Revert r239178 and implement two new functions, namely

"device_free_softc()" and "device_claim_softc()",
to allow USB serial drivers refcounting the softc.
These functions are used to grab the softc from
auto-free and to free the softc back to the correct
malloc type, respectivly.

Discussed with:	jhb
MFC after:	2 weeks

1 files changed, 33 insertions, 14 deletions

diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index 1356684..fa19cfd 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -2406,8 +2406,8 @@ device_get_softc(device_t dev)
 void
 device_set_softc(device_t dev, void *softc)
 {
-	if (dev->softc != NULL && !(dev->flags & DF_EXTERNALSOFTC))
-		DEVICE_FREE_SOFTC(dev, dev->softc);
+	if (dev->softc && !(dev->flags & DF_EXTERNALSOFTC))
+		free(dev->softc, M_BUS_SC);
 	dev->softc = softc;
 	if (dev->softc)
 		dev->flags |= DF_EXTERNALSOFTC;
@@ -2416,6 +2416,35 @@ device_set_softc(device_t dev, void *softc)
 }
 
 /**
+ * @brief Free claimed softc
+ *
+ * Most drivers do not need to use this since the softc is freed
+ * automatically when the driver is detached.
+ */
+void
+device_free_softc(void *softc)
+{
+	free(softc, M_BUS_SC);
+}
+
+/**
+ * @brief Claim softc
+ *
+ * This function can be used to let the driver free the automatically
+ * allocated softc using "device_free_softc()". This function is
+ * useful when the driver is refcounting the softc and the softc
+ * cannot be freed when the "device_detach" method is called.
+ */
+void
+device_claim_softc(device_t dev)
+{
+	if (dev->softc)
+		dev->flags |= DF_EXTERNALSOFTC;
+	else
+		dev->flags &= ~DF_EXTERNALSOFTC;
+}
+
+/**
  * @brief Get the device's ivars field
  *
  * The ivars field is used by the parent device to store per-device
@@ -2604,8 +2633,8 @@ device_set_driver(device_t dev, driver_t *driver)
 	if (dev->driver == driver)
 		return (0);
 
-	if (dev->softc != NULL && !(dev->flags & DF_EXTERNALSOFTC)) {
-		DEVICE_FREE_SOFTC(dev, dev->softc);
+	if (dev->softc && !(dev->flags & DF_EXTERNALSOFTC)) {
+		free(dev->softc, M_BUS_SC);
 		dev->softc = NULL;
 	}
 	device_set_desc(dev, NULL);
@@ -4797,13 +4826,3 @@ bus_free_resource(device_t dev, int type, struct resource *r)
 		return (0);
 	return (bus_release_resource(dev, type, rman_get_rid(r), r));
 }
-
-/*
- * The "dev" argument passed to "device_free_softc()" is allowed to be
- * NULL, if the device freeing the soft is not available.
- */
-void
-device_free_softc(device_t dev, void *softc)
-{
-	free(softc, M_BUS_SC);
-}