tools/testing/nvdimm: kaddr and pfn can be NULL to ->direct_access()

[ Upstream commit 45df5d3dc0c7289c1e67afe6d2ba806ad5174314 ]

The mock / test version of pmem_direct_access() needs to check the
validity of pointers kaddr and pfn for NULL assignment. If anyone
equals to NULL, it doesn't need to calculate the value.

If pointer equals to NULL, that is to say callers may have no need for
kaddr or pfn, so this patch is prepared for allowing them to pass in
NULL instead of having to pass in a local pointer or variable that
they then just throw away.

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/testing/nvdimm/pmem-dax.c b/tools/testing/nvdimm/pmem-dax.c
index b53596ad601bb4964231c58151308f61221868f5..2e7fd822796911c2875a1dad87dca67fe185d589 100644 (file)
--- a/tools/testing/nvdimm/pmem-dax.c
+++ b/tools/testing/nvdimm/pmem-dax.c
@@ -31,17 +31,21 @@ long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
        if (get_nfit_res(pmem->phys_addr + offset)) {
                struct page *page;
 
-               *kaddr = pmem->virt_addr + offset;
+               if (kaddr)
+                       *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));
 
                return 1;
        }
 
-       *kaddr = pmem->virt_addr + offset;
-       *pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
+       if (kaddr)
+               *kaddr = pmem->virt_addr + offset;
+       if (pfn)
+               *pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
 
        /*
         * If badblocks are present, limit known good range to the