linux-kernel - Re: [PATCH] mm/migrate: fix migrate_pgmap_owner w/o CONFIG_MMU

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Date:   Thu, 6 Aug 2020 16:39:58 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Ralph Campbell <rcampbell@...dia.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     Jerome Glisse <jglisse@...hat.com>,
        John Hubbard <jhubbard@...dia.com>,
        Christoph Hellwig <hch@....de>,
        Jason Gunthorpe <jgg@...lanox.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] mm/migrate: fix migrate_pgmap_owner w/o
 CONFIG_MMU_NOTIFIER

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@...dia.com>
> Reported-by: Randy Dunlap <rdunlap@...radead.org>

Acked-by: Randy Dunlap <rdunlap@...radead.org> # 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