Fix xdp in ena driver

From: Sameeh Jubran <[email protected]>

This patchset includes 2 XDP related bug fixes

Difference from v1:
* Fixed "Fixes" tag

Sameeh Jubran (2):
net: ena: xdp: XDP_TX: fix memory leak
net: ena: xdp: update napi budget for DROP and ABORTED

 drivers/net/ethernet/amazon/ena/ena_netdev.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

2.24.1.AMZN

From: Sameeh Jubran <[email protected]>

When sending very high packet rate, the XDP tx queues can get full and start dropping packets. In this case we don't free the pages which results in ena driver draining the system memory.

Fix:
Simply free the pages when necessary.

---
 drivers/net/ethernet/amazon/ena/ena_netdev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 281896542..ec115b753 100644
@@ -355,7 +355,7 @@ error_unmap_dma:
 	ena_unmap_tx_buff(xdp_ring, tx_info);
 	tx_info->xdpf = NULL;
 error_drop_packet:
-
+	__free_page(tx_info->xdp_rx_page);
 	return NETDEV_TX_OK;
 }
 

2.24.1.AMZN

From: Sameeh Jubran <[email protected]>

This patch fixes two issues with XDP:

1. If the XDP verdict is XDP_ABORTED we break the loop, which results in us handling one buffer per napi cycle instead of the total budget (usually 64). To overcome this simply change the xdp_verdict check to != XDP_PASS. When the verdict is XDP_PASS, the skb is not expected to be NULL.

2. Update the residual budget for XDP_DROP and XDP_ABORTED, since packets are handled in these cases.

---
 drivers/net/ethernet/amazon/ena/ena_netdev.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

index ec115b753..2beccda7e 100644
@@ -1638,11 +1638,9 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
 					 &next_to_clean);
 
 		if (unlikely(!skb)) {
-			if (xdp_verdict == XDP_TX) {
+			if (xdp_verdict == XDP_TX)
 				ena_free_rx_page(rx_ring,
 						 &rx_ring->rx_buffer_info[rx_ring->ena_bufs[0].req_id]);
-				res_budget--;
-			}
 			for (i = 0; i < ena_rx_ctx.descs; i++) {
 				rx_ring->free_ids[next_to_clean] =
 					rx_ring->ena_bufs[i].req_id;

@@ -1650,8 +1648,10 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
 					ENA_RX_RING_IDX_NEXT(next_to_clean,
 							     rx_ring->ring_size);
 			}
-			if (xdp_verdict == XDP_TX || xdp_verdict == XDP_DROP)
+			if (xdp_verdict != XDP_PASS) {
+				res_budget--;
 				continue;
+			}
 			break;
 		}
 

2.24.1.AMZN

All clean now :)

LGTM

Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

From: <[email protected]>
Date: Wed, 3 Jun 2020 08:50:21 +0000

Series applied, thanks.