Expand CONFIG_DEBUG_LIST to several other list operations

When list debugging is enabled, we aim to readably show list corruption
errors, and the basic list_add/list_del operations end up having extra
debugging code in them to do some basic validation of the list entries.

However, "list_del_init()" and "list_move[_tail]()" ended up avoiding
the debug code due to how they were written. This fixes that.

So the _next_ time we have list_move() problems with stale list entries,
we'll hopefully have an easier time finding them..

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 26 insertions, 13 deletions

diff --git a/lib/list_debug.c b/lib/list_debug.c
index 344c710d16ca..b8029a5583ff 100644
--- a/lib/list_debug.c
+++ b/lib/list_debug.c
@@ -35,6 +35,31 @@ 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.
@@ -43,19 +68,7 @@ EXPORT_SYMBOL(__list_add);
  */
 void list_del(struct list_head *entry)
 {
-	WARN(entry->next == LIST_POISON1,
-		"list_del corruption, next is LIST_POISON1 (%p)\n",
-		LIST_POISON1);
-	WARN(entry->next != LIST_POISON1 && entry->prev == LIST_POISON2,
-		"list_del corruption, prev is LIST_POISON2 (%p)\n",
-		LIST_POISON2);
-	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;
 }