Function vnet_data_alloc

freebsd/net/vnet.c:373–399

* When a module is loaded and requires storage for a virtualized global * variable, allocate space from the modspace free list. This interface * should be used only by the kernel linker. */

 * should be used only by the kernel linker.
 */
void *
vnet_data_alloc(int size)
{
	struct vnet_data_free *df;
	void *s;

	s = NULL;
	size = roundup2(size, sizeof(void *));
	sx_xlock(&vnet_data_free_lock);
	TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) {
		if (df->vnd_len < size)
			continue;
		if (df->vnd_len == size) {
			s = (void *)df->vnd_start;
			TAILQ_REMOVE(&vnet_data_free_head, df, vnd_link);
			free(df, M_VNET_DATA_FREE);
			break;
		}
		s = (void *)df->vnd_start;
		df->vnd_len -= size;
		df->vnd_start = df->vnd_start + size;
		break;
	}
	sx_xunlock(&vnet_data_free_lock);

	return (s);
}

/*
 * Free space for a virtualized global variable on module unload.