iwlwifi: cleanup iwl_good_ack_health

Make ack health code easies to read. Compared to previous
code, we do not print debug messages when expected_ack_cnt_delta == 0
and also do check against negative deltas.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 35 insertions, 34 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 096f8ad0f1b1..50be23b5fea2 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -1407,34 +1407,37 @@ static void iwl_irq_tasklet(struct iwl_priv *priv)
 /**
  * iwl_good_ack_health - checks for ACK count ratios, BA timeout retries.
  *
- * When the ACK count ratio is 0 and aggregated BA timeout retries exceeding
+ * When the ACK count ratio is low and aggregated BA timeout retries exceeding
  * the BA_TIMEOUT_MAX, reload firmware and bring system back to normal
  * operation state.
  */
-bool iwl_good_ack_health(struct iwl_priv *priv,
-                                struct iwl_rx_packet *pkt)
+bool iwl_good_ack_health(struct iwl_priv *priv, struct iwl_rx_packet *pkt)
 {
-        bool rc = true;
-        int actual_ack_cnt_delta, expected_ack_cnt_delta;
-        int ba_timeout_delta;
-
-        actual_ack_cnt_delta =
-                le32_to_cpu(pkt->u.stats.tx.actual_ack_cnt) -
-                le32_to_cpu(priv->_agn.statistics.tx.actual_ack_cnt);
-        expected_ack_cnt_delta =
-                le32_to_cpu(pkt->u.stats.tx.expected_ack_cnt) -
-                le32_to_cpu(priv->_agn.statistics.tx.expected_ack_cnt);
-        ba_timeout_delta =
-                le32_to_cpu(pkt->u.stats.tx.agg.ba_timeout) -
-                le32_to_cpu(priv->_agn.statistics.tx.agg.ba_timeout);
-        if ((priv->_agn.agg_tids_count > 0) &&
-            (expected_ack_cnt_delta > 0) &&
-            (((actual_ack_cnt_delta * 100) / expected_ack_cnt_delta)
-                < ACK_CNT_RATIO) &&
-            (ba_timeout_delta > BA_TIMEOUT_CNT)) {
-                IWL_DEBUG_RADIO(priv, "actual_ack_cnt delta = %d,"
-                                " expected_ack_cnt = %d\n",
-                                actual_ack_cnt_delta, expected_ack_cnt_delta);
+        int actual_delta, expected_delta, ba_timeout_delta;
+        struct statistics_tx *cur, *old;
+
+        if (priv->_agn.agg_tids_count)
+                return true;
+
+        cur = &pkt->u.stats.tx;
+        old = &priv->_agn.statistics.tx;
+
+        actual_delta = le32_to_cpu(cur->actual_ack_cnt) -
+                       le32_to_cpu(old->actual_ack_cnt);
+        expected_delta = le32_to_cpu(cur->expected_ack_cnt) -
+                         le32_to_cpu(old->expected_ack_cnt);
+
+        /* Values should not be negative, but we do not trust the firmware */
+        if (actual_delta <= 0 || expected_delta <= 0)
+                return true;
+
+        ba_timeout_delta = le32_to_cpu(cur->agg.ba_timeout) -
+                           le32_to_cpu(old->agg.ba_timeout);
+
+        if ((actual_delta * 100 / expected_delta) < ACK_CNT_RATIO &&
+            ba_timeout_delta > BA_TIMEOUT_CNT) {
+                IWL_DEBUG_RADIO(priv, "deltas: actual %d expected %d ba_timeout %d\n",
+                                actual_delta, expected_delta, ba_timeout_delta);
 
 #ifdef CONFIG_IWLWIFI_DEBUGFS
                 /*
@@ -1442,20 +1445,18 @@ bool iwl_good_ack_health(struct iwl_priv *priv,
                  * statistics aren't available. If DEBUGFS is set but
                  * DEBUG is not, these will just compile out.
                  */
-                IWL_DEBUG_RADIO(priv, "rx_detected_cnt delta = %d\n",
+                IWL_DEBUG_RADIO(priv, "rx_detected_cnt delta %d\n",
                                 priv->_agn.delta_statistics.tx.rx_detected_cnt);
                 IWL_DEBUG_RADIO(priv,
-                                "ack_or_ba_timeout_collision delta = %d\n",
-                                priv->_agn.delta_statistics.tx.
-                                ack_or_ba_timeout_collision);
+                                "ack_or_ba_timeout_collision delta %d\n",
+                                priv->_agn.delta_statistics.tx.ack_or_ba_timeout_collision);
 #endif
-                IWL_DEBUG_RADIO(priv, "agg ba_timeout delta = %d\n",
-                                ba_timeout_delta);
-                if (!actual_ack_cnt_delta &&
-                    (ba_timeout_delta >= BA_TIMEOUT_MAX))
-                        rc = false;
+
+                if (ba_timeout_delta >= BA_TIMEOUT_MAX)
+                        return false;
         }
-        return rc;
+
+        return true;
 }