Resending the patch adding linux-acpi in CC, as suggested by Rafael.
Everyone else: apologies for the noise.

Commit 242831eb15a0 ("Memory hotplug / ACPI: Simplify memory removal")
introduced an assumption whereas when control
reaches remove_memory the corresponding memory has been already
offlined. In that case, the acpi_memhotplug was making sure that
the assumption held.
This assumption, however, is not necessarily true if offlining
and removal are not done by the same "controller" (for example,
when first offlining via sysfs).

Removing this assumption for the generic remove_memory code
and moving it in the specific acpi_memhotplug code. This is
a dependency for the software-aided arm64 offlining and removal
process.

Signed-off-by: Andrea Reale <redacted>
Signed-off-by: Maciej Bielski <redacted>
---
 drivers/acpi/acpi_memhotplug.c |  2 +-
 include/linux/memory_hotplug.h |  9 ++++++---
 mm/memory_hotplug.c            | 13 +++++++++----
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 6b0d3ef..b0126a0 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c

@@ -282,7 +282,7 @@ static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
                        nid = memory_add_physaddr_to_nid(info->start_addr);

                acpi_unbind_memory_blocks(info);
-               remove_memory(nid, info->start_addr, info->length);
+               BUG_ON(remove_memory(nid, info->start_addr, info->length));