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/20211004093605.5830-1-david@redhat.com
Link: https://lkml.kernel.org/r/20211004093605.5830-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Jianyong Wu <Jianyong.Wu@arm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Shahab Vahedi <shahab@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0aa7ca3..9d254e8 100644 (file)
--- 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;
 }