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Date:   Thu, 14 Nov 2019 10:24:09 -0400
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     Ralph Campbell <rcampbell@nvidia.com>
Cc:     Jerome Glisse <jglisse@redhat.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Christoph Hellwig <hch@lst.de>, Shuah Khan <shuah@kernel.org>,
        linux-rdma@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v4 1/2] mm/hmm: make full use of walk_page_range()
Message-ID: <20191114142409.GA785@ziepe.ca>
References: <20191104222141.5173-1-rcampbell@nvidia.com>
 <20191104222141.5173-2-rcampbell@nvidia.com>
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On Mon, Nov 04, 2019 at 02:21:40PM -0800, Ralph Campbell wrote:
> hmm_range_fault() calls find_vma() and walk_page_range() in a loop.
> This is unnecessary duplication since walk_page_range() calls find_vma()
> in a loop already.
> Simplify hmm_range_fault() by defining a walk_test() callback function
> to filter unhandled vmas.
> This also fixes a bug where hmm_range_fault() was not checking
> start >= vma->vm_start before checking vma->vm_flags so hmm_range_fault()
> could return an error based on the wrong vma for the requested range.
> It also fixes a bug when the vma has no read access and the caller did
> not request a fault, there shouldn't be any error return code.
> 
> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
> Cc: "Jérôme Glisse" <jglisse@redhat.com>
> Cc: Jason Gunthorpe <jgg@mellanox.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>  mm/hmm.c | 121 ++++++++++++++++++++++++++-----------------------------
>  1 file changed, 58 insertions(+), 63 deletions(-)

Applied to hmm.git with Christoph's hunk merged in

Thanks,
Jason