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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 E8610C433DF for ; Fri, 5 Jun 2020 17:13:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C50752077D for ; Fri, 5 Jun 2020 17:13:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727018AbgFERNP (ORCPT ); Fri, 5 Jun 2020 13:13:15 -0400 Received: from mga11.intel.com ([192.55.52.93]:62614 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726090AbgFERNO (ORCPT ); Fri, 5 Jun 2020 13:13:14 -0400 IronPort-SDR: m78o2lRndsVRUxuXvV9mueNAVtBf6Su0AzxPpTyjp39kn8c3uclHFALrh0Us1QpUkCxYvV4hnY bQi7gYYAk3fw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jun 2020 10:13:14 -0700 IronPort-SDR: 8dXeibKw9Oymx4zZCYxphg3R+QpK3j/MMW6EYOklYlz1iNt6dXs2V1i7rgC+IijYWiuL9QozSq vrfI0EMm/8Og== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,477,1583222400"; d="scan'208";a="273530919" Received: from iweiny-desk2.sc.intel.com ([10.3.52.147]) by orsmga006.jf.intel.com with ESMTP; 05 Jun 2020 10:13:13 -0700 Date: Fri, 5 Jun 2020 10:13:13 -0700 From: Ira Weiny To: Vaibhav Jain Cc: linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, Dan Williams , "Aneesh Kumar K . V" , Michael Ellerman , Oliver O'Halloran , Santosh Sivaraj , Steven Rostedt Subject: Re: [PATCH v10 4/6] powerpc/papr_scm: Improve error logging and handling papr_scm_ndctl() Message-ID: <20200605171313.GO1505637@iweiny-DESK2.sc.intel.com> References: <20200604234136.253703-1-vaibhav@linux.ibm.com> <20200604234136.253703-5-vaibhav@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200604234136.253703-5-vaibhav@linux.ibm.com> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 05, 2020 at 05:11:34AM +0530, Vaibhav Jain wrote: > Since papr_scm_ndctl() can be called from outside papr_scm, its > exposed to the possibility of receiving NULL as value of 'cmd_rc' > argument. This patch updates papr_scm_ndctl() to protect against such > possibility by assigning it pointer to a local variable in case cmd_rc > == NULL. > > Finally the patch also updates the 'default' clause of the switch-case > block removing a 'return' statement thereby ensuring that value of > 'cmd_rc' is always logged when papr_scm_ndctl() returns. > > Cc: "Aneesh Kumar K . V" > Cc: Dan Williams > Cc: Michael Ellerman > Cc: Ira Weiny > Signed-off-by: Vaibhav Jain > --- > Changelog: > > v9..v10 > * New patch in the series Thanks for making this a separate patch it is easier to see what is going on here. > --- > arch/powerpc/platforms/pseries/papr_scm.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c > index 0c091622b15e..6512fe6a2874 100644 > --- a/arch/powerpc/platforms/pseries/papr_scm.c > +++ b/arch/powerpc/platforms/pseries/papr_scm.c > @@ -355,11 +355,16 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, > { > struct nd_cmd_get_config_size *get_size_hdr; > struct papr_scm_priv *p; > + int rc; > > /* Only dimm-specific calls are supported atm */ > if (!nvdimm) > return -EINVAL; > > + /* Use a local variable in case cmd_rc pointer is NULL */ > + if (!cmd_rc) > + cmd_rc = &rc; > + This protects you from the NULL. However... > p = nvdimm_provider_data(nvdimm); > > switch (cmd) { > @@ -381,12 +386,13 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, > break; > > default: > - return -EINVAL; > + dev_dbg(&p->pdev->dev, "Unknown command = %d\n", cmd); > + *cmd_rc = -EINVAL; ... I think you are conflating rc and cmd_rc... > } > > dev_dbg(&p->pdev->dev, "returned with cmd_rc = %d\n", *cmd_rc); > > - return 0; > + return *cmd_rc; ... this changes the behavior of the current commands. Now if the underlying papr_scm_meta_[get|set]() fails you return that failure as rc rather than 0. Is that ok? Also 'logging cmd_rc' in the invalid cmd case does not seem quite right unless you really want rc to be cmd_rc. The architecture is designed to separate errors which occur in the kernel vs errors in the firmware/dimm. Are they always the same? The current code differentiates them. Ira > } > > static ssize_t flags_show(struct device *dev, > -- > 2.26.2 >