On Wed, Jul 16, 2014 at 11:42 PM, Andy Zhou <az...@nicira.com> wrote:
> Remove get_dp() API, it becomes get_dp__() which is for internal
> use only. Added the following APIs to make it clear of the locking
> requirement.
>
> o get_dp_rcu() requires its caller to hold rcu lock.
> o get_dp_ovsl() requires its caller to hold ovs lock.
> o get_dp_ovsl_rcu() requires its caller to hold either ovs lock or
> rcu lock.
>
I think this is getting bit complicate. I am not sure if it is worth
adding this complexity at this point.
> Signed-off-by: Andy Zhou <az...@nicira.com>
> ---
> datapath/datapath.c | 53
> ++++++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 38 insertions(+), 15 deletions(-)
>
> diff --git a/datapath/datapath.c b/datapath/datapath.c
> index 065356f..f018bd4 100644
> --- a/datapath/datapath.c
> +++ b/datapath/datapath.c
> @@ -140,24 +140,47 @@ static int queue_gso_packets(struct datapath *dp,
> struct sk_buff *,
> static int queue_userspace_packet(struct datapath *dp, struct sk_buff *,
> const struct dp_upcall_info *);
>
> -/* Must be called with rcu_read_lock or ovs_mutex. */
> -static struct datapath *get_dp(struct net *net, int dp_ifindex)
> +/* Must be called with rcu_read_lock. */
> +static struct datapath *get_dp_rcu(struct net *net, int dp_ifindex)
> {
> + struct net_device *dev = dev_get_by_index_rcu(net, dp_ifindex);
> struct datapath *dp = NULL;
> - struct net_device *dev;
>
> - rcu_read_lock();
> - dev = dev_get_by_index_rcu(net, dp_ifindex);
> if (dev) {
> struct vport *vport = ovs_internal_dev_get_vport(dev);
> if (vport)
> dp = vport->dp;
> }
> +
> + return dp;
> +}
> +
> +static struct datapath *get_dp__(struct net *net, int dp_ifindex)
> +{
> + struct datapath *dp;
> +
> + rcu_read_lock();
> + dp = get_dp_rcu(net, dp_ifindex);
> rcu_read_unlock();
>
> return dp;
> }
>
> +/* The caller must hold either ovs_mutex or rcu_read_lock to keep the
> + * returned dp pointer valid. */
> +static inline struct datapath *get_dp_ovsl_rcu(struct net *net,
> + int dp_ifindex)
> +{
> + WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_ovsl_is_held());
> + return get_dp__(net, dp_ifindex);
> +}
> +
> +static struct datapath *get_dp_ovsl(struct net *net, int dp_ifindex)
> +{
> + ASSERT_OVSL();
> + return get_dp__(net, dp_ifindex);
> +}
> +
> /* Must be called with rcu_read_lock or ovs_mutex. */
> const char *ovs_dp_name(const struct datapath *dp)
> {
> @@ -595,7 +618,7 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb,
> struct genl_info *info)
> packet->mark = flow->key.phy.skb_mark;
>
> rcu_read_lock();
> - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
> + dp = get_dp_rcu(sock_net(skb->sk), ovs_header->dp_ifindex);
> err = -ENODEV;
> if (!dp)
> goto err_unlock;
> @@ -926,7 +949,7 @@ static int ovs_flow_cmd_new(struct sk_buff *skb, struct
> genl_info *info)
> }
>
> ovs_lock();
> - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
> + dp = get_dp_ovsl(sock_net(skb->sk), ovs_header->dp_ifindex);
> if (unlikely(!dp)) {
> error = -ENODEV;
> goto err_unlock_ovs;
> @@ -1076,7 +1099,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct
> genl_info *info)
> }
>
> ovs_lock();
> - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
> + dp = get_dp_ovsl(sock_net(skb->sk), ovs_header->dp_ifindex);
> if (unlikely(!dp)) {
> error = -ENODEV;
> goto err_unlock_ovs;
> @@ -1154,7 +1177,7 @@ static int ovs_flow_cmd_get(struct sk_buff *skb, struct
> genl_info *info)
> return err;
>
> ovs_lock();
> - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
> + dp = get_dp_ovsl(sock_net(skb->sk), ovs_header->dp_ifindex);
> if (!dp) {
> err = -ENODEV;
> goto unlock;
> @@ -1199,7 +1222,7 @@ static int ovs_flow_cmd_del(struct sk_buff *skb, struct
> genl_info *info)
> }
>
> ovs_lock();
> - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
> + dp = get_dp_ovsl(sock_net(skb->sk), ovs_header->dp_ifindex);
> if (unlikely(!dp)) {
> err = -ENODEV;
> goto unlock;
> @@ -1252,7 +1275,7 @@ static int ovs_flow_cmd_dump(struct sk_buff *skb,
> struct netlink_callback *cb)
> struct datapath *dp;
>
> rcu_read_lock();
> - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
> + dp = get_dp_rcu(sock_net(skb->sk), ovs_header->dp_ifindex);
> if (!dp) {
> rcu_read_unlock();
> return -ENODEV;
> @@ -1392,7 +1415,7 @@ static struct datapath *lookup_datapath(struct net *net,
> struct datapath *dp;
>
> if (!a[OVS_DP_ATTR_NAME])
> - dp = get_dp(net, ovs_header->dp_ifindex);
> + dp = get_dp_ovsl_rcu(net, ovs_header->dp_ifindex);
> else {
> struct vport *vport;
>
> @@ -1801,7 +1824,7 @@ static struct vport *lookup_vport(struct net *net,
> if (port_no >= DP_MAX_PORTS)
> return ERR_PTR(-EFBIG);
>
> - dp = get_dp(net, ovs_header->dp_ifindex);
> + dp = get_dp_ovsl_rcu(net, ovs_header->dp_ifindex);
> if (!dp)
> return ERR_PTR(-ENODEV);
>
> @@ -1838,7 +1861,7 @@ static int ovs_vport_cmd_new(struct sk_buff *skb,
> struct genl_info *info)
> return -ENOMEM;
>
> ovs_lock();
> - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
> + dp = get_dp_ovsl(sock_net(skb->sk), ovs_header->dp_ifindex);
> err = -ENODEV;
> if (!dp)
> goto exit_unlock_free;
> @@ -2019,7 +2042,7 @@ static int ovs_vport_cmd_dump(struct sk_buff *skb,
> struct netlink_callback *cb)
> int i, j = 0;
>
> rcu_read_lock();
> - dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
> + dp = get_dp_rcu(sock_net(skb->sk), ovs_header->dp_ifindex);
> if (!dp) {
> rcu_read_unlock();
> return -ENODEV;
> --
> 1.9.1
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> http://openvswitch.org/mailman/listinfo/dev
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