mac80211: make tx() operation return void

The return value of the tx operation is commonly
misused by drivers, leading to errors. All drivers
will drop frames if they fail to TX the frame, and
they must also properly manage the queues (if they
didn't, mac80211 would already warn).

Removing the ability for drivers to return a BUSY
value also allows significant cleanups of the TX
TX handling code in mac80211.

Note that this also fixes a bug in ath9k_htc, the
old "return -1" there was wrong.

Signed-off-by: Johannes Berg <[e-mail]>
Tested-by: Sedat Dilek <[e-mail]> [ath5k]
Acked-by: Gertjan van Wingerde <[e-mail]> [rt2x00]
Acked-by: Larry Finger <[e-mail]> [b43, rtl8187, rtlwifi]
Acked-by: Luciano Coelho <[e-mail]> [wl12xx]
Signed-off-by: John W. Linville <[e-mail]>

drivers/net/wireless/adm8211.c

···
 }
 
 /* Put adm8211_tx_hdr on skb and transmit */
-static int adm8211_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
+static void adm8211_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
 {
 	struct adm8211_tx_hdr *txhdr;
 	size_t payload_len, hdrlen;
···
 	txhdr->retry_limit = info->control.rates[0].count;
 
 	adm8211_tx_raw(dev, skb, plcp_signal, hdrlen);
-
-	return NETDEV_TX_OK;
 }
 
 static int adm8211_alloc_rings(struct ieee80211_hw *dev)

drivers/net/wireless/at76c50x-usb.c

···
 	ieee80211_wake_queues(priv->hw);
 }
 
-static int at76_mac80211_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void at76_mac80211_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct at76_priv *priv = hw->priv;
 	struct at76_tx_buffer *tx_buffer = priv->bulk_out_buffer;
···
 	if (priv->tx_urb->status == -EINPROGRESS) {
 		wiphy_err(priv->hw->wiphy,
 			  "%s called while tx urb is pending\n", __func__);
-		return NETDEV_TX_BUSY;
+		dev_kfree_skb_any(skb);
+		return;
 	}
 
 	/* The following code lines are important when the device is going to
···
 				  priv->tx_urb,
 				  priv->tx_urb->hcpriv, priv->tx_urb->complete);
 	}
-
-	return 0;
 }
 
 static int at76_mac80211_start(struct ieee80211_hw *hw)

drivers/net/wireless/ath/ar9170/ar9170.h

···
 int ar9170_nag_limiter(struct ar9170 *ar);
 
 /* MAC */
-int ar9170_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
+void ar9170_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
 int ar9170_init_mac(struct ar9170 *ar);
 int ar9170_set_qos(struct ar9170 *ar);
 int ar9170_update_multicast(struct ar9170 *ar, const u64 mc_hast);

drivers/net/wireless/ath/ar9170/main.c

···
 				     msecs_to_jiffies(AR9170_JANITOR_DELAY));
 }
 
-int ar9170_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+void ar9170_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct ar9170 *ar = hw->priv;
 	struct ieee80211_tx_info *info;
···
 	skb_queue_tail(&ar->tx_pending[queue], skb);
 
 	ar9170_tx(ar);
-	return NETDEV_TX_OK;
+	return;
 
 err_free:
 	dev_kfree_skb_any(skb);
-	return NETDEV_TX_OK;
 }
 
 static int ar9170_op_add_interface(struct ieee80211_hw *hw,

drivers/net/wireless/ath/ath5k/ath5k.h

···
 
 void set_beacon_filter(struct ieee80211_hw *hw, bool enable);
 bool ath_any_vif_assoc(struct ath5k_softc *sc);
-int ath5k_tx_queue(struct ieee80211_hw *hw, struct sk_buff *skb,
-		   struct ath5k_txq *txq);
+void ath5k_tx_queue(struct ieee80211_hw *hw, struct sk_buff *skb,
+		    struct ath5k_txq *txq);
 int ath5k_init_hw(struct ath5k_softc *sc);
 int ath5k_stop_hw(struct ath5k_softc *sc);
 void ath5k_mode_setup(struct ath5k_softc *sc, struct ieee80211_vif *vif);

