From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 063E04E781E; Thu, 17 Sep 2026 15:42:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789659771; cv=none; b=VlnEV0BymLPObMh75An+Qgns7YSml6x5RWvEZWpei/mn3gb9NBfkUqtqZLtMoK9vLjJMUg7K9kNXnXm5EuBkoATwTQE8SqfwdRdAlZZkQm7eFqodxle1mkGW6bMFw2dOq/2GIzVwAm+D6K9UtQexDgzFr87GeHXOslqVEaRxysE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789659771; c=relaxed/simple; bh=xNnLYnynsCrDHDtlOZyFyBrt2Yt6xlEiQKfaiVtjr6Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jQLXdA+sXWT9Ua0hjZ9go+PnymBITvwe60pCeGtA2nB/n3v+mXjzotwPlikbb6sb+b3OIjZpFCvz2fXDdwufjpnaLstM7ac1P5GPW/gItJiIrnIOPcPtY8dBEA4TC/86MUodQ70KCTsNguiru6+4o6SX3BcDAk9/1BoMPJjxRsA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gxMX4w9S; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="gxMX4w9S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C8FE1F00893; Thu, 17 Sep 2026 15:42:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789659764; bh=b8HxYjuIsvsx5kwYxxxB0gUoUJEjJ36GppEBl6AmU00=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gxMX4w9Syz4hMSqdpnmmlU0RzQS7ooR7fDplBc7ayJTypg0m4yFkMAIDizIuQS2Sv KKMenSHoKFaHPQh1Xqv2fK/YUkhymDe4ms0gojFFMqSZpWpUjg4OtAJU7VYzmzZyIw 69Side8FmZNXVUhOAuYIiuqW34vJ9QSTgRYbu/qk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Joe Damato , Linus Walleij , Paolo Abeni , Sasha Levin Subject: [PATCH 7.2 365/733] net: ethernet: cortina: Count RX drops once per frame Date: Thu, 17 Sep 2026 16:11:13 +0100 Message-ID: <20260917151400.715835132@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Linus Walleij [ Upstream commit 6520198c430c81bcc367f0dd5e32f2fb740b9d51 ] The absence of a partial skb means either that the driver is not assembling a frame or that the current frame was already dropped. Consequently, repeated descriptor errors can increment rx_dropped more than once, while an orphaned descriptor chain can reach EOF without being counted at all. Track the dropping state across NAPI polls. Clear it at frame boundaries and route mapping failures and orphaned continuations through the common drop path so each discarded frame is counted exactly once. Fixes: 4d5ae32f5e1e ("net: ethernet: Add a driver for Gemini gigabit ethernet") Reported-by: Joe Damato Closes: https://lore.kernel.org/netdev/apdK5aMmvYssz35F@devvm20253.cco0.facebook.com/ Assisted-by: LLM Signed-off-by: Linus Walleij Link: https://patch.msgid.link/20260903-gemini-ethernet-fixes-v2-4-2bbbd598ca6e@kernel.org Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/ethernet/cortina/gemini.c | 41 +++++++++++++++------------ 1 file changed, 23 insertions(+), 18 deletions(-) diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c index 33e9763b32fe8..9ba8524fa3710 100644 --- a/drivers/net/ethernet/cortina/gemini.c +++ b/drivers/net/ethernet/cortina/gemini.c @@ -124,6 +124,7 @@ struct gemini_ethernet_port { unsigned int rx_coalesce_nsecs; struct sk_buff *rx_skb; unsigned int rx_frag_nr; + bool rx_dropping; unsigned int freeq_refill; struct gmac_txq txq[TX_QUEUE_NUM]; @@ -1451,6 +1452,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) struct gmac_rxdesc *rx = NULL; struct gmac_queue_page *gpage; unsigned int received = 0; + bool dropping = port->rx_dropping; union gmac_rxdesc_0 word0; union gmac_rxdesc_1 word1; union gmac_rxdesc_3 word3; @@ -1472,6 +1474,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) w = rw.bits.wptr; while (budget && w != r) { + page = NULL; rx = port->rxq_ring + r; word0 = rx->word0; word1 = rx->word1; @@ -1485,6 +1488,16 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) frame_len = word1.bits.byte_count; page_offs = mapping & ~PAGE_MASK; + if (word3.bits32 & SOF_BIT) { + if (skb) { + napi_free_frags(&port->napi); + port->stats.rx_dropped++; + skb = NULL; + frag_nr = 0; + } + dropping = false; + } + if (!mapping) { netdev_err(netdev, "rxq[%u]: HW BUG: zero DMA desc\n", r); @@ -1495,24 +1508,11 @@ 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); - skb = NULL; - frag_nr = 0; - } - goto next_desc; + goto err_drop; } page = gpage->page; if (word3.bits32 & SOF_BIT) { - if (skb) { - napi_free_frags(&port->napi); - port->stats.rx_dropped++; - skb = NULL; - frag_nr = 0; - } - skb = gmac_skb_if_good_frame(port, word0, frame_len); if (!skb) goto err_drop; @@ -1522,8 +1522,7 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) frag_nr = 0; } else if (!skb) { - put_page(page); - goto next_desc; + goto err_drop; } if (word3.bits32 & EOF_BIT) @@ -1556,21 +1555,26 @@ static unsigned int gmac_rx(struct net_device *netdev, unsigned int budget) frag_nr = 0; } - if (mapping) + if (page) put_page(page); - port->stats.rx_dropped++; + if (!dropping) { + port->stats.rx_dropped++; + dropping = true; + } next_desc: /* Final or single-descriptor fragment, advance things */ if (word3.bits32 & EOF_BIT) { budget--; received++; + dropping = false; } } port->rx_skb = skb; port->rx_frag_nr = frag_nr; + port->rx_dropping = dropping; writew(r, ptr_reg); return received; } @@ -1900,6 +1904,7 @@ static int gmac_stop(struct net_device *netdev) napi_disable(&port->napi); port->rx_skb = NULL; port->rx_frag_nr = 0; + port->rx_dropping = false; gmac_enable_irq(netdev, 0); gmac_cleanup_rxq(netdev); -- 2.53.0