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Date:   Thu, 1 Aug 2019 18:34:53 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Christoph Hellwig <hch@lst.de>, john.hubbard@gmail.com,
        Andrew Morton <akpm@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Christian Benvenuti <benve@cisco.com>,
        Christoph Hellwig <hch@infradead.org>,
        Dan Williams <dan.j.williams@intel.com>,
        "Darrick J . Wong" <darrick.wong@oracle.com>,
        Dave Chinner <david@fromorbit.com>,
        Ira Weiny <ira.weiny@intel.com>, Jan Kara <jack@suse.cz>,
        Jens Axboe <axboe@kernel.dk>,
        Jerome Glisse <jglisse@redhat.com>,
        "Kirill A . Shutemov" <kirill@shutemov.name>,
        Matthew Wilcox <willy@infradead.org>,
        Michal Hocko <mhocko@kernel.org>,
        Mike Marciniszyn <mike.marciniszyn@intel.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
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        linux-mm@kvack.org, linux-xfs@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        John Hubbard <jhubbard@nvidia.com>
Subject: Re: [PATCH v4 1/3] mm/gup: add make_dirty arg to
 put_user_pages_dirty_lock()
Message-ID: <20190801163453.GA26588@lst.de>
References: <20190730205705.9018-1-jhubbard@nvidia.com> <20190730205705.9018-2-jhubbard@nvidia.com> <20190801060755.GA14893@lst.de> <20190801141906.GC23899@ziepe.ca>
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On Thu, Aug 01, 2019 at 11:19:06AM -0300, Jason Gunthorpe wrote:
> Sadly usnic does not use the core rdma umem abstraction but open codes
> an old version of it.
> 
> In this version each sge in the sgl is exactly one page. See
> usnic_uiom_get_pages - so I think this loop is not a bug?

Actually, yes - I think we are fine given that we pass in the number
of elements.  Thus merging by iommus won't affect the list.