[RFC 1/2] ath11k: drop tx_status_fifo

[John Crispin <john@phrozen.org>]

perf top showed that 10% of the cpu time was spent on the memcpy used to
populate the fifo when the device is under high load. There is no apparent
benefit from using a fifo so lets just drop it.

Signed-off-by: John Crispin <john@phrozen.org>
---
 drivers/net/wireless/ath/ath11k/dp.c     | 13 ---------
 drivers/net/wireless/ath/ath11k/dp.h     |  5 ----
 drivers/net/wireless/ath/ath11k/dp_tx.c  | 37 +++++-------------------
 drivers/net/wireless/ath/ath11k/hal_tx.c |  5 ----
 drivers/net/wireless/ath/ath11k/hal_tx.h |  1 -
 5 files changed, 8 insertions(+), 53 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/dp.c b/drivers/net/wireless/ath/ath11k/dp.c
index 3f5174a0c622..7e0a67d9e5c1 100644
--- a/drivers/net/wireless/ath/ath11k/dp.c
+++ b/drivers/net/wireless/ath/ath11k/dp.c
@@ -839,10 +839,6 @@ void ath11k_dp_free(struct ath11k_base *sc)
 			     ath11k_dp_tx_pending_cleanup, sc);
 		idr_destroy(&dp->tx_ring[i].txbuf_idr);
 		spin_unlock_bh(&dp->tx_ring[i].tx_idr_lock);
-
-		spin_lock_bh(&dp->tx_ring[i].tx_status_lock);
-		kfifo_free(&dp->tx_ring[i].tx_status_fifo);
-		spin_unlock_bh(&dp->tx_ring[i].tx_status_lock);
 	}
 
 	/* Deinit any SOC level resource */
@@ -888,12 +884,6 @@ int ath11k_dp_alloc(struct ath11k_base *sc)
 		idr_init(&dp->tx_ring[i].txbuf_idr);
 		spin_lock_init(&dp->tx_ring[i].tx_idr_lock);
 		dp->tx_ring[i].tcl_data_ring_id = i;
-
-		spin_lock_init(&dp->tx_ring[i].tx_status_lock);
-		ret = kfifo_alloc(&dp->tx_ring[i].tx_status_fifo, size,
-				  GFP_KERNEL);
-		if (ret)
-			goto fail_cmn_srng_cleanup;
 	}
 
 	for (i = 0; i < HAL_DSCP_TID_MAP_TBL_NUM_ENTRIES_MAX; i++)
@@ -903,9 +893,6 @@ int ath11k_dp_alloc(struct ath11k_base *sc)
 
 	return 0;
 
-fail_cmn_srng_cleanup:
-	ath11k_dp_srng_common_cleanup(sc);
-
 fail_link_desc_cleanup:
 	ath11k_dp_link_desc_cleanup(sc, dp->link_desc_banks,
 				    HAL_WBM_IDLE_LINK, &dp->wbm_idle_ring);
diff --git a/drivers/net/wireless/ath/ath11k/dp.h b/drivers/net/wireless/ath/ath11k/dp.h
index e09065690481..b654277cb68d 100644
--- a/drivers/net/wireless/ath/ath11k/dp.h
+++ b/drivers/net/wireless/ath/ath11k/dp.h
@@ -66,11 +66,6 @@ struct dp_tx_ring {
 	u32 num_tx_pending;
 	/* Protects txbuf_idr and num_pending */
 	spinlock_t tx_idr_lock;
-	DECLARE_KFIFO_PTR(tx_status_fifo, struct hal_wbm_release_ring);
-	/* lock to protect tx_status_fifo because tx_status_fifo can be
-	 * accessed concurrently.
-	 */
-	spinlock_t tx_status_lock;
 };
 
 struct ath11k_pdev_mon_stats {
diff --git a/drivers/net/wireless/ath/ath11k/dp_tx.c b/drivers/net/wireless/ath/ath11k/dp_tx.c
index e7229f6289c1..b3d5995fc657 100644
--- a/drivers/net/wireless/ath/ath11k/dp_tx.c
+++ b/drivers/net/wireless/ath/ath11k/dp_tx.c
@@ -448,47 +448,28 @@ void ath11k_dp_tx_completion_handler(struct ath11k_base *ab, int ring_id)
 	int hal_ring_id = dp->tx_ring[ring_id].tcl_comp_ring.ring_id;
 	struct hal_srng *status_ring = &ab->hal.srng_list[hal_ring_id];
 	struct sk_buff *msdu;
-	struct hal_wbm_release_ring tx_status;
 	struct hal_tx_status ts;
 	struct dp_tx_ring *tx_ring = &dp->tx_ring[ring_id];
-	u32 *desc;
 	u32 msdu_id;
+	u32 *desc;
 	u8 mac_id;
 
 	spin_lock_bh(&status_ring->lock);
 
 	ath11k_hal_srng_access_begin(ab, status_ring);
 
