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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 pvtp new_dhp new_pvtp 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 Non-zero

static int
xxdevmap_dup(devmap_cookie_t dhp, void *pvtp, \e
 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