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From:   Jian-Hong Pan <jian-hong@endlessm.com>
To:     David Woodhouse <dwmw2@infradead.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>
Cc:     iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
        linux@endlessm.com, Jian-Hong Pan <jian-hong@endlessm.com>
Subject: [PATCH] iommu/intel-iommu: set as DUMMY_DEVICE_DOMAIN_INFO if no IOMMU
Date:   Mon,  3 Feb 2020 17:10:10 +0800
Message-Id: <20200203091009.196658-1-jian-hong@endlessm.com>
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Sender: linux-kernel-owner@vger.kernel.org
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If the device has no IOMMU, it still invokes iommu_need_mapping during
intel_alloc_coherent. However, iommu_need_mapping can only check the
device is DUMMY_DEVICE_DOMAIN_INFO or not. This patch marks the device
is a DUMMY_DEVICE_DOMAIN_INFO if the device has no IOMMU.

Signed-off-by: Jian-Hong Pan <jian-hong@endlessm.com>
---
 drivers/iommu/intel-iommu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 35a4a3abedc6..878bc986a015 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5612,8 +5612,10 @@ static int intel_iommu_add_device(struct device *dev)
 	int ret;
 
 	iommu = device_to_iommu(dev, &bus, &devfn);
-	if (!iommu)
+	if (!iommu) {
+		dev->archdata.iommu = DUMMY_DEVICE_DOMAIN_INFO;
 		return -ENODEV;
+	}
 
 	iommu_device_link(&iommu->iommu, dev);
 
-- 
2.25.0