Patch "arm64: dma-mapping: Only swizzle DMA ops for IOMMU_DOMAIN_DMA" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

arm64: dma-mapping: Only swizzle DMA ops for IOMMU_DOMAIN_DMA

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm64-dma-mapping-only-swizzle-dma-ops-for-iommu_domain_dma.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Will Deacon <[email protected]>
Date: Fri, 6 Jan 2017 10:49:12 +0000
Subject: arm64: dma-mapping: Only swizzle DMA ops for IOMMU_DOMAIN_DMA

From: Will Deacon <[email protected]>

[ Upstream commit 4a8d8a14c0d08c2437cb80c05e88f6cc1ca3fb2c ]

The arm64 DMA-mapping implementation sets the DMA ops to the IOMMU DMA ops if we detect that an IOMMU is present for the master and the DMA ranges are valid.

In the case when the IOMMU domain for the device is not of type IOMMU_DOMAIN_DMA, then we have no business swizzling the ops, since we're not in control of the underlying address space. This patch leaves the DMA ops alone for masters attached to non-DMA IOMMU domains.

---
 arch/arm64/mm/dma-mapping.c |   17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

@@ -836,14 +836,21 @@ static bool do_iommu_attach(struct devic
 	 * then the IOMMU core will have already configured a group for this
 	 * device, and allocated the default domain for that group.
 	 */
-	if (!domain || iommu_dma_init_domain(domain, dma_base, size, dev)) {
-		pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
-			dev_name(dev));
-		return false;
+	if (!domain)
+		goto out_err;
+
+	if (domain->type == IOMMU_DOMAIN_DMA) {
+		if (iommu_dma_init_domain(domain, dma_base, size, dev))
+			goto out_err;
+
+		dev->archdata.dma_ops = &iommu_dma_ops;
 	}
 
-	dev->archdata.dma_ops = &iommu_dma_ops;
 	return true;
+out_err:
+	pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
+		 dev_name(dev));
+	return false;
 }
 
 static void queue_iommu_attach(struct device *dev, const struct iommu_ops *ops,

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/iommu-arm-smmu-v3-clear-prior-settings-when-updating-stes.patch queue-4.9/arm64-dma-mapping-only-swizzle-dma-ops-for-iommu_domain_dma.patch