+int _ja_node_set_nth(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ uint8_t n,
+ struct cds_ja_inode_flag *child_node_flag)
+{
+ switch (type->type_class) {
+ case RCU_JA_LINEAR:
+ return ja_linear_node_set_nth(type, node, shadow_node, n,
+ child_node_flag);
+ case RCU_JA_POOL:
+ return ja_pool_node_set_nth(type, node, shadow_node, n,
+ child_node_flag);
+ case RCU_JA_PIGEON:
+ return ja_pigeon_node_set_nth(type, node, shadow_node, n,
+ child_node_flag);
+ case RCU_JA_NULL:
+ return -ENOSPC;
+ default:
+ assert(0);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static
+int ja_linear_node_clear_ptr(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr)
+{
+ uint8_t nr_child;
+ uint8_t *nr_child_ptr;
+
+ assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
+
+ nr_child_ptr = &node->u.data[0];
+ dbg_printf("linear clear ptr: nr_child_ptr %p\n", nr_child_ptr);
+ nr_child = *nr_child_ptr;
+ assert(nr_child <= type->max_linear_child);
+
+ if (shadow_node->fallback_removal_count) {
+ shadow_node->fallback_removal_count--;
+ } else {
+ if (shadow_node->nr_child <= type->min_child) {
+ /* We need to try recompacting the node */
+ return -EFBIG;
+ }
+ }
+ assert(*node_flag_ptr != NULL);
+ rcu_assign_pointer(*node_flag_ptr, NULL);
+ /*
+ * Value and nr_child are never changed (would cause ABA issue).
+ * Instead, we leave the pointer to NULL and recompact the node
+ * once in a while. It is allowed to set a NULL pointer to a new
+ * value without recompaction though.
+ * Only update the shadow node accounting.
+ */
+ shadow_node->nr_child--;
+ dbg_printf("linear clear ptr: %u child, shadow: %u child, for node %p shadow %p\n",
+ (unsigned int) CMM_LOAD_SHARED(*nr_child_ptr),
+ (unsigned int) shadow_node->nr_child,
+ node, shadow_node);
+
+ return 0;
+}
+
+static
+int ja_pool_node_clear_ptr(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr,
+ uint8_t n)
+{
+ struct cds_ja_inode *linear;
+
+ assert(type->type_class == RCU_JA_POOL);
+ linear = (struct cds_ja_inode *)
+ &node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
+ return ja_linear_node_clear_ptr(type, linear, shadow_node, node_flag_ptr);
+}
+
+static
+int ja_pigeon_node_clear_ptr(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr)
+{
+ assert(type->type_class == RCU_JA_PIGEON);
+ dbg_printf("ja_pigeon_node_clear_ptr: clearing ptr: %p\n", *node_flag_ptr);
+ rcu_assign_pointer(*node_flag_ptr, NULL);
+ shadow_node->nr_child--;
+ return 0;
+}
+
+/*
+ * _ja_node_clear_ptr: clear ptr item within a node. Return an error
+ * (negative error value) if it is not found (-ENOENT).
+ */
+static
+int _ja_node_clear_ptr(const struct cds_ja_type *type,
+ struct cds_ja_inode *node,
+ struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr,
+ uint8_t n)
+{
+ switch (type->type_class) {
+ case RCU_JA_LINEAR:
+ return ja_linear_node_clear_ptr(type, node, shadow_node, node_flag_ptr);
+ case RCU_JA_POOL:
+ return ja_pool_node_clear_ptr(type, node, shadow_node, node_flag_ptr, n);
+ case RCU_JA_PIGEON:
+ return ja_pigeon_node_clear_ptr(type, node, shadow_node, node_flag_ptr);
+ case RCU_JA_NULL:
+ return -ENOENT;
+ default:
+ assert(0);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * ja_node_recompact_add: recompact a node, adding a new child.
+ * TODO: for pool type, take selection bit(s) into account.
+ * Return 0 on success, -EAGAIN if need to retry, or other negative
+ * error value otherwise.
