[PATCH intel-net 1/3] ice: put Rx buffers after being done with current frame

[Maciej Fijalkowski <maciej.fijalkowski@intel.com>]

Introduce a new helper ice_put_rx_mbuf() that will go through gathered
frags from current frame and will call ice_put_rx_buf() on them. Current
logic that was supposed to simplify and optimize the driver where we go
through a batch of all buffers processed in current NAPI instance turned
out to be broken for jumbo frames and very heavy load that was coming
from both multi-thread iperf and nginx/wrk pair between server and
client. The delay introduced by approach that we are dropping is simply
too big and we need to take the decision regarding page
recycling/releasing as quick as we can.

While at it, address an error path of ice_add_xdp_frag() - we were
missing buffer putting from day 1 there.

As a nice side effect we get rid of annoying and repetetive three-liner:

	xdp->data = NULL;
	rx_ring->first_desc = ntc;
	rx_ring->nr_frags = 0;

by embedding it within introduced routine.

Fixes: 1dc1a7e7f410 ("ice: Centrallize Rx buffer recycling")
Reported-and-tested-by: Xu Du <xudu@redhat.com>
Co-developed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
---
 drivers/net/ethernet/intel/ice/ice_txrx.c | 67 +++++++++++++----------
 1 file changed, 38 insertions(+), 29 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
index 5d2d7736fd5f..501df1bc881d 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
@@ -1103,6 +1103,37 @@ ice_put_rx_buf(struct ice_rx_ring *rx_ring, struct ice_rx_buf *rx_buf)
 	rx_buf->page = NULL;
 }
 
+static void ice_put_rx_mbuf(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
+			    u32 *xdp_xmit)
+{
+	u32 nr_frags = rx_ring->nr_frags + 1;
+	u32 idx = rx_ring->first_desc;
+	u32 cnt = rx_ring->count;
+	struct ice_rx_buf *buf;
+
+	for (int i = 0; i < nr_frags; i++) {
+		buf = &rx_ring->rx_buf[idx];
+
+		if (buf->act & (ICE_XDP_TX | ICE_XDP_REDIR)) {
+			ice_rx_buf_adjust_pg_offset(buf, xdp->frame_sz);
+			*xdp_xmit |= buf->act;
+		} else if (buf->act & ICE_XDP_CONSUMED) {
+			buf->pagecnt_bias++;
+		} else if (buf->act == ICE_XDP_PASS) {
+			ice_rx_buf_adjust_pg_offset(buf, xdp->frame_sz);
+		}
+
+		ice_put_rx_buf(rx_ring, buf);
+
+		if (++idx == cnt)
+			idx = 0;
+	}
+
+	xdp->data = NULL;
+	rx_ring->first_desc = ntc;
+	rx_ring->nr_frags = 0;
+}
+
 /**
  * ice_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf
  * @rx_ring: Rx descriptor ring to transact packets on
@@ -1120,7 +1151,6 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 	unsigned int total_rx_bytes = 0, total_rx_pkts = 0;
 	unsigned int offset = rx_ring->rx_offset;
 	struct xdp_buff *xdp = &rx_ring->xdp;
-	u32 cached_ntc = rx_ring->first_desc;
 	struct ice_tx_ring *xdp_ring = NULL;
 	struct bpf_prog *xdp_prog = NULL;
 	u32 ntc = rx_ring->next_to_clean;
@@ -1128,7 +1158,6 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 	u32 xdp_xmit = 0;
 	u32 cached_ntu;
 	bool failure;
-	u32 first;
 
 	xdp_prog = READ_ONCE(rx_ring->xdp_prog);
 	if (xdp_prog) {
@@ -1190,6 +1219,7 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 			xdp_prepare_buff(xdp, hard_start, offset, size, !!offset);
 			xdp_buff_clear_frags_flag(xdp);
 		} else if (ice_add_xdp_frag(rx_ring, xdp, rx_buf, size)) {
+			ice_put_rx_mbuf(rx_ring, xdp, NULL);
 			break;
 		}
 		if (++ntc == cnt)
@@ -1205,9 +1235,8 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 		total_rx_bytes += xdp_get_buff_len(xdp);
 		total_rx_pkts++;
 
-		xdp->data = NULL;
-		rx_ring->first_desc = ntc;
-		rx_ring->nr_frags = 0;
+		ice_put_rx_mbuf(rx_ring, xdp, &xdp_xmit);
+
 		continue;
 construct_skb:
 		if (likely(ice_ring_uses_build_skb(rx_ring)))
@@ -1221,14 +1250,11 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 			if (unlikely(xdp_buff_has_frags(xdp)))
 				ice_set_rx_bufs_act(xdp, rx_ring,
 						    ICE_XDP_CONSUMED);
-			xdp->data = NULL;
-			rx_ring->first_desc = ntc;
-			rx_ring->nr_frags = 0;
-			break;
 		}
-		xdp->data = NULL;
-		rx_ring->first_desc = ntc;
-		rx_ring->nr_frags = 0;
+		ice_put_rx_mbuf(rx_ring, xdp, &xdp_xmit);
+
+		if (!skb)
+			break;
 
 		stat_err_bits = BIT(ICE_RX_FLEX_DESC_STATUS0_RXE_S);
 		if (unlikely(ice_test_staterr(rx_desc->wb.status_error0,
@@ -1257,23 +1283,6 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 		total_rx_pkts++;
 	}
 
-	first = rx_ring->first_desc;
-	while (cached_ntc != first) {
-		struct ice_rx_buf *buf = &rx_ring->rx_buf[cached_ntc];
-
-		if (buf->act & (ICE_XDP_TX | ICE_XDP_REDIR)) {
-			ice_rx_buf_adjust_pg_offset(buf, xdp->frame_sz);
-			xdp_xmit |= buf->act;
-		} else if (buf->act & ICE_XDP_CONSUMED) {
-			buf->pagecnt_bias++;
-		} else if (buf->act == ICE_XDP_PASS) {
-			ice_rx_buf_adjust_pg_offset(buf, xdp->frame_sz);
-		}
-
-		ice_put_rx_buf(rx_ring, buf);
-		if (++cached_ntc >= cnt)
-			cached_ntc = 0;
-	}
 	rx_ring->next_to_clean = ntc;
 	/* return up to cleaned_count buffers to hardware */
 	failure = ice_alloc_rx_bufs(rx_ring, ICE_RX_DESC_UNUSED(rx_ring));
-- 
2.43.0