From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Tue, 5 Feb 2008 06:29:16 +0000 (-0800)
Subject: arch_rebalance_pgtables call
X-Git-Tag: v2.6.25-rc1~940
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=08e7d9b557299ba6ce57165ce8df310780bd681c;p=linux-2.6

arch_rebalance_pgtables call

In order to change the layout of the page tables after an mmap has crossed the
adress space limit of the current page table layout a architecture hook in
get_unmapped_area is needed.  The arguments are the address of the new mapping
and the length of it.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/mmap.c b/mm/mmap.c
index 8295577a83..bb4c963cc5 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -36,6 +36,10 @@
 #define arch_mmap_check(addr, len, flags)	(0)
 #endif
 
+#ifndef arch_rebalance_pgtables
+#define arch_rebalance_pgtables(addr, len)		(addr)
+#endif
+
 static void unmap_region(struct mm_struct *mm,
 		struct vm_area_struct *vma, struct vm_area_struct *prev,
 		unsigned long start, unsigned long end);
@@ -1424,7 +1428,7 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 	if (addr & ~PAGE_MASK)
 		return -EINVAL;
 
-	return addr;
+	return arch_rebalance_pgtables(addr, len);
 }
 
 EXPORT_SYMBOL(get_unmapped_area);