ath11k: rx path optimizations

During RX, accessing the reo dest ring descriptor directly is consuming
a lot of CPU cycles. Accessing the descriptor after copying it locally
has improved CPU usage by around ~10-15% while measuring throughput
in RX DBTC test cases(all radios are involved in the throughput
measurement).

HW tested: IPQ8074
Signed-off-by: Manikanta Pubbisetty <mpubbise@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1586421797-885-1-git-send-email-mpubbise@codeaurora.org

drivers/net/wireless/ath/ath11k/dp_rx.c

@@ -2403,12 +2403,12 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
 
 try_again:
 	while ((rx_desc = ath11k_hal_srng_dst_get_next_entry(ab, srng))) {
-		struct hal_reo_dest_ring *desc = (struct hal_reo_dest_ring *)rx_desc;
+		struct hal_reo_dest_ring desc = *(struct hal_reo_dest_ring *)rx_desc;
 		enum hal_reo_dest_ring_push_reason push_reason;
 		u32 cookie;
 
 		cookie = FIELD_GET(BUFFER_ADDR_INFO1_SW_COOKIE,
-				   desc->buf_addr_info.info1);
+				   desc.buf_addr_info.info1);
 		buf_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_BUF_ID,
 				   cookie);
 		mac_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_PDEV_ID, cookie);
@@ -2436,7 +2436,7 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
 		total_msdu_reaped++;
 
 		push_reason = FIELD_GET(HAL_REO_DEST_RING_INFO0_PUSH_REASON,
-					desc->info0);
+					desc.info0);
 		if (push_reason !=
 		    HAL_REO_DEST_RING_PUSH_REASON_ROUTING_INSTRUCTION) {
 			dev_kfree_skb_any(msdu);
@@ -2444,15 +2444,15 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
 			continue;
 		}
 
-		rxcb->is_first_msdu = !!(desc->rx_msdu_info.info0 &
+		rxcb->is_first_msdu = !!(desc.rx_msdu_info.info0 &
 					 RX_MSDU_DESC_INFO0_FIRST_MSDU_IN_MPDU);
-		rxcb->is_last_msdu = !!(desc->rx_msdu_info.info0 &
+		rxcb->is_last_msdu = !!(desc.rx_msdu_info.info0 &
 					RX_MSDU_DESC_INFO0_LAST_MSDU_IN_MPDU);
-		rxcb->is_continuation = !!(desc->rx_msdu_info.info0 &
+		rxcb->is_continuation = !!(desc.rx_msdu_info.info0 &
 					   RX_MSDU_DESC_INFO0_MSDU_CONTINUATION);
 		rxcb->mac_id = mac_id;
 		rxcb->tid = FIELD_GET(HAL_REO_DEST_RING_INFO0_RX_QUEUE_NUM,
-				      desc->info0);
+				      desc.info0);
 
 		__skb_queue_tail(&msdu_list, msdu);