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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 079BDC2D0DB for ; Fri, 27 Dec 2019 18:14:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA45E208C4 for ; Fri, 27 Dec 2019 18:14:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577470497; bh=9EID52D7e5jdDMIxVggjeOppsxxQ4OeaDCj5xbY+c7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kt/c0WFqbobgfaN3+jfOUmJxuzZb4r9PL6ce0jNR46s0j96QuKqKO/gItvKiv2HAq 9T3KehDUmUsHAnOiKMZ7uJiaNw4TuEVPduy8Nn90QY5p9AdnDzeifQPQ5Ky0DtdbTF 36HDHTkPlUddL3xIn0uka99QnNx33k6FBn3qLEgc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727558AbfL0SO5 (ORCPT ); Fri, 27 Dec 2019 13:14:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:39306 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727471AbfL0SOx (ORCPT ); Fri, 27 Dec 2019 13:14:53 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2B675208C4; Fri, 27 Dec 2019 18:14:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577470492; bh=9EID52D7e5jdDMIxVggjeOppsxxQ4OeaDCj5xbY+c7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=le8sKo134EwGqP1oRJSuoiDogzs7a3/4/0aVITapZ/hLK0LulyTJ5d0HyXGWOaJst y1JcHBukbFQm2jjcyKkQY7EvojrrKVAkeE/atBeuD4SuslU7r2OKS2/6J3T84oWga8 FOj0O4mCjkPysxXbHiCcRSMNnsbsmxEz9yvxpe78= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Netanel Belgazal , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 13/38] net: ena: fix napi handler misbehavior when the napi budget is zero Date: Fri, 27 Dec 2019 13:14:10 -0500 Message-Id: <20191227181435.7644-13-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191227181435.7644-1-sashal@kernel.org> References: <20191227181435.7644-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Netanel Belgazal [ Upstream commit 24dee0c7478d1a1e00abdf5625b7f921467325dc ] In netpoll the napi handler could be called with budget equal to zero. Current ENA napi handler doesn't take that into consideration. The napi handler handles Rx packets in a do-while loop. Currently, the budget check happens only after decrementing the budget, therefore the napi handler, in rare cases, could run over MAX_INT packets. In addition to that, this moves all budget related variables to int calculation and stop mixing u32 to avoid ambiguity Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)") Signed-off-by: Netanel Belgazal Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c index 0780900b37c7..961f31c8356b 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -1105,8 +1105,8 @@ static int ena_io_poll(struct napi_struct *napi, int budget) struct ena_ring *tx_ring, *rx_ring; struct ena_eth_io_intr_reg intr_reg; - u32 tx_work_done; - u32 rx_work_done; + int tx_work_done; + int rx_work_done = 0; int tx_budget; int napi_comp_call = 0; int ret; @@ -1122,7 +1122,11 @@ static int ena_io_poll(struct napi_struct *napi, int budget) } tx_work_done = ena_clean_tx_irq(tx_ring, tx_budget); - rx_work_done = ena_clean_rx_irq(rx_ring, napi, budget); + /* On netpoll the budget is zero and the handler should only clean the + * tx completions. + */ + if (likely(budget)) + rx_work_done = ena_clean_rx_irq(rx_ring, napi, budget); if ((budget > rx_work_done) && (tx_budget > tx_work_done)) { napi_complete_done(napi, rx_work_done); -- 2.20.1