[src/trunk]: src/sys/kern 1) Make clear that we want the space allocated for ...

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

details:   https://anonhg.NetBSD.org/src/rev/de90a3e94783
branches:  trunk
changeset: 330163:de90a3e94783
user:      maxv <maxv%NetBSD.org@localhost>
date:      Wed Jun 25 16:35:12 2014 +0000

description:
1) Make clear that we want the space allocated for the KMEM_SIZE header to be
   aligned, by using kmem_roundup_size(). There's no functional difference with
   the current MAX().

2) If there isn't enough space in the page padding for the red zone, allocate
   one more page, not just 2 bytes. We only poison 1 or 2 bytes in this page,
   depending on the space left in the previous page. That way 'allocsz' is
   properly aligned. Again, there's no functional difference since the shift
   already handles it correctly.

diffstat:

 sys/kern/subr_kmem.c |  14 +++++++-------
 1 files changed, 7 insertions(+), 7 deletions(-)

diffs (56 lines):

diff -r 71ab4938aec0 -r de90a3e94783 sys/kern/subr_kmem.c
--- a/sys/kern/subr_kmem.c      Wed Jun 25 16:30:42 2014 +0000
+++ b/sys/kern/subr_kmem.c      Wed Jun 25 16:35:12 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_kmem.c,v 1.55 2014/06/25 16:05:22 maxv Exp $      */
+/*     $NetBSD: subr_kmem.c,v 1.56 2014/06/25 16:35:12 maxv Exp $      */
 
 /*-
  * Copyright (c) 2009 The NetBSD Foundation, Inc.
@@ -69,7 +69,7 @@
 
 /*
  * KMEM_REDZONE: detect overrun bugs.
- *     Add a 2-byte pattern (allocate some more bytes if needed) at the end
+ *     Add a 2-byte pattern (allocate one more page if needed) at the end
  *     of each allocated buffer. Check this pattern on kmem_free.
  *
  * KMEM_POISON: detect modify-after-free bugs.
@@ -90,7 +90,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.55 2014/06/25 16:05:22 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.56 2014/06/25 16:35:12 maxv Exp $");
 
 #include <sys/param.h>
 #include <sys/callback.h>
@@ -196,7 +196,7 @@
 #endif /* defined(KMEM_REDZONE) */
 
 #if defined(KMEM_SIZE)
-#define        SIZE_SIZE       (MAX(KMEM_ALIGN, sizeof(size_t)))
+#define        SIZE_SIZE       kmem_roundup_size(sizeof(size_t))
 static void kmem_size_set(void *, size_t);
 static void kmem_size_check(void *, size_t);
 #else
@@ -244,8 +244,8 @@
 #ifdef KMEM_REDZONE
        if (size - requested_size < REDZONE_SIZE) {
                /* If there isn't enough space in the page padding,
-                * allocate two more bytes for the red zone. */
-               allocsz += REDZONE_SIZE;
+                * allocate one more page for the red zone. */
+               allocsz += kmem_roundup_size(REDZONE_SIZE);
        }
 #endif
 
@@ -322,7 +322,7 @@
 
 #ifdef KMEM_REDZONE
        if (size - requested_size < REDZONE_SIZE) {
-               allocsz += REDZONE_SIZE;
+               allocsz += kmem_roundup_size(REDZONE_SIZE);
        }
 #endif