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

From: Randy Dunlap
Date: Thu Aug 06 2020 - 19:40:23 EST


On 8/6/20 12:33 PM, Ralph Campbell wrote:
> 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>

Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> # build-tested

Thanks.


> ---
>
> 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,
>


--
~Randy