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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 81398C6778C for ; Wed, 4 Jul 2018 06:42:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 44E95244E8 for ; Wed, 4 Jul 2018 06:42:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 44E95244E8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zoho.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933504AbeGDGmD (ORCPT ); Wed, 4 Jul 2018 02:42:03 -0400 Received: from sender-pp-092.zoho.com ([135.84.80.237]:25319 "EHLO sender-pp-092.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753620AbeGDGmB (ORCPT ); Wed, 4 Jul 2018 02:42:01 -0400 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=LliPjvUzYO4o+TVXLfkzPUuleY0bdrs79U+Mg8aBtvUSWuZLmYz063NBrSUma/+2UKEbTVU5PLho Y8KvGHq5jeM2ylmoh0YUj2jEvTimOr1zMKHalHwz8j/Ot9e8+uXG Received: from YEHS1XR956R00D1.lenovo.com (114.246.209.104 [114.246.209.104]) by mx.zohomail.com with SMTPS id 1530686491031778.8665211216824; Tue, 3 Jul 2018 23:41:31 -0700 (PDT) From: Huaisheng Ye To: linux-nvdimm@lists.01.org Cc: dan.j.williams@intel.com, ross.zwisler@linux.intel.com, mawilcox@microsoft.com, vishal.l.verma@intel.com, dave.jiang@intel.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, viro@zeniv.linux.org.uk, martin.petersen@oracle.com, axboe@kernel.dk, gregkh@linuxfoundation.org, bart.vanassche@wdc.com, jack@suse.com, chengnt@lenovo.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, Huaisheng Ye Subject: [PATCH 2/3] drivers/s390/block/dcssblk: check the validity of the pointer pfn Date: Wed, 4 Jul 2018 14:40:57 +0800 Message-Id: <20180704064058.1344-2-yehs2007@zoho.com> X-Mailer: git-send-email 2.17.0.windows.1 In-Reply-To: <20180704064058.1344-1-yehs2007@zoho.com> References: <20180704064058.1344-1-yehs2007@zoho.com> X-ZohoMailClient: External Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Huaisheng Ye Some functions within fs/dax don't need to get gfn from direct_access. Assigning NULL to gfn of dax_direct_access is more intuitive and simple than offering a useless local variable. So direct_access needs to check validity of the pointer pfn For NULL assignment. If pfn equals to NULL, it doesn't need to calculate its value. Signed-off-by: Huaisheng Ye --- drivers/s390/block/dcssblk.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index 0a312e4..5cdfa02 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -916,7 +916,8 @@ static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show, 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), + if (pfn) + *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), PFN_DEV|PFN_SPECIAL); return (dev_sz - offset) / PAGE_SIZE; -- 1.8.3.1