[src/trunk]: src/sys/netinet6 Allow in6_lltable_free_entry to be called witho...

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

details:   https://anonhg.NetBSD.org/src/rev/255520b98862
branches:  trunk
changeset: 354579:255520b98862
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Thu Jun 22 09:29:23 2017 +0000

description:
Allow in6_lltable_free_entry to be called without holding the afdata lock of ifp as well as in_lltable_free_entry

This behavior is a bit odd and should be fixed in the future...

diffstat:

 sys/netinet6/in6.c |  15 +++++++++------
 1 files changed, 9 insertions(+), 6 deletions(-)

diffs (57 lines):

diff -r 69a1d377ec0e -r 255520b98862 sys/netinet6/in6.c
--- a/sys/netinet6/in6.c        Thu Jun 22 09:26:43 2017 +0000
+++ b/sys/netinet6/in6.c        Thu Jun 22 09:29:23 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: in6.c,v 1.246 2017/06/21 09:05:31 ozaki-r Exp $        */
+/*     $NetBSD: in6.c,v 1.247 2017/06/22 09:29:23 ozaki-r Exp $        */
 /*     $KAME: in6.c,v 1.198 2001/07/18 09:12:38 itojun Exp $   */
 
 /*
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: in6.c,v 1.246 2017/06/21 09:05:31 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: in6.c,v 1.247 2017/06/22 09:29:23 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -2416,15 +2416,16 @@
 in6_lltable_free_entry(struct lltable *llt, struct llentry *lle)
 {
        struct ifnet *ifp = llt->llt_ifp;
+       bool locked = false;
 
-       IF_AFDATA_WLOCK_ASSERT(ifp);
        LLE_WLOCK_ASSERT(lle);
 
        /* Unlink entry from table */
        if ((lle->la_flags & LLE_LINKED) != 0) {
-
+               IF_AFDATA_WLOCK_ASSERT(ifp);
                lltable_unlink_entry(llt, lle);
                KASSERT((lle->la_flags & LLE_LINKED) == 0);
+               locked = true;
        }
        /*
         * We need to release the lock here to lle_timer proceeds;
@@ -2434,7 +2435,8 @@
         */
        LLE_ADDREF(lle);
        LLE_WUNLOCK(lle);
-       IF_AFDATA_WUNLOCK(ifp);
+       if (locked)
+               IF_AFDATA_WUNLOCK(ifp);
 
 #ifdef NET_MPSAFE
        callout_halt(&lle->lle_timer, NULL);
@@ -2450,7 +2452,8 @@
        lltable_drop_entry_queue(lle);
        LLE_FREE_LOCKED(lle);
 
-       IF_AFDATA_WLOCK(ifp);
+       if (locked)
+               IF_AFDATA_WLOCK(ifp);
 }
 
 static int