[PATCH v2 1/5] mm/memory_hotplug: handle memblock_add_node() failures in add_memory_resource()

David Hildenbrand
2021-10-04T09:36:31Z

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.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
mm/memory_hotplug.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 9fd0be32a281..917b3528636d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1384,8 +1384,11 @@ 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)
@@ -1458,6 +1461,7 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
rollback_node_hotadd(nid);
if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
memblock_remove(start, size);
+error_mem_hotplug_end:
mem_hotplug_done();
return ret;
}
--
2.31.1