mm: name the anonymous MMOP enum as enum mmop

Give the MMOP enum (MMOP_OFFLINE, MMOP_ONLINE, etc) a proper type name so
the compiler can help catch invalid values being assigned to variables of
this type.

Leave the existing functions returning int alone to allow for
value-or-error pattern to remain unchanged without churn.

mmop_default_online_type is left as int because it uses the -1 sentinal
value to signal it hasn't been initialized yet.

Keep the uint8_t buffer in offline_and_remove_memory() as-is for space
efficiency, with an explicit cast when we consume the value.

Move the enum definition before the CONFIG_MEMORY_HOTPLUG guard so it is
unconditionally available for struct memory_block in memory.h.

No functional change.

Link: https://lore.kernel.org/linux-mm/3424eba7-523b-4351-abd0-3a888a3e5e61@kernel.org/
Link: https://lkml.kernel.org/r/20260211215447.2194189-1-gourry@gourry.net
Signed-off-by: Gregory Price <gourry@gourry.net>
Suggested-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Suggested-by: "David Hildenbrand (arm)" <david@kernel.org>
Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 8 insertions, 8 deletions

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index f2f16cdd73ee..e77ef3d7ff73 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -16,11 +16,8 @@ struct resource;
 struct vmem_altmap;
 struct dev_pagemap;
 
-#ifdef CONFIG_MEMORY_HOTPLUG
-struct page *pfn_to_online_page(unsigned long pfn);
-
 /* Types for control the zone type of onlined and offlined memory */
-enum {
+enum mmop {
 	/* Offline the memory. */
 	MMOP_OFFLINE = 0,
 	/* Online the memory. Zone depends, see default_zone_for_pfn(). */
@@ -31,6 +28,9 @@ enum {
 	MMOP_ONLINE_MOVABLE,
 };
 
+#ifdef CONFIG_MEMORY_HOTPLUG
+struct page *pfn_to_online_page(unsigned long pfn);
+
 /* Flags for add_memory() and friends to specify memory hotplug details. */
 typedef int __bitwise mhp_t;
 
@@ -286,8 +286,8 @@ static inline void __remove_memory(u64 start, u64 size) {}
 
 #ifdef CONFIG_MEMORY_HOTPLUG
 /* Default online_type (MMOP_*) when new memory blocks are added. */
-extern int mhp_get_default_online_type(void);
-extern void mhp_set_default_online_type(int online_type);
+extern enum mmop mhp_get_default_online_type(void);
+extern void mhp_set_default_online_type(enum mmop online_type);
 extern void __ref free_area_init_core_hotplug(struct pglist_data *pgdat);
 extern int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
 extern int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
@@ -310,8 +310,8 @@ extern void sparse_remove_section(unsigned long pfn, unsigned long nr_pages,
 				  struct vmem_altmap *altmap);
 extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
 					  unsigned long pnum);
-extern struct zone *zone_for_pfn_range(int online_type, int nid,
-		struct memory_group *group, unsigned long start_pfn,
+extern struct zone *zone_for_pfn_range(enum mmop online_type,
+		int nid, struct memory_group *group, unsigned long start_pfn,
 		unsigned long nr_pages);
 extern int arch_create_linear_mapping(int nid, u64 start, u64 size,
 				      struct mhp_params *params);