drivers/net/wireless/ath/ath5k/base.c

···
 * TX Handling *
 \*************/
 
-int
+void
 ath5k_tx_queue(struct ieee80211_hw *hw, struct sk_buff *skb,
 	       struct ath5k_txq *txq)
 {
···
 		spin_unlock_irqrestore(&sc->txbuflock, flags);
 		goto drop_packet;
 	}
-	return NETDEV_TX_OK;
+	return;
 
 drop_packet:
 	dev_kfree_skb_any(skb);
-	return NETDEV_TX_OK;
 }
 
 static void

drivers/net/wireless/ath/ath5k/mac80211-ops.c

···
 * Mac80211 functions *
 \********************/
 
-static int
+static void
 ath5k_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct ath5k_softc *sc = hw->priv;
···
 
 	if (WARN_ON(qnum >= sc->ah->ah_capabilities.cap_queues.q_tx_num)) {
 		dev_kfree_skb_any(skb);
-		return 0;
+		return;
 	}
 
-	return ath5k_tx_queue(hw, skb, &sc->txqs[qnum]);
+	ath5k_tx_queue(hw, skb, &sc->txqs[qnum]);
 }
 
 

drivers/net/wireless/ath/ath9k/htc_drv_main.c

···
 /* mac80211 Callbacks */
 /**********************/
 
-static int ath9k_htc_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void ath9k_htc_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct ieee80211_hdr *hdr;
 	struct ath9k_htc_priv *priv = hw->priv;
···
 	padsize = padpos & 3;
 	if (padsize && skb->len > padpos) {
 		if (skb_headroom(skb) < padsize)
-			return -1;
+			goto fail_tx;
 		skb_push(skb, padsize);
 		memmove(skb->data, skb->data + padsize, padpos);
 	}
···
 		goto fail_tx;
 	}
 
-	return 0;
+	return;
 
 fail_tx:
 	dev_kfree_skb_any(skb);
-	return 0;
 }
 
 static int ath9k_htc_start(struct ieee80211_hw *hw)

drivers/net/wireless/ath/ath9k/main.c

···
 	return r;
 }
 
-static int ath9k_tx(struct ieee80211_hw *hw,
-		    struct sk_buff *skb)
+static void ath9k_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct ath_softc *sc = hw->priv;
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
···
 		goto exit;
 	}
 
-	return 0;
+	return;
 exit:
 	dev_kfree_skb_any(skb);
-	return 0;
 }
 
 static void ath9k_stop(struct ieee80211_hw *hw)

drivers/net/wireless/ath/carl9170/carl9170.h

···
 void carl9170_handle_command_response(struct ar9170 *ar, void *buf, u32 len);
 
 /* TX */
-int carl9170_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
+void carl9170_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
 void carl9170_tx_janitor(struct work_struct *work);
 void carl9170_tx_process_status(struct ar9170 *ar,
 				const struct carl9170_rsp *cmd);

drivers/net/wireless/ath/carl9170/tx.c

···
 	return false;
 }
 
-int carl9170_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+void carl9170_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct ar9170 *ar = hw->priv;
 	struct ieee80211_tx_info *info;
···
 	}
 
 	carl9170_tx(ar);
-	return NETDEV_TX_OK;
+	return;
 
 err_free:
 	ar->tx_dropped++;
 	dev_kfree_skb_any(skb);
-	return NETDEV_TX_OK;
 }
 
 void carl9170_tx_scheduler(struct ar9170 *ar)

drivers/net/wireless/b43/main.c

···
 	mutex_unlock(&wl->mutex);
 }
 
-static int b43_op_tx(struct ieee80211_hw *hw,
+static void 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;
+		return;
 	}
 	B43_WARN_ON(skb_shinfo(skb)->nr_frags);
 
 	skb_queue_tail(&wl->tx_queue, skb);
 	ieee80211_queue_work(wl->hw, &wl->tx_work);
-
-	return NETDEV_TX_OK;
 }
 
