[src/trunk]: src/sys/uvm in uvm_map_clean(), fix the case where the start off...

[chs <chs%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/20ab19d92a82
branches:  trunk
changeset: 503394:20ab19d92a82
user:      chs <chs%NetBSD.org@localhost>
date:      Mon Feb 05 11:29:54 2001 +0000

description:
in uvm_map_clean(), fix the case where the start offset is within the last
entry in the map.  the old code would walk around the end of the linked list,
through the header entry, and keep going from the first map entry until it
found a gap in the map, at which point it would return an error.  if the map
had no gaps then it would loop forever.  reported by k-abe%cs.utah.edu@localhost.
while I'm here, clean up this function a bit.

also, use MIN() instead of min(), since the latter takes arguments of
type "int" but we're passing it values of type "vaddr_t", which can be
a larger size.

diffstat:

 sys/uvm/uvm_map.c |  36 +++++++++++-------------------------
 1 files changed, 11 insertions(+), 25 deletions(-)

diffs (97 lines):

diff -r c8f04dfa72f6 -r 20ab19d92a82 sys/uvm/uvm_map.c
--- a/sys/uvm/uvm_map.c Mon Feb 05 11:16:31 2001 +0000
+++ b/sys/uvm/uvm_map.c Mon Feb 05 11:29:54 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_map.c,v 1.89 2001/01/28 23:30:44 thorpej Exp $     */
+/*     $NetBSD: uvm_map.c,v 1.90 2001/02/05 11:29:54 chs Exp $ */
 
 /* 
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -1589,7 +1589,7 @@
                while (entry->start < end && entry != &srcmap->header) {
                        if (copy_ok) {
                                oldoffset = (entry->start + fudge) - start;
-                               elen = min(end, entry->end) -
+                               elen = MIN(end, entry->end) -
                                    (entry->start + fudge);
                                pmap_copy(dstmap->pmap, srcmap->pmap,
                                    dstaddr + oldoffset, elen,
@@ -2441,8 +2441,6 @@
  * => we may sleep while cleaning if SYNCIO [with map read-locked]
  */
 
-int    amap_clean_works = 1;   /* XXX for now, just in case... */
-
 int
 uvm_map_clean(map, start, end, flags)
        vm_map_t map;
@@ -2480,8 +2478,10 @@
                        vm_map_unlock_read(map);
                        return (KERN_INVALID_ARGUMENT);
                }
-               if (end > current->end && (current->next == &map->header ||
-                   current->end != current->next->start)) {
+               if (end <= current->end) {
+                       break;
+               }
+               if (current->end != current->next->start) {
                        vm_map_unlock_read(map);
                        return (KERN_INVALID_ADDRESS);
                }
@@ -2489,7 +2489,7 @@
 
        error = KERN_SUCCESS;
 
-       for (current = entry; current->start < end; current = current->next) {
+       for (current = entry; start < end; current = current->next) {
                amap = current->aref.ar_amap;   /* top layer */
                uobj = current->object.uvm_obj; /* bottom layer */
                KASSERT(start >= current->start);
@@ -2502,22 +2502,13 @@
                 *      (2) We're not deactivating or freeing pages.
                 */
 
-               if (amap == NULL ||
-                   (flags & (PGO_DEACTIVATE|PGO_FREE)) == 0)
-                       goto flush_object;
-
-               /* XXX for now, just in case... */
-               if (amap_clean_works == 0)
+               if (amap == NULL || (flags & (PGO_DEACTIVATE|PGO_FREE)) == 0)
                        goto flush_object;
 
                amap_lock(amap);
-
                offset = start - current->start;
-               size = (end <= current->end ? end : current->end) -
-                   start;
-
-               for (/* nothing */; size != 0; size -= PAGE_SIZE,
-                    offset += PAGE_SIZE) {
+               size = MIN(end, current->end) - start;
+               for ( ; size != 0; size -= PAGE_SIZE, offset += PAGE_SIZE) {
                        anon = amap_lookup(&current->aref, offset);
                        if (anon == NULL)
                                continue;
@@ -2599,11 +2590,7 @@
                        default:
                                panic("uvm_map_clean: wierd flags");
                        }
-#ifdef DIAGNOSTIC
-                       panic("uvm_map_clean: unreachable code");
-#endif
                }
-
                amap_unlock(amap);
 
  flush_object:
@@ -2612,8 +2599,7 @@
                 */
 
                offset = current->offset + (start - current->start);
-               size = (end <= current->end ? end : current->end) - start;
-
+               size = MIN(end, current->end) - start;
                if (uobj != NULL) {
                        simple_lock(&uobj->vmobjlock);
                        rv = uobj->pgops->pgo_flush(uobj, offset,