Get rid of useless use of rcu_read_lock.

These code paths are fully protected by the Generic Netlink genl_mutex,
which is taken by genl_rcv() that calls dp_genl_openflow(), so there is
no need for them to take the rcu_read_lock.

diff --git a/datapath/chain.c b/datapath/chain.c
index c857e9a..fd13a86 100644 (file)
--- a/datapath/chain.c
+++ b/datapath/chain.c
@@ -138,9 +138,7 @@ int chain_timeout(struct sw_chain *chain)
 
        for (i = 0; i < chain->n_tables; i++) {
                struct sw_table *t = chain->tables[i];
-               rcu_read_lock();
                count += t->timeout(chain->dp, t);
-               rcu_read_unlock();
        }
        return count;
 }

diff --git a/datapath/datapath.c b/datapath/datapath.c
index a4c6a2d..f81388d 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1028,32 +1028,23 @@ static int dp_genl_openflow(struct sk_buff *skb, struct genl_info *info)
        struct datapath *dp;
        struct ofp_header *oh;
        struct sender sender;
-       int err;
 
        if (!info->attrs[DP_GENL_A_DP_IDX] || !va)
                return -EINVAL;
 
-       rcu_read_lock();
        dp = dp_get(nla_get_u32(info->attrs[DP_GENL_A_DP_IDX]));
-       if (!dp) {
-               err = -ENOENT;
-               goto out;
-       }
+       if (!dp)
+               return -ENOENT;
 
-       if (nla_len(va) < sizeof(struct ofp_header)) {
-               err = -EINVAL;
-               goto out;
-       }
+       if (nla_len(va) < sizeof(struct ofp_header))
+               return -EINVAL;
        oh = nla_data(va);
 
        sender.xid = oh->xid;
        sender.pid = info->snd_pid;
        sender.seq = info->snd_seq;
-       err = fwd_control_input(dp->chain, &sender, nla_data(va), nla_len(va));
-
-out:
-       rcu_read_unlock();
-       return err;
+       return fwd_control_input(dp->chain, &sender,
+                                nla_data(va), nla_len(va));
 }
 
 static struct nla_policy dp_genl_openflow_policy[DP_GENL_A_MAX + 1] = {
@@ -1368,7 +1359,6 @@ dp_genl_openflow_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
         * struct genl_ops.  This kluge supports earlier versions also. */
        cb->done = dp_genl_openflow_done;
 
-       rcu_read_lock();
        if (!cb->args[0]) {
                struct nlattr *attrs[DP_GENL_A_MAX + 1];
                struct ofp_stats_request *rq;
@@ -1381,21 +1371,17 @@ dp_genl_openflow_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
                if (err < 0)
                        return err;
 
-               err = -EINVAL;
-
                if (!attrs[DP_GENL_A_DP_IDX])
-                       goto out;
+                       return -EINVAL;
                dp_idx = nla_get_u16(attrs[DP_GENL_A_DP_IDX]);
                dp = dp_get(dp_idx);
-               if (!dp) {
-                       err = -ENOENT;
-                       goto out;
-               }
+               if (!dp)
+                       return -ENOENT;
 
                va = attrs[DP_GENL_A_OPENFLOW];
                len = nla_len(va);
                if (!va || len < sizeof *rq)
-                       goto out;
+                       return -EINVAL;
 
                rq = nla_data(va);
                type = ntohs(rq->type);
@@ -1404,12 +1390,12 @@ dp_genl_openflow_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
                    || ntohs(rq->header.length) != len
                    || type >= ARRAY_SIZE(stats)
                    || !stats[type].dump)
-                       goto out;
+                       return -EINVAL;
 
                s = &stats[type];
                body_len = len - offsetof(struct ofp_stats_request, body);
                if (body_len < s->min_body || body_len > s->max_body)
-                       goto out;
+                       return -EINVAL;
 
                cb->args[0] = 1;
                cb->args[1] = dp_idx;
@@ -1419,7 +1405,7 @@ dp_genl_openflow_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
                        void *state;
                        err = s->init(dp, rq->body, body_len, &state);
                        if (err)
-                               goto out;
+                               return err;
                        cb->args[4] = (long) state;
                }
        } else if (cb->args[0] == 1) {
@@ -1427,13 +1413,10 @@ dp_genl_openflow_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
                s = &stats[cb->args[2]];
 
                dp = dp_get(dp_idx);
-               if (!dp) {
-                       err = -ENOENT;
-                       goto out;
-               }
+               if (!dp)
+                       return -ENOENT;
        } else {
-               err = 0;
-               goto out;
+               return 0;
        }
 
        sender.xid = cb->args[3];
@@ -1442,10 +1425,8 @@ dp_genl_openflow_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 
        osr = put_openflow_headers(dp, skb, OFPT_STATS_REPLY, &sender,
                                   &max_openflow_len);
-       if (IS_ERR(osr)) {
-               err = PTR_ERR(osr);
-               goto out;
-       }
+       if (IS_ERR(osr))
+               return PTR_ERR(osr);
        osr->type = htons(s - stats);
        osr->flags = 0;
        resize_openflow_skb(skb, &osr->header, max_openflow_len);
@@ -1464,8 +1445,6 @@ dp_genl_openflow_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
                err = skb->len;
        }
 
-out:
-       rcu_read_unlock();
        return err;
 }