From 2cb156213093a62b80cf40b1ec71738e93491971 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Sat, 9 May 2026 00:13:36 +0200 Subject: [PATCH 1/3] net: ethernet: cortina: No mapping is a dropped rx Increase stats.rx_dropped++ even if this is the first fragment (skb == NULL) so we are doing proper accounting. Fixes: b266bacba796 ("net: ethernet: cortina: Drop half-assembled SKB") Link: https://sashiko.dev/#/patchset/20260505-gemini-ethernet-fix-v2-1-997c31d06079%40kernel.org Signed-off-by: Linus Walleij Link: https://patch.msgid.link/20260509-gemini-ethernet-fixes-v1-1-6c5d20ddc35b@kernel.org Signed-off-by: Paolo Abeni --- drivers/net/ethernet/cortina/gemini.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c index 065cbbf52686..466445c9e08b 100644 --- a/drivers/net/ethernet/cortina/gemini.c +++ b/drivers/net/ethernet/cortina/gemini.c @@ -1491,9 +1491,9 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) gpage = gmac_get_queue_page(geth, port, mapping + PAGE_SIZE); if (!gpage) { dev_err(geth->dev, "could not find mapping\n"); + port->stats.rx_dropped++; if (skb) { napi_free_frags(&port->napi); - port->stats.rx_dropped++; skb = NULL; } continue; From 06937db21ee311ed07eba47954447245041a982d Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Sat, 9 May 2026 00:13:37 +0200 Subject: [PATCH 2/3] net: ethernet: cortina: Make RX SKB per-port The SKB used to assemble packets from fragments in gmac_rx() is static local, but the Gemini has two ethernet ports, meaning there can be races between the ports on a bad day if a device is using both. Make the RX SKB a per-port variable and carry it over between invocations in the port struct instead. Zero the pointer once we call napi_gro_frags(), on error (after calling napi_free_frags()) or if the port is stopped. Zero it in some place where not strictly necessary just to emphasize what is going on. This was found by Sashiko during normal patch review. Fixes: 4d5ae32f5e1e ("net: ethernet: Add a driver for Gemini gigabit ethernet") Link: https://sashiko.dev/#/patchset/20260505-gemini-ethernet-fix-v2-1-997c31d06079%40kernel.org Signed-off-by: Linus Walleij Link: https://patch.msgid.link/20260509-gemini-ethernet-fixes-v1-2-6c5d20ddc35b@kernel.org Signed-off-by: Paolo Abeni --- drivers/net/ethernet/cortina/gemini.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c index 466445c9e08b..d5a56366fb43 100644 --- a/drivers/net/ethernet/cortina/gemini.c +++ b/drivers/net/ethernet/cortina/gemini.c @@ -122,6 +122,8 @@ struct gemini_ethernet_port { struct napi_struct napi; struct hrtimer rx_coalesce_timer; unsigned int rx_coalesce_nsecs; + struct sk_buff *rx_skb; + unsigned int freeq_refill; struct gmac_txq txq[TX_QUEUE_NUM]; unsigned int txq_order; @@ -1442,10 +1444,10 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) unsigned short m = (1 << port->rxq_order) - 1; struct gemini_ethernet *geth = port->geth; void __iomem *ptr_reg = port->rxq_rwptr; + struct sk_buff *skb = port->rx_skb; unsigned int frame_len, frag_len; struct gmac_rxdesc *rx = NULL; struct gmac_queue_page *gpage; - static struct sk_buff *skb; union gmac_rxdesc_0 word0; union gmac_rxdesc_1 word1; union gmac_rxdesc_3 word3; @@ -1504,6 +1506,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) if (skb) { napi_free_frags(&port->napi); port->stats.rx_dropped++; + skb = NULL; } skb = gmac_skb_if_good_frame(port, word0, frame_len); @@ -1554,6 +1557,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) port->stats.rx_dropped++; } + port->rx_skb = skb; writew(r, ptr_reg); return