PERFORCE change 126025 for review

[Constantine A. Murenin]

http://perforce.freebsd.org/chv.cgi?CH=126025

Change 126025 by cnst at dale on 2007/09/03 23:23:34

	remove noops and put the Giant lock instead.
	
	The Giant lock is used by the sysctl logic with every sysctl call,
	so its use in these attach/detach sensor device driver functions
	is similar (if not better) in nature to the spl usage on OpenBSD.
	
	thanks to rwarson and astrodog for some Giant chat on irc :)
	(although we had a general discussion
	not specifically related to this code,
	so reasonable comments are welcome :)

Affected files ...

.. //depot/projects/soc2007/cnst-sensors/sys.kern/kern_sensors.c#9 edit

Differences ...

==== //depot/projects/soc2007/cnst-sensors/sys.kern/kern_sensors.c#9 (text+ko) ====

@@ -1,4 +1,4 @@
-/*	$P4: //depot/projects/soc2007/cnst-sensors/sys.kern/kern_sensors.c#8 $	*/
+/*	$P4: //depot/projects/soc2007/cnst-sensors/sys.kern/kern_sensors.c#9 $	*/
 /*	$FreeBSD$	*/
 /*	$OpenBSD: kern_sensors.c,v 1.19 2007/06/04 18:42:05 deraadt Exp $	*/
 /*	$OpenBSD: kern_sysctl.c,v 1.154 2007/06/01 17:29:10 beck Exp $	*/
@@ -31,6 +31,8 @@
 #include <sys/queue.h>
 #include <sys/types.h>
 #include <sys/time.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
 
 #include <sys/sysctl.h>
 #include <sys/sensors.h>
@@ -60,9 +62,8 @@
 sensordev_install(struct ksensordev *sensdev)
 {
 	struct ksensordev *v, *nv;
-	int s;
 
-	s = splhigh();
+	mtx_lock(&Giant);
 	if (sensordev_count == 0) {
 		sensdev->num = 0;
 		SLIST_INSERT_HEAD(&sensordev_list, sensdev, list);
@@ -75,7 +76,7 @@
 		SLIST_INSERT_AFTER(v, sensdev, list);
 	}
 	sensordev_count++;
-	splx(s);
+	mtx_unlock(&Giant);
 }
 
 void
@@ -83,9 +84,9 @@
 {
 	struct ksensor *v, *nv;
 	struct ksensors_head *sh;
-	int s, i;
+	int i;
 
-	s = splhigh();
+	mtx_lock(&Giant);
 	sh = &sensdev->sensors_list;
 	if (sensdev->sensors_count == 0) {
 		for (i = 0; i < SENSOR_MAX_TYPES; i++)
@@ -111,27 +112,24 @@
 	if (sensdev->maxnumt[sens->type] == sens->numt)
 		sensdev->maxnumt[sens->type]++;
 	sensdev->sensors_count++;
-	splx(s);
+	mtx_unlock(&Giant);
 }
 
 void
 sensordev_deinstall(struct ksensordev *sensdev)
 {
-	int s;
-
-	s = splhigh();
+	mtx_lock(&Giant);
 	sensordev_count--;
 	SLIST_REMOVE(&sensordev_list, sensdev, ksensordev, list);
-	splx(s);
+	mtx_unlock(&Giant);
 }
 
 void
 sensor_detach(struct ksensordev *sensdev, struct ksensor *sens)
 {
 	struct ksensors_head *sh;
-	int s;
 
-	s = splhigh();
+	mtx_lock(&Giant);
 	sh = &sensdev->sensors_list;
 	sensdev->sensors_count--;
 	SLIST_REMOVE(sh, sens, ksensor, list);
@@ -140,7 +138,7 @@
 	 */
 	if (sens->numt == sensdev->maxnumt[sens->type] - 1)
 		sensdev->maxnumt[sens->type]--;
-	splx(s);
+	mtx_unlock(&Giant);
 }
 
 struct ksensordev *