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> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> --- 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 b53596ad601b..d4cb5281b30e 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