introduce the walk_process_tree() helper

[platform/kernel/linux-starfive.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index 11c5c8a..135b7a4 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2053,6 +2053,38 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
 }
 #endif
 
+void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data)
+{
+       struct task_struct *leader, *parent, *child;
+       int res;
+
+       read_lock(&tasklist_lock);
+       leader = top = top->group_leader;
+down:
+       for_each_thread(leader, parent) {
+               list_for_each_entry(child, &parent->children, sibling) {
+                       res = visitor(child, data);
+                       if (res) {
+                               if (res < 0)
+                                       goto out;
+                               leader = child;
+                               goto down;
+                       }
+up:
+                       ;
+               }
+       }
+
+       if (leader != top) {
+               child = leader;
+               parent = child->real_parent;
+               leader = parent->group_leader;
+               goto up;
+       }
+out:
+       read_unlock(&tasklist_lock);
+}
+
 #ifndef ARCH_MIN_MMSTRUCT_ALIGN
 #define ARCH_MIN_MMSTRUCT_ALIGN 0
 #endif