libertas: clean up lbs_hard_start_xmit()

Having merged the nest of functions into one, now we can clean it up and
fix the error handling, and the duplication -- and at least make a start
on the locking.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 63 insertions, 70 deletions

diff --git a/drivers/net/wireless/libertas/tx.c b/drivers/net/wireless/libertas/tx.c
index 7bc212438259..aefe52419baa 100644
--- a/drivers/net/wireless/libertas/tx.c
+++ b/drivers/net/wireless/libertas/tx.c
@@ -58,22 +58,16 @@ static u32 convert_radiotap_rate_to_mv(u8 rate)
  */
 int lbs_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
+        unsigned long flags;
         struct lbs_private *priv = dev->priv;
-        int ret = -1;
-        struct txpd localtxpd;
-        struct txpd *plocaltxpd = &localtxpd;
-        u8 *p802x_hdr;
-        struct tx_radiotap_hdr *pradiotap_hdr;
-        u32 new_rate;
-        u8 *ptr = priv->tmptxbuf;
+        struct txpd *txpd;
+        char *p802x_hdr;
+        uint16_t pkt_len;
+        int ret;
 
         lbs_deb_enter(LBS_DEB_TX);
 
-        lbs_deb_hex(LBS_DEB_TX, "TX Data", skb->data, min_t(unsigned int, skb->len, 100));
-
-        netif_stop_queue(priv->dev);
-        if (priv->mesh_dev)
-                netif_stop_queue(priv->mesh_dev);
+        ret = NETDEV_TX_BUSY;
 
         if (priv->dnld_sent) {
                 lbs_pr_alert( "TX error: dnld_sent = %d, not sending\n",
@@ -94,98 +88,97 @@ int lbs_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
         }
 
         if (priv->surpriseremoved)
-                return -1;
+                goto drop;
 
         if (!skb->len || (skb->len > MRVDRV_ETH_TX_PACKET_BUFFER_SIZE)) {
                 lbs_deb_tx("tx err: skb length %d 0 or > %zd\n",
                        skb->len, MRVDRV_ETH_TX_PACKET_BUFFER_SIZE);
-                goto done_tx;
+                /* We'll never manage to send this one; drop it and return 'OK' */
+                goto drop;
         }
 
-        ret = 0;
-        memset(plocaltxpd, 0, sizeof(struct txpd));
-
-        plocaltxpd->tx_packet_length = cpu_to_le16(skb->len);
+        lbs_deb_hex(LBS_DEB_TX, "TX Data", skb->data, min_t(unsigned int, skb->len, 100));
 
-        /* offset of actual data */
-        plocaltxpd->tx_packet_location = cpu_to_le32(sizeof(struct txpd));
+        txpd = (void *)priv->tmptxbuf;
+        memset(txpd, 0, sizeof(struct txpd));
 
         p802x_hdr = skb->data;
-        if (priv->monitormode != LBS_MONITOR_OFF) {
+        pkt_len = skb->len;
 
-                /* locate radiotap header */
-                pradiotap_hdr = (struct tx_radiotap_hdr *)skb->data;
+        if (priv->monitormode != LBS_MONITOR_OFF) {
+                struct tx_radiotap_hdr *rtap_hdr = (void *)skb->data;
 
                 /* set txpd fields from the radiotap header */
-                new_rate = convert_radiotap_rate_to_mv(pradiotap_hdr->rate);
-                if (new_rate != 0) {
-                        /* use new tx_control[4:0] */
-                        plocaltxpd->tx_control = cpu_to_le32(new_rate);
-                }
+                txpd->tx_control = cpu_to_le32(convert_radiotap_rate_to_mv(rtap_hdr->rate));
 
                 /* skip the radiotap header */
-                p802x_hdr += sizeof(struct tx_radiotap_hdr);
-                plocaltxpd->tx_packet_length =
-                        cpu_to_le16(le16_to_cpu(plocaltxpd->tx_packet_length)
-                                    - sizeof(struct tx_radiotap_hdr));
+                p802x_hdr += sizeof(*rtap_hdr);
+                pkt_len -= sizeof(*rtap_hdr);
 
+                /* copy destination address from 802.11 header */
+                memcpy(txpd->tx_dest_addr_high, p802x_hdr + 4, ETH_ALEN);
+        } else {
+                /* copy destination address from 802.3 header */
+                memcpy(txpd->tx_dest_addr_high, p802x_hdr, ETH_ALEN);
         }
-        /* copy destination address from 802.3 or 802.11 header */
-        if (priv->monitormode != LBS_MONITOR_OFF)
-                memcpy(plocaltxpd->tx_dest_addr_high, p802x_hdr + 4, ETH_ALEN);
-        else
-                memcpy(plocaltxpd->tx_dest_addr_high, p802x_hdr, ETH_ALEN);
 
