1 files changed, 52 insertions, 8 deletions

diff --git a/lib/list_debug.c b/lib/list_debug.c
index 1a39f4e3ae1f..c24c2f7e296f 100644
--- a/lib/list_debug.c
+++ b/lib/list_debug.c
@@ -6,8 +6,11 @@
  * DEBUG_LIST.
  */
 
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/list.h>
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/rculist.h>
 
 /*
  * Insert a new entry between two known consecutive entries.
@@ -28,6 +31,9 @@ void __list_add(struct list_head *new,
 		"list_add corruption. prev->next should be "
 		"next (%p), but was %p. (prev=%p).\n",
 		next, prev->next, prev);
+	WARN(new == prev || new == next,
+	     "list_add double add: new=%p, prev=%p, next=%p.\n",
+	     new, prev, next);
 	next->prev = new;
 	new->next = next;
 	new->prev = prev;
@@ -35,6 +41,31 @@ void __list_add(struct list_head *new,
 }
 EXPORT_SYMBOL(__list_add);
 
+void __list_del_entry(struct list_head *entry)
+{
+	struct list_head *prev, *next;
+
+	prev = entry->prev;
+	next = entry->next;
+
+	if (WARN(next == LIST_POISON1,
+		"list_del corruption, %p->next is LIST_POISON1 (%p)\n",
+		entry, LIST_POISON1) ||
+	    WARN(prev == LIST_POISON2,
+		"list_del corruption, %p->prev is LIST_POISON2 (%p)\n",
+		entry, LIST_POISON2) ||
+	    WARN(prev->next != entry,
+		"list_del corruption. prev->next should be %p, "
+		"but was %p\n", entry, prev->next) ||
+	    WARN(next->prev != entry,
+		"list_del corruption. next->prev should be %p, "
+		"but was %p\n", entry, next->prev))
+		return;
+
+	__list_del(prev, next);
+}
+EXPORT_SYMBOL(__list_del_entry);
+
 /**
  * list_del - deletes entry from list.
  * @entry: the element to delete from the list.
@@ -43,14 +74,27 @@ EXPORT_SYMBOL(__list_add);
  */
 void list_del(struct list_head *entry)
 {
-	WARN(entry->prev->next != entry,
-		"list_del corruption. prev->next should be %p, "
-		"but was %p\n", entry, entry->prev->next);
-	WARN(entry->next->prev != entry,
-		"list_del corruption. next->prev should be %p, "
-		"but was %p\n", entry, entry->next->prev);
-	__list_del(entry->prev, entry->next);
+	__list_del_entry(entry);
 	entry->next = LIST_POISON1;
 	entry->prev = LIST_POISON2;
 }
 EXPORT_SYMBOL(list_del);
+
+/*
+ * RCU variants.
+ */
+void __list_add_rcu(struct list_head *new,
+		    struct list_head *prev, struct list_head *next)
+{
+	WARN(next->prev != prev,
+		"list_add_rcu corruption. next->prev should be prev (%p), but was %p. (next=%p).\n",
+		prev, next->prev, next);
+	WARN(prev->next != next,
+		"list_add_rcu corruption. prev->next should be next (%p), but was %p. (prev=%p).\n",
+		next, prev->next, prev);
+	new->next = next;
+	new->prev = prev;
+	rcu_assign_pointer(list_next_rcu(prev), new);
+	next->prev = new;
+}
+EXPORT_SYMBOL(__list_add_rcu);