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Date:   Wed, 27 Jul 2022 00:10:33 +0100
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Keith Busch <kbusch@fb.com>
Cc:     linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
        io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        axboe@kernel.dk, hch@lst.de, Keith Busch <kbusch@kernel.org>
Subject: Re: [PATCH 2/5] iov_iter: introduce type for preregistered dma tags
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References: <20220726173814.2264573-1-kbusch@fb.com>
 <20220726173814.2264573-3-kbusch@fb.com>
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On Tue, Jul 26, 2022 at 10:38:11AM -0700, Keith Busch wrote:

> +void iov_iter_dma_tag(struct iov_iter *i, unsigned int direction,
> +			void *dma_tag, unsigned int dma_offset,
> +			unsigned long nr_segs, size_t count)
> +{
> +	WARN_ON(direction & ~(READ | WRITE));
> +	*i = (struct iov_iter){
> +		.iter_type = ITER_DMA_TAG,
> +		.data_source = direction,
> +		.nr_segs = nr_segs,

Could you can that cargo-culting?  Just what the hell is nr_segs
here?