mm/memory_hotplug: skip adjust_managed_page_count() for PageOffline() pages when offlining

We currently have a hack for virtio-mem in place to handle memory
offlining with PageOffline pages for which we already adjusted the managed
page count.

Let's enlighten memory offlining code so we can get rid of that hack, and
document the situation.

Link: https://lkml.kernel.org/r/20240607090939.89524-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Marco Elver <elver@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 7a9ff464608d..ebe876930e78 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -175,8 +175,8 @@ extern int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages,
 extern void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages);
 extern int online_pages(unsigned long pfn, unsigned long nr_pages,
 			struct zone *zone, struct memory_group *group);
-extern void __offline_isolated_pages(unsigned long start_pfn,
-				     unsigned long end_pfn);
+extern unsigned long __offline_isolated_pages(unsigned long start_pfn,
+		unsigned long end_pfn);
 
 typedef void (*online_page_callback_t)(struct page *page, unsigned int order);