ipw2200: fix ucode assertion for RX queue overrun

Restock the RX queue when there are a lot of unused frames so that the
RX ring buffer doesn't overrun, causing a ucode assertion.  Backport of
patch "iwlwifi: fix ucode assertion for RX queue overrun".

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ipw2200.c b/drivers/net/wireless/ipw2200.c
index 3e6ad7b92c8316e488ca20575c1146aea6e10063..a56d9fc6354f90fce9d0f2e79b6b5ecf6eafea93 100644 (file)
--- a/drivers/net/wireless/ipw2200.c
+++ b/drivers/net/wireless/ipw2200.c
@@ -3365,7 +3365,6 @@ static void ipw_rx_queue_reset(struct ipw_priv *priv,
        /* Set us so that we have processed and used all buffers, but have
         * not restocked the Rx queue with fresh buffers */
        rxq->read = rxq->write = 0;
-       rxq->processed = RX_QUEUE_SIZE - 1;
        rxq->free_count = 0;
        spin_unlock_irqrestore(&rxq->lock, flags);
 }
@@ -3607,7 +3606,22 @@ static int ipw_load(struct ipw_priv *priv)
  * Driver allocates buffers of this size for Rx
  */
 
-static inline int ipw_queue_space(const struct clx2_queue *q)
+/**
+ * ipw_rx_queue_space - Return number of free slots available in queue.
+ */
+static int ipw_rx_queue_space(const struct ipw_rx_queue *q)
+{
+       int s = q->read - q->write;
+       if (s <= 0)
+               s += RX_QUEUE_SIZE;
+       /* keep some buffer to not confuse full and empty queue */
+       s -= 2;
+       if (s < 0)
+               s = 0;
+       return s;
+}
+
+static inline int ipw_tx_queue_space(const struct clx2_queue *q)
 {
        int s = q->last_used - q->first_empty;
        if (s <= 0)
@@ -4947,7 +4961,7 @@ static int ipw_queue_tx_reclaim(struct ipw_priv *priv,
                priv->tx_packets++;
        }
       done:
-       if ((ipw_queue_space(q) > q->low_mark) &&
+       if ((ipw_tx_queue_space(q) > q->low_mark) &&
            (qindex >= 0) &&
            (priv->status & STATUS_ASSOCIATED) && netif_running(priv->net_dev))
                netif_wake_queue(priv->net_dev);
@@ -4965,7 +4979,7 @@ static int ipw_queue_tx_hcmd(struct ipw_priv *priv, int hcmd, void *buf,
        struct clx2_queue *q = &txq->q;
        struct tfd_frame *tfd;
 
-       if (ipw_queue_space(q) < (sync ? 1 : 2)) {
+       if (ipw_tx_queue_space(q) < (sync ? 1 : 2)) {
                IPW_ERROR("No space for Tx\n");
                return -EBUSY;
        }
@@ -5070,7 +5084,7 @@ static void ipw_rx_queue_restock(struct ipw_priv *priv)
 
        spin_lock_irqsave(&rxq->lock, flags);
        write = rxq->write;
-       while ((rxq->write != rxq->processed) && (rxq->free_count)) {
+       while ((ipw_rx_queue_space(rxq) > 0) && (rxq->free_count)) {
                element = rxq->rx_free.next;
                rxb = list_entry(element, struct ipw_rx_mem_buffer, list);
                list_del(element);
@@ -5187,7 +5201,6 @@ static struct ipw_rx_queue *ipw_rx_queue_alloc(struct ipw_priv *priv)
        /* Set us so that we have processed and used all buffers, but have
         * not restocked the Rx queue with fresh buffers */
        rxq->read = rxq->write = 0;
-       rxq->processed = RX_QUEUE_SIZE - 1;
        rxq->free_count = 0;
 
        return rxq;
@@ -8223,13 +8236,17 @@ static void ipw_rx(struct ipw_priv *priv)
        struct ieee80211_hdr_4addr *header;
        u32 r, w, i;
        u8 network_packet;
+       u8 fill_rx = 0;
        DECLARE_MAC_BUF(mac);
        DECLARE_MAC_BUF(mac2);
        DECLARE_MAC_BUF(mac3);
 
        r = ipw_read32(priv, IPW_RX_READ_INDEX);
        w = ipw_read32(priv, IPW_RX_WRITE_INDEX);
-       i = (priv->rxq->processed + 1) % RX_QUEUE_SIZE;
+       i = priv->rxq->read;
+
+       if (ipw_rx_queue_space (priv->rxq) > (RX_QUEUE_SIZE / 2))
+               fill_rx = 1;
 
        while (i != r) {
                rxb = priv->rxq->queue[i];
@@ -8404,11 +8421,17 @@ static void ipw_rx(struct ipw_priv *priv)
                list_add_tail(&rxb->list, &priv->rxq->rx_used);
 
                i = (i + 1) % RX_QUEUE_SIZE;
+
+               /* If there are a lot of unsued frames, restock the Rx queue
+                * so the ucode won't assert */
+               if (fill_rx) {
+                       priv->rxq->read = i;
+                       ipw_rx_queue_replenish(priv);
+               }
        }
 
        /* Backtrack one entry */
-       priv->rxq->processed = (i ? i : RX_QUEUE_SIZE) - 1;
-
+       priv->rxq->read = i;
        ipw_rx_queue_restock(priv);
 }
 
@@ -10336,7 +10359,7 @@ static int ipw_tx_skb(struct ipw_priv *priv, struct ieee80211_txb *txb,
        q->first_empty = ipw_queue_inc_wrap(q->first_empty, q->n_bd);
        ipw_write32(priv, q->reg_w, q->first_empty);
 
-       if (ipw_queue_space(q) < q->high_mark)
+       if (ipw_tx_queue_space(q) < q->high_mark)
                netif_stop_queue(priv->net_dev);
 
        return NETDEV_TX_OK;
@@ -10357,7 +10380,7 @@ static int ipw_net_is_queue_full(struct net_device *dev, int pri)
        struct clx2_tx_queue *txq = &priv->txq[0];
 #endif                         /* CONFIG_IPW2200_QOS */
 
-       if (ipw_queue_space(&txq->q) < txq->q.high_mark)
+       if (ipw_tx_queue_space(&txq->q) < txq->q.high_mark)
                return 1;
 
        return 0;