net: fix problem in dequeuing from input_pkt_queue
Fix some issues introduced in batch skb dequeuing for input_pkt_queue.
The primary issue it that the queue head must be incremented only
after a packet has been processed, that is only after
__netif_receive_skb has been called. This is needed for the mechanism
to prevent OOO packet in RFS. Also when flushing the input_pkt_queue
and process_queue, the process queue should be done first to prevent
OOO packets.
Because the input_pkt_queue has been effectively split into two queues,
the calculation of the tail ptr is no longer correct. The correct value
would be head+input_pkt_queue->len+process_queue->len. To avoid
this calculation we added an explict input_queue_tail in softnet_data.
The tail value is simply incremented when queuing to input_pkt_queue.
Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a1bff65..2564195 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1407,17 +1407,25 @@
struct softnet_data *rps_ipi_next;
unsigned int cpu;
unsigned int input_queue_head;
+ unsigned int input_queue_tail;
#endif
unsigned dropped;
struct sk_buff_head input_pkt_queue;
struct napi_struct backlog;
};
-static inline void input_queue_head_add(struct softnet_data *sd,
- unsigned int len)
+static inline void input_queue_head_incr(struct softnet_data *sd)
{
#ifdef CONFIG_RPS
- sd->input_queue_head += len;
+ sd->input_queue_head++;
+#endif
+}
+
+static inline void input_queue_tail_incr_save(struct softnet_data *sd,
+ unsigned int *qtail)
+{
+#ifdef CONFIG_RPS
+ *qtail = ++sd->input_queue_tail;
#endif
}