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Add new device method to free the automatically

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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
This commit is contained in:
Hans Petter Selasky 2012-08-10 15:02:49 +00:00
parent 2203949434
commit ea1bd564ac
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=239178
3 changed files with 26 additions and 4 deletions
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11
sys/kern/device_if.m
View File

@ -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;

18
sys/kern/subr_bus.c
View File

@ -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 *driver)
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, 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);
}

1
sys/sys/bus.h
View File

@ -468,6 +468,7 @@ int device_set_unit(device_t dev, int unit); /* XXX DONT USE XXX */
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.