iwlwifi: cleanup and bugfix tx aggregation code

Since the driver split, there's no need for no_agg_framecnt_info since
all devices have this set to false. Secondly, the compressed block ack
handling code was broken. Fix this.

(1) A shift less than zero simply implies that the buffer wrapped, this
is expected. Remove the incorrect comment.

(2) The (agg->frame_count > (64-sh)) condition can happen if the last
frame is dropped. E.g., if I send 7 frames and the 6th is received but
the 7th is lost, the other side may only shift the window 6, not 7
frames since the last bit is a 0. This is perfectly fine behavior and
doesn't invalidate the feedback.

(3) Store the feedback from a Compressed BA in the first newly received
frame, rather than the start of the window. This way it will get
processed by the rate selection code. Feedback stored in a non-received
frame is likely to get overwritten by the retransmission.
    This is based on the approach taken by minstrel_ht.

Signed-off-by: Daniel Halperin <dhalperi@cs.washington.edu>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index fb63a03..cb8eacd 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -1263,11 +1263,11 @@ static int iwlagn_tx_status_reply_compressed_ba(struct iwl_priv *priv,
                                 struct iwl_compressed_ba_resp *ba_resp)
 
 {
-       int i, sh, ack;
+       int sh;
        u16 seq_ctl = le16_to_cpu(ba_resp->seq_ctl);
        u16 scd_flow = le16_to_cpu(ba_resp->scd_flow);
-       int successes = 0;
        struct ieee80211_tx_info *info;
+       u64 bitmap, sent_bitmap;
 
        if (unlikely(!agg->wait_for_ba))  {
                if (unlikely(ba_resp->bitmap))
@@ -1281,70 +1281,42 @@ static int iwlagn_tx_status_reply_compressed_ba(struct iwl_priv *priv,
 
        /* Calculate shift to align block-ack bits with our Tx window bits */
        sh = agg->start_idx - SEQ_TO_INDEX(seq_ctl >> 4);
-       if (sh < 0) /* tbw something is wrong with indices */
+       if (sh < 0)
                sh += 0x100;
 
-       if (agg->frame_count > (64 - sh)) {
-               IWL_DEBUG_TX_REPLY(priv, "more frames than bitmap size");
-               return -1;
-       }
-       if (!priv->cfg->base_params->no_agg_framecnt_info && ba_resp->txed) {
+       /*
+        * Check for success or failure according to the
+        * transmitted bitmap and block-ack bitmap
+        */
+       bitmap = le64_to_cpu(ba_resp->bitmap) >> sh;
+       sent_bitmap = bitmap & agg->bitmap;
+
+       /* Sanity check values reported by uCode */
+       if (ba_resp->txed_2_done > ba_resp->txed) {
+               IWL_DEBUG_TX_REPLY(priv,
+                       "bogus sent(%d) and ack(%d) count\n",
+                       ba_resp->txed, ba_resp->txed_2_done);
                /*
-                * sent and ack information provided by uCode
-                * use it instead of figure out ourself
+                * set txed_2_done = txed,
+                * so it won't impact rate scale
                 */
-               if (ba_resp->txed_2_done > ba_resp->txed) {
-                       IWL_DEBUG_TX_REPLY(priv,
-                               "bogus sent(%d) and ack(%d) count\n",
-                               ba_resp->txed, ba_resp->txed_2_done);
-                       /*
-                        * set txed_2_done = txed,
-                        * so it won't impact rate scale
-                        */
-                       ba_resp->txed = ba_resp->txed_2_done;
-               }
-               IWL_DEBUG_HT(priv, "agg frames sent:%d, acked:%d\n",
-                               ba_resp->txed, ba_resp->txed_2_done);
-       } else {
-               u64 bitmap, sent_bitmap;
-
-               /* don't use 64-bit values for now */
-               bitmap = le64_to_cpu(ba_resp->bitmap) >> sh;
-
-               /* check for success or failure according to the
-                * transmitted bitmap and block-ack bitmap */
-               sent_bitmap = bitmap & agg->bitmap;
-
-               /* For each frame attempted in aggregation,
-                * update driver's record of tx frame's status. */
-               i = 0;
-               while (sent_bitmap) {
-                       ack = sent_bitmap & 1ULL;
-                       successes += ack;
-                       IWL_DEBUG_TX_REPLY(priv, "%s ON i=%d idx=%d raw=%d\n",
-                               ack ? "ACK" : "NACK", i,
-                               (agg->start_idx + i) & 0xff,
-                               agg->start_idx + i);
-                       sent_bitmap >>= 1;
-                       ++i;
-               }
+               ba_resp->txed = ba_resp->txed_2_done;
+       }
+       IWL_DEBUG_HT(priv, "agg frames sent:%d, acked:%d\n",
+                       ba_resp->txed, ba_resp->txed_2_done);
 
-               IWL_DEBUG_TX_REPLY(priv, "Bitmap %llx\n",
-                                  (unsigned long long)bitmap);
+       /* Find the first ACKed frame to store the TX status */
+       while (sent_bitmap && !(sent_bitmap & 1)) {
+               agg->start_idx = (agg->start_idx + 1) & 0xff;
+               sent_bitmap >>= 1;
        }
 
        info = IEEE80211_SKB_CB(priv->txq[scd_flow].txb[agg->start_idx].skb);
        memset(&info->status, 0, sizeof(info->status));
        info->flags |= IEEE80211_TX_STAT_ACK;
        info->flags |= IEEE80211_TX_STAT_AMPDU;
-       if (!priv->cfg->base_params->no_agg_framecnt_info && ba_resp->txed) {
-               info->status.ampdu_ack_len = ba_resp->txed_2_done;
-               info->status.ampdu_len = ba_resp->txed;
-
-       } else {
-               info->status.ampdu_ack_len = successes;
-               info->status.ampdu_len = agg->frame_count;
-       }
+       info->status.ampdu_ack_len = ba_resp->txed_2_done;
+       info->status.ampdu_len = ba_resp->txed;
        iwlagn_hwrate_to_tx_control(priv, agg->rate_n_flags, info);
 
        return 0;

diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index 1f4f6dd..3e680af 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -281,8 +281,6 @@ struct iwl_mod_params {
  * @chain_noise_calib_by_driver: driver has the capability to perform
  *     chain noise calibration operation
  * @shadow_reg_enable: HW shadhow register bit
- * @no_agg_framecnt_info: uCode do not provide aggregation frame count
- *     information
  */
 struct iwl_base_params {
        int eeprom_size;
@@ -312,7 +310,6 @@ struct iwl_base_params {
        const bool sensitivity_calib_by_driver;
        const bool chain_noise_calib_by_driver;
        const bool shadow_reg_enable;
-       const bool no_agg_framecnt_info;
 };
 /*
  * @advanced_bt_coexist: support advanced bt coexist