helpers.linux.fs: update for_each_mount() for changes in Linux 6.8

Starting with kernel v6.8 the mnt_list int struct mnt_namespace git
converted to a rb-tree.

Reflect this change in drgn's for_each_mount() helper.

Signed-off-by: Johannes Thumshirn <[email protected]>

drgn/helpers/linux/fs.py

@@ -21,6 +21,7 @@
     list_for_each_entry,
     list_for_each_entry_reverse,
 )
+from drgn.helpers.linux.rbtree import rbtree_inorder_for_each_entry
 
 __all__ = (
     "path_lookup",
@@ -301,7 +302,15 @@ def for_each_mount(
         dst = os.fsencode(dst)
     if fstype:
         fstype = os.fsencode(fstype)
-    for mnt in list_for_each_entry("struct mount", ns.list.address_of_(), "mnt_list"):
+    try:
+        mounts = rbtree_inorder_for_each_entry(
+                "struct mount", ns.mounts, "mnt_node"
+        )
+    except AttributeError:
+        mounts = list_for_each_entry(
+                "struct mount", ns.list.address_of_(), "mnt_list"
+        )
+    for mnt in mounts:
         if (
             (src is None or mount_src(mnt) == src)
             and (dst is None or mount_dst(mnt) == dst)