 static void b43_qos_params_upload(struct b43_wldev *dev,

drivers/net/wireless/b43legacy/main.c

···
 	return err;
 }
 
-static int b43legacy_op_tx(struct ieee80211_hw *hw,
-			   struct sk_buff *skb)
+static void b43legacy_op_tx(struct ieee80211_hw *hw,
+			    struct sk_buff *skb)
 {
 	struct b43legacy_wl *wl = hw_to_b43legacy_wl(hw);
 	struct b43legacy_wldev *dev = wl->current_dev;
···
 		/* Drop the packet. */
 		dev_kfree_skb_any(skb);
 	}
-	return NETDEV_TX_OK;
 }
 
 static int b43legacy_op_conf_tx(struct ieee80211_hw *hw, u16 queue,

drivers/net/wireless/iwlegacy/iwl-4965.h

···
 int  iwl4965_eeprom_check_version(struct iwl_priv *priv);
 
 /* mac80211 handlers (for 4965) */
-int iwl4965_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
+void iwl4965_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
 int iwl4965_mac_start(struct ieee80211_hw *hw);
 void iwl4965_mac_stop(struct ieee80211_hw *hw);
 void iwl4965_configure_filter(struct ieee80211_hw *hw,

drivers/net/wireless/iwlegacy/iwl3945-base.c

···
 	IWL_DEBUG_MAC80211(priv, "leave\n");
 }
 
-static int iwl3945_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void iwl3945_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct iwl_priv *priv = hw->priv;
 
···
 		dev_kfree_skb_any(skb);
 
 	IWL_DEBUG_MAC80211(priv, "leave\n");
-	return NETDEV_TX_OK;
 }
 
 void iwl3945_config_ap(struct iwl_priv *priv)

drivers/net/wireless/iwlegacy/iwl4965-base.c

···
 	IWL_DEBUG_MAC80211(priv, "leave\n");
 }
 
-int iwl4965_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+void iwl4965_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct iwl_priv *priv = hw->priv;
 
···
 		dev_kfree_skb_any(skb);
 
 	IWL_DEBUG_MACDUMP(priv, "leave\n");
-	return NETDEV_TX_OK;
 }
 
 void iwl4965_mac_update_tkip_key(struct ieee80211_hw *hw,

drivers/net/wireless/iwlwifi/iwl-agn.c

···
 	IWL_DEBUG_MAC80211(priv, "leave\n");
 }
 
-int iwlagn_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+void iwlagn_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct iwl_priv *priv = hw->priv;
 
···
 		dev_kfree_skb_any(skb);
 
 	IWL_DEBUG_MACDUMP(priv, "leave\n");
-	return NETDEV_TX_OK;
 }
 
 void iwlagn_mac_update_tkip_key(struct ieee80211_hw *hw,

drivers/net/wireless/iwlwifi/iwl-agn.h

···
 			   struct iwl_notification_wait *wait_entry);
 
 /* mac80211 handlers (for 4965) */
-int iwlagn_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
+void iwlagn_mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
 int iwlagn_mac_start(struct ieee80211_hw *hw);
 void iwlagn_mac_stop(struct ieee80211_hw *hw);
 void iwlagn_configure_filter(struct ieee80211_hw *hw,

drivers/net/wireless/libertas_tf/main.c

···
 	lbtf_deb_leave(LBTF_DEB_MAIN);
 }
 
-static int lbtf_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void lbtf_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct lbtf_private *priv = hw->priv;
 
···
 	 * there are no buffered multicast frames to send
 	 */
 	ieee80211_stop_queues(priv->hw);
-	return NETDEV_TX_OK;
 }
 
 static void lbtf_tx_work(struct work_struct *work)

drivers/net/wireless/mac80211_hwsim.c

···
 }
 
 
-static int mac80211_hwsim_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void mac80211_hwsim_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	bool ack;
 	struct ieee80211_tx_info *txi;
···
 	if (skb->len < 10) {
 		/* Should not happen; just a sanity check for addr1 use */
 		dev_kfree_skb(skb);
-		return NETDEV_TX_OK;
+		return;
 	}
 
 	ack = mac80211_hwsim_tx_frame(hw, skb);
···
 	if (!(txi->flags & IEEE80211_TX_CTL_NO_ACK) && ack)
 		txi->flags |= IEEE80211_TX_STAT_ACK;
 	ieee80211_tx_status_irqsafe(hw, skb);
-	return NETDEV_TX_OK;
 }
 
