[PATCH V1 1/5] vfio: maintain dma_list order

[Steve Sistare <steven.sistare@oracle.com>]

Keep entries properly sorted in the dma_list rb_tree so that iterating
over multiple entries across a range with gaps works, without requiring
one to delete each visited entry as in vfio_dma_do_unmap.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 drivers/vfio/vfio_iommu_type1.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 5fbf0c1..02228d0 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -157,20 +157,24 @@ static struct vfio_group *vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
 static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu,
 				      dma_addr_t start, size_t size)
 {
+	struct vfio_dma *res = 0;
 	struct rb_node *node = iommu->dma_list.rb_node;
 
 	while (node) {
 		struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
 
-		if (start + size <= dma->iova)
+		if (start < dma->iova + dma->size) {
+			res = dma;
+			if (start >= dma->iova)
+				break;
 			node = node->rb_left;
-		else if (start >= dma->iova + dma->size)
+		} else {
 			node = node->rb_right;
-		else
-			return dma;
+		}
 	}
-
-	return NULL;
+	if (res && size && res->iova >= start + size)
+		res = 0;
+	return res;
 }
 
 static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
@@ -182,7 +186,7 @@ static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
 		parent = *link;
 		dma = rb_entry(parent, struct vfio_dma, node);
 
-		if (new->iova + new->size <= dma->iova)
+		if (new->iova < dma->iova)
 			link = &(*link)->rb_left;
 		else
 			link = &(*link)->rb_right;
-- 
1.8.3.1