From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6AE4C43381 for ; Mon, 25 Feb 2019 21:50:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9C0F52083D for ; Mon, 25 Feb 2019 21:50:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551131413; bh=h4BWWu+CulK9A7x1hhncLze98ZpmSXQchpaoMbxVHzY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TVt8GsDFuzcCAafPPQahYsXgqxW0ahOj7K0sQplDaVYx70mT7HEIbXAjA88w2hzXm 6Z9ou0Si0odYVlPPW3tgjO6GqpMl3LOKKzeyyokAtMnZuzoAEaxtwHfgYQBaR1HL+v ORyi/u9q1uGWD5jLQ7jjin7+6Fq1IY4I6sD2gH7s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731075AbfBYVuL (ORCPT ); Mon, 25 Feb 2019 16:50:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:59436 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731320AbfBYVYz (ORCPT ); Mon, 25 Feb 2019 16:24:55 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AB3E820C01; Mon, 25 Feb 2019 21:24:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551129894; bh=h4BWWu+CulK9A7x1hhncLze98ZpmSXQchpaoMbxVHzY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t6HWRT8ZRqbsgga30pee7MuxxbzMAv8uPo+8cyRjpdYBEgE9pI0S8xo4fQodaD/Fb Iz6X3yXxVFQNpU/M6LS1qWIlPkev4VREHzN/hoZsbK4C1yOTxNfVDjHoupg0NY2wdh G6md5OgiuESAUdHkIgGdOKJNh4PoCCKXcGiZRzZc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Joao Pinto , "David S. Miller" , Giuseppe Cavallaro , Alexandre Torgue , Jose Abreu , Sasha Levin Subject: [PATCH 4.19 064/152] net: stmmac: Prevent RX starvation in stmmac_napi_poll() Date: Mon, 25 Feb 2019 22:10:56 +0100 Message-Id: <20190225195047.810547535@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190225195043.645958524@linuxfoundation.org> References: <20190225195043.645958524@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit fa0be0a43f101888ac677dba31b590963eafeaa1 ] Currently, TX is given a budget which is consumed by stmmac_tx_clean() and stmmac_rx() is given the remaining non-consumed budget. This is wrong and in case we are sending a large number of packets this can starve RX because remaining budget will be low. Let's give always the same budget for RX and TX clean. While at it, check if we missed any interrupts while we were in NAPI callback by looking at DMA interrupt status. Cc: Joao Pinto Cc: David S. Miller Cc: Giuseppe Cavallaro Cc: Alexandre Torgue Signed-off-by: Jose Abreu Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- .../net/ethernet/stmicro/stmmac/stmmac_main.c | 27 ++++++++++--------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 24ae244c2ee33..123b74e25ed81 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -3522,27 +3522,28 @@ static int stmmac_napi_poll(struct napi_struct *napi, int budget) struct stmmac_channel *ch = container_of(napi, struct stmmac_channel, napi); struct stmmac_priv *priv = ch->priv_data; - int work_done = 0, work_rem = budget; + int work_done, rx_done = 0, tx_done = 0; u32 chan = ch->index; priv->xstats.napi_poll++; - if (ch->has_tx) { - int done = stmmac_tx_clean(priv, work_rem, chan); + if (ch->has_tx) + tx_done = stmmac_tx_clean(priv, budget, chan); + if (ch->has_rx) + rx_done = stmmac_rx(priv, budget, chan); - work_done += done; - work_rem -= done; - } - - if (ch->has_rx) { - int done = stmmac_rx(priv, work_rem, chan); + work_done = max(rx_done, tx_done); + work_done = min(work_done, budget); - work_done += done; - work_rem -= done; - } + if (work_done < budget && napi_complete_done(napi, work_done)) { + int stat; - if (work_done < budget && napi_complete_done(napi, work_done)) stmmac_enable_dma_irq(priv, priv->ioaddr, chan); + stat = stmmac_dma_interrupt_status(priv, priv->ioaddr, + &priv->xstats, chan); + if (stat && napi_reschedule(napi)) + stmmac_disable_dma_irq(priv, priv->ioaddr, chan); + } return work_done; } -- 2.19.1