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From:   Huaisheng Ye <yehs2007@zoho.com>
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,
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        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 <yehs1@lenovo.com>
Subject: [PATCH 1/3] nvdimm/pmem: check the validity of the pointer pfn
Date:   Wed,  4 Jul 2018 14:40:56 +0800
Message-Id: <20180704064058.1344-1-yehs2007@zoho.com>
Sender: linux-kernel-owner@vger.kernel.org
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From: Huaisheng Ye <yehs1@lenovo.com>

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.

Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
---
 drivers/nvdimm/pmem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 9d71492..018f990 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -233,7 +233,8 @@ __weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
 					PFN_PHYS(nr_pages))))
 		return -EIO;
 	*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