mm, soft-offline: convert parameter to pfn

Currently soft_offline_page() receives struct page, and its sibling
memory_failure() receives pfn.  This discrepancy looks weird and makes
precheck on pfn validity tricky.  So let's align them.

Link: http://lkml.kernel.org/r/20191016234706.GA5493@www9186uo.sakura.ne.jp
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 84c4e1f7..d65ecde 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -538,12 +538,7 @@ static ssize_t soft_offline_page_store(struct device *dev,
 	if (kstrtoull(buf, 0, &pfn) < 0)
 		return -EINVAL;
 	pfn >>= PAGE_SHIFT;
-	if (!pfn_valid(pfn))
-		return -ENXIO;
-	/* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */
-	if (!pfn_to_online_page(pfn))
-		return -EIO;
-	ret = soft_offline_page(pfn_to_page(pfn), 0);
+	ret = soft_offline_page(pfn, 0);
 	return ret == 0 ? count : ret;
 }