From 13a7f5a6a1d3e9232eb038ebf3c87b2a5ac22cc8 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Sun, 12 Aug 2012 13:06:53 -0400 Subject: [PATCH] rcuja: set node update, rcu-ize get node/set node Signed-off-by: Mathieu Desnoyers --- rcuja/rcuja.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/rcuja/rcuja.c b/rcuja/rcuja.c index 348789e..7364e07 100644 --- a/rcuja/rcuja.c +++ b/rcuja/rcuja.c @@ -281,6 +281,11 @@ uint8_t *align_ptr_size(uint8_t *ptr) return (uint8_t *) JA_ALIGN((unsigned long) ptr, sizeof(void *)); } +/* + * The order in which values and pointers are does does not matter: if + * a value is missing, we return NULL. If a value is there, but its + * associated pointers is still NULL, we return NULL too. + */ static struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type, struct rcu_ja_node *node, @@ -294,21 +299,20 @@ struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type, assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL); - nr_child = node->u.data[0]; - cmm_smp_rmb(); /* read nr_child before values */ + nr_child = CMM_LOAD_SHARED(node->u.data[0]); + cmm_smp_rmb(); /* read nr_child before values and pointers */ assert(nr_child <= type->max_linear_child); assert(type->type_class != RCU_JA_LINEAR || nr_child >= type->min_child); values = &node->u.data[1]; for (i = 0; i < nr_child; i++) { - if (values[i] == n) + if (CMM_LOAD_SHARED(values[i]) == n) break; } if (i >= nr_child) return NULL; - cmm_smp_rmb(); /* read values before pointer */ pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[type->max_linear_child]); - ptr = pointers[i]; + ptr = rcu_dereference(pointers[i]); assert(ja_node_ptr(ptr) != NULL); return ptr; } @@ -332,10 +336,13 @@ struct rcu_ja_node_flag *ja_pigeon_node_get_nth(const struct rcu_ja_type *type, uint8_t n) { assert(type->type_class == RCU_JA_PIGEON); - return ((struct rcu_ja_node_flag **) node->u.data)[n]; + return rcu_dereference(((struct rcu_ja_node_flag **) node->u.data)[n]); } -/* ja_node_get_nth: get nth item from a node */ +/* + * ja_node_get_nth: get nth item from a node. + * node_flag is already rcu_dereference'd. + */ static struct rcu_ja_node_flag *ja_node_get_nth(struct rcu_ja_node_flag *node_flag, uint8_t n) @@ -344,7 +351,6 @@ struct rcu_ja_node_flag *ja_node_get_nth(struct rcu_ja_node_flag *node_flag, struct rcu_ja_node *node; const struct rcu_ja_type *type; - node_flag = rcu_dereference(node_flag); node = ja_node_ptr(node_flag); assert(node != NULL); type_index = ja_node_type(node_flag); @@ -391,8 +397,11 @@ int ja_linear_node_set_nth(const struct rcu_ja_type *type, return -ENOSPC; } pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[type->max_linear_child]); - pointers[nr_child] = child_node_flag; - (*nr_child_ptr)++; + assert(pointers[nr_child] == NULL); + rcu_assign_pointer(pointers[nr_child], child_node_flag); + CMM_STORE_SHARED(values[nr_child], n); + cmm_smp_wmb(); /* write value and pointer before nr_child */ + CMM_STORE_SHARED(*nr_child_ptr, nr_child + 1); return 0; } -- 2.34.1