Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 6 May 2019 23:40:00 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Tom Murphy <tmurphy@arista.com>
Cc:     iommu@lists.linux-foundation.org, murphyt7@tcd.ie,
        Joerg Roedel <joro@8bytes.org>,
        Will Deacon <will.deacon@arm.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Kukjin Kim <kgene@kernel.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Andy Gross <andy.gross@linaro.org>,
        David Brown <david.brown@linaro.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Rob Clark <robdclark@gmail.com>,
        Heiko Stuebner <heiko@sntech.de>,
        Gerald Schaefer <gerald.schaefer@de.ibm.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-mediatek@lists.infradead.org,
        linux-rockchip@lists.infradead.org, linux-s390@vger.kernel.org,
        linux-tegra@vger.kernel.org
Subject: Re: [PATCH v3 2/4] iommu/dma-iommu: Handle deferred devices
Message-ID: <20190507064000.GB5173@infradead.org>
References: <20190506185207.31069-1-tmurphy@arista.com>
 <20190506185207.31069-3-tmurphy@arista.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190506185207.31069-3-tmurphy@arista.com>
User-Agent: Mutt/1.9.2 (2017-12-15)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, May 06, 2019 at 07:52:04PM +0100, Tom Murphy wrote:
> +static int handle_deferred_device(struct device *dev)
> +{
> +	struct iommu_domain *domain;
> +	const struct iommu_ops *ops;
> +
> +	if (!is_kdump_kernel())
> +		return 0;
> +
> +	domain = iommu_get_domain_for_dev(dev);

> -	dma_handle =__iommu_dma_map(dev, phys, size,
> +	if (unlikely(handle_deferred_device(dev)))
> +		return DMA_MAPPING_ERROR;
> +
> +	dma_handle = __iommu_dma_map(dev, phys, size,

__iommu_dma_map already looks up the domain, and as far as I can
tell all callers need the handle_deferred_device call.  Should we
just move it to there and pass the domain from the caller?

Also shouldn't the iommu_attach_device call inside
handle_deferred_device also get an unlikely marker?