Re: 2.6.25-git2: BUG: unable to handle kernel paging request at ffffffffffffffff

[Paul E. McKenney]

And here is an update with one bug fixed -- testing continues.
This is an update of http://lkml.org/lkml/2008/4/20/217, deleting
list_for_each_safe_rcu() and fixing hlist_for_each_entry_rcu().
Testing continues...

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---

 list.h |   48 +++++++++++++++---------------------------------
 1 file changed, 15 insertions(+), 33 deletions(-)
 
diff -urpNa -X dontdiff linux-2.6.25/include/linux/list.h linux-2.6.25-rcu-list/include/linux/list.h
--- linux-2.6.25/include/linux/list.h	2008-04-16 19:49:44.000000000 -0700
+++ linux-2.6.25-rcu-list/include/linux/list.h	2008-04-20 21:48:29.000000000 -0700
@@ -631,31 +631,14 @@ static inline void list_splice_init_rcu(
  * as long as the traversal is guarded by rcu_read_lock().
  */
 #define list_for_each_rcu(pos, head) \
-	for (pos = (head)->next; \
-		prefetch(rcu_dereference(pos)->next), pos != (head); \
-        	pos = pos->next)
+	for (pos = rcu_dereference((head)->next); \
+		prefetch(pos->next), pos != (head); \
+        	pos = rcu_dereference(pos->next))
 
 #define __list_for_each_rcu(pos, head) \
-	for (pos = (head)->next; \
-		rcu_dereference(pos) != (head); \
-        	pos = pos->next)
-
-/**
- * list_for_each_safe_rcu
- * @pos:	the &struct list_head to use as a loop cursor.
- * @n:		another &struct list_head to use as temporary storage
- * @head:	the head for your list.
- *
- * Iterate over an rcu-protected list, safe against removal of list entry.
- *
- * This list-traversal primitive may safely run concurrently with
- * the _rcu list-mutation primitives such as list_add_rcu()
- * as long as the traversal is guarded by rcu_read_lock().
- */
-#define list_for_each_safe_rcu(pos, n, head) \
-	for (pos = (head)->next; \
-		n = rcu_dereference(pos)->next, pos != (head); \
-		pos = n)
+	for (pos = rcu_dereference((head)->next); \
+		pos != (head); \
+        	pos = rcu_dereference(pos->next))
 
 /**
  * list_for_each_entry_rcu	-	iterate over rcu list of given type
@@ -668,10 +651,9 @@ static inline void list_splice_init_rcu(
  * as long as the traversal is guarded by rcu_read_lock().
  */
 #define list_for_each_entry_rcu(pos, head, member) \
-	for (pos = list_entry((head)->next, typeof(*pos), member); \
-		prefetch(rcu_dereference(pos)->member.next), \
-			&pos->member != (head); \
-		pos = list_entry(pos->member.next, typeof(*pos), member))
+	for (pos = list_entry(rcu_dereference((head)->next), typeof(*pos), member); \
+		prefetch(pos->member.next), &pos->member != (head); \
+		pos = list_entry(rcu_dereference(pos->member.next), typeof(*pos), member))
 
 
 /**
@@ -686,9 +668,9 @@ static inline void list_splice_init_rcu(
  * as long as the traversal is guarded by rcu_read_lock().
  */
 #define list_for_each_continue_rcu(pos, head) \
-	for ((pos) = (pos)->next; \
-		prefetch(rcu_dereference((pos))->next), (pos) != (head); \
-        	(pos) = (pos)->next)
+	for ((pos) = rcu_dereference((pos)->next); \
+		prefetch((pos)->next), (pos) != (head); \
+        	(pos) = rcu_dereference((pos)->next))
 
 /*
  * Double linked lists with a single pointer list head.
@@ -986,10 +968,10 @@ static inline void hlist_add_after_rcu(s
  * as long as the traversal is guarded by rcu_read_lock().
  */
 #define hlist_for_each_entry_rcu(tpos, pos, head, member)		 \
-	for (pos = (head)->first;					 \
-	     rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) &&	 \
+	for (pos = rcu_dereference((head)->first);			 \
+	        pos && ({ prefetch(pos->next); 1;}) &&			 \
 		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
-	     pos = pos->next)
+	     pos = rcu_dereference(pos->next))
 
 #else
 #warning "don't include kernel headers in userspace"
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