net: frag helper functions for mem limit tracking

This change is primarily a preparation to ease the extension of memory
limit tracking.

The change does reduce the number atomic operation, during freeing of
a frag queue.  This does introduce a some performance improvement, as
these atomic operations are at the core of the performance problems
seen on NUMA systems.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 28 insertions, 1 deletions

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 8e4c42523f59..f2fabc2a79de 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -79,4 +79,31 @@ static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f
                 inet_frag_destroy(q, f, NULL);
 }
 
+/* Memory Tracking Functions. */
+
+static inline int frag_mem_limit(struct netns_frags *nf)
+{
+        return atomic_read(&nf->mem);
+}
+
+static inline void sub_frag_mem_limit(struct inet_frag_queue *q, int i)
+{
+        atomic_sub(i, &q->net->mem);
+}
+
+static inline void add_frag_mem_limit(struct inet_frag_queue *q, int i)
+{
+        atomic_add(i, &q->net->mem);
+}
+
+static inline void init_frag_mem_limit(struct netns_frags *nf)
+{
+        atomic_set(&nf->mem, 0);
+}
+
+static inline int sum_frag_mem_limit(struct netns_frags *nf)
+{
+        return atomic_read(&nf->mem);
+}
+
 #endif
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index c1878f7049c8..dc30b60975ef 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -288,7 +288,7 @@ static inline int ip6_frag_nqueues(struct net *net)
 
 static inline int ip6_frag_mem(struct net *net)
 {
-        return atomic_read(&net->ipv6.frags.mem);
+        return sum_frag_mem_limit(&net->ipv6.frags);
 }
 #endif