From: David Howells <dhowells@redhat.com>
Date: Thu, 25 Mar 2010 16:48:38 +0000 (+0000)
Subject: NOMMU: Revert 'nommu: get_user_pages(): pin last page on non-page-aligned start'
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7561e8ca0dfaf6fca3feef982830de3b65300e5b;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

NOMMU: Revert 'nommu: get_user_pages(): pin last page on non-page-aligned start'

Revert the following patch:

	commit c08c6e1f54c85fc299cf9f88cf330d6dd28a9a1d
	Author: Steven J. Magnani <steve@digidescorp.com>
	Date:   Fri Mar 5 13:42:24 2010 -0800

	nommu: get_user_pages(): pin last page on non-page-aligned start

As it assumes that the mappings begin at the start of pages - something that
isn't necessarily true on NOMMU systems.  On NOMMU systems, it is possible for
a mapping to only occupy part of the page, and not necessarily touch either end
of it; in fact it's also possible for multiple non-overlapping mappings to
coexist on one page (consider direct mappings of ROMFS files, for example).

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/nommu.c b/mm/nommu.c
index e4b8f4d28a3f..089982f5a4cf 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -146,7 +146,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 			(VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
 
 	for (i = 0; i < nr_pages; i++) {
-		vma = find_extend_vma(mm, start);
+		vma = find_vma(mm, start);
 		if (!vma)
 			goto finish_or_fault;
 
@@ -764,7 +764,7 @@ EXPORT_SYMBOL(find_vma);
  */
 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
 {
-	return find_vma(mm, addr & PAGE_MASK);
+	return find_vma(mm, addr);
 }
 
 /*