[PATCH 3.4 03/45] ibmveth: Fix endian issues with rx_no_buffer statistic

Zefan Li
2014-09-23T02:34:19Z

From: Anton Blanchard <anton@samba.org>

3.4.104-rc1 review patch. If anyone has any objections, please let me know.

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

commit cbd5228199d8be45d895d9d0cc2b8ce53835fc21 upstream.

Hidden away in the last 8 bytes of the buffer_list page is a solitary
statistic. It needs to be byte swapped or else ethtool -S will
produce numbers that terrify the user.

Since we do this in multiple places, create a helper function with a
comment explaining what is going on.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
drivers/net/ethernet/ibm/ibmveth.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 33a1760..b2b715f 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -293,6 +293,18 @@ failure:
atomic_add(buffers_added, &(pool->available));
}

+/*
+ * The final 8 bytes of the buffer list is a counter of frames dropped
+ * because there was not a buffer in the buffer list capable of holding
+ * the frame.
+ */
+static void ibmveth_update_rx_no_buffer(struct ibmveth_adapter *adapter)
+{
+ __be64 *p = adapter->buffer_list_addr + 4096 - 8;
+
+ adapter->rx_no_buffer = be64_to_cpup(p);
+}
+
/* replenish routine */
static void ibmveth_replenish_task(struct ibmveth_adapter *adapter)
{
@@ -308,8 +320,7 @@ static void ibmveth_replenish_task(struct ibmveth_adapter *adapter)
ibmveth_replenish_buffer_pool(adapter, pool);
}

- adapter->rx_no_buffer = *(u64 *)(((char*)adapter->buffer_list_addr) +
- 4096 - 8);
+ ibmveth_update_rx_no_buffer(adapter);
}

/* empty and free ana buffer pool - also used to do cleanup in error paths */
@@ -692,8 +703,7 @@ static int ibmveth_close(struct net_device *netdev)

free_irq(netdev->irq, netdev);

- adapter->rx_no_buffer = *(u64 *)(((char *)adapter->buffer_list_addr) +
- 4096 - 8);
+ ibmveth_update_rx_no_buffer(adapter);

ibmveth_cleanup(adapter);

--
1.7.9.5