Add a function to lookup a device_t object by name.

This just walks the global list of devices looking for one with the
requested name.  The one use case outside of devctl2's implementation
is for DDB commands that wish to lookup devices by name.

2 files changed, 17 insertions, 6 deletions

diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index caf9202..81be368 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -5125,6 +5125,18 @@ bus_free_resource(device_t dev, int type, struct resource *r)
 	return (bus_release_resource(dev, type, rman_get_rid(r), r));
 }
 
+device_t
+device_lookup_by_name(const char *name)
+{
+	device_t dev;
+
+	TAILQ_FOREACH(dev, &bus_data_devices, devlink) {
+		if (dev->nameunit != NULL && strcmp(dev->nameunit, name) == 0)
+			return (dev);
+	}
+	return (NULL);
+}
+
 /*
  * /dev/devctl2 implementation.  The existing /dev/devctl device has
  * implicit semantics on open, so it could not be reused for this.
@@ -5145,12 +5157,10 @@ find_device(struct devreq *req, device_t *devp)
 	 * Second, try to find an attached device whose name matches
 	 * 'name'.
 	 */
-	TAILQ_FOREACH(dev, &bus_data_devices, devlink) {
-		if (dev->nameunit != NULL &&
-		    strcmp(dev->nameunit, req->dr_name) == 0) {
-			*devp = dev;
-			return (0);
-		}
+	dev = device_lookup_by_name(req->dr_name);
+	if (dev != NULL) {
+		*devp = dev;
+		return (0);
 	}
 
 	/* Finally, give device enumerators a chance. */
diff --git a/sys/sys/bus.h b/sys/sys/bus.h
index e0297cc..01b98f5 100644
--- a/sys/sys/bus.h
+++ b/sys/sys/bus.h
@@ -524,6 +524,7 @@ int	device_is_attached(device_t dev);	/* did attach succeed? */
 int	device_is_enabled(device_t dev);
 int	device_is_suspended(device_t dev);
 int	device_is_quiet(device_t dev);
+device_t device_lookup_by_name(const char *name);
 int	device_print_prettyname(device_t dev);
 int	device_printf(device_t dev, const char *, ...) __printflike(2, 3);
 int	device_probe(device_t dev);