devctl (alike?) for devfs

[Kostik Belousov]

On Tue, May 13, 2008 at 11:40:21PM +0300, Andriy Gapon wrote:
> on 13/05/2008 22:16 Kostik Belousov said the following:
> >I looked at your previous patch, and it seems it is much simpler to
> >do drop the devmtx once more then to try to abuse free lists.
> >In the destroy_devl(), after the 
> >
> >	while (dev->si_threadcount != 0) {
> >		/* Use unique dummy wait ident */
> >		msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10);
> >	}
> >
> >loop, add
> >
> >	mtx_unlock(&devmtx);
> >	if (!cold)
> >		devctl_notify("DEVFS", dev->si_name, "DESTROY", NULL);
> >	mtx_lock(&devmtx);
> 
> Thank you again! This is simply perfect.
> 
> 
> -- 
> Andriy Gapon

> diff --git a/sys/kern/kern_conf.c b/sys/kern/kern_conf.c
> index 1db25f8..f90e469 100644

I do not like abusing the subsystem to communicate the data.

What about this instead ? The created/destroyed cdev name is available
in the $cdev variable, example clause for devd.conf looks like this:

notify 1000 {
	system "DEVFS";
	subsystem "CDEV";
	action "echo $type $cdev >/dev/console";
};

diff --git a/sys/kern/kern_conf.c b/sys/kern/kern_conf.c
index e911913..a5ed25c 100644
--- a/sys/kern/kern_conf.c
+++ b/sys/kern/kern_conf.c
@@ -30,6 +30,7 @@ __FBSDID("$FreeBSD: src/sys/kern/kern_conf.c,v 1.211 2008/04/02 11:11:58 kib Exp
 #include <sys/param.h>
 #include <sys/kernel.h>
 #include <sys/systm.h>
+#include <sys/bus.h>
 #include <sys/bio.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
@@ -526,6 +527,37 @@ unit2minor(int unit)
 	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
 }
 
+static void
+notify(struct cdev *dev, const char *ev)
+{
+	static const char prefix[] = "cdev=";
+	char *data;
+	int namelen;
+
+	if (cold)
+		return;
+	namelen = strlen(dev->si_name);
+	data = malloc(namelen + sizeof(prefix), M_TEMP, M_WAITOK);
+	memcpy(data, prefix, sizeof(prefix) - 1);
+	memcpy(data + sizeof(prefix) - 1, dev->si_name, namelen + 1);
+	devctl_notify("DEVFS", "CDEV", ev, data);
+	free(data, M_TEMP);
+}
+
+static void
+notify_create(struct cdev *dev)
+{
+
+	notify(dev, "CREATE");
+}
+
+static void
+notify_destroy(struct cdev *dev)
+{
+
+	notify(dev, "DESTROY");
+}
+
 static struct cdev *
 newdev(struct cdevsw *csw, int y, struct cdev *si)
 {
@@ -706,6 +738,9 @@ make_dev_credv(int flags, struct cdevsw *devsw, int minornr,
 	devfs_create(dev);
 	clean_unrhdrl(devfs_inos);
 	dev_unlock_and_free();
+
+	notify_create(dev);
+
 	return (dev);
 }
 
@@ -794,6 +829,9 @@ make_dev_alias(struct cdev *pdev, const char *fmt, ...)
 	clean_unrhdrl(devfs_inos);
 	dev_unlock();
 	dev_depends(pdev, dev);
+
+	notify_create(dev);
+
 	return (dev);
 }
 
@@ -842,6 +880,10 @@ destroy_devl(struct cdev *dev)
 		msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10);
 	}
 
+	mtx_unlock(&devmtx);
+	notify_destroy(dev);
+	mtx_lock(&devmtx);
+
 	dev->si_drv1 = 0;
 	dev->si_drv2 = 0;
 	bzero(&dev->__si_u, sizeof(dev->__si_u));
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