Fix: handle sys_futex() FUTEX_WAIT interrupted by signal

[urcu.git] / urcu / rculist.h

diff --git a/urcu/rculist.h b/urcu/rculist.h
index 575e1fb0d8f4f836166695f80b732898d8c0265a..1fd2df388f57cefc0ea19fa02a0c8c0b627847e8 100644 (file)
--- a/urcu/rculist.h
+++ b/urcu/rculist.h
@@ -29,20 +29,34 @@
 #include <urcu/arch.h>
 #include <urcu-pointer.h>
 
-/* Add new element at the head of the list.
- */
-static inline void cds_list_add_rcu(struct cds_list_head *newp, struct cds_list_head *head)
+/* Add new element at the head of the list. */
+static inline
+void cds_list_add_rcu(struct cds_list_head *newp, struct cds_list_head *head)
 {
        newp->next = head->next;
        newp->prev = head;
-       cmm_smp_wmb();
        head->next->prev = newp;
-       head->next = newp;
+       rcu_assign_pointer(head->next, newp);
+}
+
+/* Add new element at the tail of the list. */
+static inline
+void cds_list_add_tail_rcu(struct cds_list_head *newp,
+               struct cds_list_head *head)
+{
+       newp->next = head;
+       newp->prev = head->prev;
+       rcu_assign_pointer(head->prev->next, newp);
+       head->prev = newp;
 }
 
-/* replace an old entry atomically.
+/*
+ * Replace an old entry atomically with respect to concurrent RCU
+ * traversal. Mutual exclusion against concurrent updates is required
+ * though.
  */
-static inline void cds_list_replace_rcu(struct cds_list_head *old, struct cds_list_head *_new)
+static inline
+void cds_list_replace_rcu(struct cds_list_head *old, struct cds_list_head *_new)
 {
        _new->next = old->next;
        _new->prev = old->prev;
@@ -51,10 +65,11 @@ static inline void cds_list_replace_rcu(struct cds_list_head *old, struct cds_li
 }
 
 /* Remove element from list. */
-static inline void cds_list_del_rcu(struct cds_list_head *elem)
+static inline
+void cds_list_del_rcu(struct cds_list_head *elem)
 {
        elem->next->prev = elem->prev;
-       elem->prev->next = elem->next;
+       CMM_STORE_SHARED(elem->prev->next, elem->next);
 }
 
 /*
@@ -64,15 +79,14 @@ static inline void cds_list_del_rcu(struct cds_list_head *elem)
 
 /* Iterate forward over the elements of the list.  */
 #define cds_list_for_each_rcu(pos, head) \
-  for (pos = rcu_dereference((head)->next); pos != (head); \
-       pos = rcu_dereference(pos->next))
+       for (pos = rcu_dereference((head)->next); pos != (head); \
+               pos = rcu_dereference(pos->next))
 
 
-/* Iterate through elements of the list.
- */
-#define cds_list_for_each_entry_rcu(pos, head, member)                         \
-       for (pos = cds_list_entry(rcu_dereference((head)->next), typeof(*pos), member); \
-            &pos->member != (head);                                    \
-            pos = cds_list_entry(rcu_dereference(pos->member.next), typeof(*pos), member))
+/* Iterate through elements of the list. */
+#define cds_list_for_each_entry_rcu(pos, head, member) \
+       for (pos = cds_list_entry(rcu_dereference((head)->next), __typeof__(*pos), member); \
+               &pos->member != (head); \
+               pos = cds_list_entry(rcu_dereference(pos->member.next), __typeof__(*pos), member))
 
 #endif /* _URCU_RCULIST_H */