[PATCH AUTOSEL 5.10 4/7] tg3: Move the [rt]x_dropped counters to tg3_napi

Sasha Levin
2023-11-22T15:41:09Z

From: Alex Pakhunov <alexey.pakhunov@spacex.com>

[ Upstream commit 907d1bdb8b2cc0357d03a1c34d2a08d9943760b1 ]

This change moves [rt]x_dropped counters to tg3_napi so that they can be
updated by a single writer, race-free.

Signed-off-by: Alex Pakhunov <alexey.pakhunov@spacex.com>
Signed-off-by: Vincent Wong <vincent.wong2@spacex.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20231113182350.37472-1-alexey.pakhunov@spacex.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/broadcom/tg3.c | 38 +++++++++++++++++++++++++----
drivers/net/ethernet/broadcom/tg3.h | 4 +--
2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 5647833303a44..a2c6c204fe9d4 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -6864,7 +6864,7 @@ static int tg3_rx(struct tg3_napi *tnapi, int budget)
desc_idx, *post_ptr);
drop_it_no_recycle:
/* Other statistics kept track of by card. */
- tp->rx_dropped++;
+ tnapi->rx_dropped++;
goto next_pkt;
}

@@ -8161,7 +8161,7 @@ static netdev_tx_t tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
drop:
dev_kfree_skb_any(skb);
drop_nofree:
- tp->tx_dropped++;
+ tnapi->tx_dropped++;
return NETDEV_TX_OK;
}

@@ -9340,7 +9340,7 @@ static void __tg3_set_rx_mode(struct net_device *);
/* tp->lock is held. */
static int tg3_halt(struct tg3 *tp, int kind, bool silent)
{
- int err;
+ int err, i;

tg3_stop_fw(tp);

@@ -9361,6 +9361,13 @@ static int tg3_halt(struct tg3 *tp, int kind, bool silent)

/* And make sure the next sample is new data */
memset(tp->hw_stats, 0, sizeof(struct tg3_hw_stats));
+
+ for (i = 0; i < TG3_IRQ_MAX_VECS; ++i) {
+ struct tg3_napi *tnapi = &tp->napi[i];
+
+ tnapi->rx_dropped = 0;
+ tnapi->tx_dropped = 0;
+ }
}

return err;
@@ -11915,6 +11922,9 @@ static void tg3_get_nstats(struct tg3 *tp, struct rtnl_link_stats64 *stats)
{
struct rtnl_link_stats64 *old_stats = &tp->net_stats_prev;
struct tg3_hw_stats *hw_stats = tp->hw_stats;
+ unsigned long rx_dropped;
+ unsigned long tx_dropped;
+ int i;

stats->rx_packets = old_stats->rx_packets +
get_stat64(&hw_stats->rx_ucast_packets) +
@@ -11961,8 +11971,26 @@ static void tg3_get_nstats(struct tg3 *tp, struct rtnl_link_stats64 *stats)
stats->rx_missed_errors = old_stats->rx_missed_errors +
get_stat64(&hw_stats->rx_discards);

- stats->rx_dropped = tp->rx_dropped;
- stats->tx_dropped = tp->tx_dropped;
+ /* Aggregate per-queue counters. The per-queue counters are updated
+ * by a single writer, race-free. The result computed by this loop
+ * might not be 100% accurate (counters can be updated in the middle of
+ * the loop) but the next tg3_get_nstats() will recompute the current
+ * value so it is acceptable.
+ *
+ * Note that these counters wrap around at 4G on 32bit machines.
+ */
+ rx_dropped = (unsigned long)(old_stats->rx_dropped);
+ tx_dropped = (unsigned long)(old_stats->tx_dropped);
+
+ for (i = 0; i < tp->irq_cnt; i++) {
+ struct tg3_napi *tnapi = &tp->napi[i];
+
+ rx_dropped += tnapi->rx_dropped;
+ tx_dropped += tnapi->tx_dropped;
+ }
+
+ stats->rx_dropped = rx_dropped;
+ stats->tx_dropped = tx_dropped;
}

static int tg3_get_regs_len(struct net_device *dev)
diff --git a/drivers/net/ethernet/broadcom/tg3.h b/drivers/net/ethernet/broadcom/tg3.h
index 1000c894064f0..8d753f8c5b065 100644
--- a/drivers/net/ethernet/broadcom/tg3.h
+++ b/drivers/net/ethernet/broadcom/tg3.h
@@ -3018,6 +3018,7 @@ struct tg3_napi {
u16 *rx_rcb_prod_idx;
struct tg3_rx_prodring_set prodring;
struct tg3_rx_buffer_desc *rx_rcb;
+ unsigned long rx_dropped;

u32 tx_prod ____cacheline_aligned;
u32 tx_cons;
@@ -3026,6 +3027,7 @@ struct tg3_napi {
u32 prodmbox;
struct tg3_tx_buffer_desc *tx_ring;
struct tg3_tx_ring_info *tx_buffers;
+ unsigned long tx_dropped;

dma_addr_t status_mapping;
dma_addr_t rx_rcb_mapping;
@@ -3219,8 +3221,6 @@ struct tg3 {

/* begin "everything else" cacheline(s) section */
- unsigned long rx_dropped;
- unsigned long tx_dropped;
struct rtnl_link_stats64 net_stats_prev;
struct tg3_ethtool_stats estats_prev;

--
2.42.0