Fix madvise(MADV_WILLNEED) to properly handle individual mappings larger

than 4GB.  Specifically, the inlined version of 'ptoa' of the the 'int'
count of pages overflowed on 64-bit platforms.  While here, change
vm_object_madvise() to accept two vm_pindex_t parameters (start and end)
rather than a (start, count) tuple to match other VM APIs as suggested
by alc@.

1 files changed, 10 insertions, 12 deletions

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index a180601..6198629 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -2100,8 +2100,7 @@ vm_map_madvise(
 		}
 		vm_map_unlock(map);
 	} else {
-		vm_pindex_t pindex;
-		int count;
+		vm_pindex_t pstart, pend;
 
 		/*
 		 * madvise behaviors that are implemented in the underlying
@@ -2119,30 +2118,29 @@ vm_map_madvise(
 			if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
 				continue;
 
-			pindex = OFF_TO_IDX(current->offset);
-			count = atop(current->end - current->start);
+			pstart = OFF_TO_IDX(current->offset);
+			pend = pstart + atop(current->end - current->start);
 			useStart = current->start;
 
 			if (current->start < start) {
-				pindex += atop(start - current->start);
-				count -= atop(start - current->start);
+				pstart += atop(start - current->start);
 				useStart = start;
 			}
 			if (current->end > end)
-				count -= atop(current->end - end);
+				pend -= atop(current->end - end);
 
-			if (count <= 0)
+			if (pstart >= pend)
 				continue;
 
-			vm_object_madvise(current->object.vm_object,
-					  pindex, count, behav);
+			vm_object_madvise(current->object.vm_object, pstart,
+			    pend, behav);
 			if (behav == MADV_WILLNEED) {
 				vm_map_pmap_enter(map,
 				    useStart,
 				    current->protection,
 				    current->object.vm_object,
-				    pindex,
-				    (count << PAGE_SHIFT),
+				    pstart,
+				    ptoa(pend - pstart),
 				    MAP_PREFAULT_MADVISE
 				);
 			}