datapath: Add casts for direct freeing of RCU data.

There are a few places where we have two levels of RCU protected
data to allow the second level to change independently of the
first.  Although the two pieces are independent, they have the
same users and lifetime of the first level always exceeds that
of the second level.  This means that we can directly free the
second level when it is safe to free the first.  This implies
that we directly access RCU-protected data, which is generally
not allowed.  There are no locks to check, so none of the normal
RCU functions apply.  Instead, this adds an explicit cast.

Found with sparse.

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

diff --git a/datapath/flow.c b/datapath/flow.c
index 5cf0d54..b33b315 100644 (file)
--- a/datapath/flow.c
+++ b/datapath/flow.c
@@ -175,7 +175,7 @@ void flow_put(struct sw_flow *flow)
                return;
 
        if (atomic_dec_and_test(&flow->refcnt)) {
-               kfree(flow->sf_acts);
+               kfree((struct sf_flow_acts __force *)flow->sf_acts);
                kmem_cache_free(flow_cache, flow);
        }
 }

diff --git a/datapath/tunnel.c b/datapath/tunnel.c
index ee9e45d..d49d928 100644 (file)
--- a/datapath/tunnel.c
+++ b/datapath/tunnel.c
@@ -1456,10 +1456,11 @@ error:
 
 static void free_port_rcu(struct rcu_head *rcu)
 {
-       struct tnl_vport *tnl_vport = container_of(rcu, struct tnl_vport, rcu);
+       struct tnl_vport *tnl_vport = container_of(rcu,
+                                                  struct tnl_vport, rcu);
 
-       free_cache(tnl_vport->cache);
-       kfree(tnl_vport->mutable);
+       free_cache((struct tnl_cache __force *)tnl_vport->cache);
+       kfree((struct tnl_mutable __force *)tnl_vport->mutable);
        vport_free(tnl_vport_to_vport(tnl_vport));
 }
 

diff --git a/datapath/vport-patch.c b/datapath/vport-patch.c
index ef9778f..67b68a3 100644 (file)
--- a/datapath/vport-patch.c
+++ b/datapath/vport-patch.c
@@ -185,9 +185,9 @@ error:
 static void free_port_rcu(struct rcu_head *rcu)
 {
        struct patch_vport *patch_vport = container_of(rcu,
-                                                     struct patch_vport, rcu);
+                                         struct patch_vport, rcu);
 
-       kfree(patch_vport->devconf);
+       kfree((struct device_config __force *)patch_vport->devconf);
        vport_free(vport_from_priv(patch_vport));
 }