mm/memory_hotplug: handle memblock_add_node() failures in add_memory_resource()

Patch series "mm/memory_hotplug: full support for add_memory_driver_managed() with CONFIG_ARCH_KEEP_MEMBLOCK", v2.

Architectures that require CONFIG_ARCH_KEEP_MEMBLOCK=y, such as arm64,
don't cleanly support add_memory_driver_managed() yet.  Most
prominently, kexec_file can still end up placing kexec images on such
driver-managed memory, resulting in undesired behavior, for example,
having kexec images located on memory not part of the firmware-provided
memory map.

Teaching kexec to not place images on driver-managed memory is
especially relevant for virtio-mem.  Details can be found in commit
7b7b27214bba ("mm/memory_hotplug: introduce
add_memory_driver_managed()").

Extend memblock with a new flag and set it from memory hotplug code when
applicable.  This is required to fully support virtio-mem on arm64,
making also kexec_file behave like on x86-64.

This patch (of 2):

If memblock_add_node() fails, we're most probably running out of memory.
While this is unlikely to happen, it can happen and having memory added
without a memblock can be problematic for architectures that use
memblock to detect valid memory.  Let's fail in a nice way instead of
silently ignoring the error.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Jianyong Wu <[email protected]>
Cc: "Aneesh Kumar K . V" <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: Jiaxun Yang <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Eric Biederman <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Shahab Vahedi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 6 insertions, 2 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0aa7ca3dfbc9..9d254e88221e 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1369,8 +1369,11 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
 
 	mem_hotplug_begin();
 
-	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
-		memblock_add_node(start, size, nid);
+	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
+		ret = memblock_add_node(start, size, nid);
+		if (ret)
+			goto error_mem_hotplug_end;
+	}
 
 	ret = __try_online_node(nid, false);
 	if (ret < 0)
@@ -1443,6 +1446,7 @@ error:
 		rollback_node_hotadd(nid);
 	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
 		memblock_remove(start, size);
+error_mem_hotplug_end:
 	mem_hotplug_done();
 	return ret;
 }