nommu: get_user_pages(): pin last page on non-page-aligned start
Steven J. Magnani [Fri, 5 Mar 2010 21:42:24 +0000 (13:42 -0800)]
The noMMU version of get_user_pages() fails to pin the last page when the
start address isn't page-aligned.  The patch fixes this in a way that
makes find_extend_vma() congruent to its MMU cousin.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/nommu.c

index 55727a7..b9b5cce 100644 (file)
@@ -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_vma(mm, start);
+               vma = find_extend_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);
+       return find_vma(mm, addr & PAGE_MASK);
 }
 
 /*