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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B14C2C433EF for ; Fri, 19 Nov 2021 15:30:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 929A461B1E for ; Fri, 19 Nov 2021 15:30:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234788AbhKSPdb (ORCPT ); Fri, 19 Nov 2021 10:33:31 -0500 Received: from smtp1.axis.com ([195.60.68.17]:63125 "EHLO smtp1.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231563AbhKSPdb (ORCPT ); Fri, 19 Nov 2021 10:33:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1637335829; x=1668871829; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=J0Q2eQn/3bf2Y/52GQfblqSKUvkUXmIj55C006lwxiI=; b=Lj8btmMfbs9UjOZ8ai1Xj4HoK2vbHkgqE3tUFZidWvWhArBdp7RevUZa LHoB2oqBMh0LsilDAPwPrv6igPqsnzijft1aWt+vZ9P4nqm8jDweMTHM6 WRqfik5NGIj7NIN77axRjXTXgM1Eq29c4k/ltJ2dn/Cd61f0tY0ctZrvI zrwQlbgEHm+7fnl5JyNzPuOnSMipOVMFZwqkoLuz3Yl+D043DMMTt5WfG zhMoYPTOWQ82m61bLFnZIlTgZV793bpAwHOyDEr7NVAadvC8D/sarvaOb vP2IlbKrY2v/my5oacwZQLfDsRAtNsQmEJlfKBGDszk89xabWM4AuR/0i g==; Date: Fri, 19 Nov 2021 16:30:27 +0100 From: Vincent Whitchurch To: Viresh Kumar CC: "wsa@kernel.org" , "jie.deng@intel.com" , "conghui.chen@intel.com" , "mst@redhat.com" , "virtualization@lists.linux-foundation.org" , "linux-i2c@vger.kernel.org" , "linux-kernel@vger.kernel.org" , kernel Subject: Re: [PATCH v2 1/2] i2c: virtio: disable timeout handling Message-ID: <20211119153025.GA17236@axis.com> References: <20211111160412.11980-1-vincent.whitchurch@axis.com> <20211111160412.11980-2-vincent.whitchurch@axis.com> <20211112023529.2nypmrnm6mufcpjt@vireshk-i7> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20211112023529.2nypmrnm6mufcpjt@vireshk-i7> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On Fri, Nov 12, 2021 at 03:35:29AM +0100, Viresh Kumar wrote: > On 11-11-21, 17:04, Vincent Whitchurch wrote: > > static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > @@ -141,7 +140,6 @@ static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > struct virtio_i2c *vi = i2c_get_adapdata(adap); > > struct virtqueue *vq = vi->vq; > > struct virtio_i2c_req *reqs; > > - unsigned long time_left; > > int count; > > > > reqs = kcalloc(num, sizeof(*reqs), GFP_KERNEL); > > @@ -164,11 +162,9 @@ static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > reinit_completion(&vi->completion); > > virtqueue_kick(vq); > > > > - time_left = wait_for_completion_timeout(&vi->completion, adap->timeout); > > - if (!time_left) > > - dev_err(&adap->dev, "virtio i2c backend timeout.\n"); > > + wait_for_completion(&vi->completion); > > I thought we decided on making this in insanely high value instead ? That wasn't my impression from the previous email thread. Jie was OK with doing it either way, and only disabling the timeout entirely makes sense to me given the risk for memory corruption otherwise. What "insanely high" timeout value do you have in mind and why would it be acceptable to corrupt kernel memory after that time? 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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4391C433F5 for ; Fri, 19 Nov 2021 15:30:36 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3825561AFB for ; Fri, 19 Nov 2021 15:30:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3825561AFB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=axis.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id ED273401E9; Fri, 19 Nov 2021 15:30:35 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ceaWpazMN5Xn; 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Fri, 19 Nov 2021 15:30:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1637335831; x=1668871831; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=J0Q2eQn/3bf2Y/52GQfblqSKUvkUXmIj55C006lwxiI=; b=JAVoJWlzLinNsPrm5Iuq3v1fG0JkJw8Z+VxhZdmCpe4V1t5cR4ilU7sV 5UBUqd7mczfTTYpU+m1um+p5fYegc4AxaBLPYtV9iuR5K/nxsMRAaIQnA 6ldUOzAKjoqw0qpXxLSCMqmsAYbd5+vTUJBMdMnUC5z1nRaED8h1Xjeg+ tzc4XN149By1aaboRSlZVNhe76qSHgnOaocp6ziEP7WPSUnOIzmyS/TmR j4OvoVEjK7Vo4EbYfkhUyY6wq50GiswBCvkxeqaSt5DJ5rctw0x/ggVN4 n88GmE84rbl3LkCXQQEIag+eWnxHmdcFUraw+IxMP5O8MFsVsD43/ZhwX w==; Date: Fri, 19 Nov 2021 16:30:27 +0100 From: Vincent Whitchurch To: Viresh Kumar Subject: Re: [PATCH v2 1/2] i2c: virtio: disable timeout handling Message-ID: <20211119153025.GA17236@axis.com> References: <20211111160412.11980-1-vincent.whitchurch@axis.com> <20211111160412.11980-2-vincent.whitchurch@axis.com> <20211112023529.2nypmrnm6mufcpjt@vireshk-i7> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20211112023529.2nypmrnm6mufcpjt@vireshk-i7> User-Agent: Mutt/1.10.1 (2018-07-13) Cc: "mst@redhat.com" , "linux-kernel@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "wsa@kernel.org" , kernel , "linux-i2c@vger.kernel.org" , "conghui.chen@intel.com" X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Fri, Nov 12, 2021 at 03:35:29AM +0100, Viresh Kumar wrote: > On 11-11-21, 17:04, Vincent Whitchurch wrote: > > static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > @@ -141,7 +140,6 @@ static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > struct virtio_i2c *vi = i2c_get_adapdata(adap); > > struct virtqueue *vq = vi->vq; > > struct virtio_i2c_req *reqs; > > - unsigned long time_left; > > int count; > > > > reqs = kcalloc(num, sizeof(*reqs), GFP_KERNEL); > > @@ -164,11 +162,9 @@ static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > reinit_completion(&vi->completion); > > virtqueue_kick(vq); > > > > - time_left = wait_for_completion_timeout(&vi->completion, adap->timeout); > > - if (!time_left) > > - dev_err(&adap->dev, "virtio i2c backend timeout.\n"); > > + wait_for_completion(&vi->completion); > > I thought we decided on making this in insanely high value instead ? That wasn't my impression from the previous email thread. Jie was OK with doing it either way, and only disabling the timeout entirely makes sense to me given the risk for memory corruption otherwise. What "insanely high" timeout value do you have in mind and why would it be acceptable to corrupt kernel memory after that time? _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization