ibmveth: fix bad UDP checksums
This patch fixes a ibmveth bug where bad UDP checksums are being transmitted
when checksum offloading is enabled.
The hypervisor does checksum offloading only on TCP packets, so ibmveth calls
skb_checksum_help() for any other protocol. The bug happens because
the packet is being modified after the DMA map, so we would need a memory
barrier before making the hypervisor call. Reordering the code so that the
DMA map happens after skb_checksum_help() has the additional advantage of
fixing a DMA map leak if skb_checksum_help() where to fail.
Signed-off-by: Santiago Leon <santil@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c
index a03fe1f..c2d57f8 100644
--- a/drivers/net/ibmveth.c
+++ b/drivers/net/ibmveth.c
@@ -904,8 +904,6 @@
unsigned long data_dma_addr;
desc.fields.flags_len = IBMVETH_BUF_VALID | skb->len;
- data_dma_addr = dma_map_single(&adapter->vdev->dev, skb->data,
- skb->len, DMA_TO_DEVICE);
if (skb->ip_summed == CHECKSUM_PARTIAL &&
ip_hdr(skb)->protocol != IPPROTO_TCP && skb_checksum_help(skb)) {
@@ -924,6 +922,8 @@
buf[1] = 0;
}
+ data_dma_addr = dma_map_single(&adapter->vdev->dev, skb->data,
+ skb->len, DMA_TO_DEVICE);
if (dma_mapping_error(&adapter->vdev->dev, data_dma_addr)) {
if (!firmware_has_feature(FW_FEATURE_CMO))
ibmveth_error_printk("tx: unable to map xmit buffer\n");
@@ -932,6 +932,7 @@
desc.fields.address = adapter->bounce_buffer_dma;
tx_map_failed++;
used_bounce = 1;
+ wmb();
} else
desc.fields.address = data_dma_addr;