iwlwifi: error checking for number of tfds in queue

When receive reply_tx and ready to decrement the count for number of
tfds in queue, do error checking to prevent error condition and
tfds_in_queue become negative number.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
CC: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/iwlwifi/iwl-4965.c b/drivers/net/wireless/iwlwifi/iwl-4965.c
index 9b4b8b5..3146281 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-4965.c
+++ b/drivers/net/wireless/iwlwifi/iwl-4965.c
@@ -2008,7 +2008,7 @@ static void iwl4965_rx_reply_tx(struct iwl_priv *priv,
                        IWL_DEBUG_TX_REPLY(priv, "Retry scheduler reclaim scd_ssn "
                                           "%d index %d\n", scd_ssn , index);
                        freed = iwl_tx_queue_reclaim(priv, txq_id, index);
-                       priv->stations[sta_id].tid[tid].tfds_in_queue -= freed;
+                       iwl_free_tfds_in_queue(priv, sta_id, tid, freed);
 
                        if (priv->mac80211_registered &&
                            (iwl_queue_space(&txq->q) > txq->q.low_mark) &&

diff --git a/drivers/net/wireless/iwlwifi/iwl-5000.c b/drivers/net/wireless/iwlwifi/iwl-5000.c
index de45f30..f27c514 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-5000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-5000.c
@@ -1125,7 +1125,7 @@ static void iwl5000_rx_reply_tx(struct iwl_priv *priv,
                                        scd_ssn , index, txq_id, txq->swq_id);
 
                        freed = iwl_tx_queue_reclaim(priv, txq_id, index);
-                       priv->stations[sta_id].tid[tid].tfds_in_queue -= freed;
+                       iwl_free_tfds_in_queue(priv, sta_id, tid, freed);
 
                        if (priv->mac80211_registered &&
                            (iwl_queue_space(&txq->q) > txq->q.low_mark) &&
@@ -1154,7 +1154,7 @@ static void iwl5000_rx_reply_tx(struct iwl_priv *priv,
 
                freed = iwl_tx_queue_reclaim(priv, txq_id, index);
                if (ieee80211_is_data_qos(tx_resp->frame_ctrl))
-                       priv->stations[sta_id].tid[tid].tfds_in_queue -= freed;
+                       iwl_free_tfds_in_queue(priv, sta_id, tid, freed);
 
                if (priv->mac80211_registered &&
                    (iwl_queue_space(&txq->q) > txq->q.low_mark))

diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index 675b7df..fe37d6a 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -446,6 +446,8 @@ void iwl_hw_txq_ctx_free(struct iwl_priv *priv);
 int iwl_hw_tx_queue_init(struct iwl_priv *priv,
                         struct iwl_tx_queue *txq);
 int iwl_txq_update_write_ptr(struct iwl_priv *priv, struct iwl_tx_queue *txq);
+void iwl_free_tfds_in_queue(struct iwl_priv *priv,
+                           int sta_id, int tid, int freed);
 int iwl_tx_queue_init(struct iwl_priv *priv, struct iwl_tx_queue *txq,
                      int slots_num, u32 txq_id);
 void iwl_tx_queue_free(struct iwl_priv *priv, int txq_id);

diff --git a/drivers/net/wireless/iwlwifi/iwl-tx.c b/drivers/net/wireless/iwlwifi/iwl-tx.c
index 87ce2bd..72136c8 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-tx.c
@@ -120,6 +120,20 @@ int iwl_txq_update_write_ptr(struct iwl_priv *priv, struct iwl_tx_queue *txq)
 EXPORT_SYMBOL(iwl_txq_update_write_ptr);
 
 
+void iwl_free_tfds_in_queue(struct iwl_priv *priv,
+                           int sta_id, int tid, int freed)
+{
+       if (priv->stations[sta_id].tid[tid].tfds_in_queue >= freed)
+               priv->stations[sta_id].tid[tid].tfds_in_queue -= freed;
+       else {
+               IWL_ERR(priv, "free more than tfds_in_queue (%u:%d)\n",
+                       priv->stations[sta_id].tid[tid].tfds_in_queue,
+                       freed);
+               priv->stations[sta_id].tid[tid].tfds_in_queue = 0;
+       }
+}
+EXPORT_SYMBOL(iwl_free_tfds_in_queue);
+
 /**
  * iwl_tx_queue_free - Deallocate DMA queue.
  * @txq: Transmit queue to deallocate.
@@ -1559,7 +1573,7 @@ void iwl_rx_reply_compressed_ba(struct iwl_priv *priv,
        if (txq->q.read_ptr != (ba_resp_scd_ssn & 0xff)) {
                /* calculate mac80211 ampdu sw queue to wake */
                int freed = iwl_tx_queue_reclaim(priv, scd_flow, index);
-               priv->stations[sta_id].tid[tid].tfds_in_queue -= freed;
+               iwl_free_tfds_in_queue(priv, sta_id, tid, freed);
 
                if ((iwl_queue_space(&txq->q) > txq->q.low_mark) &&
                    priv->mac80211_registered &&