b43: Remove TX spinlock

This removes the TX spinlock and defers TX to a workqueue to allow
locking wl->mutex instead and to allow sleeping for register accesses.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 43 insertions, 37 deletions

diff --git a/drivers/net/wireless/b43/b43.h b/drivers/net/wireless/b43/b43.h
index d63af926d058..1cd470d6e2da 100644
--- a/drivers/net/wireless/b43/b43.h
+++ b/drivers/net/wireless/b43/b43.h
@@ -683,6 +683,11 @@ struct b43_wl {
          * This is scheduled when we determine that the actual TX output
          * power doesn't match what we want. */
         struct work_struct txpower_adjust_work;
+
+        /* Packet transmit work */
+        struct work_struct tx_work;
+        /* Queue of packets to be transmitted. */
+        struct sk_buff_head tx_queue;
 };
 
 /* The type of the firmware file. */
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 80b688441ffe..fca2fe947d7d 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -690,7 +690,6 @@ static void b43_short_slot_timing_disable(struct b43_wldev *dev)
  */
 void b43_dummy_transmission(struct b43_wldev *dev, bool ofdm, bool pa_on)
 {
-        struct b43_wl *wl = dev->wl;
         struct b43_phy *phy = &dev->phy;
         unsigned int i, max_loop;
         u16 value;
@@ -710,8 +709,6 @@ void b43_dummy_transmission(struct b43_wldev *dev, bool ofdm, bool pa_on)
                 buffer[0] = 0x000B846E;
         }
 
-        write_lock_irq(&wl->tx_lock);
-
         for (i = 0; i < 5; i++)
                 b43_ram_write(dev, i * 4, buffer[i]);
 
@@ -767,8 +764,6 @@ void b43_dummy_transmission(struct b43_wldev *dev, bool ofdm, bool pa_on)
         }
         if (phy->radio_ver == 0x2050 && phy->radio_rev <= 0x5)
                 b43_radio_write16(dev, 0x0051, 0x0037);
-
-        write_unlock_irq(&wl->tx_lock);
 }
 
 static void key_write(struct b43_wldev *dev,
@@ -3098,42 +3093,49 @@ static int b43_rng_init(struct b43_wl *wl)
         return err;
 }
 
-static int b43_op_tx(struct ieee80211_hw *hw,
-                     struct sk_buff *skb)
+static void b43_tx_work(struct work_struct *work)
 {
-        struct b43_wl *wl = hw_to_b43_wl(hw);
-        struct b43_wldev *dev = wl->current_dev;
-        unsigned long flags;
-        int err;
+        struct b43_wl *wl = container_of(work, struct b43_wl, tx_work);
+        struct b43_wldev *dev;
+        struct sk_buff *skb;
+        int err = 0;
 
-        if (unlikely(skb->len < 2 + 2 + 6)) {
-                /* Too short, this can't be a valid frame. */
-                goto drop_packet;
+        mutex_lock(&wl->mutex);
+        dev = wl->current_dev;
+        if (unlikely(!dev || b43_status(dev) < B43_STAT_STARTED)) {
+                mutex_unlock(&wl->mutex);
+                return;
         }
-        B43_WARN_ON(skb_shinfo(skb)->nr_frags);
-        if (unlikely(!dev))
-                goto drop_packet;
 
-        /* Transmissions on seperate queues can run concurrently. */
-        read_lock_irqsave(&wl->tx_lock, flags);
+        while (skb_queue_len(&wl->tx_queue)) {
+                skb = skb_dequeue(&wl->tx_queue);
 
-        err = -ENODEV;
-        if (likely(b43_status(dev) >= B43_STAT_STARTED)) {
                 if (b43_using_pio_transfers(dev))
                         err = b43_pio_tx(dev, skb);
                 else
                         err = b43_dma_tx(dev, skb);
+                if (unlikely(err))
+                        dev_kfree_skb(skb); /* Drop it */
         }
 
