[src/trunk]: src/sys/net Remove IFNET_GLOBAL_LOCK where it's unnecessary beca...

[ozaki-r <ozaki-r%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/17648801cb34
branches:  trunk
changeset: 358160:17648801cb34
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Fri Dec 15 04:04:58 2017 +0000

description:
Remove IFNET_GLOBAL_LOCK where it's unnecessary because IFNET_LOCK is held

diffstat:

 sys/net/if.c |  26 +++++++++++++++++++-------
 1 files changed, 19 insertions(+), 7 deletions(-)

diffs (62 lines):

diff -r 01a0e659183c -r 17648801cb34 sys/net/if.c
--- a/sys/net/if.c      Fri Dec 15 04:03:46 2017 +0000
+++ b/sys/net/if.c      Fri Dec 15 04:04:58 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if.c,v 1.415 2017/12/15 04:03:46 ozaki-r Exp $ */
+/*     $NetBSD: if.c,v 1.416 2017/12/15 04:04:58 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 1.415 2017/12/15 04:03:46 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if.c,v 1.416 2017/12/15 04:04:58 ozaki-r Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_inet.h"
@@ -1792,11 +1792,18 @@
 
        ifa->ifa_ifp = ifp;
 
-       IFNET_GLOBAL_LOCK();
+       /*
+        * Check !IFF_RUNNING for initialization routines that normally don't
+        * take IFNET_LOCK but it's safe because there is no competitor.
+        * XXX there are false positive cases because IFF_RUNNING can be off on
+        * if_stop.
+        */
+       KASSERT(!ISSET(ifp->if_flags, IFF_RUNNING) ||
+           IFNET_LOCKED(ifp));
+
        TAILQ_INSERT_TAIL(&ifp->if_addrlist, ifa, ifa_list);
        IFADDR_ENTRY_INIT(ifa);
        IFADDR_WRITER_INSERT_TAIL(ifp, ifa);
-       IFNET_GLOBAL_UNLOCK();
 
        ifaref(ifa);
 }
@@ -1806,14 +1813,19 @@
 {
 
        KASSERT(ifa->ifa_ifp == ifp);
-
-       IFNET_GLOBAL_LOCK();
+       /*
+        * if_is_deactivated indicates ifa_remove is called form if_detach
+        * where is safe even if IFNET_LOCK isn't held.
+        */
+       KASSERT(if_is_deactivated(ifp) || IFNET_LOCKED(ifp));
+
        TAILQ_REMOVE(&ifp->if_addrlist, ifa, ifa_list);
        IFADDR_WRITER_REMOVE(ifa);
 #ifdef NET_MPSAFE
+       IFNET_GLOBAL_LOCK();
        pserialize_perform(ifnet_psz);
+       IFNET_GLOBAL_UNLOCK();
 #endif
-       IFNET_GLOBAL_UNLOCK();
 
 #ifdef NET_MPSAFE
        psref_target_destroy(&ifa->ifa_psref, ifa_psref_class);