 

drivers/net/wireless/mwl8k.c

···
 	txq->txd = NULL;
 }
 
-static int
+static void
 mwl8k_txq_xmit(struct ieee80211_hw *hw, int index, struct sk_buff *skb)
 {
 	struct mwl8k_priv *priv = hw->priv;
···
 		wiphy_debug(hw->wiphy,
 			    "failed to dma map skb, dropping TX frame.\n");
 		dev_kfree_skb(skb);
-		return NETDEV_TX_OK;
+		return;
 	}
 
 	spin_lock_bh(&priv->tx_lock);
···
 	mwl8k_tx_start(priv);
 
 	spin_unlock_bh(&priv->tx_lock);
-
-	return NETDEV_TX_OK;
 }
 
 
···
 /*
  * Core driver operations.
  */
-static int mwl8k_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void mwl8k_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct mwl8k_priv *priv = hw->priv;
 	int index = skb_get_queue_mapping(skb);
-	int rc;
 
 	if (!priv->radio_on) {
 		wiphy_debug(hw->wiphy,
 			    "dropped TX frame since radio disabled\n");
 		dev_kfree_skb(skb);
-		return NETDEV_TX_OK;
+		return;
 	}
 
-	rc = mwl8k_txq_xmit(hw, index, skb);
-
-	return rc;
+	mwl8k_txq_xmit(hw, index, skb);
 }
 
 static int mwl8k_start(struct ieee80211_hw *hw)

drivers/net/wireless/p54/lmac.h

···
 void p54_unregister_leds(struct p54_common *priv);
 
 /* xmit functions */
-int p54_tx_80211(struct ieee80211_hw *dev, struct sk_buff *skb);
+void p54_tx_80211(struct ieee80211_hw *dev, struct sk_buff *skb);
 int p54_tx_cancel(struct p54_common *priv, __le32 req_id);
 void p54_tx(struct p54_common *priv, struct sk_buff *skb);
 

drivers/net/wireless/p54/main.c

···
 	 * to cancel the old beacon template by hand, instead the firmware
 	 * will release the previous one through the feedback mechanism.
 	 */
-	WARN_ON(p54_tx_80211(priv->hw, beacon));
+	p54_tx_80211(priv->hw, beacon);
 	priv->tsf_high32 = 0;
 	priv->tsf_low32 = 0;
 

drivers/net/wireless/p54/txrx.c

···
 	}
 }
 
-int p54_tx_80211(struct ieee80211_hw *dev, struct sk_buff *skb)
+void p54_tx_80211(struct ieee80211_hw *dev, struct sk_buff *skb)
 {
 	struct p54_common *priv = dev->priv;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
···
 			    &hdr_flags, &aid, &burst_allowed);
 
 	if (p54_tx_qos_accounting_alloc(priv, skb, queue)) {
-		if (!IS_QOS_QUEUE(queue)) {
-			dev_kfree_skb_any(skb);
-			return NETDEV_TX_OK;
-		} else {
-			return NETDEV_TX_BUSY;
-		}
+		dev_kfree_skb_any(skb);
+		return;
 	}
 
 	padding = (unsigned long)(skb->data - (sizeof(*hdr) + sizeof(*txhdr))) & 3;
···
 	p54info->extra_len = extra_len;
 
 	p54_tx(priv, skb);
-	return NETDEV_TX_OK;
 }

drivers/net/wireless/rt2x00/rt2x00.h

···
 /*
  * mac80211 handlers.
  */
-int rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
+void rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
 int rt2x00mac_start(struct ieee80211_hw *hw);
 void rt2x00mac_stop(struct ieee80211_hw *hw);
 int rt2x00mac_add_interface(struct ieee80211_hw *hw,

drivers/net/wireless/rt2x00/rt2x00mac.c

···
 	return retval;
 }
 
-int rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+void rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;
 	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
···
 	if (rt2x00queue_threshold(queue))
 		rt2x00queue_pause_queue(queue);
 
