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

devmap_dup - device mapping duplication entry point

#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);

illumos DDI specific (illumos DDI).

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.

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.

devmap_dup() returns the following values:

0

Successful completion.

Non-zero

An error occurred.


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);
}

fork(2), devmap_callback_ctl(9S)

Writing Device Drivers

June 18, 2021 OmniOS