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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 AFBC5C54E4A for ; Tue, 12 May 2020 09:13:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9680220575 for ; Tue, 12 May 2020 09:13:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729167AbgELJNa (ORCPT ); Tue, 12 May 2020 05:13:30 -0400 Received: from mx2.suse.de ([195.135.220.15]:53538 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725776AbgELJNa (ORCPT ); Tue, 12 May 2020 05:13:30 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id CFD8EAC6C; Tue, 12 May 2020 09:13:31 +0000 (UTC) Subject: Re: [PATCH 1/2] xen/xenbus: avoid large structs and arrays on the stack To: Boris Ostrovsky , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Cc: Stefano Stabellini , Arnd Bergmann References: <20200511073151.19043-1-jgross@suse.com> <20200511073151.19043-2-jgross@suse.com> <965e1d65-3a0c-3a71-ca58-2b5c04f98bce@oracle.com> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Tue, 12 May 2020 11:13:27 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <965e1d65-3a0c-3a71-ca58-2b5c04f98bce@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11.05.20 20:01, Boris Ostrovsky wrote: > On 5/11/20 3:31 AM, Juergen Gross wrote: >> >> static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev, > > > I wonder whether we can drop valloc/vfree from xenbus_ring_ops' names. I can do that. > > >> + struct map_ring_valloc *info, >> grant_ref_t *gnt_ref, >> unsigned int nr_grefs, >> void **vaddr) >> { >> - struct xenbus_map_node *node; >> + struct xenbus_map_node *node = info->node; >> int err; >> void *addr; >> bool leaked = false; >> - struct map_ring_valloc_hvm info = { >> - .idx = 0, >> - }; >> unsigned int nr_pages = XENBUS_PAGES(nr_grefs); >> >> - if (nr_grefs > XENBUS_MAX_RING_GRANTS) >> - return -EINVAL; >> - >> - *vaddr = NULL; >> - >> - node = kzalloc(sizeof(*node), GFP_KERNEL); >> - if (!node) >> - return -ENOMEM; >> - >> err = alloc_xenballooned_pages(nr_pages, node->hvm.pages); >> if (err) >> goto out_err; >> >> gnttab_foreach_grant(node->hvm.pages, nr_grefs, >> xenbus_map_ring_setup_grant_hvm, >> - &info); >> + info); >> >> err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles, >> - info.phys_addrs, GNTMAP_host_map, &leaked); >> + info, GNTMAP_host_map, &leaked); >> node->nr_handles = nr_grefs; >> >> if (err) >> @@ -641,11 +654,13 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev, >> spin_unlock(&xenbus_valloc_lock); >> >> *vaddr = addr; >> + info->node = NULL; > > > Is this so that xenbus_map_ring_valloc() doesn't free it accidentally? Yes. Juergen