-	return NETDEV_TX_OK;
+	return;
 
  exit_fail:
 	ieee80211_stop_queue(rt2x00dev->hw, qid);
 	dev_kfree_skb_any(skb);
-	return NETDEV_TX_OK;
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_tx);
 

drivers/net/wireless/rtl818x/rtl8180/dev.c

···
 	return IRQ_HANDLED;
 }
 
-static int rtl8180_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
+static void rtl8180_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
 {
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
···
 	spin_unlock_irqrestore(&priv->lock, flags);
 
 	rtl818x_iowrite8(priv, &priv->map->TX_DMA_POLLING, (1 << (prio + 4)));
-
-	return 0;
 }
 
 void rtl8180_set_anaparam(struct rtl8180_priv *priv, u32 anaparam)
···
 	struct ieee80211_hw *dev = vif_priv->dev;
 	struct ieee80211_mgmt *mgmt;
 	struct sk_buff *skb;
-	int err = 0;
 
 	/* don't overflow the tx ring */
 	if (ieee80211_queue_stopped(dev, 0))
···
 	/* TODO: use actual beacon queue */
 	skb_set_queue_mapping(skb, 0);
 
-	err = rtl8180_tx(dev, skb);
-	WARN_ON(err);
+	rtl8180_tx(dev, skb);
 
 resched:
 	/*

drivers/net/wireless/rtl818x/rtl8187/dev.c

···
 	}
 }
 
-static int rtl8187_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
+static void rtl8187_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
 {
 	struct rtl8187_priv *priv = dev->priv;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
···
 	urb = usb_alloc_urb(0, GFP_ATOMIC);
 	if (!urb) {
 		kfree_skb(skb);
-		return NETDEV_TX_OK;
+		return;
 	}
 
 	flags = skb->len;
···
 		kfree_skb(skb);
 	}
 	usb_free_urb(urb);
-
-	return NETDEV_TX_OK;
 }
 
 static void rtl8187_rx_cb(struct urb *urb)

drivers/net/wireless/rtlwifi/core.c

···
 	mutex_unlock(&rtlpriv->locks.conf_mutex);
 }
 
-static int rtl_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void rtl_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_hal *rtlhal = rtl_hal(rtl_priv(hw));
···
 
 	rtlpriv->intf_ops->adapter_tx(hw, skb);
 
-	return NETDEV_TX_OK;
+	return;
 
 err_free:
 	dev_kfree_skb_any(skb);
-	return NETDEV_TX_OK;
 }
 
 static int rtl_op_add_interface(struct ieee80211_hw *hw,

drivers/net/wireless/wl1251/main.c

···
 	mutex_unlock(&wl->mutex);
 }
 
-static int wl1251_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void wl1251_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct wl1251 *wl = hw->priv;
 	unsigned long flags;
···
 		wl->tx_queue_stopped = true;
 		spin_unlock_irqrestore(&wl->wl_lock, flags);
 	}
-
-	return NETDEV_TX_OK;
 }
 
 static int wl1251_op_start(struct ieee80211_hw *hw)

drivers/net/wireless/wl12xx/main.c

···
 	return ret;
 }
 
-static int wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct wl1271 *wl = hw->priv;
 	unsigned long flags;
···
 
 	if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags))
 		ieee80211_queue_work(wl->hw, &wl->tx_work);
-
-	return NETDEV_TX_OK;
 }
 
 static struct notifier_block wl1271_dev_notifier = {

drivers/net/wireless/zd1211rw/zd_mac.c

···
  * control block of the skbuff will be initialized. If necessary the incoming
  * mac80211 queues will be stopped.
  */
-static int zd_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void zd_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct zd_mac *mac = zd_hw_mac(hw);
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
···
 	r = zd_usb_tx(&mac->chip.usb, skb);
 	if (r)
 		goto fail;
-	return 0;
+	return;
 
 fail:
 	dev_kfree_skb(skb);
-	return 0;
 }
 
 /**

drivers/staging/brcm80211/sys/wl_mac80211.c

···
 static void wl_release_fw(struct wl_info *wl);
 
