diff mbox

[net-next] mlx4: do not use priv->stats_lock in mlx4_en_auto_moderation()

Message ID 1479923212.8455.515.camel@edumazet-glaptop3.roam.corp.google.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Eric Dumazet Nov. 23, 2016, 5:46 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

Per RX ring packets/bytes counters are not protected by global
priv->stats_lock.

Better not confuse the reader, and use READ_ONCE() to show we read
these counters without surrounding synchronization.

Interrupt moderation is best effort, and we do not really care of
ultra precise counters.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_netdev.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

Comments

David Miller Nov. 27, 2016, 8:26 p.m. UTC | #1 
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 23 Nov 2016 09:46:52 -0800

> From: Eric Dumazet <edumazet@google.com>
> 
> Per RX ring packets/bytes counters are not protected by global
> priv->stats_lock.
> 
> Better not confuse the reader, and use READ_ONCE() to show we read
> these counters without surrounding synchronization.
> 
> Interrupt moderation is best effort, and we do not really care of
> ultra precise counters.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied.
diff mbox

Patch

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 9a807e93c9fdd81e61e561208aa1480a244d0bdb..b964bdcd4ae509a7e693215e8b32f040218e252c 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -1391,10 +1391,8 @@  static void mlx4_en_auto_moderation(struct mlx4_en_priv *priv)
 		return;
 
 	for (ring = 0; ring < priv->rx_ring_num; ring++) {
-		spin_lock_bh(&priv->stats_lock);
-		rx_packets = priv->rx_ring[ring]->packets;
-		rx_bytes = priv->rx_ring[ring]->bytes;
-		spin_unlock_bh(&priv->stats_lock);
+		rx_packets = READ_ONCE(priv->rx_ring[ring]->packets);
+		rx_bytes = READ_ONCE(priv->rx_ring[ring]->bytes);
 
 		rx_pkt_diff = ((unsigned long) (rx_packets -
 				priv->last_moder_packets[ring]));