Ath5k: lock beacons

Beacons setup and config was racy with beacon send. Ensure that
ISR and reset functions see consistent state of bbuf.

Use also dev_kfree_skb_any in ath5k_txbuf_free since we call it
from atomic now.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Nick Kossifidis <mickflemm@gmail.com>
Cc: Luis R. Rodriguez <mcgrof@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath5k/base.c

@@ -251,7 +251,7 @@ static inline void ath5k_txbuf_free(struct ath5k_softc *sc,
 		return;
 	pci_unmap_single(sc->pdev, bf->skbaddr, bf->skb->len,
 			PCI_DMA_TODEVICE);
-	dev_kfree_skb(bf->skb);
+	dev_kfree_skb_any(bf->skb);
 	bf->skb = NULL;
 }
 
@@ -466,6 +466,7 @@ ath5k_pci_probe(struct pci_dev *pdev,
 	mutex_init(&sc->lock);
 	spin_lock_init(&sc->rxbuflock);
 	spin_lock_init(&sc->txbuflock);
+	spin_lock_init(&sc->block);
 
 	/* Set private data */
 	pci_set_drvdata(pdev, hw);
@@ -2179,8 +2180,11 @@ ath5k_beacon_config(struct ath5k_softc *sc)
 
 		sc->imask |= AR5K_INT_SWBA;
 
-		if (ath5k_hw_hasveol(ah))
+		if (ath5k_hw_hasveol(ah)) {
+			spin_lock(&sc->block);
 			ath5k_beacon_send(sc);
+			spin_unlock(&sc->block);
+		}
 	}
 	/* TODO else AP */
 
@@ -2403,7 +2407,9 @@ ath5k_intr(int irq, void *dev_id)
 						  TSF_TO_TU(tsf),
 						  (unsigned long long) tsf);
 				} else {
+					spin_lock(&sc->block);
 					ath5k_beacon_send(sc);
+					spin_unlock(&sc->block);
 				}
 			}
 			if (status & AR5K_INT_RXEOL) {
@@ -3050,6 +3056,7 @@ static int
 ath5k_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct ath5k_softc *sc = hw->priv;
+	unsigned long flags;
 	int ret;
 
 	ath5k_debug_dump_skb(sc, skb, "BC  ", 1);
@@ -3059,12 +3066,14 @@ ath5k_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb)
 		goto end;
 	}
 
+	spin_lock_irqsave(&sc->block, flags);
 	ath5k_txbuf_free(sc, sc->bbuf);
 	sc->bbuf->skb = skb;
 	ret = ath5k_beacon_setup(sc, sc->bbuf);
 	if (ret)
 		sc->bbuf->skb = NULL;
-	else {
+	spin_unlock_irqrestore(&sc->block, flags);
+	if (!ret) {
 		ath5k_beacon_config(sc);
 		mmiowb();
 	}

drivers/net/wireless/ath5k/base.h

@@ -172,6 +172,7 @@ struct ath5k_softc {
 	struct tasklet_struct	txtq;		/* tx intr tasklet */
 	struct ath5k_led	tx_led;		/* tx led */
 
+	spinlock_t		block;		/* protects beacon */
 	struct ath5k_buf	*bbuf;		/* beacon buffer */
 	unsigned int		bhalq,		/* SW q for outgoing beacons */
 				bmisscount,	/* missed beacon transmits */