 /* local prototypes */
-static int wl_start(struct sk_buff *skb, struct wl_info *wl);
-static int wl_start_int(struct wl_info *wl, struct ieee80211_hw *hw,
-			struct sk_buff *skb);
 static void wl_dpc(unsigned long data);
 
 MODULE_AUTHOR("Broadcom Corporation");
···
 
 #define HW_TO_WL(hw)	 (hw->priv)
 #define WL_TO_HW(wl)	  (wl->pub->ieee_hw)
-static int wl_ops_tx(struct ieee80211_hw *hw, struct sk_buff *skb);
 static int wl_ops_start(struct ieee80211_hw *hw);
 static void wl_ops_stop(struct ieee80211_hw *hw);
 static int wl_ops_add_interface(struct ieee80211_hw *hw,
···
 			   enum ieee80211_ampdu_mlme_action action,
 			   struct ieee80211_sta *sta, u16 tid, u16 *ssn);
 
-static int wl_ops_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
+static void wl_ops_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
-	int status;
 	struct wl_info *wl = hw->priv;
 	WL_LOCK(wl);
 	if (!wl->pub->up) {
 		WL_ERROR("ops->tx called while down\n");
-		status = -ENETDOWN;
+		kfree_skb(skb);
 		goto done;
 	}
-	status = wl_start(skb, wl);
+	wlc_sendpkt_mac80211(wl->wlc, skb, hw);
  done:
 	WL_UNLOCK(wl);
-	return status;
 }
 
 static int wl_ops_start(struct ieee80211_hw *hw)
···
 
 
 	osl_detach(osh);
-}
-
-/* transmit a packet */
-static int BCMFASTPATH wl_start(struct sk_buff *skb, struct wl_info *wl)
-{
-	if (!wl)
-		return -ENETDOWN;
-
-	return wl_start_int(wl, WL_TO_HW(wl), skb);
-}
-
-static int BCMFASTPATH
-wl_start_int(struct wl_info *wl, struct ieee80211_hw *hw, struct sk_buff *skb)
-{
-	wlc_sendpkt_mac80211(wl->wlc, skb, hw);
-	return NETDEV_TX_OK;
 }
 
 void wl_txflowcontrol(struct wl_info *wl, struct wl_if *wlif, bool state,

drivers/staging/winbond/wbusb.c

···
 	*total_flags = new_flags;
 }
 
-static int wbsoft_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
+static void wbsoft_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
 {
 	struct wbsoft_priv *priv = dev->priv;
 
 	if (priv->sMlmeFrame.IsInUsed != PACKET_FREE_TO_USE) {
 		priv->sMlmeFrame.wNumTxMMPDUDiscarded++;
-		return NETDEV_TX_BUSY;
+		kfree_skb(skb);
+		return;
 	}
 
 	priv->sMlmeFrame.IsInUsed = PACKET_COME_FROM_MLME;
···
 	 */
 
 	Mds_Tx(priv);
-
-	return NETDEV_TX_OK;
 }
 
 static int wbsoft_start(struct ieee80211_hw *dev)

include/net/mac80211.h

···
  *	aborted before it expires. This callback may sleep.
  */
 struct ieee80211_ops {
-	int (*tx)(struct ieee80211_hw *hw, struct sk_buff *skb);
+	void (*tx)(struct ieee80211_hw *hw, struct sk_buff *skb);
 	int (*start)(struct ieee80211_hw *hw);
 	void (*stop)(struct ieee80211_hw *hw);
 	int (*add_interface)(struct ieee80211_hw *hw,

net/mac80211/driver-ops.h

···
 #include "ieee80211_i.h"
 #include "driver-trace.h"
 