budget; } @@ -1881,6 +1885,7 @@ static int gmac_stop(struct net_device *netdev) gmac_disable_tx_rx(netdev); gmac_stop_dma(port); napi_disable(&port->napi); + port->rx_skb = NULL; gmac_enable_irq(netdev, 0); gmac_cleanup_rxq(netdev); From ebd8ec2b309e3a447851b456ccaf8fb39f3661e7 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Sat, 9 May 2026 00:13:38 +0200 Subject: [PATCH 3/3] net: ethernet: cortina: Carry over frag counter The gmac_rx() NAPI poll function assembles packets in an SKB from a ring buffer. If the ring buffer gets completely emptied during a poll cycle, we exit gmac_rx(), but the packet is not yet completely assembled in the SKB, yet the fragment counter frag_nr is reset to zero on the next invocation. Solve this by making the RX fragment counter a part of the port struct, and carry it over between invocations. Reset the fragment counter only right after calling napi_gro_frags(), on error (after calling napi_free_frags()) or if stopping the port. Reset it in some place where not strictly necessary just to emphasize what is going on. This was found by Sashiko during normal patch review. Fixes: 4d5ae32f5e1e ("net: ethernet: Add a driver for Gemini gigabit ethernet") Link: https://sashiko.dev/#/patchset/20260505-gemini-ethernet-fix-v2-1-997c31d06079%40kernel.org Signed-off-by: Linus Walleij Link: https://patch.msgid.link/20260509-gemini-ethernet-fixes-v1-3-6c5d20ddc35b@kernel.org Signed-off-by: Paolo Abeni --- drivers/net/ethernet/cortina/gemini.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c index d5a56366fb43..4c762229ce42 100644 --- a/drivers/net/ethernet/cortina/gemini.c +++ b/drivers/net/ethernet/cortina/gemini.c @@ -123,6 +123,7 @@ struct gemini_ethernet_port { struct hrtimer rx_coalesce_timer; unsigned int rx_coalesce_nsecs; struct sk_buff *rx_skb; + unsigned int rx_frag_nr; unsigned int freeq_refill; struct gmac_txq txq[TX_QUEUE_NUM]; @@ -1444,6 +1445,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) unsigned short m = (1 << port->rxq_order) - 1; struct gemini_ethernet *geth = port->geth; void __iomem *ptr_reg = port->rxq_rwptr; + unsigned int frag_nr = port->rx_frag_nr; struct sk_buff *skb = port->rx_skb; unsigned int frame_len, frag_len; struct gmac_rxdesc *rx = NULL; @@ -1457,7 +1459,6 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) unsigned short r, w; union dma_rwptr rw; dma_addr_t mapping; - int frag_nr = 0; spin_lock_irqsave(&geth->irq_lock, flags); rw.bits32 = readl(ptr_reg); @@ -1497,6 +1498,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) if (skb) { napi_free_frags(&port->napi); skb = NULL; + frag_nr = 0; } continue; } @@ -1507,6 +1509,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) napi_free_frags(&port->napi); port->stats.rx_dropped++; skb = NULL; + frag_nr = 0; } skb = gmac_skb_if_good_frame(port, word0, frame_len); @@ -1541,6 +1544,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) if (word3.bits32 & EOF_BIT) { napi_gro_frags(&port->napi); skb = NULL; + frag_nr = 0; --budget; } continue; @@ -1549,6 +1553,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) if (skb) { napi_free_frags(&port->napi); skb = NULL; + frag_nr = 0; } if (mapping) @@ -1558,6 +1563,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) } port->rx_skb = skb; + port->rx_frag_nr = frag_nr; writew(r, ptr_reg); return budget; } @@ -1886,6 +1892,7 @@ static int gmac_stop(struct net_device *netdev) gmac_stop_dma(port); napi_disable(&port->napi); port->rx_skb = NULL; + port->rx_frag_nr = 0; gmac_enable_irq(netdev, 0); gmac_cleanup_rxq(netdev);