drivers/base/node: consolidate node device subsystem initialization in node_dev_init()

...  and call node_dev_init() after memory_dev_init() from driver_init(),
so before any of the existing arch/subsys calls.  All online nodes should
be known at that point: early during boot, arch code determines node and
zone ranges and sets the relevant nodes online; usually this happens in
setup_arch().

This is in line with memory_dev_init(), which initializes the memory
device subsystem and creates all memory block devices.

Similar to memory_dev_init(), panic() if anything goes wrong, we don't
want to continue with such basic initialization errors.

The important part is that node_dev_init() gets called after
memory_dev_init() and after cpu_dev_init(), but before any of the relevant
archs call register_cpu() to register the new cpu device under the node
device.  The latter should be the case for the current users of
topology_init().

Link: https://lkml.kernel.org/r/20220203105212.30385-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Anatoly Pugachev <matorola@gmail.com> (sparc64)
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 18 insertions, 13 deletions

diff --git a/drivers/base/init.c b/drivers/base/init.c
index a9f57c22fb9e..d8d0fe687111 100644
--- a/drivers/base/init.c
+++ b/drivers/base/init.c
@@ -35,5 +35,6 @@ void __init driver_init(void)
 	auxiliary_bus_init();
 	cpu_dev_init();
 	memory_dev_init();
+	node_dev_init();
 	container_dev_init();
 }
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 87acc47e8951..a133981a12fc 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -1065,26 +1065,30 @@ static const struct attribute_group *cpu_root_attr_groups[] = {
 };
 
 #define NODE_CALLBACK_PRI	2	/* lower than SLAB */
-static int __init register_node_type(void)
+void __init node_dev_init(void)
 {
-	int ret;
+	static struct notifier_block node_memory_callback_nb = {
+		.notifier_call = node_memory_callback,
+		.priority = NODE_CALLBACK_PRI,
+	};
+	int ret, i;
 
  	BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
  	BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
 
 	ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
-	if (!ret) {
-		static struct notifier_block node_memory_callback_nb = {
-			.notifier_call = node_memory_callback,
-			.priority = NODE_CALLBACK_PRI,
-		};
-		register_hotmemory_notifier(&node_memory_callback_nb);
-	}
+	if (ret)
+		panic("%s() failed to register subsystem: %d\n", __func__, ret);
+
+	register_hotmemory_notifier(&node_memory_callback_nb);
 
 	/*
-	 * Note:  we're not going to unregister the node class if we fail
-	 * to register the node state class attribute files.
+	 * Create all node devices, which will properly link the node
+	 * to applicable memory block devices and already created cpu devices.
 	 */
-	return ret;
+	for_each_online_node(i) {
+		ret = register_one_node(i);
+		if (ret)
+			panic("%s() failed to add node: %d\n", __func__, ret);
+	}
 }
-postcore_initcall(register_node_type);