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=-20.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 BD7BDC433DF for ; Fri, 21 Aug 2020 15:30:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 99C522078B for ; Fri, 21 Aug 2020 15:30:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="BOLOIn2b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728174AbgHUP3n (ORCPT ); Fri, 21 Aug 2020 11:29:43 -0400 Received: from linux.microsoft.com ([13.77.154.182]:47226 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728253AbgHUP3D (ORCPT ); Fri, 21 Aug 2020 11:29:03 -0400 Received: from testvm-timer.0wqf5yk0ngwuzjntifuk1ppqse.cx.internal.cloudapp.net (unknown [40.65.222.102]) by linux.microsoft.com (Postfix) with ESMTPSA id 7AE1320B4908; Fri, 21 Aug 2020 08:29:02 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 7AE1320B4908 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1598023743; bh=1Xx3fDRP6HUhJQ0/HwzwV1+TX9mHcQq7j3/A5j4Vz/s=; h=From:To:Cc:Subject:Date:From; b=BOLOIn2bYM+SGapuZTTujMnaSM6QFuksi5YdgkIXG/JxKQ7d4OKh2ap5o8+iMMUqd E5FvTQb4DW+TvE6MTI9Q/Gai+6/UDnKDEpXxrRZaE+Z2PCkj0agWIzPqDdnGExjZW2 M+4Emlcn9JP16t4F41OOo+vIq2TwLr4Efg/Lvz2Y= From: Vineeth Pillai To: Haiyang Zhang , Stephen Hemminger , Wei Liu Cc: Vineeth Pillai , "K . Y . Srinivasan" , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] hv_utils: drain the timesync packets on onchannelcallback Date: Fri, 21 Aug 2020 15:28:49 +0000 Message-Id: <20200821152849.99517-1-viremana@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org There could be instances where a system stall prevents the timesync packaets 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 --- v2: - s/pr_warn/pr_warn_once/ --- 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 1f86e8d9b018..a4e8d96513c2 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)]; -- 2.17.1