-        lbs_deb_hex(LBS_DEB_TX, "txpd", (u8 *) plocaltxpd, sizeof(struct txpd));
+        txpd->tx_packet_length = cpu_to_le16(pkt_len);
+        txpd->tx_packet_location = cpu_to_le32(sizeof(struct txpd));
 
-        if (IS_MESH_FRAME(skb)) {
-                plocaltxpd->tx_control |= cpu_to_le32(TxPD_MESH_FRAME);
-        }
+        if (dev == priv->mesh_dev)
+                txpd->tx_control |= cpu_to_le32(TxPD_MESH_FRAME);
 
-        memcpy(ptr, plocaltxpd, sizeof(struct txpd));
+        lbs_deb_hex(LBS_DEB_TX, "txpd", (u8 *) &txpd, sizeof(struct txpd));
 
-        ptr += sizeof(struct txpd);
+        lbs_deb_hex(LBS_DEB_TX, "Tx Data", (u8 *) p802x_hdr, le16_to_cpu(txpd->tx_packet_length));
 
-        lbs_deb_hex(LBS_DEB_TX, "Tx Data", (u8 *) p802x_hdr, le16_to_cpu(plocaltxpd->tx_packet_length));
-        memcpy(ptr, p802x_hdr, le16_to_cpu(plocaltxpd->tx_packet_length));
-        ret = priv->hw_host_to_card(priv, MVMS_DAT,
-                                    priv->tmptxbuf,
-                                    le16_to_cpu(plocaltxpd->tx_packet_length) +
-                                    sizeof(struct txpd));
+        memcpy(&txpd[1], p802x_hdr, le16_to_cpu(txpd->tx_packet_length));
 
-        if (ret) {
-                lbs_deb_tx("tx err: hw_host_to_card returned 0x%X\n", ret);
-                goto done_tx;
-        }
+        /* We need to protect against the queues being restarted before
+           we get round to stopping them */
+        spin_lock_irqsave(&priv->driver_lock, flags);
 
-        lbs_deb_tx("%s succeeds\n", __func__);
+        ret = priv->hw_host_to_card(priv, MVMS_DAT, priv->tmptxbuf,
+                                    pkt_len + sizeof(struct txpd));
 
-done_tx:
         if (!ret) {
+                lbs_deb_tx("%s succeeds\n", __func__);
+
+                /* Stop processing outgoing pkts before submitting */
+                netif_stop_queue(priv->dev);
+                if (priv->mesh_dev)
+                        netif_stop_queue(priv->mesh_dev);
+
                 priv->stats.tx_packets++;
                 priv->stats.tx_bytes += skb->len;
 
-                dev->trans_start = jiffies;
-        } else {
-                priv->stats.tx_dropped++;
-                priv->stats.tx_errors++;
+                dev->trans_start = jiffies;
+
+                if (priv->monitormode != LBS_MONITOR_OFF) {
+                        /* Keep the skb to echo it back once Tx feedback is
+                           received from FW */
+                        skb_orphan(skb);
+
+                        /* Keep the skb around for when we get feedback */
+                        priv->currenttxskb = skb;
+                }
         }
+        
+        spin_unlock_irqrestore(&priv->driver_lock, flags);
 
-        if (!ret && priv->monitormode != LBS_MONITOR_OFF) {
-                /* Keep the skb to echo it back once Tx feedback is
-                   received from FW */
-                skb_orphan(skb);
-                /* stop processing outgoing pkts */
-                netif_stop_queue(priv->dev);
-                if (priv->mesh_dev)
-                        netif_stop_queue(priv->mesh_dev);
+        if (ret) {
+                lbs_deb_tx("tx err: hw_host_to_card returned 0x%X\n", ret);
+drop:
+                priv->stats.tx_dropped++;
+                priv->stats.tx_errors++;
 
-                /* Keep the skb around for when we get feedback */
-                priv->currenttxskb = skb;
-        } else {
                 dev_kfree_skb_any(skb);
         }
 
+        /* Even if we dropped the packet, return OK. Otherwise the
+           packet gets requeued. */
+        ret = NETDEV_TX_OK;
+
 done:
         lbs_deb_leave_args(LBS_DEB_TX, "ret %d", ret);
         return ret;