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=-13.1 required=3.0 tests=BAYES_00,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=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 110B4C433E6 for ; Mon, 31 Aug 2020 15:30:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D56B420E65 for ; Mon, 31 Aug 2020 15:30:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598887824; bh=TNr20Rhq1tcURGtfYe8xVwLGmJ82ca1qiqhUd7CC3Ns=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vIqxvYLSmKyFNUFrUsSFqWcVlJhnbcQFgeBVwDLe6kvPeCR92rahVhLxV8ZMj2z/O cHdmJI0hjnZmdgE4+YSVQ2X8wYaQL00WGT9ZbrjfW0OCq+A1qidV2krGD9F/IArDW6 JhuyyA5WGk/3vMnc9zeJDc9FeTWeh6k8OMF435Qc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728609AbgHaPaX (ORCPT ); Mon, 31 Aug 2020 11:30:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:39106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728546AbgHaPaM (ORCPT ); Mon, 31 Aug 2020 11:30:12 -0400 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 A2B232151B; Mon, 31 Aug 2020 15:30:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598887810; bh=TNr20Rhq1tcURGtfYe8xVwLGmJ82ca1qiqhUd7CC3Ns=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JSHVZ2JT7XZTYmLU1JNPU4/hflzH0AJ9gWCI2V33tl3mc69sssllxuegoyf9EGvKQ LlDRMt2F30hbAo4R5W7n9u3hyC1zk0py0Tw1HDHzH1BXZqjQWC1sZMiH0w+/VhdlKt pJ/jyj5OGr+o3Vxo5SQPTnBxjRktRwQuWGX6MnPs= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vineeth Pillai , Michael Kelley , Wei Liu , Sasha Levin , linux-hyperv@vger.kernel.org Subject: [PATCH AUTOSEL 5.8 24/42] hv_utils: drain the timesync packets on onchannelcallback Date: Mon, 31 Aug 2020 11:29:16 -0400 Message-Id: <20200831152934.1023912-24-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200831152934.1023912-1-sashal@kernel.org> References: <20200831152934.1023912-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vineeth Pillai [ Upstream commit b46b4a8a57c377b72a98c7930a9f6969d2d4784e ] There could be instances where a system stall prevents the timesync packets to be consumed. And this might lead to more than one packet pending in the ring buffer. Current code empties one packet per callback and it might be a stale one. So drain all the packets from ring buffer on each callback. Signed-off-by: Vineeth Pillai Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20200821152849.99517-1-viremana@linux.microsoft.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin --- drivers/hv/hv_util.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c index 1f86e8d9b018d..a4e8d96513c22 100644 --- a/drivers/hv/hv_util.c +++ b/drivers/hv/hv_util.c @@ -387,10 +387,23 @@ static void timesync_onchannelcallback(void *context) struct ictimesync_ref_data *refdata; u8 *time_txf_buf = util_timesynch.recv_buffer; - vmbus_recvpacket(channel, time_txf_buf, - HV_HYP_PAGE_SIZE, &recvlen, &requestid); + /* + * Drain the ring buffer and use the last packet to update + * host_ts + */ + while (1) { + int ret = vmbus_recvpacket(channel, time_txf_buf, + HV_HYP_PAGE_SIZE, &recvlen, + &requestid); + if (ret) { + pr_warn_once("TimeSync IC pkt recv failed (Err: %d)\n", + ret); + break; + } + + if (!recvlen) + break; - if (recvlen > 0) { icmsghdrp = (struct icmsg_hdr *)&time_txf_buf[ sizeof(struct vmbuspipe_hdr)]; -- 2.25.1