new helper: iterate_mounts()

apply function to vfsmounts in set returned by collect_mounts(),
stop if it returns non-zero.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 15 insertions, 0 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index d25d4602ab50..d5906c19e08e 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1246,6 +1246,21 @@ void drop_collected_mounts(struct vfsmount *mnt)
         release_mounts(&umount_list);
 }
 
+int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,
+                   struct vfsmount *root)
+{
+        struct vfsmount *mnt;
+        int res = f(root, arg);
+        if (res)
+                return res;
+        list_for_each_entry(mnt, &root->mnt_list, mnt_list) {
+                res = f(mnt, arg);
+                if (res)
+                        return res;
+        }
+        return 0;
+}
+
 static void cleanup_group_ids(struct vfsmount *mnt, struct vfsmount *end)
 {
         struct vfsmount *p;