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Date:   Wed, 30 Jun 2021 09:29:51 +0300
From:   Leon Romanovsky <leon@kernel.org>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Doug Ledford <dledford@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Maor Gottlieb <maorg@nvidia.com>,
        Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
        linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
        Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>,
        Yishai Hadas <yishaih@nvidia.com>,
        Zhu Yanjun <zyjzyj2000@gmail.com>
Subject: Re: [PATCH rdma-next v1 1/2] lib/scatterlist: Fix wrong update of
 orig_nents
Message-ID: <YNwPX7BxPl22En9U@unreal>
References: <cover.1624955710.git.leonro@nvidia.com>
 <dadb01a81e7498f6415233cf19cfc2a0d9b312f2.1624955710.git.leonro@nvidia.com>
 <YNwIL4OguRO/CH6K@infradead.org>
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On Wed, Jun 30, 2021 at 06:59:11AM +0100, Christoph Hellwig wrote:
> On Tue, Jun 29, 2021 at 11:40:01AM +0300, Leon Romanovsky wrote:
> > 2. Add a new field total_nents to reflect the total number of entries
> >    in the table. This is required for the release flow (sg_free_table).
> >    This filed should be used internally only by scatterlist.
> 
> No, please don't bloat the common structure.

Somehow we need to store that total_nents value and our internal
proposal was to wrap sg_table with another private structure that is
visible in lib/scatterlist.c only.

Something like that:
struct sg_table_private {
  struct sg_table table;
  unsigned int total_nents;
};

But it looks awkward.

> 
> > +	/* The fields below should be used internally only by
> > +	 * scatterlist implementation.
> > +	 */
> 
> And this is not the way kernel comments work.

It is netdev style.

Thanks