linux-kernel - Re: [PATCH 2/4] blk-mq-dma: unify DMA unmap routine

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Message-ID: <aO1Ku5DCIMVRirdu@kbusch-mbp>
Date: Mon, 13 Oct 2025 12:53:47 -0600
From: Keith Busch <kbusch@...nel.org>
To: Leon Romanovsky <leon@...nel.org>
Cc: Christoph Hellwig <hch@....de>, Jens Axboe <axboe@...nel.dk>,
	Leon Romanovsky <leonro@...dia.com>,
	Jason Gunthorpe <jgg@...dia.com>, linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-nvme@...ts.infradead.org,
	Sagi Grimberg <sagi@...mberg.me>
Subject: Re: [PATCH 2/4] blk-mq-dma: unify DMA unmap routine

On Mon, Oct 13, 2025 at 06:34:10PM +0300, Leon Romanovsky wrote:
> +bool blk_rq_dma_unmap(struct request *req, struct device *dma_dev,
> +		struct dma_iova_state *state, size_t mapped_len)
> +{
> +	struct bio_integrity_payload *bip = bio_integrity(req->bio);
> +
> +	if ((!bip && req->cmd_flags & REQ_P2PDMA) ||
> +	    bio_integrity_flagged(req->bio, BIP_P2P_DMA))
> +		return true;

I don't think you can unify it at this part here because the data
payload might not be P2P but the integrity payload could be. The data
payload needs to proceed to the next unmapping step in that case, but
this change would have it return true early.