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Christian Marangi
8dff4c9a34
Airoha reported some bug in the TX/RX descriptor handling and PPE. Backport
the fix for such bug merged in net staging tree.
It's expected that these patch will be dropped in future minor kernel
version when submitted to stable staging tree.
All affected patch automatically refreshed.
(cherry picked from commit 1b9922d5e8)
Link: https://github.com/openwrt/openwrt/pull/23151
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
105 lines
3.5 KiB
Diff
105 lines
3.5 KiB
Diff
From b94769eb2f30e61e86cd8551c084c34134290d89 Mon Sep 17 00:00:00 2001
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From: Lorenzo Bianconi <lorenzo@kernel.org>
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Date: Thu, 16 Apr 2026 12:30:12 +0200
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Subject: [PATCH] net: airoha: Fix possible TX queue stall in
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airoha_qdma_tx_napi_poll()
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Since multiple net_device TX queues can share the same hw QDMA TX queue,
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there is no guarantee we have inflight packets queued in hw belonging to a
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net_device TX queue stopped in the xmit path because hw QDMA TX queue
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can be full. In this corner case the net_device TX queue will never be
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re-activated. In order to avoid any potential net_device TX queue stall,
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we need to wake all the net_device TX queues feeding the same hw QDMA TX
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queue in airoha_qdma_tx_napi_poll routine.
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Fixes: 23020f0493270 ("net: airoha: Introduce ethernet support for EN7581 SoC")
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Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
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Reviewed-by: Simon Horman <horms@kernel.org>
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Link: https://patch.msgid.link/20260416-airoha-txq-potential-stall-v2-1-42c732074540@kernel.org
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Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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---
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drivers/net/ethernet/airoha/airoha_eth.c | 37 ++++++++++++++++++++----
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drivers/net/ethernet/airoha/airoha_eth.h | 1 +
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2 files changed, 33 insertions(+), 5 deletions(-)
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--- a/drivers/net/ethernet/airoha/airoha_eth.c
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+++ b/drivers/net/ethernet/airoha/airoha_eth.c
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@@ -843,6 +843,21 @@ static int airoha_qdma_init_rx(struct ai
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return 0;
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}
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+static void airoha_qdma_wake_netdev_txqs(struct airoha_queue *q)
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+{
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+ struct airoha_qdma *qdma = q->qdma;
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+ struct airoha_eth *eth = qdma->eth;
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+ int i;
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+
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+ for (i = 0; i < ARRAY_SIZE(eth->ports); i++) {
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+ struct airoha_gdm_port *port = eth->ports[i];
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+
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+ if (port && port->qdma == qdma)
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+ netif_tx_wake_all_queues(port->dev);
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+ }
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+ q->txq_stopped = false;
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+}
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+
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static int airoha_qdma_tx_napi_poll(struct napi_struct *napi, int budget)
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{
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struct airoha_tx_irq_queue *irq_q;
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@@ -919,12 +934,21 @@ static int airoha_qdma_tx_napi_poll(stru
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txq = netdev_get_tx_queue(skb->dev, queue);
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netdev_tx_completed_queue(txq, 1, skb->len);
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- if (netif_tx_queue_stopped(txq) &&
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- q->ndesc - q->queued >= q->free_thr)
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- netif_tx_wake_queue(txq);
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-
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dev_kfree_skb_any(skb);
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}
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+
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+ if (q->txq_stopped && q->ndesc - q->queued >= q->free_thr) {
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+ /* Since multiple net_device TX queues can share the
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+ * same hw QDMA TX queue, there is no guarantee we have
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+ * inflight packets queued in hw belonging to a
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+ * net_device TX queue stopped in the xmit path.
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+ * In order to avoid any potential net_device TX queue
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+ * stall, we need to wake all the net_device TX queues
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+ * feeding the same hw QDMA TX queue.
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+ */
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+ airoha_qdma_wake_netdev_txqs(q);
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+ }
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+
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unlock:
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spin_unlock_bh(&q->lock);
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}
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@@ -2016,6 +2040,7 @@ static netdev_tx_t airoha_dev_xmit(struc
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if (q->queued + nr_frags >= q->ndesc) {
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/* not enough space in the queue */
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netif_tx_stop_queue(txq);
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+ q->txq_stopped = true;
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spin_unlock_bh(&q->lock);
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return NETDEV_TX_BUSY;
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}
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@@ -2071,8 +2096,10 @@ static netdev_tx_t airoha_dev_xmit(struc
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TX_RING_CPU_IDX_MASK,
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FIELD_PREP(TX_RING_CPU_IDX_MASK, index));
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- if (q->ndesc - q->queued < q->free_thr)
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+ if (q->ndesc - q->queued < q->free_thr) {
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netif_tx_stop_queue(txq);
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+ q->txq_stopped = true;
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+ }
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spin_unlock_bh(&q->lock);
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--- a/drivers/net/ethernet/airoha/airoha_eth.h
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+++ b/drivers/net/ethernet/airoha/airoha_eth.h
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@@ -193,6 +193,7 @@ struct airoha_queue {
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int ndesc;
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int free_thr;
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int buf_size;
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+ bool txq_stopped;
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struct napi_struct napi;
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struct page_pool *page_pool;
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