+ */
+static
+int ja_node_recompact(enum ja_recompact mode,
+ struct cds_ja *ja,
+ unsigned int old_type_index,
+ const struct cds_ja_type *old_type,
+ struct cds_ja_inode *old_node,
+ struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **old_node_flag_ptr, uint8_t n,
+ struct cds_ja_inode_flag *child_node_flag,
+ struct cds_ja_inode_flag **nullify_node_flag_ptr)
+{
+ unsigned int new_type_index;
+ struct cds_ja_inode *new_node;
+ struct cds_ja_shadow_node *new_shadow_node = NULL;
+ const struct cds_ja_type *new_type;
+ struct cds_ja_inode_flag *new_node_flag, *old_node_flag;
+ int ret;
+ int fallback = 0;
+
+ old_node_flag = *old_node_flag_ptr;
+
+ switch (mode) {
+ case JA_RECOMPACT:
+ new_type_index = old_type_index;
+ break;
+ case JA_RECOMPACT_ADD:
+ if (!shadow_node || old_type_index == NODE_INDEX_NULL) {
+ new_type_index = 0;
+ } else {
+ new_type_index = old_type_index + 1;
+ }
+ break;
+ case JA_RECOMPACT_DEL:
+ if (old_type_index == 0) {
+ new_type_index = NODE_INDEX_NULL;
+ } else {
+ new_type_index = old_type_index - 1;
+ }
+ break;
+ default:
+ assert(0);
+ }
+
+retry: /* for fallback */
+ dbg_printf("Recompact from type %d to type %d\n",
+ old_type_index, new_type_index);
+ new_type = &ja_types[new_type_index];
+ if (new_type_index != NODE_INDEX_NULL) {
+ new_node = alloc_cds_ja_node(new_type);
+ if (!new_node)
+ return -ENOMEM;
+ new_node_flag = ja_node_flag(new_node, new_type_index);
+ dbg_printf("Recompact inherit lock from %p\n", shadow_node);
+ new_shadow_node = rcuja_shadow_set(ja->ht, new_node_flag, shadow_node, ja);
+ if (!new_shadow_node) {
+ free(new_node);
+ return -ENOMEM;
+ }
+ if (fallback)
+ new_shadow_node->fallback_removal_count =
+ JA_FALLBACK_REMOVAL_COUNT;
+ } else {
+ new_node = NULL;
+ new_node_flag = NULL;
+ }
+
+ assert(mode != JA_RECOMPACT_ADD || old_type->type_class != RCU_JA_PIGEON);
+
+ if (new_type_index == NODE_INDEX_NULL)
+ goto skip_copy;
+
+ switch (old_type->type_class) {
+ case RCU_JA_LINEAR:
+ {
+ uint8_t nr_child =
+ ja_linear_node_get_nr_child(old_type, old_node);
+ unsigned int i;
+
+ for (i = 0; i < nr_child; i++) {
+ struct cds_ja_inode_flag *iter;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(old_type, old_node, i, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_shadow_node,
+ v, iter);
+ if (new_type->type_class == RCU_JA_POOL && ret) {
+ goto fallback_toosmall;
+ }
+ assert(!ret);
+ }
+ break;
+ }
+ case RCU_JA_POOL:
+ {
+ unsigned int pool_nr;
+
+ for (pool_nr = 0; pool_nr < (1U << old_type->nr_pool_order); pool_nr++) {
+ struct cds_ja_inode *pool =
+ ja_pool_node_get_ith_pool(old_type,
+ old_node, pool_nr);
+ uint8_t nr_child =
+ ja_linear_node_get_nr_child(old_type, pool);
+ unsigned int j;
+
+ for (j = 0; j < nr_child; j++) {
+ struct cds_ja_inode_flag *iter;
+ uint8_t v;
+
+ ja_linear_node_get_ith_pos(old_type, pool,
+ j, &v, &iter);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_shadow_node,
+ v, iter);
+ if (new_type->type_class == RCU_JA_POOL
+ && ret) {
+ goto fallback_toosmall;
+ }
+ assert(!ret);
+ }
+ }
+ break;
+ }
+ case RCU_JA_NULL:
+ assert(mode == JA_RECOMPACT_ADD);
+ break;
+ case RCU_JA_PIGEON:
+ {
+ uint8_t nr_child;
+ unsigned int i;
+
+ assert(mode == JA_RECOMPACT_DEL);
+ nr_child = shadow_node->nr_child;
+ for (i = 0; i < nr_child; i++) {
+ struct cds_ja_inode_flag *iter;
+
+ iter = ja_pigeon_node_get_ith_pos(old_type, old_node, i);
+ if (!iter)
+ continue;
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
+ continue;
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_shadow_node,
+ i, iter);
+ if (new_type->type_class == RCU_JA_POOL && ret) {
+ goto fallback_toosmall;
+ }
+ assert(!ret);
+ }
+ break;
+ }
+ default:
+ assert(0);
+ ret = -EINVAL;
+ goto end;
+ }
+skip_copy:
+
+ if (mode == JA_RECOMPACT_ADD) {
+ /* add node */
+ ret = _ja_node_set_nth(new_type, new_node,
+ new_shadow_node,
+ n, child_node_flag);
+ assert(!ret);
+ }
+ /* Return pointer to new recompacted node through old_node_flag_ptr */
+ *old_node_flag_ptr = new_node_flag;
+ if (old_node) {
+ int flags;
+
+ flags = RCUJA_SHADOW_CLEAR_FREE_NODE;
+ /*
+ * It is OK to free the lock associated with a node
+ * going to NULL, since we are holding the parent lock.
