Function vm_fault_populate

freebsd/vm/vm_fault.c:416–590

}

static int
vm_fault_populate(struct faultstate *fs)
{
	vm_offset_t vaddr;
	vm_page_t m;
	vm_pindex_t map_first, map_last, pager_first, pager_last, pidx;
	int bdry_idx, i, npages, psind, rv;

	MPASS(fs->object == fs->first_object);
	VM_OBJECT_ASSERT_WLOCKED(fs->first_object);
	MPASS(blockcount_read(&fs->first_object->paging_in_progress) > 0);
	MPASS(fs->first_object->backing_object == NULL);
	MPASS(fs->lookup_still_valid);

	pager_first = OFF_TO_IDX(fs->entry->offset);
	pager_last = pager_first + atop(fs->entry->end - fs->entry->start) - 1;
	unlock_map(fs);
	unlock_vp(fs);

	/*
	 * Call the pager (driver) populate() method.
	 *
	 * There is no guarantee that the method will be called again
	 * if the current fault is for read, and a future fault is
	 * for write.  Report the entry's maximum allowed protection
	 * to the driver.
	 */
	rv = vm_pager_populate(fs->first_object, fs->first_pindex,
	    fs->fault_type, fs->entry->max_protection, &pager_first,
	    &pager_last);

	VM_OBJECT_ASSERT_WLOCKED(fs->first_object);
	if (rv == VM_PAGER_BAD) {
		/*
		 * VM_PAGER_BAD is the backdoor for a pager to request
		 * normal fault handling.
		 */
		vm_fault_restore_map_lock(fs);
		if (fs->map->timestamp != fs->map_generation)
			return (KERN_RESTART);
		return (KERN_NOT_RECEIVER);
	}
	if (rv != VM_PAGER_OK)
		return (KERN_FAILURE); /* AKA SIGSEGV */

	/* Ensure that the driver is obeying the interface. */
	MPASS(pager_first <= pager_last);
	MPASS(fs->first_pindex <= pager_last);
	MPASS(fs->first_pindex >= pager_first);
	MPASS(pager_last < fs->first_object->size);

	vm_fault_restore_map_lock(fs);
	bdry_idx = (fs->entry->eflags & MAP_ENTRY_SPLIT_BOUNDARY_MASK) >>
	    MAP_ENTRY_SPLIT_BOUNDARY_SHIFT;
	if (fs->map->timestamp != fs->map_generation) {
		if (bdry_idx == 0) {
			vm_fault_populate_cleanup(fs->first_object, pager_first,
			    pager_last);