Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
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=pe3AQ64VZyPotaj6urt89BPFozhAbjCWcLgYMM34sjLwMSwBd6dHREGcuUQoiBa6BgLcQ9zSuLUl
    GMh6savCxP5/WyOfp8rA4HzsuMvS4fEWzBXG7gKOIhdg17lVnd31  
From:   Huaisheng Ye <yehs2007@zoho.com>
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 <yehs1@lenovo.com>
Subject: [PATCH v2 2/4] nvdimm/pmem-dax: check the validity of the pointer pfn
Date:   Thu,  5 Jul 2018 00:38:21 +0800
Message-Id: <20180704163823.9980-3-yehs2007@zoho.com>
In-Reply-To: <20180704163823.9980-1-yehs2007@zoho.com>
References: <20180704163823.9980-1-yehs2007@zoho.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Huaisheng Ye <yehs1@lenovo.com>

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.

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 tools/testing/nvdimm/pmem-dax.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/testing/nvdimm/pmem-dax.c b/tools/testing/nvdimm/pmem-dax.c
index b53596a..d4cb528 100644
--- a/tools/testing/nvdimm/pmem-dax.c
+++ b/tools/testing/nvdimm/pmem-dax.c
@@ -33,7 +33,8 @@ long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
 
 		*kaddr = pmem->virt_addr + offset;
 		page = vmalloc_to_page(pmem->virt_addr + offset);
-		*pfn = page_to_pfn_t(page);
+		if (pfn)
+			*pfn = page_to_pfn_t(page);
 		pr_debug_ratelimited("%s: pmem: %p pgoff: %#lx pfn: %#lx\n",
 				__func__, pmem, pgoff, page_to_pfn(page));
 
@@ -41,7 +42,8 @@ long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
 	}
 
 	*kaddr = pmem->virt_addr + offset;
-	*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
+	if (pfn)
+		*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
 
 	/*
 	 * If badblocks are present, limit known good range to the
-- 
1.8.3.1