From patchwork Wed Jul 25 16:28:45 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huaisheng Ye X-Patchwork-Id: 10544323 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A31CC14E2 for ; Wed, 25 Jul 2018 16:29:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 90CFD2A6F0 for ; Wed, 25 Jul 2018 16:29:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8559B2A6F5; Wed, 25 Jul 2018 16:29:52 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3A1EC2A6F0 for ; Wed, 25 Jul 2018 16:29:52 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 1C115210C1EF9; Wed, 25 Jul 2018 09:29:52 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=135.84.80.237; helo=sender-pp-092.zoho.com; envelope-from=yehs2007@zoho.com; receiver=linux-nvdimm@lists.01.org Received: from sender-pp-092.zoho.com (sender-pp-092.zoho.com [135.84.80.237]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 56A1C2097FABE for ; Wed, 25 Jul 2018 09:29:50 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=zapps768; d=zoho.com; h=from:to:cc:subject:date:message-id:in-reply-to:references; b=fCbn3xBrPGxPROX/ClekHXzJkXfrE4ajrGtdYSk1LZREq7bPBZZrY7aAMGrMuv1/aN26qqtcFhWE 23z6YdEM3mk6JqEjjQDOvfK55UQakHM29TgRdF6i5B2p71bCQnih Received: from YEHS1XR956R00D1.lenovo.com (114.245.13.10 [114.245.13.10]) by mx.zohomail.com with SMTPS id 1532536166941927.3898531496442; Wed, 25 Jul 2018 09:29:26 -0700 (PDT) From: Huaisheng Ye To: linux-nvdimm@lists.01.org, dan.j.williams@intel.com Subject: [PATCH v2 2/6] s390, dcssblk: kaddr and pfn can be NULL to ->direct_access() Date: Thu, 26 Jul 2018 00:28:45 +0800 Message-Id: <20180725162849.8320-3-yehs2007@zoho.com> X-Mailer: git-send-email 2.17.0.windows.1 In-Reply-To: <20180725162849.8320-1-yehs2007@zoho.com> References: <20180725162849.8320-1-yehs2007@zoho.com> X-ZohoMailClient: External X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: axboe@kernel.dk, linux-s390@vger.kernel.org, snitzer@redhat.com, chengnt@lenovo.com, linux-fsdevel@vger.kernel.org, heiko.carstens@de.ibm.com, linux-kernel@vger.kernel.org, willy@infradead.org, colyli@suse.de, bart.vanassche@wdc.com, dm-devel@redhat.com, viro@zeniv.linux.org.uk, gregkh@linuxfoundation.org, schwidefsky@de.ibm.com, jack@suse.cz, agk@redhat.com MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP From: Huaisheng Ye dcssblk_direct_access() needs to check the validity of pointers kaddr and pfn for NULL assignment. If anyone equals to NULL, it doesn't need to calculate the value. If either of them is equal to NULL, that is to say callers may have no need for kaddr or pfn, so this patch is prepared for allowing them to pass in NULL instead of having to pass in a pointer or local variable that they then just throw away. Signed-off-by: Huaisheng Ye Acked-by: Martin Schwidefsky --- drivers/s390/block/dcssblk.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index ed60728..23e526c 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -922,9 +922,11 @@ static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show, unsigned long dev_sz; dev_sz = dev_info->end - dev_info->start + 1; - *kaddr = (void *) dev_info->start + offset; - *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), - PFN_DEV|PFN_SPECIAL); + if (kaddr) + *kaddr = (void *) dev_info->start + offset; + if (pfn) + *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), + PFN_DEV|PFN_SPECIAL); return (dev_sz - offset) / PAGE_SIZE; }