From 702d794d38b4104672f33c0778d343444c8db8ca Mon Sep 17 00:00:00 2001
From: Bob Beck <beck@cvs.openbsd.org>
Date: Thu, 7 Apr 2011 19:07:43 +0000
Subject: Revert previous diff decrementing bcstats.numbufpages here. This
 function does not do what it purports to do, it shrinks mapping, not
 allocation, as the pages have already been given away to other buffers. This
 also renames the function to make this a little more obvious

and art should not name funcitons

ok thib@, art@
---
 sys/kern/vfs_bio.c    |  7 ++++---
 sys/kern/vfs_biomem.c | 12 +++++++++---
 sys/sys/buf.h         |  4 ++--
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index c48624f9b3a..045577708c5 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vfs_bio.c,v 1.128 2011/04/02 16:47:17 beck Exp $	*/
+/*	$OpenBSD: vfs_bio.c,v 1.129 2011/04/07 19:07:42 beck Exp $	*/
 /*	$NetBSD: vfs_bio.c,v 1.44 1996/06/11 11:15:36 pk Exp $	*/
 
 /*
@@ -463,9 +463,10 @@ bread_cluster_callback(struct buf *bp)
 		size_t newsize = xbpp[1]->b_bufsize;
 
 		/*
-		 * Shrink this buffer to only cover its part of the total I/O.
+		 * Shrink this buffer's mapping to only cover its part of
+		 * the total I/O.
 		 */
-		buf_shrink_mem(bp, newsize);
+		buf_fix_mapping(bp, newsize);
 		bp->b_bcount = newsize;
 	}
 
diff --git a/sys/kern/vfs_biomem.c b/sys/kern/vfs_biomem.c
index 17c5007441a..e0e1a5f1b39 100644
--- a/sys/kern/vfs_biomem.c
+++ b/sys/kern/vfs_biomem.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vfs_biomem.c,v 1.16 2011/04/05 21:31:58 beck Exp $ */
+/*	$OpenBSD: vfs_biomem.c,v 1.17 2011/04/07 19:07:42 beck Exp $ */
 /*
  * Copyright (c) 2007 Artur Grabowski <art@openbsd.org>
  *
@@ -223,15 +223,21 @@ buf_dealloc_mem(struct buf *bp)
 	return (1);
 }
 
+/*
+ * Only used by bread_cluster. 
+ */
 void
-buf_shrink_mem(struct buf *bp, vsize_t newsize)
+buf_fix_mapping(struct buf *bp, vsize_t newsize)
 {
 	vaddr_t va = (vaddr_t)bp->b_data;
 
 	if (newsize < bp->b_bufsize) {
 		pmap_kremove(va + newsize, bp->b_bufsize - newsize);
 		pmap_update(pmap_kernel());
-		bcstats.numbufpages -= atop(bp->b_bufsize - newsize);
+		/*
+		 * Note: the size we lost is actually with the other
+		 * buffers read in by bread_cluster
+		 */
 		bp->b_bufsize = newsize;
 	}
 }
diff --git a/sys/sys/buf.h b/sys/sys/buf.h
index 4f3a5a75b49..f383fb6d135 100644
--- a/sys/sys/buf.h
+++ b/sys/sys/buf.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: buf.h,v 1.75 2011/04/03 13:52:09 beck Exp $	*/
+/*	$OpenBSD: buf.h,v 1.76 2011/04/07 19:07:42 beck Exp $	*/
 /*	$NetBSD: buf.h,v 1.25 1997/04/09 21:12:17 mycroft Exp $	*/
 
 /*
@@ -295,7 +295,7 @@ void	buf_acquire_unmapped(struct buf *);
 void	buf_map(struct buf *);
 void	buf_release(struct buf *);
 int	buf_dealloc_mem(struct buf *);
-void	buf_shrink_mem(struct buf *, vsize_t);
+void	buf_fix_mapping(struct buf *, vsize_t);
 void	buf_alloc_pages(struct buf *, vsize_t);
 void	buf_free_pages(struct buf *);
 
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