illumos: manual page: devmap

DEVMAP_DUP(9E) Driver Entry Points DEVMAP_DUP(9E)

NAME

devmap_dup - device mapping duplication entry point

SYNOPSIS

#include <sys/ddi.h>
#include <sys/sunddi.h>

int prefixdevmap_dup(devmap_cookie_t dhp, void *pvtp,
devmap_cookie_t new_dhp, void **new_pvtp);

INTERFACE LEVEL

illumos DDI specific (illumos DDI).

ARGUMENTS

dhp
An opaque mapping handle that the system uses to describe
the mapping currently being duplicated.

pvtp
Driver private mapping data for the mapping currently being
duplicated.

new_dhp
An opaque data structure that the system uses to describe
the duplicated device mapping.

new_pvtp
A pointer to be filled in by device drivers with the driver
private mapping data for the duplicated device mapping.

DESCRIPTION

The system calls devmap_dup() when a device mapping is duplicated, such
as during the execution of the fork(2) system call. The system expects
devmap_dup() to generate new driver private data for the new mapping, and
to set new_pvtp to point to it. new_dhp is the handle of the new mapped
object.

A non-zero return value from devmap_dup() will cause a corresponding
operation such as fork() to fail.

RETURN VALUES

devmap_dup() returns the following values:

0
Successful completion.

Non-zero
An error occurred.

EXAMPLES

static int
xxdevmap_dup(devmap_cookie_t dhp, void *pvtp, \
devmap_cookie_t new_dhp,
void **new_pvtp)
{
struct xxpvtdata *prvtdata;
struct xxpvtdata *p = (struct xxpvtdata *)pvtp;
struct xx_softc *softc = p->softc;
mutex_enter(&softc->mutex);
/* Allocate a new private data structure */
prvtdata = kmem_alloc(sizeof (struct xxpvtdata), KM_SLEEP);
/* Return the new data */
prvtdata->off = p->off;
prvtdata->len = p->len;
prvtdata->ctx = p->ctx;
prvtdata->dhp = new_dhp;
prvtdata->softc = p->softc;
*new_pvtp = prvtdata;
mutex_exit(&softc->mutex);
return (0);
}