[src/trunk]: src/sys/rump/net/lib/libshmif * use atomic ops instead of __cpu_...

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

details:   https://anonhg.NetBSD.org/src/rev/b9e78c332884
branches:  trunk
changeset: 757012:b9e78c332884
user:      pooka <pooka%NetBSD.org@localhost>
date:      Tue Aug 10 18:17:12 2010 +0000

description:
* use atomic ops instead of __cpu_simple_luck
* this interface is un-IFF_SIMPLEX

diffstat:

 sys/rump/net/lib/libshmif/if_shmem.c |  20 +++++++++++++++-----
 1 files changed, 15 insertions(+), 5 deletions(-)

diffs (63 lines):

diff -r 79384010c010 -r b9e78c332884 sys/rump/net/lib/libshmif/if_shmem.c
--- a/sys/rump/net/lib/libshmif/if_shmem.c      Tue Aug 10 18:06:10 2010 +0000
+++ b/sys/rump/net/lib/libshmif/if_shmem.c      Tue Aug 10 18:17:12 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_shmem.c,v 1.12 2010/07/29 22:48:11 pooka Exp $      */
+/*     $NetBSD: if_shmem.c,v 1.13 2010/08/10 18:17:12 pooka Exp $      */
 
 /*
  * Copyright (c) 2009 Antti Kantee.  All Rights Reserved.
@@ -28,9 +28,10 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.12 2010/07/29 22:48:11 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.13 2010/08/10 18:17:12 pooka Exp $");
 
 #include <sys/param.h>
+#include <sys/atomic.h>
 #include <sys/fcntl.h>
 #include <sys/kmem.h>
 #include <sys/kthread.h>
@@ -89,6 +90,9 @@
 
 static uint32_t numif;
 
+#define LOCK_UNLOCKED  0
+#define LOCK_LOCKED    1
+
 /*
  * This locking needs work and will misbehave severely if:
  * 1) the backing memory has to be paged in
@@ -98,14 +102,20 @@
 lockbus(struct shmif_sc *sc)
 {
 
-       __cpu_simple_lock((__cpu_simple_lock_t *)sc->sc_busmem);
+       while (atomic_cas_uint((void *)sc->sc_busmem,
+           LOCK_UNLOCKED, LOCK_LOCKED) == LOCK_LOCKED)
+               continue;
+       membar_enter();
 }
 
 static void
 unlockbus(struct shmif_sc *sc)
 {
+       unsigned int old;
 
-       __cpu_simple_unlock((__cpu_simple_lock_t *)sc->sc_busmem);
+       membar_exit();
+       old = atomic_swap_uint((void *)sc->sc_busmem, LOCK_UNLOCKED);
+       KASSERT(old == LOCK_LOCKED);
 }
 
 static uint32_t
@@ -221,7 +231,7 @@
 
        sprintf(ifp->if_xname, "shmif%d", mynum);
        ifp->if_softc = sc;
-       ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
+       ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST;
        ifp->if_init = shmif_init;
        ifp->if_ioctl = shmif_ioctl;
        ifp->if_start = shmif_start;