[PATCH v2 2/4] nvdimm/pmem-dax: check the validity of the pointer pfn

From: Huaisheng Ye
Date: Wed Jul 04 2018 - 12:42:53 EST


From: Huaisheng Ye <yehs1@xxxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Huaisheng Ye <yehs1@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
---
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