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/20170403202337.GA12482@dhcp22.suse.cz)

Link: http://lkml.kernel.org/r/20170515085827.16474-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 0440d95c9b5be421118fd519e360338f042d1531..db769d3148b7487599a7662a8307d0f7017ada32 100644 (file)
--- 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);
 }