[PATCH net-next v5 1/8] net: bcmgenet: ring the doorbell when the last frame of a batch is dropped
flat view
WARM1d
REVIEWED: 15 (15M)
From: Nicolai Buchwitz <nb@tipi-net.de>
Date: 2026-10-13 14:20:44
Also in:
lkml
Subsystem:
broadcom genet ethernet driver, networking drivers, the rest · Maintainers:
Doug Berger, Florian Fainelli, Nicolai Buchwitz, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Revision v5 of 5 in this series; 1 review trailer (1 from subsystem maintainers).
Revisions (5)
bcmgenet_xmit() only writes the producer index at the end of a batch. The
error exits return before that write. If the dropped frame was the last of
an xmit_more batch, the frames queued before it stay in the ring until the
next transmit. The queue is still running, so the watchdog does not fire.
Found by a sashiko review, not by a bug report. The existing exits only
trigger on an allocation or DMA mapping failure, and the padding in a later
patch adds three more.
Write the producer index on those exits too.
Fixes: ddd0ca5d60b3 ("net: bcmgenet: add support for xmit_more")
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de>
---
drivers/net/ethernet/broadcom/genet/bcmgenet.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index 4c9db2f9fc25..06ec8c211dd7 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c@@ -2119,6 +2119,15 @@ static void bcmgenet_hide_tsb(struct sk_buff *skb) __skb_pull(skb, sizeof(struct status_64)); } +static void bcmgenet_tx_kick(struct bcmgenet_priv *priv, + struct bcmgenet_tx_ring *ring, + struct netdev_queue *txq) +{ + if (!netdev_xmit_more() || netif_xmit_stopped(txq)) + bcmgenet_tdma_ring_writel(priv, ring->index, + ring->prod_index, TDMA_PROD_INDEX); +} + static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev) { struct bcmgenet_priv *priv = netdev_priv(dev);
@@ -2155,10 +2164,8 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev) /* add the Transmit Status Block */ skb = bcmgenet_add_tsb(dev, skb, ring); - if (!skb) { - ret = NETDEV_TX_OK; - goto out; - } + if (!skb) + goto drop; for (i = 0; i <= nr_frags; i++) { tx_cb_ptr = bcmgenet_get_txcb(priv, ring);
@@ -2183,7 +2190,6 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev) if (ret) { priv->mib.tx_dma_failed++; netif_err(priv, tx_err, dev, "Tx DMA map failed\n"); - ret = NETDEV_TX_OK; goto out_unmap_frags; } dma_unmap_addr_set(tx_cb_ptr, dma_addr, mapping);
@@ -2225,10 +2231,7 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev) if (ring->free_bds <= (MAX_SKB_FRAGS + 1)) netif_tx_stop_queue(txq); - if (!netdev_xmit_more() || netif_xmit_stopped(txq)) - /* Packets are ready, update producer index */ - bcmgenet_tdma_ring_writel(priv, ring->index, - ring->prod_index, TDMA_PROD_INDEX); + bcmgenet_tx_kick(priv, ring, txq); out: spin_unlock(&ring->lock);
@@ -2245,6 +2248,10 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev) } dev_kfree_skb(skb); +drop: + /* The dropped frame may have been the last one of the batch */ + bcmgenet_tx_kick(priv, ring, txq); + ret = NETDEV_TX_OK; goto out; }
--
2.53.0