Add 'devctl delete' that calls device_delete_child().

'devctl delete' can be used to delete a device that is no longer present.
As an anti-foot-shooting measure, 'delete' will not delete a device
unless it's parent bus says it is no longer present.  This can be
overridden by passing the force ('-f') flag.

Note that this command should be used with care.  If a device is deleted
that is actually present it can't be resurrected unless the parent bus
device's driver supports rescans.

Differential Revision:	https://reviews.freebsd.org/D6019

lib/libdevctl/devctl.3

@@ -31,6 +31,7 @@
 .Sh NAME
 .Nm devctl ,
 .Nm devctl_attach ,
+.Nm devctl_delete ,
 .Nm devctl_detach ,
 .Nm devctl_disable ,
 .Nm devctl_enable ,
@@ -46,6 +47,8 @@
 .Ft int
 .Fn devctl_attach "const char *device"
 .Ft int
+.Fn devctl_delete "const char *device" "bool force"
+.Ft int
 .Fn devctl_detach "const char *device" "bool force"
 .Ft int
 .Fn devctl_disable "const char *device" "bool force_detach"
@@ -110,6 +113,15 @@ is true,
 the current device driver will be detached even if the device is busy.
 .Pp
 The
+.Fn devctl_delete
+function deletes a device from the device tree.
+No
+If
+.Fa force
+is true,
+the device is deleted even if the device is physically present.
+.Pp
+The
 .Fn devctl_disable
 function disables a device.
 If the device is currently attached to a device driver,
@@ -158,8 +170,8 @@ The
 function rescans a bus device checking for devices that have been added or
 removed.
 .Sh RETURN VALUES
-.Rv -std devctl_attach devctl_detach devctl_disable devctl_enable \
-devctl_suspend devctl_rescan devctl_resume devctl_set_driver
+.Rv -std devctl_attach devctl_delete devctl_detach devctl_disable \
+devctl_enable devctl_suspend devctl_rescan devctl_resume devctl_set_driver
 .Sh ERRORS
 In addition to specific errors noted below,
 all of the
@@ -298,6 +310,19 @@ The device is not attached to a driver.
 .It Bq Er ENXIO
 The bus driver does not support rescanning.
 .El
+.Pp
+The
+.Fn devctl_delete
+function may fail if:
+.Bl -tag -width Er
+.It Bq Er EBUSY
+The device is physically present and
+.Fa force
+is false.
+.It Bq Er EINVAL
+.Fa dev
+is the root device of the device tree.
+.El
 .Sh SEE ALSO
 .Xr devinfo 3 ,
 .Xr devstat 3 ,

lib/libdevctl/devctl.c

@@ -129,3 +129,11 @@ devctl_rescan(const char *device)
 
 	return (devctl_simple_request(DEV_RESCAN, device, 0));
 }
+
+int
+devctl_delete(const char *device, bool force)
+{
+
+	return (devctl_simple_request(DEV_DELETE, device, force ?
+	    DEVF_FORCE_DELETE : 0));
+}

lib/libdevctl/devctl.h

@@ -39,5 +39,6 @@ int	devctl_suspend(const char *device);
 int	devctl_resume(const char *device);
 int	devctl_set_driver(const char *device, const char *driver, bool force);
 int	devctl_rescan(const char *device);
+int	devctl_delete(const char *device, bool force);
 
