1 files changed, 50 insertions, 13 deletions

diff --git a/drivers/pci/iova.c b/drivers/pci/iova.c
index 717fafaa7e0..a84571c2936 100644
--- a/drivers/pci/iova.c
+++ b/drivers/pci/iova.c
@@ -57,12 +57,28 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
 		iovad->cached32_node = rb_next(&free->node);
 }
 
-static int __alloc_iova_range(struct iova_domain *iovad,
-	unsigned long size, unsigned long limit_pfn, struct iova *new)
+/* Computes the padding size required, to make the
+ * the start address naturally aligned on its size
+ */
+static int
+iova_get_pad_size(int size, unsigned int limit_pfn)
+{
+	unsigned int pad_size = 0;
+	unsigned int order = ilog2(size);
+
+	if (order)
+		pad_size = (limit_pfn + 1) % (1 << order);
+
+	return pad_size;
+}
+
+static int __alloc_iova_range(struct iova_domain *iovad, unsigned long size,
+		unsigned long limit_pfn, struct iova *new, bool size_aligned)
 {
 	struct rb_node *curr = NULL;
 	unsigned long flags;
 	unsigned long saved_pfn;
+	unsigned int pad_size = 0;
 
 	/* Walk the tree backwards */
 	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
@@ -72,22 +88,32 @@ static int __alloc_iova_range(struct iova_domain *iovad,
 		struct iova *curr_iova = container_of(curr, struct iova, node);
 		if (limit_pfn < curr_iova->pfn_lo)
 			goto move_left;
-		if (limit_pfn < curr_iova->pfn_hi)
+		else if (limit_pfn < curr_iova->pfn_hi)
 			goto adjust_limit_pfn;
-		if ((curr_iova->pfn_hi + size) <= limit_pfn)
-			break;	/* found a free slot */
+		else {
+			if (size_aligned)
+				pad_size = iova_get_pad_size(size, limit_pfn);
+			if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn)
+				break;	/* found a free slot */
+		}
 adjust_limit_pfn:
 		limit_pfn = curr_iova->pfn_lo - 1;
 move_left:
 		curr = rb_prev(curr);
 	}
 
-	if ((!curr) && !(IOVA_START_PFN + size <= limit_pfn)) {
-		spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
-		return -ENOMEM;
+	if (!curr) {
+		if (size_aligned)
+			pad_size = iova_get_pad_size(size, limit_pfn);
+		if ((IOVA_START_PFN + size + pad_size) > limit_pfn) {
+			spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+			return -ENOMEM;
+		}
 	}
-	new->pfn_hi = limit_pfn;
-	new->pfn_lo = limit_pfn - size + 1;
+
+	/* pfn_lo will point to size aligned address if size_aligned is set */
+	new->pfn_lo = limit_pfn - (size + pad_size) + 1;
+	new->pfn_hi = new->pfn_lo + size - 1;
 
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
 	return 0;
@@ -119,12 +145,16 @@ iova_insert_rbtree(struct rb_root *root, struct iova *iova)
  * @iovad - iova domain in question
  * @size - size of page frames to allocate
  * @limit_pfn - max limit address
+ * @size_aligned - set if size_aligned address range is required
  * This function allocates an iova in the range limit_pfn to IOVA_START_PFN
- * looking from limit_pfn instead from IOVA_START_PFN.
+ * looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned
+ * flag is set then the allocated address iova->pfn_lo will be naturally
+ * aligned on roundup_power_of_two(size).
  */
 struct iova *
 alloc_iova(struct iova_domain *iovad, unsigned long size,
-	unsigned long limit_pfn)
+	unsigned long limit_pfn,
+	bool size_aligned)
 {
 	unsigned long flags;
 	struct iova *new_iova;
@@ -134,8 +164,15 @@ alloc_iova(struct iova_domain *iovad, unsigned long size,
 	if (!new_iova)
 		return NULL;
 
+	/* If size aligned is set then round the size to
+	 * to next power of two.
+	 */
+	if (size_aligned)
+		size = __roundup_pow_of_two(size);
+
 	spin_lock_irqsave(&iovad->iova_alloc_lock, flags);
-	ret = __alloc_iova_range(iovad, size, limit_pfn, new_iova);
+	ret = __alloc_iova_range(iovad, size, limit_pfn, new_iova,
+			size_aligned);
 
 	if (ret) {
 		spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags);