datapath: Check locks on access to flow table.

When accessing the flow table without holding rcu_read_lcok
we need to hold the lock on the datapath.  This enables lockdep
to validate that that is the case.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 8960a06..796c40c 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -94,6 +94,11 @@ static struct datapath *get_dp_locked(int dp_idx)
        return dp;
 }
 
+static struct tbl *get_table_protected(struct datapath *dp)
+{
+       return rcu_dereference_protected(dp->table, lockdep_is_held(&dp->mutex));
+}
+
 /* Must be called with rcu_read_lock or RTNL lock. */
 const char *dp_name(const struct datapath *dp)
 {
@@ -643,7 +648,7 @@ err:
 
 static int flush_flows(struct datapath *dp)
 {
-       struct tbl *old_table = rcu_dereference(dp->table);
+       struct tbl *old_table = get_table_protected(dp);
        struct tbl *new_table;
 
        new_table = tbl_create(0);
@@ -790,7 +795,7 @@ static void clear_stats(struct sw_flow *flow)
 
 static int expand_table(struct datapath *dp)
 {
-       struct tbl *old_table = rcu_dereference(dp->table);
+       struct tbl *old_table = get_table_protected(dp);
        struct tbl *new_table;
 
        new_table = tbl_expand(old_table);
@@ -811,7 +816,7 @@ static int do_put_flow(struct datapath *dp, struct odp_flow_put *uf,
        struct tbl *table;
        int error;
 
-       table = rcu_dereference(dp->table);
+       table = get_table_protected(dp);
        flow_node = tbl_lookup(table, &uf->flow.key, flow_hash(&uf->flow.key), flow_cmp);
        if (!flow_node) {
                /* No such flow. */
@@ -826,7 +831,7 @@ static int do_put_flow(struct datapath *dp, struct odp_flow_put *uf,
                        error = expand_table(dp);
                        if (error)
                                goto error;
-                       table = rcu_dereference(dp->table);
+                       table = get_table_protected(dp);
                }
 
                /* Allocate flow. */
@@ -962,7 +967,7 @@ static int answer_query(struct sw_flow *flow, u32 query_flags,
 
 static struct sw_flow *do_del_flow(struct datapath *dp, struct odp_flow_key *key)
 {
-       struct tbl *table = rcu_dereference(dp->table);
+       struct tbl *table = get_table_protected(dp);
        struct tbl_node *flow_node;
        int error;
 
@@ -1001,7 +1006,7 @@ static int del_flow(struct datapath *dp, struct odp_flow __user *ufp)
 
 static int do_query_flows(struct datapath *dp, const struct odp_flowvec *flowvec)
 {
-       struct tbl *table = rcu_dereference(dp->table);
+       struct tbl *table = get_table_protected(dp);
        u32 i;
 
        for (i = 0; i < flowvec->n_flows; i++) {
@@ -1060,7 +1065,7 @@ static int do_list_flows(struct datapath *dp, const struct odp_flowvec *flowvec)
        cbdata.n_flows = flowvec->n_flows;
        cbdata.listed_flows = 0;
 
-       error = tbl_foreach(rcu_dereference(dp->table), list_flow, &cbdata);
+       error = tbl_foreach(get_table_protected(dp), list_flow, &cbdata);
        return error ? error : cbdata.listed_flows;
 }
 
@@ -1166,7 +1171,7 @@ static int execute_packet(struct datapath *dp, const struct odp_execute __user *
 
 static int get_dp_stats(struct datapath *dp, struct odp_stats __user *statsp)
 {
-       struct tbl *table = rcu_dereference(dp->table);
+       struct tbl *table = get_table_protected(dp);
        struct odp_stats stats;
        int i;
 
@@ -1588,7 +1593,7 @@ static int compat_query_flows(struct datapath *dp,
                              struct compat_odp_flow __user *flows,
                              u32 n_flows)
 {
-       struct tbl *table = rcu_dereference(dp->table);
+       struct tbl *table = get_table_protected(dp);
        u32 i;
 
        for (i = 0; i < n_flows; i++) {
@@ -1648,7 +1653,7 @@ static int compat_list_flows(struct datapath *dp,
        cbdata.n_flows = n_flows;
        cbdata.listed_flows = 0;
 
-       error = tbl_foreach(rcu_dereference(dp->table), compat_list_flow, &cbdata);
+       error = tbl_foreach(get_table_protected(dp), compat_list_flow, &cbdata);
        return error ? error : cbdata.listed_flows;
 }