2017-11-03 5:16 GMT+01:00 Willem de Bruijn [off-list ref]:

quoted

+/**
+ * tp4q_enqueue_from_array - Enqueue entries from packet array to tp4 queue
+ *
+ * @a: Pointer to the packet array to enqueue from
+ * @dcnt: Max number of entries to enqueue
+ *
+ * Returns 0 for success or an errno at failure
+ **/
+static inline int tp4q_enqueue_from_array(struct tp4_packet_array *a,
+                                         u32 dcnt)
+{
+       struct tp4_queue *q = a->tp4q;
+       unsigned int used_idx = q->used_idx;
+       struct tpacket4_desc *d = a->items;
+       int i;
+
+       if (q->num_free < dcnt)
+               return -ENOSPC;
+
+       q->num_free -= dcnt;

perhaps annotate with a lockdep_is_held to document which lock
ensures mutual exclusion on the ring. Different for tx and rx?

Good idea. I'll give that a try!

quoted

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index b39be424ec0e..190598eb3461 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c

@@ -189,6 +189,9 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
 #define BLOCK_O2PRIV(x)        ((x)->offset_to_priv)
 #define BLOCK_PRIV(x)          ((void *)((char *)(x) + BLOCK_O2PRIV(x)))

+#define RX_RING 0
+#define TX_RING 1
+

Not needed if using bool for tx_ring below. The test effectively already
treats it as bool: does not explicitly test these constants.

quoted

+static void packet_clear_ring(struct sock *sk, int tx_ring)
+{
+       struct packet_sock *po = pkt_sk(sk);
+       struct packet_ring_buffer *rb;
+       union tpacket_req_u req_u;
+
+       rb = tx_ring ? &po->tx_ring : &po->rx_ring;

I meant here.

Yup, I'll remove/clean this up.


Björn