mm: use mmget_not_zero() helper

We already have the helper, we can convert the rest of the kernel
mechanically using:

  git grep -l 'atomic_inc_not_zero.*mm_users' | xargs sed -i 's/atomic_inc_not_zero(&\(.*\)->mm_users)/mmget_not_zero\(\1\)/'

This is needed for a later patch that hooks into the helper, but might
be a worthwhile cleanup on its own.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vegard Nossum <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: David Rientjes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

kernel/events/uprobes.c

@@ -747,7 +747,7 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
 			continue;
 		}
 
-		if (!atomic_inc_not_zero(&vma->vm_mm->mm_users))
+		if (!mmget_not_zero(vma->vm_mm))
 			continue;
 
 		info = prev;