From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id 710316B0273 for ; Thu, 5 Jul 2018 02:59:45 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id a12-v6so4261482pfn.12 for ; Wed, 04 Jul 2018 23:59:45 -0700 (PDT) Received: from mga05.intel.com (mga05.intel.com. [192.55.52.43]) by mx.google.com with ESMTPS id j135-v6si6084553pfd.207.2018.07.04.23.59.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 04 Jul 2018 23:59:43 -0700 (PDT) Subject: [PATCH 08/13] s390/block/dcssblk: check the validity of the pointer pfn From: Dan Williams Date: Wed, 04 Jul 2018 23:49:45 -0700 Message-ID: <153077338570.40830.10517740093746798315.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <153077334130.40830.2714147692560185329.stgit@dwillia2-desk3.amr.corp.intel.com> References: <153077334130.40830.2714147692560185329.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: Huaisheng Ye , Jan Kara , vishal.l.verma@intel.com, hch@lst.de, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org From: Huaisheng Ye direct_access needs to check the validity of pointer pfn for NULL assignment. If pfn equals to NULL, it doesn't need to calculate the value. Signed-off-by: Huaisheng Ye Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- drivers/s390/block/dcssblk.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index ed607288e696..a645b2c93c34 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -923,8 +923,9 @@ __dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff, 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 (pfn) + *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), + PFN_DEV|PFN_SPECIAL); return (dev_sz - offset) / PAGE_SIZE; }