/proc/pid/maps: don't show pgoff of pure ANON VMAs

Recently, it's argued that what proc/pid/maps shows is ugly when a 32bit
binary runs on 64bit host.

/proc/pid/maps outputs vma's pgoff member but vma->pgoff is of no use
information is the vma is for ANON.  With this patch, /proc/pid/maps shows
just 0 if no file backing store.

[akpm@linux-foundation.org: coding-style fixes]
[kamezawa.hiroyu@jp.fujitsu.com: coding-style fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mike Waychison <mikew@google.com>
Reported-by: Ying Han <yinghan@google.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 863464d5519c..12c20377772d 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -126,6 +126,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
         struct file *file;
         dev_t dev = 0;
         int flags, len;
+        unsigned long long pgoff = 0;
 
         flags = vma->vm_flags;
         file = vma->vm_file;
@@ -134,6 +135,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
                 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
                 dev = inode->i_sb->s_dev;
                 ino = inode->i_ino;
+                pgoff = (loff_t)vma->pg_off << PAGE_SHIFT;
         }
 
         seq_printf(m,
@@ -144,7 +146,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
                    flags & VM_WRITE ? 'w' : '-',
                    flags & VM_EXEC ? 'x' : '-',
                    flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
-                   (unsigned long long) vma->vm_pgoff << PAGE_SHIFT,
+                   pgoff,
                    MAJOR(dev), MINOR(dev), ino, &len);
 
         if (file) {