rcuja: for each key iteration

[urcu.git] / urcu / rcuja.h

diff --git a/urcu/rcuja.h b/urcu/rcuja.h
index 421e8388eb563112c894d6897b6e990d1e772911..7546332d5ea2a2638a7543e23dc742318f39471a 100644 (file)
--- a/urcu/rcuja.h
+++ b/urcu/rcuja.h
@@ -71,17 +71,32 @@ void cds_ja_node_init(struct cds_ja_node *node)
 struct cds_ja_node *cds_ja_lookup(struct cds_ja *ja, uint64_t key);
 
 /*
- * cds_ja_lookup_lower_equal - look up first node with key <= @key.
+ * cds_ja_lookup_below_equal - look up first node with key <= @key.
  * @ja: the Judy array.
  * @key: key to look up.
+ * @result_key: key found.
  *
  * Returns the first node of a duplicate chain if a node is present in
- * the tree which has a key lower or equal to @key, else returns NULL.
+ * the tree which has a key below or equal to @key, else returns NULL.
  * A RCU read-side lock should be held across call to this function and
  * use of its return value.
  */
-struct cds_ja_node *cds_ja_lookup_lower_equal(struct cds_ja *ja,
-               uint64_t key);
+struct cds_ja_node *cds_ja_lookup_below_equal(struct cds_ja *ja,
+               uint64_t key, uint64_t *result_key);
+
+/*
+ * cds_ja_lookup_above_equal - look up first node with key >= @key.
+ * @ja: the Judy array.
+ * @key: key to look up.
+ * @result_key: key found.
+ *
+ * Returns the first node of a duplicate chain if a node is present in
+ * the tree which has a key above or equal to @key, else returns NULL.
+ * A RCU read-side lock should be held across call to this function and
+ * use of its return value.
+ */
+struct cds_ja_node *cds_ja_lookup_above_equal(struct cds_ja *ja,
+               uint64_t key, uint64_t *result_key);
 
 /*
  * cds_ja_add - Add @node at @key, allowing duplicates.
@@ -147,19 +162,69 @@ struct cds_ja *cds_ja_new(unsigned int key_bits)
  * on the Judy array while it is being destroyed (ensured by the caller).
  * There is no need for the @rcu_free_node_cb callback to wait for grace
  * periods, since there are no more concurrent users of the Judy array.
+ * RCU read-side lock should _not_ be held when calling this function,
+ * however, QSBR threads need to be online.
  */
 int cds_ja_destroy(struct cds_ja *ja,
                void (*free_node_cb)(struct cds_ja_node *node));
 
 /*
+ * cds_ja_for_each_duplicate_rcu: Iterate through duplicates.
+ * @pos: struct cds_ja_node *, start of duplicate list and loop cursor.
+ *
  * Iterate through duplicates returned by cds_ja_lookup*()
  * This must be done while rcu_read_lock() is held.
  * Receives a struct cds_ja_node * as parameter, which is used as start
  * of duplicate list and loop cursor.
+ * _NOT_ safe against node removal within iteration.
  */
 #define cds_ja_for_each_duplicate_rcu(pos)                             \
        for (; (pos) != NULL; (pos) = rcu_dereference((pos)->next))
 
+/*
+ * cds_ja_for_each_duplicate_safe_rcu: Iterate through duplicates.
+ * @pos: struct cds_ja_node *, start of duplicate list and loop cursor.
+ * @p: struct cds_ja_node *, temporary pointer to next.
+ *
+ * Iterate through duplicates returned by cds_ja_lookup*()
+ * This must be done while rcu_read_lock() is held.
+ * Safe against node removal within iteration.
+ */
+#define cds_ja_for_each_duplicate_safe_rcu(pos, p)                     \
+       for (; (pos) != NULL ?                                          \
+                       ((p) = rcu_dereference((pos)->next), 1) : 0;    \
+                       (pos) = (p))
+
+/*
+ * cds_ja_for_each_key_rcu: Iterate over all keys in ascending order.
+ * @ja: Judy array on which iteration should be done.
+ * @key: Key cursor, needs to be a uint64_t.
+ * @pos: struct cds_ja_node *, used as loop cursor.
+ *
+ * Iterate over all keys of a RCU Judy array (_not_ duplicates) in
+ * ascending order.
+ * This must be done while rcu_read_lock() is held.
+ * Safe against node removal during iteration.
+ */
+#define cds_ja_for_each_key_rcu(ja, key, pos)                          \
+       for ((key) = 0;                                                 \
+               ((pos) = cds_ja_lookup_above_equal(ja, key, &(key))); )
+
+/*
+ * cds_ja_for_each_key_prev_rcu: Iterate over all keys in descending order.
+ * @ja: Judy array on which iteration should be done.
+ * @key: Key cursor, needs to be a uint64_t.
+ * @pos: struct cds_ja_node *, used as loop cursor.
+ *
+ * Iterate over all keys of a RCU Judy array (_not_ duplicates) in
+ * descending order.
+ * This must be done while rcu_read_lock() is held.
+ * Safe against node removal during iteration.
+ */
+#define cds_ja_for_each_key_prev_rcu(ja, key, pos)                     \
+       for ((key) = UINT64_MAX;                                        \
+               ((pos) = cds_ja_lookup_below_equal(ja, key, &(key))); )
+
 #ifdef __cplusplus
 }
 #endif