-        read_unlock_irqrestore(&wl->tx_lock, flags);
+        mutex_unlock(&wl->mutex);
+}
 
-        if (unlikely(err))
-                goto drop_packet;
-        return NETDEV_TX_OK;
+static int b43_op_tx(struct ieee80211_hw *hw,
+                     struct sk_buff *skb)
+{
+        struct b43_wl *wl = hw_to_b43_wl(hw);
+
+        if (unlikely(skb->len < 2 + 2 + 6)) {
+                /* Too short, this can't be a valid frame. */
+                dev_kfree_skb_any(skb);
+                return NETDEV_TX_OK;
+        }
+        B43_WARN_ON(skb_shinfo(skb)->nr_frags);
+
+        skb_queue_tail(&wl->tx_queue, skb);
+        ieee80211_queue_work(wl->hw, &wl->tx_work);
 
-drop_packet:
-        /* We can not transmit this packet. Drop it. */
-        dev_kfree_skb_any(skb);
         return NETDEV_TX_OK;
 }
 
@@ -3686,18 +3688,12 @@ static int b43_op_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
         u8 algorithm;
         u8 index;
         int err;
-        unsigned long flags;
         static const u8 bcast_addr[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 
         if (modparam_nohwcrypt)
                 return -ENOSPC; /* User disabled HW-crypto */
 
         mutex_lock(&wl->mutex);
-        write_lock_irqsave(&wl->tx_lock, flags);
-        /* mutex     -> Every config operation must take it.
-         * tx_lock   -> We modify the dev->key array, which is accessed
-         *              in the TX handler.
-         */
 
         dev = wl->current_dev;
         err = -ENODEV;
@@ -3789,7 +3785,6 @@ out_unlock:
                        sta ? sta->addr : bcast_addr);
                 b43_dump_keymemory(dev);
         }
-        write_unlock_irqrestore(&wl->tx_lock, flags);
         mutex_unlock(&wl->mutex);
 
         return err;
@@ -3846,9 +3841,10 @@ redo:
         if (!dev || b43_status(dev) < B43_STAT_STARTED)
                 return dev;
 
-        /* Disable periodic work. Unlock to avoid deadlocks. */
+        /* Cancel work. Unlock to avoid deadlocks. */
         mutex_unlock(&wl->mutex);
         cancel_delayed_work_sync(&dev->periodic_work);
+        cancel_work_sync(&wl->tx_work);
         mutex_lock(&wl->mutex);
         dev = wl->current_dev;
         if (!dev || b43_status(dev) < B43_STAT_STARTED) {
@@ -3883,6 +3879,10 @@ redo:
         }
         B43_WARN_ON(b43_read32(dev, B43_MMIO_GEN_IRQ_MASK));
 
+        /* Drain the TX queue */
+        while (skb_queue_len(&wl->tx_queue))
+                dev_kfree_skb(skb_dequeue(&wl->tx_queue));
+
         b43_pio_stop(dev);
         b43_mac_suspend(dev);
         free_irq(dev->dev->irq, dev);
@@ -4866,7 +4866,6 @@ static int b43_wireless_init(struct ssb_device *dev)
 
         /* Initialize struct b43_wl */
         wl->hw = hw;
-        rwlock_init(&wl->tx_lock);
         spin_lock_init(&wl->leds_lock);
         spin_lock_init(&wl->shm_lock);
         mutex_init(&wl->mutex);
@@ -4874,6 +4873,8 @@ static int b43_wireless_init(struct ssb_device *dev)
         INIT_LIST_HEAD(&wl->devlist);
         INIT_WORK(&wl->beacon_update_trigger, b43_beacon_update_trigger_work);
         INIT_WORK(&wl->txpower_adjust_work, b43_phy_txpower_adjust_work);
+        INIT_WORK(&wl->tx_work, b43_tx_work);
+        skb_queue_head_init(&wl->tx_queue);
 
         ssb_set_devtypedata(dev, wl);
         b43info(wl, "Broadcom %04X WLAN found (core revision %u)\n",