Re: 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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