From: Michal Hocko <mhocko@xxxxxxxx>
Subject: mm: drop page_initialized check from get_nid_for_pfn
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@xxxxxxxxxxxxxx)
Link: http://lkml.kernel.org/r/20170515085827.16474-4-mhocko@xxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Igor Mammedov <imammedo@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Joonsoo Kim <js1304@xxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Tobias Regnery <tobias.regnery@xxxxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/node.c | 7 -------
1 file changed, 7 deletions(-)
diff -puN drivers/base/node.c~mm-drop-page_initialized-check-from-get_nid_for_pfn drivers/base/node.c
--- a/drivers/base/node.c~mm-drop-page_initialized-check-from-get_nid_for_pfn
+++ a/drivers/base/node.c
@@ -368,21 +368,14 @@ int unregister_cpu_under_node(unsigned i
}
#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);
}
_
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