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Date:   Fri, 5 Aug 2022 09:06:09 -0300
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Alistair Popple <apopple@nvidia.com>
Cc:     linux-mm@kvack.org, akpm@linux-foundation.org,
        linux-kernel@vger.kernel.org,
        "Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>,
        Chaitanya Kulkarni <kch@nvidia.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Felix Kuehling <Felix.Kuehling@amd.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Muchun Song <songmuchun@bytedance.com>,
        Ralph Campbell <rcampbell@nvidia.com>,
        David Hildenbrand <david@redhat.com>
Subject: Re: [PATCH v2 1/2] mm/gup.c: Don't pass gup_flags to
 check_and_migrate_movable_pages()
Message-ID: <Yu0HsWC09OCgiDmd@nvidia.com>
References: <3e20a542e756bbc0f66435c9344ff674f3ff7ac7.1659680600.git-series.apopple@nvidia.com>
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On Fri, Aug 05, 2022 at 04:29:52PM +1000, Alistair Popple wrote:
> @@ -2053,7 +2046,9 @@ static long __gup_longterm_locked(struct mm_struct *mm,
>  					     NULL, gup_flags);
>  		if (rc <= 0)
>  			break;
> -		rc = check_and_migrate_movable_pages(rc, pages, gup_flags);
> +
> +		WARN_ON_ONCE(!(gup_flags & FOLL_PIN));
> +		rc = check_and_migrate_movable_pages(rc, pages);

This should be moved up:

	if (!(gup_flags & FOLL_LONGTERM))
		return __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
					       NULL, gup_flags);
	if (WARN_ON(!(gup_flags & FOLL_PIN)))
	   return  -EINVAL;
	flags = memalloc_pin_save();

Jason