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From:   David Howells <dhowells@redhat.com>
In-Reply-To: <0d62615c-57d1-922b-5ebc-32faabf33327@deltatee.com>
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To:     Logan Gunthorpe <logang@deltatee.com>
Cc:     dhowells@redhat.com, Al Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@lst.de>,
        John Hubbard <jhubbard@nvidia.com>,
        Matthew Wilcox <willy@infradead.org>,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        Christoph Hellwig <hch@infradead.org>,
        Jeff Layton <jlayton@kernel.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/4] iov_iter: Add a function to extract a page list from an iterator
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Date:   Tue, 06 Dec 2022 18:35:37 +0000
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Logan Gunthorpe <logang@deltatee.com> wrote:

> If this is going to be a general replacement for iov_iter_get_pages()
> it's going to need to pass through gup_flags. My recent patchset added
> versions with these and I think it should be in during the next merge
> cycle. [1]

Cool.  Note that the current iov_iter_get_pages2() is broken, which is why Al
wanted a replacement.  It should not be taking a ref on the pages in an
XARRAY, BVEC or PIPE - and it should be pinning rather than getting a ref on
pages in IOVEC or UBUF if the buffer is being read into.  I'm guessing that
your changes move the latter decision to the caller?

David