[src/trunk]: src extent_alloc_subregion shouldn't allocate a region pasts the...

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

details:   https://anonhg.NetBSD.org/src/rev/9f86b17182c4
branches:  trunk
changeset: 514280:9f86b17182c4
user:      enami <enami%NetBSD.org@localhost>
date:      Mon Aug 27 13:35:44 2001 +0000

description:
extent_alloc_subregion shouldn't allocate a region pasts the end of subregion.

diffstat:

 regress/sys/kern/extent/extest.exp |   8 +++++++-
 regress/sys/kern/extent/tests      |  11 ++++++++++-
 sys/kern/subr_extent.c             |  21 ++++++++++++++++++---
 3 files changed, 35 insertions(+), 5 deletions(-)

diffs (97 lines):

diff -r 56eae72eff9a -r 9f86b17182c4 regress/sys/kern/extent/extest.exp
--- a/regress/sys/kern/extent/extest.exp        Mon Aug 27 13:07:03 2001 +0000
+++ b/regress/sys/kern/extent/extest.exp        Mon Aug 27 13:35:44 2001 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: extest.exp,v 1.5 2000/07/02 22:36:50 pk Exp $
+# $NetBSD: extest.exp,v 1.6 2001/08/27 13:35:45 enami Exp $
 # real output must start in line 4
 
 output for test1
@@ -37,3 +37,9 @@
 extent `test7' (0x0 - 0xb), flags = 0x0
      0x0 - 0x6
      0x8 - 0xb
+output for test8
+result: 0x0
+error: Resource temporarily unavailable
+extent `test8' (0x0 - 0x4f), flags = 0x2
+     0x0 - 0xf
+     0x30 - 0x3f
diff -r 56eae72eff9a -r 9f86b17182c4 regress/sys/kern/extent/tests
--- a/regress/sys/kern/extent/tests     Mon Aug 27 13:07:03 2001 +0000
+++ b/regress/sys/kern/extent/tests     Mon Aug 27 13:35:44 2001 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: tests,v 1.5 2000/07/02 22:36:50 pk Exp $
+# $NetBSD: tests,v 1.6 2001/08/27 13:35:45 enami Exp $
 
 #fill up an extent, should coalesce into one allocation
 extent test1 0 0x4f
@@ -52,3 +52,12 @@
 alloc_subregion 0 11 7
 alloc_subregion 0 11 4
 print
+
+#don't allocate a region pasts the end of subregion (i.e., the second
+#alloc_subregion should fail).  subr_extent.c prior to rev. 1.43 allocates
+#region starts from 0x10.
+extent test8 0 0x4f EX_NOCOALESCE
+alloc_region 0x30 0x10
+alloc_subregion 0 0xf 0x10
+alloc_subregion 0 0xf 0x10
+print
diff -r 56eae72eff9a -r 9f86b17182c4 sys/kern/subr_extent.c
--- a/sys/kern/subr_extent.c    Mon Aug 27 13:07:03 2001 +0000
+++ b/sys/kern/subr_extent.c    Mon Aug 27 13:35:44 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_extent.c,v 1.42 2001/06/05 04:39:56 thorpej Exp $ */
+/*     $NetBSD: subr_extent.c,v 1.43 2001/08/27 13:35:44 enami Exp $   */
 
 /*-
  * Copyright (c) 1996, 1998 The NetBSD Foundation, Inc.
@@ -537,7 +537,7 @@
        u_long *result;
 {
        struct extent_region *rp, *myrp, *last, *bestlast;
-       u_long newstart, newend, beststart, bestovh, ovh;
+       u_long newstart, newend, exend, beststart, bestovh, ovh;
        u_long dontcross;
        int error;
 
@@ -623,6 +623,12 @@
        bestlast = NULL;
 
        /*
+        * Keep track of end of free region.  This is either the end of extent
+        * or the start of a region past the subend.
+        */
+       exend = ex->ex_end;
+
+       /*
         * For N allocated regions, we must make (N + 1)
         * checks for unallocated space.  The first chunk we
         * check is the area from the beginning of the subregion
@@ -665,6 +671,15 @@
 
        for (; rp != NULL; rp = rp->er_link.le_next) {
                /*
+                * If the region pasts the subend, bail out and see
+                * if we fit against the subend.
+                */
+               if (rp->er_start >= subend) {
+                       exend = rp->er_start;
+                       break;
+               }
+
+               /*
                 * Check the chunk before "rp".  Note that our
                 * comparison is safe from overflow conditions.
                 */
@@ -818,7 +833,7 @@
                 * fit, or we're taking the first fit, insert
                 * ourselves into the region list.
                 */
-               ovh = ex->ex_end - newstart - (size - 1);
+               ovh = exend - newstart - (size - 1);
                if ((flags & EX_FAST) || (ovh == 0))
                        goto found;