-static inline int drv_tx(struct ieee80211_local *local, struct sk_buff *skb)
+static inline void drv_tx(struct ieee80211_local *local, struct sk_buff *skb)
 {
-	return local->ops->tx(&local->hw, skb);
+	local->ops->tx(&local->hw, skb);
 }
 
 static inline int drv_start(struct ieee80211_local *local)

net/mac80211/tx.c

···
 #include "wme.h"
 #include "rate.h"
 
-#define IEEE80211_TX_OK		0
-#define IEEE80211_TX_AGAIN	1
-#define IEEE80211_TX_PENDING	2
-
 /* misc utils */
 
 static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, int group_addr,
···
 	return TX_CONTINUE;
 }
 
-static int __ieee80211_tx(struct ieee80211_local *local,
-			  struct sk_buff **skbp,
-			  struct sta_info *sta,
-			  bool txpending)
+/*
+ * Returns false if the frame couldn't be transmitted but was queued instead.
+ */
+static bool __ieee80211_tx(struct ieee80211_local *local, struct sk_buff **skbp,
+			   struct sta_info *sta, bool txpending)
 {
 	struct sk_buff *skb = *skbp, *next;
 	struct ieee80211_tx_info *info;
 	struct ieee80211_sub_if_data *sdata;
 	unsigned long flags;
-	int ret, len;
+	int len;
 	bool fragm = false;
 
 	while (skb) {
···
 		__le16 fc;
 
 		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
-		ret = IEEE80211_TX_OK;
 		if (local->queue_stop_reasons[q] ||
-		    (!txpending && !skb_queue_empty(&local->pending[q])))
-			ret = IEEE80211_TX_PENDING;
+		    (!txpending && !skb_queue_empty(&local->pending[q]))) {
+			/*
+			 * Since queue is stopped, queue up frames for later
+			 * transmission from the tx-pending tasklet when the
+			 * queue is woken again.
+			 */
+
+			do {
+				next = skb->next;
+				skb->next = NULL;
+				/*
+				 * NB: If txpending is true, next must already
+				 * be NULL since we must've gone through this
+				 * loop before already; therefore we can just
+				 * queue the frame to the head without worrying
+				 * about reordering of fragments.
+				 */
+				if (unlikely(txpending))
+					__skb_queue_head(&local->pending[q],
+							 skb);
+				else
+					__skb_queue_tail(&local->pending[q],
+							 skb);
+			} while ((skb = next));
+
+			spin_unlock_irqrestore(&local->queue_stop_reason_lock,
+					       flags);
+			return false;
+		}
 		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
-		if (ret != IEEE80211_TX_OK)
-			return ret;
 
 		info = IEEE80211_SKB_CB(skb);
 
···
 			info->control.sta = NULL;
 
 		fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
-		ret = drv_tx(local, skb);
-		if (WARN_ON(ret != NETDEV_TX_OK && skb->len != len)) {
-			dev_kfree_skb(skb);
-			ret = NETDEV_TX_OK;
-		}
-		if (ret != NETDEV_TX_OK) {
-			info->control.vif = &sdata->vif;
-			return IEEE80211_TX_AGAIN;
-		}
+		drv_tx(local, skb);
 
 		ieee80211_tpt_led_trig_tx(local, fc, len);
 		*skbp = skb = next;
···
 		fragm = true;
 	}
 
-	return IEEE80211_TX_OK;
+	return true;
 }
 
 /*
···
 	return 0;
 }
 
-static void ieee80211_tx(struct ieee80211_sub_if_data *sdata,
+/*
+ * Returns false if the frame couldn't be transmitted but was queued instead.
+ */
+static bool ieee80211_tx(struct ieee80211_sub_if_data *sdata,
 			 struct sk_buff *skb, bool txpending)
 {
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_tx_data tx;
 	ieee80211_tx_result res_prepare;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
-	struct sk_buff *next;
-	unsigned long flags;
-	int ret, retries;
 	u16 queue;
+	bool result = true;
 
 	queue = skb_get_queue_mapping(skb);
 
 	if (unlikely(skb->len < 10)) {
 		dev_kfree_skb(skb);
-		return;
+		return true;
 	}
 
 	rcu_read_lock();
···
 
 	if (unlikely(res_prepare == TX_DROP)) {
 		dev_kfree_skb(skb);
-		rcu_read_unlock();
-		return;
+		goto out;
 	} else if (unlikely(res_prepare == TX_QUEUED)) {
-		rcu_read_unlock();
-		return;
+		goto out;
 	}
 
 	tx.channel = local->hw.conf.channel;
 	info->band = tx.channel->band;
 
