net: fec: clean up transmit descriptor setup

Avoid writing any state until we're certain we can proceed with the
transmission: this avoids writing mapping error address values to the
descriptors, or setting the skbuff pointer until we have successfully
mapped the skb.

Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 70853a5..9c5570a 100644 (file)
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -373,6 +373,7 @@ fec_enet_txq_submit_frag_skb(struct sk_buff *skb, struct net_device *ndev)
        skb_frag_t *this_frag;
        unsigned int index;
        void *bufaddr;
+       dma_addr_t addr;
        int i;
 
        for (frag = 0; frag < nr_frags; frag++) {
@@ -415,15 +416,16 @@ fec_enet_txq_submit_frag_skb(struct sk_buff *skb, struct net_device *ndev)
                                swap_buffer(bufaddr, frag_len);
                }
 
-               bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, bufaddr,
-                                               frag_len, DMA_TO_DEVICE);
-               if (dma_mapping_error(&fep->pdev->dev, bdp->cbd_bufaddr)) {
+               addr = dma_map_single(&fep->pdev->dev, bufaddr, frag_len,
+                                     DMA_TO_DEVICE);
+               if (dma_mapping_error(&fep->pdev->dev, addr)) {
                        dev_kfree_skb_any(skb);
                        if (net_ratelimit())
                                netdev_err(ndev, "Tx DMA memory map failed\n");
                        goto dma_mapping_error;
                }
 
+               bdp->cbd_bufaddr = addr;
                bdp->cbd_datlen = frag_len;
                bdp->cbd_sc = status;
        }
@@ -450,6 +452,7 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
        int nr_frags = skb_shinfo(skb)->nr_frags;
        struct bufdesc *bdp, *last_bdp;
        void *bufaddr;
+       dma_addr_t addr;
        unsigned short status;
        unsigned short buflen;
        unsigned int estatus = 0;
@@ -490,12 +493,9 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
                        swap_buffer(bufaddr, buflen);
        }
 
-       /* Push the data cache so the CPM does not get stale memory
-        * data.
-        */
-       bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, bufaddr,
-                                       buflen, DMA_TO_DEVICE);
-       if (dma_mapping_error(&fep->pdev->dev, bdp->cbd_bufaddr)) {
+       /* Push the data cache so the CPM does not get stale memory data. */
+       addr = dma_map_single(&fep->pdev->dev, bufaddr, buflen, DMA_TO_DEVICE);
+       if (dma_mapping_error(&fep->pdev->dev, addr)) {
                dev_kfree_skb_any(skb);
                if (net_ratelimit())
                        netdev_err(ndev, "Tx DMA memory map failed\n");
@@ -537,6 +537,7 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
        fep->tx_skbuff[index] = skb;
 
        bdp->cbd_datlen = buflen;
+       bdp->cbd_bufaddr = addr;
 
        /* Send it on its way.  Tell FEC it's ready, interrupt when done,
         * it's the last BD of the frame, and to put the CRC on the end.
@@ -570,12 +571,12 @@ fec_enet_txq_put_data_tso(struct sk_buff *skb, struct net_device *ndev,
        struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
        unsigned short status;
        unsigned int estatus = 0;
+       dma_addr_t addr;
 
        status = bdp->cbd_sc;
        status &= ~BD_ENET_TX_STATS;
 
        status |= (BD_ENET_TX_TC | BD_ENET_TX_READY);
-       bdp->cbd_datlen = size;
 
        if (((unsigned long) data) & FEC_ALIGNMENT ||
                id_entry->driver_data & FEC_QUIRK_SWAP_FRAME) {
@@ -586,15 +587,17 @@ fec_enet_txq_put_data_tso(struct sk_buff *skb, struct net_device *ndev,
                        swap_buffer(data, size);
        }
 
-       bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, data,
-                                       size, DMA_TO_DEVICE);
-       if (dma_mapping_error(&fep->pdev->dev, bdp->cbd_bufaddr)) {
+       addr = dma_map_single(&fep->pdev->dev, data, size, DMA_TO_DEVICE);
+       if (dma_mapping_error(&fep->pdev->dev, addr)) {
                dev_kfree_skb_any(skb);
                if (net_ratelimit())
                        netdev_err(ndev, "Tx DMA memory map failed\n");
                return NETDEV_TX_BUSY;
        }
 
+       bdp->cbd_datlen = size;
+       bdp->cbd_bufaddr = addr;
+
        if (fep->bufdesc_ex) {
                if (skb->ip_summed == CHECKSUM_PARTIAL)
                        estatus |= BD_ENET_TX_PINS | BD_ENET_TX_IINS;
@@ -801,7 +804,7 @@ static void fec_enet_bd_init(struct net_device *dev)
 
                /* Initialize the BD for every fragment in the page. */
                bdp->cbd_sc = 0;
-               if (bdp->cbd_bufaddr && fep->tx_skbuff[i]) {
+               if (fep->tx_skbuff[i]) {
                        dev_kfree_skb_any(fep->tx_skbuff[i]);
                        fep->tx_skbuff[i] = NULL;
                }
@@ -1100,6 +1103,7 @@ fec_enet_tx(struct net_device *ndev)
                index = fec_enet_get_bd_index(fep->tx_bd_base, bdp, fep);
 
                skb = fep->tx_skbuff[index];
+               fep->tx_skbuff[index] = NULL;
                if (!IS_TSO_HEADER(fep, bdp->cbd_bufaddr))
                        dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
                                        bdp->cbd_datlen, DMA_TO_DEVICE);
@@ -1154,7 +1158,6 @@ fec_enet_tx(struct net_device *ndev)
 
                /* Free the sk buffer associated with this last transmit */
                dev_kfree_skb_any(skb);
-               fep->tx_skbuff[index] = NULL;
 
                fep->dirty_tx = bdp;