iwlagn: move the check_empty logic to the transport layer

This logic is responsible to tell mac80211 when the HW queues are
empty and the BA session can be started / torn down.

Fix a bug on the way:
When the the Tx BA session is stopped and the HW queues aren't empty,
we stop the SW queue to drain the HW queue and then switch to the
legacy HW queue. This is the IWL_EMPTYING_HW_QUEUE_DELBA state.

While in this state, we never wake the SW queue, even when the HW
queue is almost empty, since we need to drain it completely. Look
at iwl_trans_pcie_reclaim regarding this.

Once the HW queue is really empty, we must wake the SW queue in order
to get traffic to the legacy queue.
This step was missing leading to an odd situation were the traffic
would just stall after we tore down a Tx BA session while the HW
queue was not empty.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-tx-pcie.c b/drivers/net/wireless/iwlwifi/iwl-trans-tx-pcie.c
index 93922265feb..da8d79eb4dc 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans-tx-pcie.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans-tx-pcie.c
@@ -1118,12 +1118,13 @@ int iwl_trans_pcie_send_cmd_pdu(struct iwl_trans *trans, u8 id, u32 flags,
 }
 
 /* Frees buffers until index _not_ inclusive */
-void iwl_tx_queue_reclaim(struct iwl_trans *trans, int txq_id, int index,
-			    struct sk_buff_head *skbs)
+int iwl_tx_queue_reclaim(struct iwl_trans *trans, int txq_id, int index,
+			 struct sk_buff_head *skbs)
 {
 	struct iwl_tx_queue *txq = &priv(trans)->txq[txq_id];
 	struct iwl_queue *q = &txq->q;
 	int last_to_free;
+	int freed = 0;
 
 	/*Since we free until index _not_ inclusive, the one before index is
 	 * the last we will free. This one must be used */
@@ -1135,14 +1136,14 @@ void iwl_tx_queue_reclaim(struct iwl_trans *trans, int txq_id, int index,
 			  "last_to_free %d is out of range [0-%d] %d %d.\n",
 			  __func__, txq_id, last_to_free, q->n_bd,
 			  q->write_ptr, q->read_ptr);
-		return;
+		return 0;
 	}
 
 	IWL_DEBUG_TX_REPLY(trans, "reclaim: [%d, %d, %d]\n", txq_id,
 			   q->read_ptr, index);
 
 	if (WARN_ON(!skb_queue_empty(skbs)))
-		return;
+		return 0;
 
 	for (;
 	     q->read_ptr != index;
@@ -1158,5 +1159,7 @@ void iwl_tx_queue_reclaim(struct iwl_trans *trans, int txq_id, int index,
 		iwlagn_txq_inval_byte_cnt_tbl(trans, txq);
 
 		iwlagn_txq_free_tfd(trans, txq, txq->q.read_ptr);
+		freed++;
 	}
+	return freed;
 }