The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e780e3193e889fd8358b862f7cd18ec5a4901caf Mon Sep 17 00:00:00 2001 From: Vladimir Oltean vladimir.oltean@nxp.com Date: Tue, 16 Aug 2022 16:53:52 +0300 Subject: [PATCH] net: mscc: ocelot: report ndo_get_stats64 from the wraparound-resistant ocelot->stats
Rather than reading the stats64 counters directly from the 32-bit hardware, it's better to rely on the output produced by the periodic ocelot_port_update_stats().
It would be even better to call ocelot_port_update_stats() right from ocelot_get_stats64() to make sure we report the current values rather than the ones from 2 seconds ago. But we need to export ocelot_port_update_stats() from the switch lib towards the switchdev driver for that, and future work will largely undo that.
There are more ocelot-based drivers waiting to be introduced, an example of which is the SPI-controlled VSC7512. In that driver's case, it will be impossible to call ocelot_port_update_stats() from ndo_get_stats64 context, since the latter is atomic, and reading the stats over SPI is sleepable. So the compromise taken here, which will also hold going forward, is to report 64-bit counters to stats64, which are not 100% up to date.
Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support") Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org
diff --git a/drivers/net/ethernet/mscc/ocelot_net.c b/drivers/net/ethernet/mscc/ocelot_net.c index 6b9d37138844..330d30841cdc 100644 --- a/drivers/net/ethernet/mscc/ocelot_net.c +++ b/drivers/net/ethernet/mscc/ocelot_net.c @@ -725,41 +725,40 @@ static void ocelot_get_stats64(struct net_device *dev, struct ocelot_port_private *priv = netdev_priv(dev); struct ocelot *ocelot = priv->port.ocelot; int port = priv->port.index; + u64 *s;
spin_lock(&ocelot->stats_lock);
- /* Configure the port to read the stats from */ - ocelot_write(ocelot, SYS_STAT_CFG_STAT_VIEW(port), - SYS_STAT_CFG); + s = &ocelot->stats[port * OCELOT_NUM_STATS];
/* Get Rx stats */ - stats->rx_bytes = ocelot_read(ocelot, SYS_COUNT_RX_OCTETS); - stats->rx_packets = ocelot_read(ocelot, SYS_COUNT_RX_SHORTS) + - ocelot_read(ocelot, SYS_COUNT_RX_FRAGMENTS) + - ocelot_read(ocelot, SYS_COUNT_RX_JABBERS) + - ocelot_read(ocelot, SYS_COUNT_RX_LONGS) + - ocelot_read(ocelot, SYS_COUNT_RX_64) + - ocelot_read(ocelot, SYS_COUNT_RX_65_127) + - ocelot_read(ocelot, SYS_COUNT_RX_128_255) + - ocelot_read(ocelot, SYS_COUNT_RX_256_511) + - ocelot_read(ocelot, SYS_COUNT_RX_512_1023) + - ocelot_read(ocelot, SYS_COUNT_RX_1024_1526) + - ocelot_read(ocelot, SYS_COUNT_RX_1527_MAX); - stats->multicast = ocelot_read(ocelot, SYS_COUNT_RX_MULTICAST); + stats->rx_bytes = s[OCELOT_STAT_RX_OCTETS]; + stats->rx_packets = s[OCELOT_STAT_RX_SHORTS] + + s[OCELOT_STAT_RX_FRAGMENTS] + + s[OCELOT_STAT_RX_JABBERS] + + s[OCELOT_STAT_RX_LONGS] + + s[OCELOT_STAT_RX_64] + + s[OCELOT_STAT_RX_65_127] + + s[OCELOT_STAT_RX_128_255] + + s[OCELOT_STAT_RX_256_511] + + s[OCELOT_STAT_RX_512_1023] + + s[OCELOT_STAT_RX_1024_1526] + + s[OCELOT_STAT_RX_1527_MAX]; + stats->multicast = s[OCELOT_STAT_RX_MULTICAST]; stats->rx_dropped = dev->stats.rx_dropped;
/* Get Tx stats */ - stats->tx_bytes = ocelot_read(ocelot, SYS_COUNT_TX_OCTETS); - stats->tx_packets = ocelot_read(ocelot, SYS_COUNT_TX_64) + - ocelot_read(ocelot, SYS_COUNT_TX_65_127) + - ocelot_read(ocelot, SYS_COUNT_TX_128_255) + - ocelot_read(ocelot, SYS_COUNT_TX_256_511) + - ocelot_read(ocelot, SYS_COUNT_TX_512_1023) + - ocelot_read(ocelot, SYS_COUNT_TX_1024_1526) + - ocelot_read(ocelot, SYS_COUNT_TX_1527_MAX); - stats->tx_dropped = ocelot_read(ocelot, SYS_COUNT_TX_DROPS) + - ocelot_read(ocelot, SYS_COUNT_TX_AGING); - stats->collisions = ocelot_read(ocelot, SYS_COUNT_TX_COLLISION); + stats->tx_bytes = s[OCELOT_STAT_TX_OCTETS]; + stats->tx_packets = s[OCELOT_STAT_TX_64] + + s[OCELOT_STAT_TX_65_127] + + s[OCELOT_STAT_TX_128_255] + + s[OCELOT_STAT_TX_256_511] + + s[OCELOT_STAT_TX_512_1023] + + s[OCELOT_STAT_TX_1024_1526] + + s[OCELOT_STAT_TX_1527_MAX]; + stats->tx_dropped = s[OCELOT_STAT_TX_DROPS] + + s[OCELOT_STAT_TX_AGED]; + stats->collisions = s[OCELOT_STAT_TX_COLLISION];
spin_unlock(&ocelot->stats_lock); }