[PATCH iwl-next v2 04/10] ixgbevf: branch prediction and cleanup

[Larysa Zaremba]

Add likely/unlikely markers for better branch prediction. While touching
some functions, cleanup the code a little bit.

This patch is not supposed to make any logic changes.

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@xxxxxxxxx>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>
Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
---
 .../net/ethernet/intel/ixgbevf/ixgbevf_main.c | 29 +++++++++----------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 4f983e1365eb..f67486e5ef45 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -570,7 +570,7 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring,
 	u16 ntu = rx_ring->next_to_use;
 
 	/* nothing to do or no valid netdev defined */
-	if (!cleaned_count || !rx_ring->netdev)
+	if (unlikely(!cleaned_count || !rx_ring->netdev))
 		return;
 
 	rx_desc = IXGBEVF_RX_DESC(rx_ring, ntu);
@@ -586,7 +586,7 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring,
 
 		rx_desc++;
 		ntu++;
-		if (unlikely(ntu == rx_ring->count)) {
+		if (unlikely(ntu == fq.count)) {
 			rx_desc = IXGBEVF_RX_DESC(rx_ring, 0);
 			ntu = 0;
 		}
@@ -823,7 +823,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 
 		rx_desc = IXGBEVF_RX_DESC(rx_ring, rx_ring->next_to_clean);
 		size = le16_to_cpu(rx_desc->wb.upper.length);
-		if (!size)
+		if (unlikely(!size))
 			break;
 
 		/* This memory barrier is needed to keep us from reading
@@ -855,7 +855,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 		}
 
 		/* exit if we failed to retrieve a buffer */
-		if (!xdp_res && !skb) {
+		if (unlikely(!xdp_res && !skb)) {
 			rx_ring->rx_stats.alloc_rx_buff_failed++;
 			break;
 		}
@@ -867,21 +867,19 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 			continue;
 
 		/* verify the packet layout is correct */
-		if (xdp_res || ixgbevf_cleanup_headers(rx_ring, rx_desc, skb)) {
+		if (xdp_res ||
+		    unlikely(ixgbevf_cleanup_headers(rx_ring, rx_desc, skb))) {
 			skb = NULL;
 			continue;
 		}
 
-		/* probably a little skewed due to removing CRC */
-		total_rx_bytes += skb->len;
-
 		/* Workaround hardware that can't do proper VEPA multicast
 		 * source pruning.
 		 */
-		if ((skb->pkt_type == PACKET_BROADCAST ||
-		     skb->pkt_type == PACKET_MULTICAST) &&
-		    ether_addr_equal(rx_ring->netdev->dev_addr,
-				     eth_hdr(skb)->h_source)) {
+		if (unlikely((skb->pkt_type == PACKET_BROADCAST ||
+			      skb->pkt_type == PACKET_MULTICAST) &&
+			     ether_addr_equal(rx_ring->netdev->dev_addr,
+					      eth_hdr(skb)->h_source))) {
 			dev_kfree_skb_irq(skb);
 			continue;
 		}
@@ -889,13 +887,14 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 		/* populate checksum, VLAN, and protocol */
 		ixgbevf_process_skb_fields(rx_ring, rx_desc, skb);
 
+		/* probably a little skewed due to removing CRC */
+		total_rx_bytes += skb->len;
+		total_rx_packets++;
+
 		ixgbevf_rx_skb(q_vector, skb);
 
 		/* reset skb pointer */
 		skb = NULL;
-
-		/* update budget accounting */
-		total_rx_packets++;
 	}
 
 	/* place incomplete frames back on ring for completion */
-- 
2.52.0