-	if (invoke_tx_handlers(&tx))
-		goto out;
-
-	retries = 0;
- retry:
-	ret = __ieee80211_tx(local, &tx.skb, tx.sta, txpending);
-	switch (ret) {
-	case IEEE80211_TX_OK:
-		break;
-	case IEEE80211_TX_AGAIN:
-		/*
-		 * Since there are no fragmented frames on A-MPDU
-		 * queues, there's no reason for a driver to reject
-		 * a frame there, warn and drop it.
-		 */
-		if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
-			goto drop;
-		/* fall through */
-	case IEEE80211_TX_PENDING:
-		skb = tx.skb;
-
-		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
-
-		if (local->queue_stop_reasons[queue] ||
-		    !skb_queue_empty(&local->pending[queue])) {
-			/*
-			 * if queue is stopped, queue up frames for later
-			 * transmission from the tasklet
-			 */
-			do {
-				next = skb->next;
-				skb->next = NULL;
-				if (unlikely(txpending))
-					__skb_queue_head(&local->pending[queue],
-							 skb);
-				else
-					__skb_queue_tail(&local->pending[queue],
-							 skb);
-			} while ((skb = next));
-
-			spin_unlock_irqrestore(&local->queue_stop_reason_lock,
-					       flags);
-		} else {
-			/*
-			 * otherwise retry, but this is a race condition or
-			 * a driver bug (which we warn about if it persists)
-			 */
-			spin_unlock_irqrestore(&local->queue_stop_reason_lock,
-					       flags);
-
-			retries++;
-			if (WARN(retries > 10, "tx refused but queue active\n"))
-				goto drop;
-			goto retry;
-		}
-	}
+	if (!invoke_tx_handlers(&tx))
+		result = __ieee80211_tx(local, &tx.skb, tx.sta, txpending);
  out:
 	rcu_read_unlock();
-	return;
-
- drop:
-	rcu_read_unlock();
-
-	skb = tx.skb;
-	while (skb) {
-		next = skb->next;
-		dev_kfree_skb(skb);
-		skb = next;
-	}
+	return result;
 }
 
 /* device xmit handlers */
···
 		skb_queue_purge(&local->pending[i]);
 }
 
+/*
+ * Returns false if the frame couldn't be transmitted but was queued instead,
+ * which in this case means re-queued -- take as an indication to stop sending
+ * more pending frames.
+ */
 static bool ieee80211_tx_pending_skb(struct ieee80211_local *local,
 				     struct sk_buff *skb)
 {
···
 	struct ieee80211_sub_if_data *sdata;
 	struct sta_info *sta;
 	struct ieee80211_hdr *hdr;
-	int ret;
-	bool result = true;
+	bool result;
 
 	sdata = vif_to_sdata(info->control.vif);
 
 	if (info->flags & IEEE80211_TX_INTFL_NEED_TXPROCESSING) {
-		ieee80211_tx(sdata, skb, true);
+		result = ieee80211_tx(sdata, skb, true);
 	} else {
 		hdr = (struct ieee80211_hdr *)skb->data;
 		sta = sta_info_get(sdata, hdr->addr1);
 
-		ret = __ieee80211_tx(local, &skb, sta, true);
-		if (ret != IEEE80211_TX_OK)
-			result = false;
+		result = __ieee80211_tx(local, &skb, sta, true);
 	}
 
 	return result;
···
 						flags);
 
 			txok = ieee80211_tx_pending_skb(local, skb);
-			if (!txok)
-				__skb_queue_head(&local->pending[i], skb);
 			spin_lock_irqsave(&local->queue_stop_reason_lock,
 					  flags);
 			if (!txok)