Function v2sizep

freebsd/vm/memguard.c:255–268

* v2sizep() converts a virtual address of the first page allocated for * an item to a pointer to u_long recording the size of the original * allocation request. * * This routine is very similar to those defined by UMA in uma_int.h. * The difference is that this routine stores the originally allocated * size in one of the page's fields that is unused when the page is * wired rather than the

 * wired rather than the object field, which is used.
 */
static u_long *
v2sizep(vm_offset_t va)
{
	vm_paddr_t pa;
	struct vm_page *p;

	pa = pmap_kextract(va);
	if (pa == 0)
		panic("MemGuard detected double-free of %p", (void *)va);
	p = PHYS_TO_VM_PAGE(pa);
	KASSERT(vm_page_wired(p) && p->a.queue == PQ_NONE,
	    ("MEMGUARD: Expected wired page %p in vtomgfifo!", p));
	return (&p->plinks.memguard.p);
}

static u_long *
v2sizev(vm_offset_t va)