mm/hwpoison-inject: check PageLRU of hpage

Hwpoison injector checks PageLRU of the raw target page to find out
whether the page is an appropriate target, but current code now filters
out thp tail pages, which prevents us from testing for such cases via this
interface.  So let's check hpage instead of p.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Dean Nelson <dnelson@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hwpoison-inject.c

@@ -34,12 +34,12 @@ static int hwpoison_inject(void *data, u64 val)
 	if (!hwpoison_filter_enable)
 		goto inject;
 
-	if (!PageLRU(p) && !PageHuge(p))
-		shake_page(p, 0);
+	if (!PageLRU(hpage) && !PageHuge(p))
+		shake_page(hpage, 0);
 	/*
 	 * This implies unable to support non-LRU pages.
 	 */
-	if (!PageLRU(p) && !PageHuge(p))
+	if (!PageLRU(hpage) && !PageHuge(p))
 		goto put_out;
 
 	/*