X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=datapath%2Fvport.c;h=cdf615a47b8b135c631988ba6d52e9666391bab3;hb=33ef7695b71a71f2d0bb0e00aab46855afb8c2a6;hp=2438590105c28b85d497159faa955f83dbf8b8c5;hpb=cc98976af50fec5643a372aa9c7a4c4e565e939e;p=openvswitch

diff --git a/datapath/vport.c b/datapath/vport.c
index 24385901..cdf615a4 100644
--- a/datapath/vport.c
+++ b/datapath/vport.c
@@ -35,17 +35,6 @@ static int n_vport_types;
 static struct hlist_head *dev_table;
 #define VPORT_HASH_BUCKETS 1024
 
-/* We limit the number of times that we pass through vport_send() to
- * avoid blowing out the stack in the event that we have a loop. There is
- * a separate counter for each CPU for both interrupt and non-interrupt
- * context in order to keep the limit deterministic for a given packet. */
-struct percpu_loop_counter {
-	int count[2];
-};
-
-static DEFINE_PER_CPU(struct percpu_loop_counter, vport_loop_counter);
-#define VPORT_MAX_LOOPS 5
-
 /* Both RTNL lock and vport_mutex need to be held when updating dev_table.
  *
  * If you use vport_locate and then perform some operations, you need to hold
@@ -1063,12 +1052,20 @@ int vport_get_stats(struct vport *vport, struct odp_vport_stats *stats)
 
 		for_each_possible_cpu(i) {
 			const struct vport_percpu_stats *percpu_stats;
+			struct vport_percpu_stats local_stats;
+			unsigned seqcount;
 
 			percpu_stats = per_cpu_ptr(vport->percpu_stats, i);
-			stats->rx_bytes		+= percpu_stats->rx_bytes;
-			stats->rx_packets	+= percpu_stats->rx_packets;
-			stats->tx_bytes		+= percpu_stats->tx_bytes;
-			stats->tx_packets	+= percpu_stats->tx_packets;
+
+			do {
+				seqcount = read_seqcount_begin(&percpu_stats->seqlock);
+				local_stats = *percpu_stats;
+			} while (read_seqcount_retry(&percpu_stats->seqlock, seqcount));
+
+			stats->rx_bytes		+= local_stats.rx_bytes;
+			stats->rx_packets	+= local_stats.rx_packets;
+			stats->tx_bytes		+= local_stats.tx_bytes;
+			stats->tx_packets	+= local_stats.tx_packets;
 		}
 
 		err = 0;
@@ -1203,10 +1200,12 @@ void vport_receive(struct vport *vport, struct sk_buff *skb)
 		struct vport_percpu_stats *stats;
 
 		local_bh_disable();
-
 		stats = per_cpu_ptr(vport->percpu_stats, smp_processor_id());
+
+		write_seqcount_begin(&stats->seqlock);
 		stats->rx_packets++;
 		stats->rx_bytes += skb->len;
+		write_seqcount_end(&stats->seqlock);
 
 		local_bh_enable();
 	}
@@ -1238,20 +1237,9 @@ static inline unsigned packet_length(const struct sk_buff *skb)
  */
 int vport_send(struct vport *vport, struct sk_buff *skb)
 {
-	int *loop_count;
 	int mtu;
 	int sent;
 
-	loop_count = &get_cpu_var(vport_loop_counter).count[!!in_interrupt()];
-	(*loop_count)++;
-
-	if (unlikely(*loop_count > VPORT_MAX_LOOPS)) {
-		if (net_ratelimit())
-			printk(KERN_WARNING "%s: dropping packet that has looped more than %d times\n",
-			       dp_name(vport_get_dp_port(vport)->dp), VPORT_MAX_LOOPS);
-		goto error;
-	}
-
 	mtu = vport_get_mtu(vport);
 	if (unlikely(packet_length(skb) > mtu && !skb_is_gso(skb))) {
 		if (net_ratelimit())
@@ -1266,25 +1254,22 @@ int vport_send(struct vport *vport, struct sk_buff *skb)
 		struct vport_percpu_stats *stats;
 
 		local_bh_disable();
-
 		stats = per_cpu_ptr(vport->percpu_stats, smp_processor_id());
+
+		write_seqcount_begin(&stats->seqlock);
 		stats->tx_packets++;
 		stats->tx_bytes += sent;
+		write_seqcount_end(&stats->seqlock);
 
 		local_bh_enable();
 	}
 
-	goto out;
+	return sent;
 
 error:
-	sent = 0;
 	kfree_skb(skb);
 	vport_record_error(vport, VPORT_E_TX_DROPPED);
-out:
-	(*loop_count)--;
-	put_cpu_var(vport_loop_counter);
-
-	return sent;
+	return 0;
 }
 
 /**