diff options
| author |   guenther <guenther@openbsd.org> | 2014-09-01 03:37:10 +0000 |
|---|---|---|
| committer | guenther <guenther@openbsd.org> | 2014-09-01 03:37:10 +0000 |
| commit | c73429fe513b33d5a02a4f6a53dc10a9549349ec (patch) | |
| tree | ff042e9b2b3bcf3dfabc82f8fa4cf4df54631245 /sys/kern/kern_rwlock.c | |
| parent | Simplify the syslog.conf example: .info means that *and higher* (diff) | |
| download | wireguard-openbsd-c73429fe513b33d5a02a4f6a53dc10a9549349ec.tar.xz wireguard-openbsd-c73429fe513b33d5a02a4f6a53dc10a9549349ec.zip | |
Add explicit membars, so that we can stop requiring rw_cas() to
provide the magic.
ok matthew@ dlg@
Diffstat (limited to 'sys/kern/kern_rwlock.c')
| -rw-r--r-- | sys/kern/kern_rwlock.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c index e1def9e874d..bf90a4428be 100644 --- a/sys/kern/kern_rwlock.c +++ b/sys/kern/kern_rwlock.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_rwlock.c,v 1.22 2014/07/09 13:32:00 guenther Exp $ */ +/* $OpenBSD: kern_rwlock.c,v 1.23 2014/09/01 03:37:10 guenther Exp $ */ /* * Copyright (c) 2002, 2003 Artur Grabowski <art@openbsd.org> @@ -22,6 +22,7 @@ #include <sys/proc.h> #include <sys/rwlock.h> #include <sys/limits.h> +#include <sys/atomic.h> #include <machine/lock.h> @@ -85,6 +86,8 @@ rw_enter_read(struct rwlock *rwl) if (__predict_false((owner & RWLOCK_WRLOCK) || rw_cas(&rwl->rwl_owner, owner, owner + RWLOCK_READ_INCR))) rw_enter(rwl, RW_READ); + else + membar_enter(); } void @@ -95,6 +98,8 @@ rw_enter_write(struct rwlock *rwl) if (__predict_false(rw_cas(&rwl->rwl_owner, 0, RW_PROC(p) | RWLOCK_WRLOCK))) rw_enter(rwl, RW_WRITE); + else + membar_enter(); } void @@ -104,6 +109,7 @@ rw_exit_read(struct rwlock *rwl) rw_assert_rdlock(rwl); + membar_exit(); if (__predict_false((owner & RWLOCK_WAIT) || rw_cas(&rwl->rwl_owner, owner, owner - RWLOCK_READ_INCR))) rw_exit(rwl); @@ -116,6 +122,7 @@ rw_exit_write(struct rwlock *rwl) rw_assert_wrlock(rwl); + membar_exit(); if (__predict_false((owner & RWLOCK_WAIT) || rw_cas(&rwl->rwl_owner, owner, 0))) rw_exit(rwl); @@ -215,6 +222,7 @@ retry: if (__predict_false(rw_cas(&rwl->rwl_owner, o, o + inc))) goto retry; + membar_enter(); /* * If old lock had RWLOCK_WAIT and RWLOCK_WRLOCK set, it means we @@ -240,6 +248,7 @@ rw_exit(struct rwlock *rwl) else rw_assert_rdlock(rwl); + membar_exit(); do { owner = rwl->rwl_owner; if (wrlock) |