libertas: Move actual transmission to main thread

The locking issues with TX, especially TX from multiple netdevs, get
_so_ much easier if you do it like this.

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

3 files changed, 71 insertions, 61 deletions

diff --git a/drivers/net/wireless/libertas/dev.h b/drivers/net/wireless/libertas/dev.h
index 04cf33da589..468140512a6 100644
--- a/drivers/net/wireless/libertas/dev.h
+++ b/drivers/net/wireless/libertas/dev.h
@@ -164,7 +164,10 @@ struct lbs_private {
 
         struct mutex lock;
 
-        u8 tmptxbuf[LBS_UPLD_SIZE];
+        /* TX packet ready to be sent... */
+        int tx_pending_len;             /* -1 while building packet */
+
+        u8 tx_pending_buf[LBS_UPLD_SIZE];
         /* protected by hard_start_xmit serialization */
 
         /** command-related variables */
diff --git a/drivers/net/wireless/libertas/main.c b/drivers/net/wireless/libertas/main.c
index 42b64b5ad08..f16c93ba6ef 100644
--- a/drivers/net/wireless/libertas/main.c
+++ b/drivers/net/wireless/libertas/main.c
@@ -739,6 +739,8 @@ static int lbs_thread(void *data)
                         shouldsleep = 0;        /* Interrupt pending. Deal with it now */
                 else if (priv->dnld_sent)
                         shouldsleep = 1;        /* Something is en route to the device already */
+                else if (priv->tx_pending_len > 0)
+                        shouldsleep = 0;        /* We've a packet to send */
                 else if (priv->cur_cmd)
                         shouldsleep = 1;        /* Can't send a command; one already running */
                 else if (!list_empty(&priv->cmdpendingq))
@@ -852,6 +854,28 @@ static int lbs_thread(void *data)
                  */
                 if (!list_empty(&priv->cmdpendingq))
                         wake_up_all(&priv->cmd_pending);
+
+                spin_lock_irq(&priv->driver_lock);
+                if (!priv->dnld_sent && priv->tx_pending_len > 0) {
+                        int ret = priv->hw_host_to_card(priv, MVMS_DAT,
+                                                        priv->tx_pending_buf,
+                                                        priv->tx_pending_len);
+                        if (ret) {
+                                lbs_deb_tx("host_to_card failed %d\n", ret);
+                                priv->dnld_sent = DNLD_RES_RECEIVED;
+                        }
+                        priv->tx_pending_len = 0;
+                        if (!priv->currenttxskb) {
+                                /* We can wake the queues immediately if we aren't
+                                   waiting for TX feedback */
+                                if (priv->connect_status == LBS_CONNECTED)
+                                        netif_wake_queue(priv->dev);
+                                if (priv->mesh_dev &&
+                                    priv->mesh_connect_status == LBS_CONNECTED)
+                                        netif_wake_queue(priv->mesh_dev);
+                        }
+                }
+                spin_unlock_irq(&priv->driver_lock);
         }
 
         del_timer(&priv->command_timer);
diff --git a/drivers/net/wireless/libertas/tx.c b/drivers/net/wireless/libertas/tx.c
index 300aa05edeb..e2141f0a67d 100644
--- a/drivers/net/wireless/libertas/tx.c
+++ b/drivers/net/wireless/libertas/tx.c
@@ -67,39 +67,45 @@ int lbs_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
         lbs_deb_enter(LBS_DEB_TX);
 
-        ret = NETDEV_TX_BUSY;
-
-        if (priv->dnld_sent) {
-                lbs_pr_alert( "TX error: dnld_sent = %d, not sending\n",
-                       priv->dnld_sent);
-                goto done;
-        }
-
-        if (priv->currenttxskb) {
-                lbs_pr_err("%s while TX skb pending\n", __func__);
-                goto done;
-        }
+        ret = NETDEV_TX_OK;
 
-        if ((priv->psstate == PS_STATE_SLEEP) ||
-            (priv->psstate == PS_STATE_PRE_SLEEP)) {
-                lbs_pr_alert("TX error: packet xmit in %ssleep mode\n",
-                             priv->psstate == PS_STATE_SLEEP?"":"pre-");
-                goto done;
-        }
+        /* We need to protect against the queues being restarted before
+           we get round to stopping them */
+        spin_lock_irqsave(&priv->driver_lock, flags);
 
         if (priv->surpriseremoved)
-                goto drop;
+                goto free;
 
         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);
                 /* We'll never manage to send this one; drop it and return 'OK' */
-                goto drop;
+
+                priv->stats.tx_dropped++;
+                priv->stats.tx_errors++;
+                goto free;
+        }
+
+
+        netif_stop_queue(priv->dev);
+        if (priv->mesh_dev)
+                netif_stop_queue(priv->mesh_dev);
+
+        if (priv->tx_pending_len) {
+                /* This can happen if packets come in on the mesh and eth 
+                   device simultaneously -- there's no mutual exclusion on 
+                   hard_start_xmit() calls between devices. */
+                lbs_deb_tx("Packet on %s while busy\n", dev->name);
+                ret = NETDEV_TX_BUSY;
+                goto unlock;
         }
 
+        priv->tx_pending_len = -1;
+        spin_unlock_irqrestore(&priv->driver_lock, flags);
+
         lbs_deb_hex(LBS_DEB_TX, "TX Data", skb->data, min_t(unsigned int, skb->len, 100));
 
-        txpd = (void *)priv->tmptxbuf;
+        txpd = (void *)priv->tx_pending_buf;
         memset(txpd, 0, sizeof(struct txpd));
 
         p802x_hdr = skb->data;
@@ -134,54 +140,31 @@ int lbs_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
         memcpy(&txpd[1], p802x_hdr, le16_to_cpu(txpd->tx_packet_length));
 
-        /* We need to protect against the queues being restarted before
-           we get round to stopping them */
         spin_lock_irqsave(&priv->driver_lock, flags);
+        priv->tx_pending_len = pkt_len + sizeof(struct txpd);
 
-        ret = priv->hw_host_to_card(priv, MVMS_DAT, priv->tmptxbuf,
-                                    pkt_len + sizeof(struct txpd));
-
-        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;
+        lbs_deb_tx("%s lined up packet\n", __func__);
 
-                if (priv->monitormode != LBS_MONITOR_OFF) {
-                        /* Keep the skb to echo it back once Tx feedback is
-                           received from FW */
-                        skb_orphan(skb);
+        priv->stats.tx_packets++;
+        priv->stats.tx_bytes += skb->len;
 
-                        /* Keep the skb around for when we get feedback */
-                        priv->currenttxskb = skb;
-                } else
-                        dev_kfree_skb_any(skb);
-                
-        }
-        
-        spin_unlock_irqrestore(&priv->driver_lock, flags);
+        dev->trans_start = jiffies;
 
-        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++;
+        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;
+        } else {
+ free:
                 dev_kfree_skb_any(skb);
         }
+ unlock:
+        spin_unlock_irqrestore(&priv->driver_lock, flags);
+        wake_up(&priv->waitq);
 
-        /* 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;
 }