[PATCH] mm/migrate: fix migrate_pgmap_owner w/o CONFIG_MMU_NOTIFIER

[Ralph Campbell]

On x86_64, when CONFIG_MMU_NOTIFIER is not set/enabled, there is a
compiler error:

../mm/migrate.c: In function 'migrate_vma_collect':
../mm/migrate.c:2481:7: error: 'struct mmu_notifier_range' has no member
named 'migrate_pgmap_owner'
  range.migrate_pgmap_owner = migrate->pgmap_owner;
       ^

Fixes: 998427b3ad2c ("mm/notifier: add migration invalidation type")
Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
---

This is based on the latest linux and is for Andrew Morton's mm tree.
MMU_NOTIFIER is selected automatically by a number of other config
options so I missed this in my own testing. Thanks to Randy Dunlap for
finding it.

 include/linux/mmu_notifier.h | 13 +++++++++++++
 mm/migrate.c                 |  6 +++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index c6f0708195cd..b8200782dede 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -521,6 +521,16 @@ static inline void mmu_notifier_range_init(struct mmu_notifier_range *range,
 	range->flags = flags;
 }
 
+static inline void mmu_notifier_range_init_migrate(
+			struct mmu_notifier_range *range, unsigned int flags,
+			struct vm_area_struct *vma, struct mm_struct *mm,
+			unsigned long start, unsigned long end, void *pgmap)
+{
+	mmu_notifier_range_init(range, MMU_NOTIFY_MIGRATE, flags, vma, mm,
+				start, end);
+	range->migrate_pgmap_owner = pgmap;
+}
+
 #define ptep_clear_flush_young_notify(__vma, __address, __ptep)		\
 ({									\
 	int __young;							\
@@ -645,6 +655,9 @@ static inline void _mmu_notifier_range_init(struct mmu_notifier_range *range,
 
 #define mmu_notifier_range_init(range,event,flags,vma,mm,start,end)  \
 	_mmu_notifier_range_init(range, start, end)
+#define mmu_notifier_range_init_migrate(range, flags, vma, mm, start, end, \
+					pgmap) \
+	_mmu_notifier_range_init(range, start, end)
 
 static inline bool
 mmu_notifier_range_blockable(const struct mmu_notifier_range *range)
diff --git a/mm/migrate.c b/mm/migrate.c
index 4fcc465736ff..d179657f8685 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2386,9 +2386,9 @@ static void migrate_vma_collect(struct migrate_vma *migrate)
 	 * that the registered device driver can skip invalidating device
 	 * private page mappings that won't be migrated.
 	 */
-	mmu_notifier_range_init(&range, MMU_NOTIFY_MIGRATE, 0, migrate->vma,
-			migrate->vma->vm_mm, migrate->start, migrate->end);
-	range.migrate_pgmap_owner = migrate->pgmap_owner;
+	mmu_notifier_range_init_migrate(&range, 0, migrate->vma,
+		migrate->vma->vm_mm, migrate->start, migrate->end,
+		migrate->pgmap_owner);
 	mmu_notifier_invalidate_range_start(&range);
 
 	walk_page_range(migrate->vma->vm_mm, migrate->start, migrate->end,
-- 
2.20.1