net: use u64_stats_t in struct pcpu_lstats

In order to fix the data-race found by KCSAN, we
can use the new u64_stats_t type and its accessors instead
of plain u64 fields. This will still generate optimal code
for both 32 and 64 bit platforms.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 47ad2478b9f350f8bf3b103bd2a9a956379c75fa..a1c77cc0041657de79b562c84408acabf9e8b99b 100644 (file)
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -106,8 +106,8 @@ void dev_lstats_read(struct net_device *dev, u64 *packets, u64 *bytes)
                lb_stats = per_cpu_ptr(dev->lstats, i);
                do {
                        start = u64_stats_fetch_begin_irq(&lb_stats->syncp);
-                       tpackets = lb_stats->packets;
-                       tbytes = lb_stats->bytes;
+                       tpackets = u64_stats_read(&lb_stats->packets);
+                       tbytes = u64_stats_read(&lb_stats->bytes);
                } while (u64_stats_fetch_retry_irq(&lb_stats->syncp, start));
                *bytes   += tbytes;
                *packets += tpackets;

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 461a36220cf46d62114efac0c4fb2b7b9a2ee386..f857f01234f774d70d8c2425498e1fbc9909d88e 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2396,8 +2396,8 @@ struct pcpu_sw_netstats {
 } __aligned(4 * sizeof(u64));
 
 struct pcpu_lstats {
-       u64 packets;
-       u64 bytes;
+       u64_stats_t packets;
+       u64_stats_t bytes;
        struct u64_stats_sync syncp;
 } __aligned(2 * sizeof(u64));
 
@@ -2408,8 +2408,8 @@ static inline void dev_lstats_add(struct net_device *dev, unsigned int len)
        struct pcpu_lstats *lstats = this_cpu_ptr(dev->lstats);
 
        u64_stats_update_begin(&lstats->syncp);
-       lstats->bytes += len;
-       lstats->packets++;
+       u64_stats_add(&lstats->bytes, len);
+       u64_stats_inc(&lstats->packets);
        u64_stats_update_end(&lstats->syncp);
 }