ibmveth: Fix alignment of rx queue bug

This patch fixes a bug found by Nish Aravamudan
(https://lkml.org/lkml/2012/5/15/220) where the driver is not following
the spec (it is not aligning the rx buffer on a 16-byte boundary) and the
hypervisor aborts the registration, making the device unusable.

The fix follows BenH's recommendation (https://lkml.org/lkml/2012/7/20/461)
to replace the kmalloc+map for a single call to dma_alloc_coherent()
because that function always aligns to a 16-byte boundary.

The stable trees will run into this bug whenever the rx buffer kmalloc call
returns something not aligned on a 16-byte boundary.

Cc: <stable@vger.kernel.org>
Signed-off-by: Santiago Leon <santil@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 9010cea68bc3094a4b9b18b06cae1aa7d9796cd7..b68d28a130e664e2042bbb9a4335710964f861a7 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -472,14 +472,9 @@ static void ibmveth_cleanup(struct ibmveth_adapter *adapter)
        }
 
        if (adapter->rx_queue.queue_addr != NULL) {
-               if (!dma_mapping_error(dev, adapter->rx_queue.queue_dma)) {
-                       dma_unmap_single(dev,
-                                       adapter->rx_queue.queue_dma,
-                                       adapter->rx_queue.queue_len,
-                                       DMA_BIDIRECTIONAL);
-                       adapter->rx_queue.queue_dma = DMA_ERROR_CODE;
-               }
-               kfree(adapter->rx_queue.queue_addr);
+               dma_free_coherent(dev, adapter->rx_queue.queue_len,
+                                 adapter->rx_queue.queue_addr,
+                                 adapter->rx_queue.queue_dma);
                adapter->rx_queue.queue_addr = NULL;
        }
 
@@ -556,10 +551,13 @@ static int ibmveth_open(struct net_device *netdev)
                goto err_out;
        }
 
+       dev = &adapter->vdev->dev;
+
        adapter->rx_queue.queue_len = sizeof(struct ibmveth_rx_q_entry) *
                                                rxq_entries;
-       adapter->rx_queue.queue_addr = kmalloc(adapter->rx_queue.queue_len,
-                                               GFP_KERNEL);
+       adapter->rx_queue.queue_addr =
+           dma_alloc_coherent(dev, adapter->rx_queue.queue_len,
+                              &adapter->rx_queue.queue_dma, GFP_KERNEL);
 
        if (!adapter->rx_queue.queue_addr) {
                netdev_err(netdev, "unable to allocate rx queue pages\n");
@@ -567,19 +565,13 @@ static int ibmveth_open(struct net_device *netdev)
                goto err_out;
        }
 
-       dev = &adapter->vdev->dev;
-
        adapter->buffer_list_dma = dma_map_single(dev,
                        adapter->buffer_list_addr, 4096, DMA_BIDIRECTIONAL);
        adapter->filter_list_dma = dma_map_single(dev,
                        adapter->filter_list_addr, 4096, DMA_BIDIRECTIONAL);
-       adapter->rx_queue.queue_dma = dma_map_single(dev,
-                       adapter->rx_queue.queue_addr,
-                       adapter->rx_queue.queue_len, DMA_BIDIRECTIONAL);
 
        if ((dma_mapping_error(dev, adapter->buffer_list_dma)) ||
-           (dma_mapping_error(dev, adapter->filter_list_dma)) ||
-           (dma_mapping_error(dev, adapter->rx_queue.queue_dma))) {
+           (dma_mapping_error(dev, adapter->filter_list_dma))) {
                netdev_err(netdev, "unable to map filter or buffer list "
                           "pages\n");
                rc = -ENOMEM;