mm: drop page_initialized check from get_nid_for_pfn

Commit c04fc586c1a4 ("mm: show node to memory section relationship with
symlinks in sysfs") has added means to export memblock<->node
association into the sysfs.  It has also introduced get_nid_for_pfn
which is a rather confusing counterpart of pfn_to_nid which checks also
whether the pfn page is already initialized (page_initialized).

This is done by checking page::lru != NULL which doesn't make any sense
at all.  Nothing in this path really relies on the lru list being used
or initialized.  Just remove it because this will become a problem with
later patches.

Thanks to Reza Arbab for testing which revealed this to be a problem
(http://lkml.kernel.org/r/[email protected])

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Michal Hocko <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Reza Arbab <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Daniel Kiper <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Igor Mammedov <[email protected]>
Cc: Jerome Glisse <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Tobias Regnery <[email protected]>
Cc: Toshi Kani <[email protected]>
Cc: Vitaly Kuznetsov <[email protected]>
Cc: Xishi Qiu <[email protected]>
Cc: Yasuaki Ishimatsu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 0 insertions, 7 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 0440d95c9b5b..db769d3148b7 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -368,21 +368,14 @@ int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
-#define page_initialized(page)  (page->lru.next)
-
 static int __ref get_nid_for_pfn(unsigned long pfn)
 {
-	struct page *page;
-
 	if (!pfn_valid_within(pfn))
 		return -1;
 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 	if (system_state < SYSTEM_RUNNING)
 		return early_pfn_to_nid(pfn);
 #endif
-	page = pfn_to_page(pfn);
-	if (!page_initialized(page))
-		return -1;
 	return pfn_to_nid(pfn);
 }