pushed down "volatility" of simplelock to actual int inside the struct.

Submitted by:    bde@zeta.org.a

2 files changed, 14 insertions, 12 deletions

diff --git a/sys/i386/i386/simplelock.s b/sys/i386/i386/simplelock.s
index 9d5226d..139aeb3 100644
--- a/sys/i386/i386/simplelock.s
+++ b/sys/i386/i386/simplelock.s
@@ -22,7 +22,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id$
+ *	$Id: simplelock.s,v 1.1 1997/07/24 23:51:33 fsmp Exp $
  */
 
 /*
@@ -35,6 +35,8 @@
 /*
  * The following impliments the primitives described in i386/i386/param.h
  * necessary for the Lite2 lock manager system.
+ * The major difference is that the "volatility" of the lock datum has been
+ * pushed down from the various functions to lock_data itself.
  */
 
 /*
@@ -46,7 +48,7 @@
  * only be used for exclusive locks.
  * 
  * struct simplelock {
- * 	int	lock_data;
+ * 	volatile int	lock_data;
  * };
  */
 
@@ -65,7 +67,7 @@ ENTRY(s_lock_init)
 
 /*
  * void
- * s_lock(__volatile struct simplelock *lkp)
+ * s_lock(struct simplelock *lkp)
  * {
  * 	while (test_and_set(&lkp->lock_data))
  * 		continue;
@@ -73,7 +75,7 @@ ENTRY(s_lock_init)
  *
  * Note:
  *	If the acquire fails we do a loop of reads waiting for the lock to
- *	become free instead of continually beating on the lock with btsl.
+ *	become free instead of continually beating on the lock with xchgl.
  *	The theory here is that the CPU will stay within its cache until
  *	a write by the other CPU updates it, instead of continually updating
  *	the local cache (and thus causing external bus writes) with repeated
@@ -96,7 +98,7 @@ gotit:
 
 /*
  * int
- * s_lock_try(__volatile struct simplelock *lkp)
+ * s_lock_try(struct simplelock *lkp)
  * {
  * 	return (!test_and_set(&lkp->lock_data));
  * }
@@ -115,7 +117,7 @@ ENTRY(s_lock_try)
 
 /*
  * void
- * s_unlock(__volatile struct simplelock *lkp)
+ * s_unlock(struct simplelock *lkp)
  * {
  * 	lkp->lock_data = 0;
  * }
@@ -129,7 +131,7 @@ ENTRY(s_unlock)
 #ifdef needed
 
 /*
- * test_and_set(struct simplelock *lkp);
+ * int test_and_set(struct simplelock *lkp);
  */
 ENTRY(test_and_set)
 	movl	4(%esp), %eax		/* get the address of the lock */
diff --git a/sys/i386/include/param.h b/sys/i386/include/param.h
index a5892c0..bb3a700 100644
--- a/sys/i386/include/param.h
+++ b/sys/i386/include/param.h
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)param.h	5.8 (Berkeley) 6/28/91
- *	$Id: param.h,v 1.4 1997/07/24 03:06:19 smp Exp smp $
+ *	$Id: param.h,v 1.30 1997/07/24 23:48:51 fsmp Exp $
  */
 
 #ifndef _MACHINE_PARAM_H_
@@ -140,7 +140,7 @@
  * of these locks while a process is sleeping.
  */
 struct simplelock {
-	int	lock_data __attribute__ ((aligned (4)));
+	volatile int	lock_data;
 };
 
 #if !defined(SIMPLELOCK_DEBUG) && NCPUS > 1
@@ -163,7 +163,7 @@ simple_lock_init(struct simplelock *lkp)
 }
 
 static __inline void
-simple_lock(__volatile struct simplelock *lkp)
+simple_lock(struct simplelock *lkp)
 {
 
 	while (test_and_set(&lkp->lock_data))
@@ -171,14 +171,14 @@ simple_lock(__volatile struct simplelock *lkp)
 }
 
 static __inline int
-simple_lock_try(__volatile struct simplelock *lkp)
+simple_lock_try(struct simplelock *lkp)
 {
 
 	return (!test_and_set(&lkp->lock_data));
 }
 
 static __inline void
-simple_unlock(__volatile struct simplelock *lkp)
+simple_unlock(struct simplelock *lkp)
 {
 
 	lkp->lock_data = 0;