 #endif /* !__DEVCTL_H__ */

sys/kern/subr_bus.c

@@ -5204,6 +5204,7 @@ devctl2_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
 	case DEV_RESUME:
 	case DEV_SET_DRIVER:
 	case DEV_RESCAN:
+	case DEV_DELETE:
 		error = priv_check(td, PRIV_DRIVER);
 		if (error == 0)
 			error = find_device(req, &dev);
@@ -5374,6 +5375,24 @@ devctl2_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
 		}
 		error = BUS_RESCAN(dev);
 		break;
+	case DEV_DELETE: {
+		device_t parent;
+
+		parent = device_get_parent(dev);
+		if (parent == NULL) {
+			error = EINVAL;
+			break;
+		}
+		if (!(req->dr_flags & DEVF_FORCE_DELETE)) {
+			if (bus_child_present(dev) != 0) {
+				error = EBUSY;
+				break;
+			}
+		}
+		
+		error = device_delete_child(parent, dev);
+		break;
+	}
 	}
 	mtx_unlock(&Giant);
 	return (error);

sys/sys/bus.h

@@ -118,6 +118,7 @@ struct devreq {
 #define	DEV_RESUME	_IOW('D', 6, struct devreq)
 #define	DEV_SET_DRIVER	_IOW('D', 7, struct devreq)
 #define	DEV_RESCAN	_IOW('D', 9, struct devreq)
+#define	DEV_DELETE	_IOW('D', 10, struct devreq)
 
 /* Flags for DEV_DETACH and DEV_DISABLE. */
 #define	DEVF_FORCE_DETACH	0x0000001
@@ -125,6 +126,9 @@ struct devreq {
 /* Flags for DEV_SET_DRIVER. */
 #define	DEVF_SET_DRIVER_DETACH	0x0000001	/* Detach existing driver. */
 
+/* Flags for DEV_DELETE. */
+#define	DEVF_FORCE_DELETE	0x0000001
+
 #ifdef _KERNEL
 
 #include <sys/eventhandler.h>

usr.sbin/devctl/devctl.8

@@ -59,6 +59,10 @@
 .Nm
 .Cm rescan
 .Ar device
+.Nm
+.Cm delete
+.Op Fl f
+.Ar device
 .Sh DESCRIPTION
 The
 .Nm
@@ -132,6 +136,18 @@ the device will not be changed.
 .It Cm rescan Ar device
 Rescan a bus device checking for devices that have been added or
 removed.
+.It Xo Cm delete
+.Op Fl
+.Ar device
+.Xc
+Delete the device from the device tree.
+If the
+.Fl f
+flag is specified,
+the device will be deleted even if it is physically present.
+This command should be used with care as a device that is deleted but present
+can no longer be used unless the parent bus device rediscovers the device via
+a rescan request.
 .El
 .Sh SEE ALSO
 .Xr devctl 3 ,

usr.sbin/devctl/devctl.c

@@ -70,14 +70,16 @@ DEVCTL_TABLE(top, set);
 static void
 usage(void)
 {
-	fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
+	fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
 	    "usage: devctl attach device",
 	    "       devctl detach [-f] device",
 	    "       devctl disable [-f] device",
 	    "       devctl enable device",
 	    "       devctl suspend device",
 	    "       devctl resume device",
-	    "       devctl set driver [-f] device driver");
+	    "       devctl set driver [-f] device driver",
+	    "       devctl rescan device",
+	    "       devctl delete [-f] device");
 	exit(1);
 }
 
@@ -271,6 +273,40 @@ rescan(int ac, char **av)
 }
 DEVCTL_COMMAND(top, rescan, rescan);
 
+static void
+delete_usage(void)
+{
+
+	fprintf(stderr, "usage: devctl delete [-f] device\n");
+	exit(1);
+}
+
+static int
+delete(int ac, char **av)
+{
+	bool force;
+	int ch;
+
+	force = false;
+	while ((ch = getopt(ac, av, "f")) != -1)
+		switch (ch) {
+		case 'f':
+			force = true;
+			break;
+		default:
+			delete_usage();
+		}
+	ac -= optind;
+	av += optind;
+
+	if (ac != 1)
+		delete_usage();
+	if (devctl_delete(av[0], force) < 0)
+		err(1, "Failed to delete %s", av[0]);
+	return (0);
+}
+DEVCTL_COMMAND(top, delete, delete);
+
 int
 main(int ac, char *av[])
 {