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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 9219DC433E8 for ; Thu, 16 Jul 2020 21:10:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AFBC20760 for ; Thu, 16 Jul 2020 21:10:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727065AbgGPVKX (ORCPT ); Thu, 16 Jul 2020 17:10:23 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:65258 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727049AbgGPVKW (ORCPT ); Thu, 16 Jul 2020 17:10:22 -0400 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06GL3I62074156; Thu, 16 Jul 2020 17:10:15 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 32aut4cqmr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 16 Jul 2020 17:10:15 -0400 Received: from m0098420.ppops.net (m0098420.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 06GL3Obu074761; Thu, 16 Jul 2020 17:10:15 -0400 Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0b-001b2d01.pphosted.com with ESMTP id 32aut4cqm6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 16 Jul 2020 17:10:15 -0400 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06GKouPK028029; Thu, 16 Jul 2020 21:10:13 GMT Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by ppma03ams.nl.ibm.com with ESMTP id 327527x09q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 16 Jul 2020 21:10:13 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06GLAAAp15597958 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 16 Jul 2020 21:10:10 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 74FECAE045; Thu, 16 Jul 2020 21:10:10 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 49316AE059; Thu, 16 Jul 2020 21:10:07 +0000 (GMT) Received: from [9.102.2.181] (unknown [9.102.2.181]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 16 Jul 2020 21:10:07 +0000 (GMT) From: Hari Bathini Subject: Re: [PATCH v3 06/12] ppc64/kexec_file: restrict memory usage of kdump kernel To: Thiago Jung Bauermann Cc: Pingfan Liu , Nayna Jain , Kexec-ml , Mahesh J Salgaonkar , Mimi Zohar , lkml , linuxppc-dev , Sourabh Jain , Petr Tesarik , Andrew Morton , Dave Young , Vivek Goyal , Eric Biederman References: <159466074408.24747.10036072269371204890.stgit@hbathini.in.ibm.com> <159466091925.24747.6840028682768745598.stgit@hbathini.in.ibm.com> <87365s9ysj.fsf@morokweng.localdomain> Message-ID: Date: Fri, 17 Jul 2020 02:40:06 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <87365s9ysj.fsf@morokweng.localdomain> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-07-16_11:2020-07-16,2020-07-16 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_spam_definite policy=outbound score=100 malwarescore=0 priorityscore=1501 adultscore=0 clxscore=1015 bulkscore=0 spamscore=100 suspectscore=0 impostorscore=0 mlxlogscore=-1000 lowpriorityscore=0 mlxscore=100 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007160140 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16/07/20 4:22 am, Thiago Jung Bauermann wrote: > > Hari Bathini writes: > >> +/** >> + * get_node_path - Get the full path of the given node. >> + * @dn: Node. >> + * @path: Updated with the full path of the node. >> + * >> + * Returns nothing. >> + */ >> +static void get_node_path(struct device_node *dn, char *path) >> +{ >> + if (!dn) >> + return; >> + >> + get_node_path(dn->parent, path); > > Is it ok to do recursion in the kernel? In this case I believe it's not > problematic since the maximum call depth will be the maximum depth of a > device tree node which shouldn't be too much. Also, there are no local > variables in this function. But I thought it was worth mentioning. You are right. We are better off avoiding the recursion here. Will change it to an iterative version instead. >> + * each representing a memory range. >> + */ >> + ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells); >> + >> + for (i = 0; i < ranges; i++) { >> + base = of_read_number(prop, n_mem_addr_cells); >> + prop += n_mem_addr_cells; >> + end = base + of_read_number(prop, n_mem_size_cells) - 1; prop is not used after the above. > You need to `prop += n_mem_size_cells` here. But yeah, adding it would make it look complete in some sense.. Thanks Hari