svn commit: r214563 - head/sys/amd64/amd64

[Alan Cox]

Author: alc
Date: Sat Oct 30 17:21:32 2010
New Revision: 214563
URL: http://svn.freebsd.org/changeset/base/214563

Log:
  Don't demote in pmap_demote_DMAP() if the specified length is zero.

Modified:
  head/sys/amd64/amd64/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Sat Oct 30 16:53:42 2010	(r214562)
+++ head/sys/amd64/amd64/pmap.c	Sat Oct 30 17:21:32 2010	(r214563)
@@ -4968,6 +4968,11 @@ pmap_demote_DMAP(vm_paddr_t base, vm_siz
 	vm_offset_t va;
 	boolean_t changed;
 
+	if (len == 0)
+		return;
+	KASSERT(powerof2(len), ("pmap_demote_DMAP: len is not a power of 2"));
+	KASSERT((base & (len - 1)) == 0,
+	    ("pmap_demote_DMAP: base is not a multiple of len"));
 	if (len < NBPDP) {
 		va = PHYS_TO_DMAP(base);
 		changed = FALSE;