mm/memory_hotplug: restrict CONFIG_MEMORY_HOTPLUG to 64 bit

32 bit support is broken in various ways: for example, we can online
memory that should actually go to ZONE_HIGHMEM to ZONE_MOVABLE or in
some cases even to one of the other kernel zones.

We marked it BROKEN in commit b59d02ed0869 ("mm/memory_hotplug: disable
the functionality for 32b") almost one year ago.  According to that
commit it might be broken at least since 2017.  Further, there is hardly
a sane use case nowadays.

Let's just depend completely on 64bit, dropping the "BROKEN" dependency
to make clear that we are not going to support it again.  Next, we'll
remove some HIGHMEM leftovers from memory hotplug code to clean up.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
Cc: Alex Shi <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/Kconfig b/mm/Kconfig
index 0148a9c4fa2a3a6dbb4c5399d27d944ef2400955..ae1f151c2924192c5cadd04d58bebfb3c7890de3 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -125,7 +125,7 @@ config MEMORY_HOTPLUG
        select MEMORY_ISOLATION
        depends on SPARSEMEM
        depends on ARCH_ENABLE_MEMORY_HOTPLUG
-       depends on 64BIT || BROKEN
+       depends on 64BIT
        select NUMA_KEEP_MEMINFO if NUMA
 
 config MEMORY_HOTPLUG_DEFAULT_ONLINE