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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 1FF23C43461 for ; Tue, 8 Sep 2020 19:57:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF55820658 for ; Tue, 8 Sep 2020 19:57:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599595073; bh=TNr20Rhq1tcURGtfYe8xVwLGmJ82ca1qiqhUd7CC3Ns=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TXMLSY7uv8GnWvB79vk7dO4Fl4jxOLSFODHYdCLuxbTXZBAwWKFd+S0dSYo05ju+N CH16PBAweQzyEu1p2RQTVgvYY23Vd5uJ38t8yXFaOrt4SKe3fWy8HQCX3lbu4VYi9/ xblfst0nc/u/fEgGSACckaizAoWj1pKhNgvgBEXk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732536AbgIHT5q (ORCPT ); Tue, 8 Sep 2020 15:57:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:60636 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730543AbgIHPfu (ORCPT ); Tue, 8 Sep 2020 11:35:50 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 567C3224DE; Tue, 8 Sep 2020 15:35:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599579301; bh=TNr20Rhq1tcURGtfYe8xVwLGmJ82ca1qiqhUd7CC3Ns=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n9tGFOjqLZFoMIbC0oeKXmZm7bTEBU80ap4Gp2NsnjyHVvGjTt6VQYXJa4Ql5envn sit+WiSfQBkSLf25PrQlw7U5W2zJc7bTz0zNSH+pAAe0eeJIhRrmJFaMrjroFdN+dl CT0h/qDaODWFOCGCounVv3BSWV3sTeCeZwtOYUAA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vineeth Pillai , Michael Kelley , Wei Liu , Sasha Levin Subject: [PATCH 5.8 021/186] hv_utils: drain the timesync packets on onchannelcallback Date: Tue, 8 Sep 2020 17:22:43 +0200 Message-Id: <20200908152242.685692310@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152241.646390211@linuxfoundation.org> References: <20200908152241.646390211@linuxfoundation.org> User-Agent: quilt/0.66 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 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