kmemcheck: move hook into __alloc_pages_nodemask() for the page allocator

Now kmemcheck_pagealloc_alloc() is only called by __alloc_pages_slowpath().
__alloc_pages_nodemask()
	__alloc_pages_slowpath()
		kmemcheck_pagealloc_alloc()

And the page will not be tracked by kmemcheck in the following path.
__alloc_pages_nodemask()
	get_page_from_freelist()

So move kmemcheck_pagealloc_alloc() into __alloc_pages_nodemask(),
like this:
__alloc_pages_nodemask()
	...
	get_page_from_freelist()
	if (!page)
		__alloc_pages_slowpath()
	kmemcheck_pagealloc_alloc()
	...
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -2842,11 +2842,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 
 nopage:
 	warn_alloc_failed(gfp_mask, order, NULL);
-	return page;
 got_pg:
-	if (kmemcheck_enabled)
-		kmemcheck_pagealloc_alloc(page, order, gfp_mask);
-
 	return page;
 }
 
@@ -2916,6 +2912,9 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
 				preferred_zone, classzone_idx, migratetype);
 	}
 
+	if (kmemcheck_enabled && page)
+		kmemcheck_pagealloc_alloc(page, order, gfp_mask);
+
 	trace_mm_page_alloc(page, order, alloc_mask, migratetype);
 
 out: