switch if_l2tp to atomic_load/store_*.

Fix missing membar_datadep_consumer -- now atomic_load_consume -- in
l2tp_lookup_session_ref.

diffstat:

 sys/net/if_l2tp.c |  24 ++++++------------------
 sys/net/if_l2tp.h |   5 ++---
 2 files changed, 8 insertions(+), 21 deletions(-)

diffs (127 lines):

diff -r a785e9711b27 -r ee07fcae8c8d sys/net/if_l2tp.c
--- a/sys/net/if_l2tp.c Sat Feb 01 02:57:55 2020 +0000
+++ b/sys/net/if_l2tp.c Sat Feb 01 02:58:05 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_l2tp.c,v 1.41 2020/01/29 04:18:34 thorpej Exp $     */
+/*     $NetBSD: if_l2tp.c,v 1.42 2020/02/01 02:58:05 riastradh Exp $   */
 
 /*
  * Copyright (c) 2017 Internet Initiative Japan Inc.
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_l2tp.c,v 1.41 2020/01/29 04:18:34 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_l2tp.c,v 1.42 2020/02/01 02:58:05 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -1061,7 +1061,6 @@
                encap_lock_exit();
                goto error;
        }
-       membar_producer();
        l2tp_variant_update(sc, nvar);
 
        mutex_exit(&sc->l2tp_lock);
@@ -1110,7 +1109,6 @@
        psref_target_init(&nvar->lv_psref, lv_psref_class);
        nvar->lv_psrc = NULL;
        nvar->lv_pdst = NULL;
-       membar_producer();
        l2tp_variant_update(sc, nvar);
 
        mutex_exit(&sc->l2tp_lock);
@@ -1185,7 +1183,6 @@
        psref_target_init(&nvar->lv_psref, lv_psref_class);
        nvar->lv_my_sess_id = my_sess_id;
        nvar->lv_peer_sess_id = peer_sess_id;
-       membar_producer();
 
        mutex_enter(&l2tp_hash.lock);
        if (ovar->lv_my_sess_id > 0 && ovar->lv_peer_sess_id > 0) {
@@ -1226,7 +1223,6 @@
        psref_target_init(&nvar->lv_psref, lv_psref_class);
        nvar->lv_my_sess_id = 0;
        nvar->lv_peer_sess_id = 0;
-       membar_producer();
 
        mutex_enter(&l2tp_hash.lock);
        if (ovar->lv_my_sess_id > 0 && ovar->lv_peer_sess_id > 0) {
@@ -1253,7 +1249,7 @@
        s = pserialize_read_enter();
        PSLIST_READER_FOREACH(sc, &l2tp_hash.lists[idx], struct l2tp_softc,
            l2tp_hash) {
-               struct l2tp_variant *var = sc->l2tp_var;
+               struct l2tp_variant *var = atomic_load_consume(&sc->l2tp_var);
                if (var == NULL)
                        continue;
                if (var->lv_my_sess_id != id)
@@ -1282,17 +1278,12 @@
 
        KASSERT(mutex_owned(&sc->l2tp_lock));
 
-       sc->l2tp_var = nvar;
+       atomic_store_release(&sc->l2tp_var, nvar);
        pserialize_perform(sc->l2tp_psz);
        psref_target_destroy(&ovar->lv_psref, lv_psref_class);
 
-       /*
-        * In the manual of atomic_swap_ptr(3), there is no mention if 2nd
-        * argument is rewrite or not. So, use sc->l2tp_var instead of nvar.
-        */
-       if (sc->l2tp_var != NULL) {
-               if (sc->l2tp_var->lv_psrc != NULL
-                   && sc->l2tp_var->lv_pdst != NULL)
+       if (nvar != NULL) {
+               if (nvar->lv_psrc != NULL && nvar->lv_pdst != NULL)
                        ifp->if_flags |= IFF_RUNNING;
                else
                        ifp->if_flags &= ~IFF_RUNNING;
@@ -1323,7 +1314,6 @@
        nvar->lv_peer_cookie = peer_cookie;
        nvar->lv_peer_cookie_len = peer_cookie_len;
        nvar->lv_use_cookie = L2TP_COOKIE_ON;
-       membar_producer();
        l2tp_variant_update(sc, nvar);
 
        mutex_exit(&sc->l2tp_lock);
@@ -1357,7 +1347,6 @@
        nvar->lv_peer_cookie = 0;
        nvar->lv_peer_cookie_len = 0;
        nvar->lv_use_cookie = L2TP_COOKIE_OFF;
-       membar_producer();
        l2tp_variant_update(sc, nvar);
 
        mutex_exit(&sc->l2tp_lock);
@@ -1376,7 +1365,6 @@
        *nvar = *sc->l2tp_var;
        psref_target_init(&nvar->lv_psref, lv_psref_class);
        nvar->lv_state = state;
-       membar_producer();
        l2tp_variant_update(sc, nvar);
 
        if (nvar->lv_state == L2TP_STATE_UP) {
diff -r a785e9711b27 -r ee07fcae8c8d sys/net/if_l2tp.h
--- a/sys/net/if_l2tp.h Sat Feb 01 02:57:55 2020 +0000
+++ b/sys/net/if_l2tp.h Sat Feb 01 02:58:05 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_l2tp.h,v 1.8 2019/09/19 06:07:24 knakahara Exp $    */
+/*     $NetBSD: if_l2tp.h,v 1.9 2020/02/01 02:58:05 riastradh Exp $    */
 
 /*
  * Copyright (c) 2017 Internet Initiative Japan Inc.
@@ -131,12 +131,11 @@
        int s;
 
        s = pserialize_read_enter();
-       var = sc->l2tp_var;
+       var = atomic_load_consume(&sc->l2tp_var);
        if (var == NULL) {
                pserialize_read_exit(s);
                return NULL;
        }
-       membar_datadep_consumer();
        psref_acquire(psref, &var->lv_psref, lv_psref_class);
        pserialize_read_exit(s);