+ * This synchronizes removal with re-add of that node.
+ */
+ if (new_type_index == NODE_INDEX_NULL)
+ flags = RCUJA_SHADOW_CLEAR_FREE_LOCK;
+ ret = rcuja_shadow_clear(ja->ht, old_node_flag, shadow_node,
+ flags);
+ assert(!ret);
+ }
+
+ ret = 0;
+end:
+ return ret;
+
+fallback_toosmall:
+ /* fallback if next pool is too small */
+ assert(new_shadow_node);
+ ret = rcuja_shadow_clear(ja->ht, new_node_flag, new_shadow_node,
+ RCUJA_SHADOW_CLEAR_FREE_NODE);
+ assert(!ret);
+
+ /* Choose fallback type: pigeon */
+ new_type_index = (1UL << JA_TYPE_BITS) - 1;
+ dbg_printf("Fallback to type %d\n", new_type_index);
+ uatomic_inc(&ja->nr_fallback);
+ fallback = 1;
+ goto retry;
+}
+
+/*
+ * Return 0 on success, -EAGAIN if need to retry, or other negative
+ * error value otherwise.
+ */
+static
+int ja_node_set_nth(struct cds_ja *ja,
+ struct cds_ja_inode_flag **node_flag, uint8_t n,
+ struct cds_ja_inode_flag *child_node_flag,
+ struct cds_ja_shadow_node *shadow_node)
+{
+ int ret;
+ unsigned int type_index;
+ const struct cds_ja_type *type;
+ struct cds_ja_inode *node;
+
+ dbg_printf("ja_node_set_nth for n=%u, node %p, shadow %p\n",
+ (unsigned int) n, ja_node_ptr(*node_flag), shadow_node);
+
+ node = ja_node_ptr(*node_flag);
+ type_index = ja_node_type(*node_flag);
+ type = &ja_types[type_index];
+ ret = _ja_node_set_nth(type, node, shadow_node,
+ n, child_node_flag);
+ switch (ret) {
+ case -ENOSPC:
+ /* Not enough space in node, need to recompact. */
+ ret = ja_node_recompact(JA_RECOMPACT_ADD, ja, type_index, type, node,
+ shadow_node, node_flag, n, child_node_flag, NULL);
+ break;
+ case -ERANGE:
+ /* Node needs to be recompacted. */
+ ret = ja_node_recompact(JA_RECOMPACT, ja, type_index, type, node,
+ shadow_node, node_flag, n, child_node_flag, NULL);
+ break;
+ }
+ return ret;
+}
+
+/*
+ * Return 0 on success, -EAGAIN if need to retry, or other negative
+ * error value otherwise.
+ */
+static
+int ja_node_clear_ptr(struct cds_ja *ja,
+ struct cds_ja_inode_flag **node_flag_ptr, /* Pointer to location to nullify */
+ struct cds_ja_inode_flag **parent_node_flag_ptr, /* Address of parent ptr in its parent */
+ struct cds_ja_shadow_node *shadow_node, /* of parent */
+ uint8_t n)