rcuja: fix iteration and lookup below/above equal

- fix iteration on entirely filled uint64_t keyspace: we need to reserve
  UINT64_MAX as end-of-iteration marker.
- fix linear lookups below/above or equal: should not re-read the
  pointer.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/rcuja/rcuja.c b/rcuja/rcuja.c
index a791d5b29687b3daf90927ff263a0a6c3f7405f0..a3acfbceb7dffebd2ce358a90094a1b41c962027 100644 (file)
--- a/rcuja/rcuja.c
+++ b/rcuja/rcuja.c
@@ -370,9 +370,9 @@ struct cds_ja_inode_flag *ja_linear_node_get_direction(const struct cds_ja_type
        uint8_t nr_child;
        uint8_t *values;
        struct cds_ja_inode_flag **pointers;
-       struct cds_ja_inode_flag *ptr = NULL;
+       struct cds_ja_inode_flag *ptr, *match_ptr = NULL;
        unsigned int i;
-       int match_idx = -1, match_v;
+       int match_v;
 
        assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
        assert(dir == JA_LEFT || dir == JA_RIGHT);
@@ -400,24 +400,23 @@ struct cds_ja_inode_flag *ja_linear_node_get_direction(const struct cds_ja_type
                if (dir == JA_LEFT) {
                        if ((int) v < n && (int) v > match_v) {
                                match_v = v;
-                               match_idx = i;
+                               match_ptr = ptr;
                        }
                } else {
                        if ((int) v > n && (int) v < match_v) {
                                match_v = v;
-                               match_idx = i;
+                               match_ptr = ptr;
                        }
                }
        }
 
-       if (match_idx < 0) {
+       if (!match_ptr) {
                return NULL;
        }
        assert(match_v >= 0 && match_v < JA_ENTRY_PER_NODE);
 
        *result_key = (uint8_t) match_v;
-       ptr = rcu_dereference(pointers[match_idx]);
-       return ptr;
+       return match_ptr;
 }
 
 static
@@ -1784,7 +1783,7 @@ struct cds_ja_node *cds_ja_lookup(struct cds_ja *ja, uint64_t key)
        unsigned int tree_depth, i;
        struct cds_ja_inode_flag *node_flag;
 
-       if (caa_unlikely(key > ja->key_max))
+       if (caa_unlikely(key > ja->key_max || key == UINT64_MAX))
                return NULL;
        tree_depth = ja->tree_depth;
        node_flag = rcu_dereference(ja->root);
@@ -1820,11 +1819,8 @@ struct cds_ja_node *cds_ja_lookup_inequality(struct cds_ja *ja, uint64_t key,
 
        switch (mode) {
        case JA_LOOKUP_BE:
-               if (caa_unlikely(key > ja->key_max))
-                       return NULL;
-               break;
        case JA_LOOKUP_AE:
-               if (caa_unlikely(key > ja->key_max))
+               if (caa_unlikely(key > ja->key_max || key == UINT64_MAX))
                        return NULL;
                break;
        default:
@@ -2202,7 +2198,7 @@ int _cds_ja_add(struct cds_ja *ja, uint64_t key,
                **node_flag_ptr;
        int ret;
 
-       if (caa_unlikely(key > ja->key_max)) {
+       if (caa_unlikely(key > ja->key_max || key == UINT64_MAX)) {
                return -EINVAL;
        }
        tree_depth = ja->tree_depth;
@@ -2533,7 +2529,7 @@ int cds_ja_del(struct cds_ja *ja, uint64_t key,
        int nr_snapshot;
        int ret;
 
-       if (caa_unlikely(key > ja->key_max))
+       if (caa_unlikely(key > ja->key_max || key == UINT64_MAX))
                return -EINVAL;
        tree_depth = ja->tree_depth;
 

diff --git a/urcu/rcuja.h b/urcu/rcuja.h
index 164b05a3fdf481904270412e0225f042a42310df..82e272bd4ede1aec436845aef287754dd1dab8b6 100644 (file)
--- a/urcu/rcuja.h
+++ b/urcu/rcuja.h
@@ -56,6 +56,10 @@ void cds_ja_node_init(struct cds_ja_node *node)
 {
 }
 
+/*
+ * Note: key UINT64_MAX is reserved internally for iteration.
+ */
+
 /*
  * cds_ja_lookup - look up by key.
  * @ja: the Judy array.
@@ -202,7 +206,9 @@ int cds_ja_destroy(struct cds_ja *ja);
  */
 #define cds_ja_for_each_key_rcu(ja, key, pos)                          \
        for ((key) = 0;                                                 \
-               ((pos) = cds_ja_lookup_above_equal(ja, key, &(key))); )
+               ((key) != UINT64_MAX ?                                  \
+                       ((pos) = cds_ja_lookup_above_equal(ja, key, &(key))) : 0); \
+               (key)++)
 
 /*
  * cds_ja_for_each_key_prev_rcu: Iterate over all keys in descending order.
@@ -216,8 +222,10 @@ int cds_ja_destroy(struct cds_ja *ja);
  * 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))); )
+       for ((key) = UINT64_MAX - 1;                                    \
+               ((key) != UINT64_MAX ?                                  \
+                       ((pos) = cds_ja_lookup_below_equal(ja, key, &(key))) : 0); \
+               (key)--)
 
 #ifdef __cplusplus
 }