[ 091/218] ibmveth: Fix alignment of rx queue bug

From: Greg Kroah-Hartman
Date: Fri Sep 28 2012 - 16:26:21 EST


3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Santiago Leon <santil@xxxxxxxxxxxxxxxxxx>

commit d90c92fee89ccd75ef2646f3bde0b4c0450666c3 upstream.

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.

Signed-off-by: Santiago Leon <santil@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/net/ethernet/ibm/ibmveth.c | 26 +++++++++-----------------
1 file changed, 9 insertions(+), 17 deletions(-)

--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -472,14 +472,9 @@ static void ibmveth_cleanup(struct ibmve
}

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_devic
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_devic
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;


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