net: Add a flow_cache_flush_deferred function

flow_cach_flush() might sleep but can be called from
atomic context via the xfrm garbage collector. So add
a flow_cache_flush_deferred() function and use this if
the xfrm garbage colector is invoked from within the
packet path.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/flow.h b/include/net/flow.h
index a094477..57f15a7 100644 (file)
--- a/include/net/flow.h
+++ b/include/net/flow.h
@@ -207,6 +207,7 @@ extern struct flow_cache_object *flow_cache_lookup(
                u8 dir, flow_resolve_t resolver, void *ctx);
 
 extern void flow_cache_flush(void);
+extern void flow_cache_flush_deferred(void);
 extern atomic_t flow_cache_genid;
 
 #endif

diff --git a/net/core/flow.c b/net/core/flow.c
index 8ae42de..e318c7e 100644 (file)
--- a/net/core/flow.c
+++ b/net/core/flow.c
@@ -358,6 +358,18 @@ void flow_cache_flush(void)
        put_online_cpus();
 }
 
+static void flow_cache_flush_task(struct work_struct *work)
+{
+       flow_cache_flush();
+}
+
+static DECLARE_WORK(flow_cache_flush_work, flow_cache_flush_task);
+
+void flow_cache_flush_deferred(void)
+{
+       schedule_work(&flow_cache_flush_work);
+}
+
 static int __cpuinit flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
 {
        struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 2118d64..9049a5c 100644 (file)
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2276,8 +2276,6 @@ static void __xfrm_garbage_collect(struct net *net)
 {
        struct dst_entry *head, *next;
 
-       flow_cache_flush();
-
        spin_lock_bh(&xfrm_policy_sk_bundle_lock);
        head = xfrm_policy_sk_bundles;
        xfrm_policy_sk_bundles = NULL;
@@ -2290,6 +2288,18 @@ static void __xfrm_garbage_collect(struct net *net)
        }
 }
 
+static void xfrm_garbage_collect(struct net *net)
+{
+       flow_cache_flush();
+       __xfrm_garbage_collect(net);
+}
+
+static void xfrm_garbage_collect_deferred(struct net *net)
+{
+       flow_cache_flush_deferred();
+       __xfrm_garbage_collect(net);
+}
+
 static void xfrm_init_pmtu(struct dst_entry *dst)
 {
        do {
@@ -2422,7 +2432,7 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
                if (likely(dst_ops->neigh_lookup == NULL))
                        dst_ops->neigh_lookup = xfrm_neigh_lookup;
                if (likely(afinfo->garbage_collect == NULL))
-                       afinfo->garbage_collect = __xfrm_garbage_collect;
+                       afinfo->garbage_collect = xfrm_garbage_collect_deferred;
                xfrm_policy_afinfo[afinfo->family] = afinfo;
        }
        write_unlock_bh(&xfrm_policy_afinfo_lock);
@@ -2516,7 +2526,7 @@ static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void
 
        switch (event) {
        case NETDEV_DOWN:
-               __xfrm_garbage_collect(dev_net(dev));
+               xfrm_garbage_collect(dev_net(dev));
        }
        return NOTIFY_DONE;
 }