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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 5E60EC04E84 for ; Thu, 16 May 2019 19:12:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4350820818 for ; Thu, 16 May 2019 19:12:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727351AbfEPTME (ORCPT ); Thu, 16 May 2019 15:12:04 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:60074 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726317AbfEPTME (ORCPT ); Thu, 16 May 2019 15:12:04 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::3d8]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 325AE133E977D; Thu, 16 May 2019 12:12:03 -0700 (PDT) Date: Thu, 16 May 2019 12:12:02 -0700 (PDT) Message-Id: <20190516.121202.232705215173348273.davem@davemloft.net> To: sunilmut@microsoft.com Cc: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, sashal@kernel.org, decui@microsoft.com, mikelley@microsoft.com, netdev@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] hv_sock: Add support for delayed close From: David Miller In-Reply-To: References: X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 16 May 2019 12:12:03 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sunil Muthuswamy Date: Wed, 15 May 2019 00:56:05 +0000 > Currently, hvsock does not implement any delayed or background close > logic. Whenever the hvsock socket is closed, a FIN is sent to the peer, and > the last reference to the socket is dropped, which leads to a call to > .destruct where the socket can hang indefinitely waiting for the peer to > close it's side. The can cause the user application to hang in the close() > call. > > This change implements proper STREAM(TCP) closing handshake mechanism by > sending the FIN to the peer and the waiting for the peer's FIN to arrive > for a given timeout. On timeout, it will try to terminate the connection > (i.e. a RST). This is in-line with other socket providers such as virtio. > > This change does not address the hang in the vmbus_hvsock_device_unregister > where it waits indefinitely for the host to rescind the channel. That > should be taken up as a separate fix. > > Signed-off-by: Sunil Muthuswamy Applied, thanks.