mm: thp: correct split_huge_pages file permission

split_huge_pages doesn't support get method at all, so the read
permission sounds confusing, change the permission to write only.

And, add "\n" to the output of set method to make it more readable.

Signed-off-by: Yang Shi <yang.shi@linaro.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index df67b53..f7daa7d 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3452,7 +3452,7 @@
 		}
 	}
 
-	pr_info("%lu of %lu THP split", split, total);
+	pr_info("%lu of %lu THP split\n", split, total);
 
 	return 0;
 }
@@ -3463,7 +3463,7 @@
 {
 	void *ret;
 
-	ret = debugfs_create_file("split_huge_pages", 0644, NULL, NULL,
+	ret = debugfs_create_file("split_huge_pages", 0200, NULL, NULL,
 			&split_huge_pages_fops);
 	if (!ret)
 		pr_warn("Failed to create split_huge_pages in debugfs");