Author: hselasky
Date: Fri Aug 10 15:02:49 2012
New Revision: 239178
URL: http://svn.freebsd.org/changeset/base/239178
Log:
Add new device method to free the automatically
allocated softc structure which is returned by
device_get_softc(). This method can be used to
easily implement softc refcounting. This can be
desirable when the softc has memory references
which are controlled by userspace handles for
example.
This solves the problem of blocking the caller
of device_detach() for a non-deterministic time.
Discussed with: kib, ed
MFC after: 2 weeks
Modified:
head/sys/kern/device_if.m
head/sys/kern/subr_bus.c
head/sys/sys/bus.h
Modified: head/sys/kern/device_if.m
==============================================================================
--- head/sys/kern/device_if.m Fri Aug 10 14:51:41 2012 (r239177)
+++ head/sys/kern/device_if.m Fri Aug 10 15:02:49 2012 (r239178)
@@ -316,3 +316,14 @@ METHOD int resume {
METHOD int quiesce {
device_t dev;
} DEFAULT null_quiesce;
+
+/**
+ * @brief Free the device softc
+ *
+ * @param _dev device pointer
+ * @param _softc pointer to softc
+ */
+METHOD void free_softc {
+ device_t _dev;
+ void *_softc;
+} DEFAULT device_free_softc;
Modified: head/sys/kern/subr_bus.c
==============================================================================
--- head/sys/kern/subr_bus.c Fri Aug 10 14:51:41 2012 (r239177)
+++ head/sys/kern/subr_bus.c Fri Aug 10 15:02:49 2012 (r239178)
@@ -2406,8 +2406,8 @@ device_get_softc(device_t dev)
void
device_set_softc(device_t dev, void *softc)
{
- if (dev->softc && !(dev->flags & DF_EXTERNALSOFTC))
- free(dev->softc, M_BUS_SC);
+ if (dev->softc != NULL && !(dev->flags & DF_EXTERNALSOFTC))
+ DEVICE_FREE_SOFTC(dev, dev->softc);
dev->softc = softc;
if (dev->softc)
dev->flags |= DF_EXTERNALSOFTC;
@@ -2604,8 +2604,8 @@ device_set_driver(device_t dev, driver_t
if (dev->driver == driver)
return (0);
- if (dev->softc && !(dev->flags & DF_EXTERNALSOFTC)) {
- free(dev->softc, M_BUS_SC);
+ if (dev->softc != NULL && !(dev->flags & DF_EXTERNALSOFTC)) {
+ DEVICE_FREE_SOFTC(dev, dev->softc);
dev->softc = NULL;
}
device_set_desc(dev, NULL);
@@ -4797,3 +4797,13 @@ bus_free_resource(device_t dev, int type
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);
+}
Modified: head/sys/sys/bus.h
==============================================================================
--- head/sys/sys/bus.h Fri Aug 10 14:51:41 2012 (r239177)
+++ head/sys/sys/bus.h Fri Aug 10 15:02:49 2012 (r239178)
@@ -468,6 +468,7 @@ int device_set_unit(device_t dev, int un
int device_shutdown(device_t dev);
void device_unbusy(device_t dev);
void device_verbose(device_t dev);
+void device_free_softc(device_t dev, void *softc);
/*
* Access functions for devclass.
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