ice: use u64_stats API to access pkts/bytes in dim sample

The __ice_update_sample and __ice_get_ethtool_stats functions directly
accesses the pkts and bytes counters from the ring stats. A following
change is going to update the fields to be u64_stats_t type, and will need
to be accessed appropriately. This will ensure that the accesses do not
cause load/store tearing.

Add helper functions similar to the ones used for updating the stats
values, and use them. This ensures use of the syncp pointer on 32-bit
architectures. Once the fields are updated to u64_stats_t, it will then
properly avoid tears on all architectures.

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c
index 91d234f31c026dabc05ad090e4e9e91430ce2c95..2c007669c19733c1ebe12e80ce5bcf4b47cb001d 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_ethtool.c
+++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
@@ -1942,25 +1942,35 @@ __ice_get_ethtool_stats(struct net_device *netdev,
        rcu_read_lock();
 
        ice_for_each_alloc_txq(vsi, j) {
+               u64 pkts, bytes;
+
                tx_ring = READ_ONCE(vsi->tx_rings[j]);
-               if (tx_ring && tx_ring->ring_stats) {
-                       data[i++] = tx_ring->ring_stats->stats.pkts;
-                       data[i++] = tx_ring->ring_stats->stats.bytes;
-               } else {
+               if (!tx_ring || !tx_ring->ring_stats) {
                        data[i++] = 0;
                        data[i++] = 0;
+                       continue;
                }
+
+               ice_fetch_tx_ring_stats(tx_ring, &pkts, &bytes);
+
+               data[i++] = pkts;
+               data[i++] = bytes;
        }
 
        ice_for_each_alloc_rxq(vsi, j) {
+               u64 pkts, bytes;
+
                rx_ring = READ_ONCE(vsi->rx_rings[j]);
-               if (rx_ring && rx_ring->ring_stats) {
-                       data[i++] = rx_ring->ring_stats->stats.pkts;
-                       data[i++] = rx_ring->ring_stats->stats.bytes;
-               } else {
+               if (!rx_ring || !rx_ring->ring_stats) {
                        data[i++] = 0;
                        data[i++] = 0;
+                       continue;
                }
+
+               ice_fetch_rx_ring_stats(rx_ring, &pkts, &bytes);
+
+               data[i++] = pkts;
+               data[i++] = bytes;
        }
 
        rcu_read_unlock();

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index ecf4ba5c79c354cfd0d75d7445825d2122193b39..c0f77d962c306196fad40bcddbb0971d4d4941de 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -3473,6 +3473,42 @@ void ice_update_rx_ring_stats(struct ice_rx_ring *rx_ring, u64 pkts, u64 bytes)
        u64_stats_update_end(&rx_ring->ring_stats->syncp);
 }
 
+/**
+ * ice_fetch_tx_ring_stats - Fetch Tx ring packet and byte counters
+ * @ring: ring to update
+ * @pkts: number of processed packets
+ * @bytes: number of processed bytes
+ */
+void ice_fetch_tx_ring_stats(const struct ice_tx_ring *ring,
+                            u64 *pkts, u64 *bytes)
+{
+       unsigned int start;
+
+       do  {
+               start = u64_stats_fetch_begin(&ring->ring_stats->syncp);
+               *pkts = ring->ring_stats->pkts;
+               *bytes = ring->ring_stats->bytes;
+       } while (u64_stats_fetch_retry(&ring->ring_stats->syncp, start));
+}
+
+/**
+ * ice_fetch_rx_ring_stats - Fetch Rx ring packet and byte counters
+ * @ring: ring to read
+ * @pkts: number of processed packets
+ * @bytes: number of processed bytes
+ */
+void ice_fetch_rx_ring_stats(const struct ice_rx_ring *ring,
+                            u64 *pkts, u64 *bytes)
+{
+       unsigned int start;
+
+       do  {
+               start = u64_stats_fetch_begin(&ring->ring_stats->syncp);
+               *pkts = ring->ring_stats->pkts;
+               *bytes = ring->ring_stats->bytes;
+       } while (u64_stats_fetch_retry(&ring->ring_stats->syncp, start));
+}
+
 /**
  * ice_is_dflt_vsi_in_use - check if the default forwarding VSI is being used
  * @pi: port info of the switch with default VSI

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.h b/drivers/net/ethernet/intel/ice/ice_lib.h
index 2cb1eb98b9dabc63c44aa20f04acb19040df56f9..49454d98dcfefc6feea8ae811aa1e80313289af5 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_lib.h
+++ b/drivers/net/ethernet/intel/ice/ice_lib.h
@@ -92,6 +92,12 @@ void ice_update_tx_ring_stats(struct ice_tx_ring *ring, u64 pkts, u64 bytes);
 
 void ice_update_rx_ring_stats(struct ice_rx_ring *ring, u64 pkts, u64 bytes);
 
+void ice_fetch_tx_ring_stats(const struct ice_tx_ring *ring,
+                            u64 *pkts, u64 *bytes);
+
+void ice_fetch_rx_ring_stats(const struct ice_rx_ring *ring,
+                            u64 *pkts, u64 *bytes);
+
 void ice_write_intrl(struct ice_q_vector *q_vector, u8 intrl);
 void ice_write_itr(struct ice_ring_container *rc, u16 itr);
 void ice_set_q_vector_intrl(struct ice_q_vector *q_vector);

diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
index ad76768a42323f7e1058a78156d18c5104a28a1e..f4196347b23a3c2bd21f1d51bfaafa381307e314 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
@@ -1087,35 +1087,36 @@ static void __ice_update_sample(struct ice_q_vector *q_vector,
                                struct dim_sample *sample,
                                bool is_tx)
 {
-       u64 packets = 0, bytes = 0;
+       u64 total_packets = 0, total_bytes = 0, pkts, bytes;
 
        if (is_tx) {
                struct ice_tx_ring *tx_ring;
 
                ice_for_each_tx_ring(tx_ring, *rc) {
-                       struct ice_ring_stats *ring_stats;
-
-                       ring_stats = tx_ring->ring_stats;
-                       if (!ring_stats)
+                       if (!tx_ring->ring_stats)
                                continue;
-                       packets += ring_stats->stats.pkts;
-                       bytes += ring_stats->stats.bytes;
+
+                       ice_fetch_tx_ring_stats(tx_ring, &pkts, &bytes);
+
+                       total_packets += pkts;
+                       total_bytes += bytes;
                }
        } else {
                struct ice_rx_ring *rx_ring;
 
                ice_for_each_rx_ring(rx_ring, *rc) {
-                       struct ice_ring_stats *ring_stats;
-
-                       ring_stats = rx_ring->ring_stats;
-                       if (!ring_stats)
+                       if (!rx_ring->ring_stats)
                                continue;
-                       packets += ring_stats->stats.pkts;
-                       bytes += ring_stats->stats.bytes;
+
+                       ice_fetch_rx_ring_stats(rx_ring, &pkts, &bytes);
+
+                       total_packets += pkts;
+                       total_bytes += bytes;
                }
        }
 
-       dim_update_sample(q_vector->total_events, packets, bytes, sample);
+       dim_update_sample(q_vector->total_events,
+                         total_packets, total_bytes, sample);
        sample->comp_ctr = 0;
 
        /* if dim settings get stale, like when not updated for 1