From: Don Dutile <ddutile@redhat.com>
Date: Tue, 1 Dec 2009 23:43:16 -0500
Subject: [pci] inte-iommu: alloc_coherent obey coherent_dma_mask
Message-id: <4B15AA14.4020905@redhat.com>
Patchwork-id: 21633
O-Subject: [RHEL5.5 PATCH V2] 5/9: INTEL_IOMMU: obey coherent_dma_mask
	for	alloc_coherent
Bugzilla: 516811 518103
RH-Acked-by: Chris Wright <chrisw@redhat.com>
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>

V2: indent clean up.

BZ 516727.

Backport of following patch from iommu-2.6.32 tree:
     intel-iommu: Obey coherent_dma_mask for alloc_coherent on passthrough
     commit e8bb910d1bbc65e7081e73aab4b3a3dd8630332c

0/9 states build & tests.

Please review & ACK.

- Don
>From 68bd044f448fca7f19779c679894367b053db460 Mon Sep 17 00:00:00 2001
From: Donald Dutile <ddutile@redhat.com>
Date: Mon, 16 Nov 2009 18:13:18 -0500
Subject: [PATCH 5/9]   INTEL_IOMMU: obey coherent_dma_mask for alloc_coherent


diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 9cb7f43..42a596d 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -2783,7 +2783,15 @@ static void *intel_alloc_coherent(struct device *hwdev, size_t size,
 
 	size = PAGE_ALIGN(size);
 	order = get_order(size);
-	flags &= ~(GFP_DMA | GFP_DMA32);
+
+	if (!iommu_no_mapping(hwdev))
+		flags &= ~(GFP_DMA | GFP_DMA32);
+	else if (hwdev->coherent_dma_mask < dma_get_required_mask(hwdev)) {
+		if (hwdev->coherent_dma_mask < DMA_BIT_MASK(32))
+			flags |= GFP_DMA;
+		else
+			flags |= GFP_DMA32;
+	}
 
 	vaddr = (void *)__get_free_pages(flags, order);
 	if (!vaddr)