5 files changed, 17 insertions, 35 deletions
diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 585574af36ec..1c835b3e1a43 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -1444,18 +1444,13 @@ static int gsi_ring_alloc(struct gsi *gsi, struct gsi_ring *ring, u32 count)
 	dma_addr_t addr;
 
 	/* Hardware requires a 2^n ring size, with alignment equal to size.
-	 * The size is a power of 2, so we can check alignment using just
-	 * the bottom 32 bits for a DMA address of any size.
+	 * The DMA address returned by dma_alloc_coherent() is guaranteed to
+	 * be a power-of-2 number of pages, which satisfies the requirement.
 	 */
 	ring->virt = dma_alloc_coherent(dev, size, &addr, GFP_KERNEL);
-	if (ring->virt && lower_32_bits(addr) % size) {
-		dma_free_coherent(dev, size, ring->virt, addr);
-		dev_err(dev, "unable to alloc 0x%x-aligned ring buffer\n",
-			size);
-		return -EINVAL;	/* Not a good error value, but distinct */
-	} else if (!ring->virt) {
+	if (!ring->virt)
 		return -ENOMEM;
-	}
+
 	ring->addr = addr;
 	ring->count = count;
 
diff --git a/drivers/net/ipa/gsi_private.h b/drivers/net/ipa/gsi_private.h
index ed7bc26f85e9..ea333a244cf5 100644
--- a/drivers/net/ipa/gsi_private.h
+++ b/drivers/net/ipa/gsi_private.h
@@ -14,7 +14,7 @@ struct gsi_trans;
 struct gsi_ring;
 struct gsi_channel;
 
-#define GSI_RING_ELEMENT_SIZE	16	/* bytes */
+#define GSI_RING_ELEMENT_SIZE	16	/* bytes; must be a power of 2 */
 
 /* Return the entry that follows one provided in a transaction pool */
 void *gsi_trans_pool_next(struct gsi_trans_pool *pool, void *element);
diff --git a/drivers/net/ipa/gsi_trans.c b/drivers/net/ipa/gsi_trans.c
index 6c3ed5b17b80..70c2b585f98d 100644
--- a/drivers/net/ipa/gsi_trans.c
+++ b/drivers/net/ipa/gsi_trans.c
@@ -153,11 +153,10 @@ int gsi_trans_pool_init_dma(struct device *dev, struct gsi_trans_pool *pool,
 	size = __roundup_pow_of_two(size);
 	total_size = (count + max_alloc - 1) * size;
 
-	/* The allocator will give us a power-of-2 number of pages.  But we
-	 * can't guarantee that, so request it.  That way we won't waste any
-	 * memory that would be available beyond the required space.
-	 *
-	 * Note that gsi_trans_pool_exit_dma() assumes the total allocated
+	/* The allocator will give us a power-of-2 number of pages
+	 * sufficient to satisfy our request.  Round up our requested
+	 * size to avoid any unused space in the allocation.  This way
+	 * gsi_trans_pool_exit_dma() can assume the total allocated
 	 * size is exactly (count * size).
 	 */
 	total_size = get_order(total_size) << PAGE_SHIFT;
diff --git a/drivers/net/ipa/ipa_data.h b/drivers/net/ipa/ipa_data.h
index e97342e80d53..769f68923527 100644
--- a/drivers/net/ipa/ipa_data.h
+++ b/drivers/net/ipa/ipa_data.h
@@ -90,8 +90,8 @@ struct ipa_qsb_data {
  * that can be included in a single transaction.
  */
 struct gsi_channel_data {
-	u16 tre_count;
-	u16 event_count;
+	u16 tre_count;			/* must be a power of 2 */
+	u16 event_count;		/* must be a power of 2 */
 	u8 tlv_count;
 };
 
diff --git a/drivers/net/ipa/ipa_table.c b/drivers/net/ipa/ipa_table.c
index 4236a50ff03a..d9538661755f 100644
--- a/drivers/net/ipa/ipa_table.c
+++ b/drivers/net/ipa/ipa_table.c
@@ -96,9 +96,6 @@
  *                 ----------------------
  */
 
-/* IPA hardware constrains filter and route tables alignment */
-#define IPA_TABLE_ALIGN			128	/* Minimum table alignment */
-
 /* Assignment of route table entries to the modem and AP */
 #define IPA_ROUTE_MODEM_MIN		0
 #define IPA_ROUTE_MODEM_COUNT		8
@@ -652,26 +649,17 @@ int ipa_table_init(struct ipa *ipa)
 
 	ipa_table_validate_build();
 
+	/* The IPA hardware requires route and filter table rules to be
+	 * aligned on a 128-byte boundary.  We put the "zero rule" at the
+	 * base of the table area allocated here.  The DMA address returned
+	 * by dma_alloc_coherent() is guaranteed to be a power-of-2 number
+	 * of pages, which satisfies the rule alignment requirement.
+	 */
 	size = IPA_ZERO_RULE_SIZE + (1 + count) * IPA_TABLE_ENTRY_SIZE;
 	virt = dma_alloc_coherent(dev, size, &addr, GFP_KERNEL);
 	if (!virt)
 		return -ENOMEM;
 
-	/* We put the "zero rule" at the base of our table area.  The IPA
-	 * hardware requires route and filter table rules to be aligned
-	 * on a 128-byte boundary.  As long as the alignment constraint
-	 * is a power of 2, we can check alignment using just the bottom
-	 * 32 bits for a DMA address of any size.
-	 */
-	BUILD_BUG_ON(!is_power_of_2(IPA_TABLE_ALIGN));
-	if (lower_32_bits(addr) % IPA_TABLE_ALIGN) {
-		dev_err(dev, "table address %pad not %u-byte aligned\n",
-			&addr, IPA_TABLE_ALIGN);
-		dma_free_coherent(dev, size, virt, addr);
-
-		return -ERANGE;
-	}
-
 	ipa->table_virt = virt;
 	ipa->table_addr = addr;