-	spin_lock_bh(&tx_ring->tx_status_lock);
-	while (!kfifo_is_full(&tx_ring->tx_status_fifo) &&
-	       (desc = ath11k_hal_srng_dst_get_next_entry(ab, status_ring))) {
-		ath11k_hal_tx_status_desc_sync((void *)desc,
-					       (void *)&tx_status);
-		kfifo_put(&tx_ring->tx_status_fifo, tx_status);
-	}
-
-	if ((ath11k_hal_srng_dst_peek(ab, status_ring) != NULL) &&
-	    kfifo_is_full(&tx_ring->tx_status_fifo)) {
-		/* TODO: Process pending tx_status messages when kfifo_is_full() */
-		ath11k_warn(ab, "Unable to process some of the tx_status ring desc because status_fifo is full\n");
-	}
-
-	spin_unlock_bh(&tx_ring->tx_status_lock);
-
-	ath11k_hal_srng_access_end(ab, status_ring);
-	spin_unlock_bh(&status_ring->lock);
-
-	spin_lock_bh(&tx_ring->tx_status_lock);
-	while (kfifo_get(&tx_ring->tx_status_fifo, &tx_status)) {
+	while ((desc = ath11k_hal_srng_dst_get_next_entry(ab, status_ring))) {
 		memset(&ts, 0, sizeof(ts));
-		ath11k_hal_tx_status_parse(ab, &tx_status, &ts);
+		ath11k_hal_tx_status_parse(ab,
+					   (struct hal_wbm_release_ring *)desc,
+					   &ts);
 
 		mac_id = FIELD_GET(DP_TX_DESC_ID_MAC_ID, ts.desc_id);
 		msdu_id = FIELD_GET(DP_TX_DESC_ID_MSDU_ID, ts.desc_id);
 
 		if (ts.buf_rel_source == HAL_WBM_REL_SRC_MODULE_FW) {
 			ath11k_dp_tx_process_htt_tx_complete(ab,
-							     (void *)&tx_status,
+							     (void *)desc,
 							     mac_id, msdu_id,
 							     tx_ring);
 			continue;
@@ -511,12 +492,10 @@ void ath11k_dp_tx_completion_handler(struct ath11k_base *ab, int ring_id)
 		if (atomic_dec_and_test(&ar->dp.num_tx_pending))
 			wake_up(&ar->dp.tx_empty_waitq);
 
-		/* TODO: Locking optimization so that tx_completion for an msdu
-		 * is not called with tx_status_lock acquired
-		 */
 		ath11k_dp_tx_complete_msdu(ar, msdu, &ts);
 	}
-	spin_unlock_bh(&tx_ring->tx_status_lock);
+	ath11k_hal_srng_access_end(ab, status_ring);
+	spin_unlock_bh(&status_ring->lock);
 }
 
 int ath11k_dp_tx_send_reo_cmd(struct ath11k_base *ab, struct dp_rx_tid *rx_tid,
diff --git a/drivers/net/wireless/ath/ath11k/hal_tx.c b/drivers/net/wireless/ath/ath11k/hal_tx.c
index 3c04ebe23c22..899fb9356f2d 100644
--- a/drivers/net/wireless/ath/ath11k/hal_tx.c
+++ b/drivers/net/wireless/ath/ath11k/hal_tx.c
@@ -79,11 +79,6 @@ void ath11k_hal_tx_desc_sync(void *tx_desc_cached, void *hw_desc)
 	       sizeof(struct hal_tcl_data_cmd));
 }
 
-void ath11k_hal_tx_status_desc_sync(void *hw_desc, void *local_desc)
-{
-	memcpy(local_desc, hw_desc, HAL_TX_STATUS_DESC_LEN);
-}
-
 void ath11k_hal_tx_status_parse(struct ath11k_base *ab,
 				struct hal_wbm_release_ring *desc,
 				struct hal_tx_status *ts)
diff --git a/drivers/net/wireless/ath/ath11k/hal_tx.h b/drivers/net/wireless/ath/ath11k/hal_tx.h
index 3b12dfda7423..b37d585355a0 100644
--- a/drivers/net/wireless/ath/ath11k/hal_tx.h
+++ b/drivers/net/wireless/ath/ath11k/hal_tx.h
@@ -70,7 +70,6 @@ void ath11k_hal_tx_desc_sync(void *tx_desc_cached, void *hw_desc);
 void ath11k_hal_tx_status_parse(struct ath11k_base *ab,
 				struct hal_wbm_release_ring *desc,
 				struct hal_tx_status *ts);
-void ath11k_hal_tx_status_desc_sync(void *hw_desc, void *local_desc);
 void ath11k_hal_tx_set_dscp_tid_map(struct ath11k_base *ab, int id);
 int ath11k_hal_reo_cmd_send(struct ath11k_base *ab, struct hal_srng *srng,
 			    enum hal_reo_cmd_type type,
-- 
2.20.1


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