mm/memory_hotplug: drop PageReserved() check in online_pages_range()

move_pfn_range_to_zone() will set all pages to PG_reserved via
memmap_init_zone().  The only way a page could no longer be reserved would
be if a MEM_GOING_ONLINE notifier would clear PG_reserved - which is not
done (the online_page callback is used for that purpose by e.g., Hyper-V
instead).  walk_system_ram_range() will never call online_pages_range()
with duplicate PFNs, so drop the PageReserved() check.

This seems to be a leftover from ancient times where the memmap was
initialized when adding memory and we wanted to check for already onlined
memory.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Arun KS <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Wei Yang <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 1 insertions, 3 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index c28e5dd017ba..c38050785d12 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -653,9 +653,7 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
 {
 	unsigned long onlined_pages = *(unsigned long *)arg;
 
-	if (PageReserved(pfn_to_page(start_pfn)))
-		onlined_pages += online_pages_blocks(start_pfn, nr_pages);
-
+	onlined_pages += online_pages_blocks(start_pfn, nr_pages);
 	online_mem_sections(start_pfn, start_pfn + nr_pages);
 
 	*(unsigned long *)arg = onlined_pages;