[PATCH v2] procfs: Use proper units for noMMU statm

[steve@digidescorp.com]

Reworked to guarantee page alignment of terms used in data size calculation
and to reduce time spent with mmap_sem held.

On no-MMU systems, sizes reported in /proc/n/statm have units of bytes. 
Per Documentation/filesystems/proc.txt, these values should be in pages.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
---

diff -uprN a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
--- a/fs/proc/task_nommu.c	2009-11-13 16:48:14.000000000 -0600
+++ b/fs/proc/task_nommu.c	2009-11-14 12:17:00.000000000 -0600
@@ -110,9 +110,13 @@ int task_statm(struct mm_struct *mm, int
 		}
 	}
 
-	size += (*text = mm->end_code - mm->start_code);
-	size += (*data = mm->start_stack - mm->start_data);
+	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
+		>> PAGE_SHIFT;
+	*data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
+		>> PAGE_SHIFT;
 	up_read(&mm->mmap_sem);
+	size >>= PAGE_SHIFT;
+	size += *text + *data;
 	*resident = size;
 	return size;
 }