net: rcu fixes

Add hlist_for_each_entry_rcu_bh() and
hlist_for_each_entry_continue_rcu_bh() macros, and use them in
ipv6_get_ifaddr(), if6_get_first() and if6_get_next() to fix lockdeps
warnings.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 29 insertions, 0 deletions

diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index 004908b104d5..4ec3b38ce9c5 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -429,6 +429,23 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
                 pos = rcu_dereference_raw(pos->next))
 
 /**
+ * hlist_for_each_entry_rcu_bh - iterate over rcu list of given type
+ * @tpos:       the type * to use as a loop cursor.
+ * @pos:        the &struct hlist_node to use as a loop cursor.
+ * @head:       the head for your list.
+ * @member:     the name of the hlist_node within the struct.
+ *
+ * This list-traversal primitive may safely run concurrently with
+ * the _rcu list-mutation primitives such as hlist_add_head_rcu()
+ * as long as the traversal is guarded by rcu_read_lock().
+ */
+#define hlist_for_each_entry_rcu_bh(tpos, pos, head, member)             \
+        for (pos = rcu_dereference_bh((head)->first);                    \
+                pos && ({ prefetch(pos->next); 1; }) &&                  \
+                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \
+                pos = rcu_dereference_bh(pos->next))
+
+/**
  * hlist_for_each_entry_continue_rcu - iterate over a hlist continuing after current point
  * @tpos:       the type * to use as a loop cursor.
  * @pos:        the &struct hlist_node to use as a loop cursor.
@@ -440,6 +457,18 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
              ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; });  \
              pos = rcu_dereference(pos->next))
 
+/**
+ * hlist_for_each_entry_continue_rcu_bh - iterate over a hlist continuing after current point
+ * @tpos:       the type * to use as a loop cursor.
+ * @pos:        the &struct hlist_node to use as a loop cursor.
+ * @member:     the name of the hlist_node within the struct.
+ */
+#define hlist_for_each_entry_continue_rcu_bh(tpos, pos, member)         \
+        for (pos = rcu_dereference_bh((pos)->next);                     \
+             pos && ({ prefetch(pos->next); 1; }) &&                    \
+             ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; });  \
+             pos = rcu_dereference_bh(pos->next))
+
 
 #endif  /* __KERNEL__ */
 #endif