Function old_dev_pager_fault

freebsd/vm/device_pager.c:332–403

}

static int
old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
    vm_page_t *mres)
{
	vm_paddr_t paddr;
	vm_page_t m_paddr, page;
	struct cdev *dev;
	struct cdevsw *csw;
	struct file *fpop;
	struct thread *td;
	vm_memattr_t memattr, memattr1;
	int ref, ret;

	memattr = object->memattr;

	VM_OBJECT_WUNLOCK(object);

	dev = object->handle;
	csw = dev_refthread(dev, &ref);
	if (csw == NULL) {
		VM_OBJECT_WLOCK(object);
		return (VM_PAGER_FAIL);
	}
	td = curthread;
	fpop = td->td_fpop;
	td->td_fpop = NULL;
	ret = csw->d_mmap(dev, offset, &paddr, prot, &memattr);
	td->td_fpop = fpop;
	dev_relthread(dev, ref);
	if (ret != 0) {
		printf(
	    "WARNING: dev_pager_getpage: map function returns error %d", ret);
		VM_OBJECT_WLOCK(object);
		return (VM_PAGER_FAIL);
	}

	/* If "paddr" is a real page, perform a sanity check on "memattr". */
	if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
	    (memattr1 = pmap_page_get_memattr(m_paddr)) != memattr) {
		/*
		 * For the /dev/mem d_mmap routine to return the
		 * correct memattr, pmap_page_get_memattr() needs to
		 * be called, which we do there.
		 */
		if ((csw->d_flags & D_MEM) == 0) {
			printf("WARNING: Device driver %s has set "
			    "\"memattr\" inconsistently (drv %u pmap %u).\n",
			    csw->d_name, memattr, memattr1);
		}
		memattr = memattr1;
	}
	if (((*mres)->flags & PG_FICTITIOUS) != 0) {
		/*
		 * If the passed in result page is a fake page, update it with
		 * the new physical address.
		 */
		page = *mres;
		VM_OBJECT_WLOCK(object);