Add a kernel function to delist our kernel character devices, so that

the device name can be re-used right away in case we are destroying
the character devices in the background.

MFC after:	4 days
Reported by:	dchagin@

3 files changed, 22 insertions, 1 deletions

diff --git a/sys/dev/usb/usb_device.c b/sys/dev/usb/usb_device.c
index e1ab279..b3b46b3 100644
--- a/sys/dev/usb/usb_device.c
+++ b/sys/dev/usb/usb_device.c
@@ -2019,7 +2019,10 @@ usb_destroy_dev(struct usb_fs_privdata *pd)
 		usb_destroy_dev_sync(pd);
 		return;
 	}
-	
+
+	/* make sure we can re-use the device name */
+	delist_dev(pd->cdev);
+
 	USB_BUS_LOCK(bus);
 	LIST_INSERT_HEAD(&bus->pd_cleanup_list, pd, pd_next);
 	/* get cleanup going */
diff --git a/sys/kern/kern_conf.c b/sys/kern/kern_conf.c
index d15e5da..8b1fdc1 100644
--- a/sys/kern/kern_conf.c
+++ b/sys/kern/kern_conf.c
@@ -1114,6 +1114,23 @@ destroy_devl(struct cdev *dev)
 	}
 }
 
+static void
+delist_dev_locked(struct cdev *dev)
+{
+	struct cdev *child;
+	devfs_destroy(dev);
+	LIST_FOREACH(child, &dev->si_children, si_siblings)
+		delist_dev_locked(child);
+}
+
+void
+delist_dev(struct cdev *dev)
+{
+	dev_lock();
+	delist_dev_locked(dev);
+	dev_unlock();
+}
+
 void
 destroy_dev(struct cdev *dev)
 {
diff --git a/sys/sys/conf.h b/sys/sys/conf.h
index 68e9d0f..035a5fd 100644
--- a/sys/sys/conf.h
+++ b/sys/sys/conf.h
@@ -245,6 +245,7 @@ void clone_cleanup(struct clonedevs **);
 int clone_create(struct clonedevs **, struct cdevsw *, int *unit, struct cdev **dev, int extra);
 
 int	count_dev(struct cdev *_dev);
+void	delist_dev(struct cdev *_dev);
 void	destroy_dev(struct cdev *_dev);
 int	destroy_dev_sched(struct cdev *dev);
 int	destroy_dev_sched_cb(struct cdev *dev, void (*cb)(void *), void *arg);