[PATCH] iseries_veth: Only call dma_unmap_single() if dma_map_single() succeeded

The iseries_veth driver unconditionally calls dma_unmap_single() even
when the corresponding dma_map_single() may have failed.

Rework the code a bit to keep the return value from dma_unmap_single()
around, and then check if it's a dma_mapping_error() before we do
the dma_unmap_single().

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

diff --git a/drivers/net/iseries_veth.c b/drivers/net/iseries_veth.c
index 427ac8cc56be94693f9ce3e5413ca35540a15f57..91d79db96e821a24f4add7391a3118e72bed9f19 100644 (file)
--- a/drivers/net/iseries_veth.c
+++ b/drivers/net/iseries_veth.c
@@ -931,7 +931,6 @@ static int veth_transmit_to_one(struct sk_buff *skb, HvLpIndex rlp,
        struct veth_lpar_connection *cnx = veth_cnx[rlp];
        struct veth_port *port = (struct veth_port *) dev->priv;
        HvLpEvent_Rc rc;
-       u32 dma_address, dma_length;
        struct veth_msg *msg = NULL;
        int err = 0;
        unsigned long flags;
@@ -959,20 +958,19 @@ static int veth_transmit_to_one(struct sk_buff *skb, HvLpIndex rlp,
 
        msg->in_use = 1;
 
-       dma_length = skb->len;
-       dma_address = dma_map_single(port->dev, skb->data,
-                                    dma_length, DMA_TO_DEVICE);
+       msg->data.addr[0] = dma_map_single(port->dev, skb->data,
+                               skb->len, DMA_TO_DEVICE);
 
-       if (dma_mapping_error(dma_address))
+       if (dma_mapping_error(msg->data.addr[0]))
                goto recycle_and_drop;
 
        /* Is it really necessary to check the length and address
         * fields of the first entry here? */
        msg->skb = skb;
        msg->dev = port->dev;
-       msg->data.addr[0] = dma_address;
-       msg->data.len[0] = dma_length;
+       msg->data.len[0] = skb->len;
        msg->data.eofmask = 1 << VETH_EOF_SHIFT;
+
        rc = veth_signaldata(cnx, VethEventTypeFrames, msg->token, &msg->data);
 
        if (rc != HvLpEvent_Rc_Good)
@@ -1076,8 +1074,9 @@ static void veth_recycle_msg(struct veth_lpar_connection *cnx,
                dma_address = msg->data.addr[0];
                dma_length = msg->data.len[0];
 
-               dma_unmap_single(msg->dev, dma_address, dma_length,
-                                DMA_TO_DEVICE);
+               if (!dma_mapping_error(dma_address))
+                       dma_unmap_single(msg->dev, dma_address, dma_length,
+                                       DMA_TO_DEVICE);
 
                if (msg->skb) {
                        dev_kfree_skb_any(msg->skb);