[Xen-changelog] [xen-unstable] page_alloc: properly honor MAX_ORDER in init_heap_pages()

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1233314063 0
# Node ID 9b9078a02f65fc010ad838de1c9c4e8aa4cf1009
# Parent  e1135b40e783e965ed4eccfd8e983e9f3f4259e8
page_alloc: properly honor MAX_ORDER in init_heap_pages()

The previous check was flawed in that it checked
- for a single bit to be set instead of a range of bits to be clear
- a machine address against a mask supposed to be used on MFNs.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
---
 xen/common/page_alloc.c |   17 ++++++++---------
 1 files changed, 8 insertions(+), 9 deletions(-)

diff -r e1135b40e783 -r 9b9078a02f65 xen/common/page_alloc.c
--- a/xen/common/page_alloc.c   Fri Jan 30 11:13:55 2009 +0000
+++ b/xen/common/page_alloc.c   Fri Jan 30 11:14:23 2009 +0000
@@ -479,7 +479,6 @@ static void free_heap_pages(
  * latter is not on a MAX_ORDER boundary, then we reserve the page by
  * not freeing it to the buddy allocator.
  */
-#define MAX_ORDER_ALIGNED (1UL << (MAX_ORDER))
 static void init_heap_pages(
     struct page_info *pg, unsigned long nr_pages)
 {
@@ -496,15 +495,15 @@ static void init_heap_pages(
             init_node_heap(nid_curr);
 
         /*
-         * free pages of the same node, or if they differ, but are on a
-         * MAX_ORDER alignement boundary (which already get reserved)
+         * Free pages of the same node, or if they differ, but are on a
+         * MAX_ORDER alignment boundary (which already get reserved).
          */
-         if ( (nid_curr == nid_prev) || (page_to_maddr(pg+i) &
-                                         MAX_ORDER_ALIGNED) )
-             free_heap_pages(pg+i, 0);
-         else
-             printk("Reserving non-aligned node boundary @ mfn %lu\n",
-                    page_to_mfn(pg+i));
+        if ( (nid_curr == nid_prev) ||
+             !(page_to_mfn(pg+i) & ((1UL << MAX_ORDER) - 1)) )
+            free_heap_pages(pg+i, 0);
+        else
+            printk("Reserving non-aligned node boundary @ mfn %#lx\n",
+                   page_to_mfn(pg+i));
 
         nid_prev = nid_curr;
     }

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