From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Huaisheng Ye Subject: [PATCH v2 3/4] s390/block/dcssblk: check the validity of the pointer pfn Date: Thu, 5 Jul 2018 00:38:22 +0800 Message-Id: <20180704163823.9980-4-yehs2007@zoho.com> In-Reply-To: <20180704163823.9980-1-yehs2007@zoho.com> References: <20180704163823.9980-1-yehs2007@zoho.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Archive: List-Post: To: linux-nvdimm@lists.01.org, dan.j.williams@intel.com Cc: ross.zwisler@linux.intel.com, willy@infradead.org, 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, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, colyli@suse.de, chengnt@lenovo.com, Huaisheng Ye List-ID: 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 --- 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