[dpdk-stable] patch 'net/mlx5: add multi-segment packets in MPRQ mode' has been queued to stable release 19.11.3

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 19.11.3

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/21/20. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Thanks.

Luca Boccassi

---
>From afca8bc661463f5f6c09ec6ecbcecd88f8f3a7ea Mon Sep 17 00:00:00 2001
From: Alexander Kozyrev <akozyrev at mellanox.com>
Date: Thu, 9 Apr 2020 22:23:53 +0000
Subject: [PATCH] net/mlx5: add multi-segment packets in MPRQ mode

[ upstream commit 775fc97b0125c29f4bd36490f46f5f1e11dc048f ]

The multi-stride operations now allow to reduce a stride size
while supporting Jumbo frames. That means that it is possible
to have mbufs configured with a size smaller than the whole
packet received. It is not an issue during normal MPRQ operations
since we attach external buffers instead of copying the data
into the mbuf itself. But it is not the case in "emergency mode"
when we have to copy every packet because of no more external
mbufs are available. Assemble a multi-segment packet to overcome
this issue in case scatter mode is enabled, drop a packet if not.

Signed-off-by: Alexander Kozyrev <akozyrev at mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo at mellanox.com>
Acked-by: Matan Azrad <matan at mellanox.com>
---
 drivers/net/mlx5/mlx5_rxtx.c | 47 ++++++++++++++++++++++++++++++------
 1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index c2007282f6..ae89406d65 100644
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -1645,22 +1645,52 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
 		 * Memcpy packets to the target mbuf if:
 		 * - The size of packet is smaller than mprq_max_memcpy_len.
 		 * - Out of buffer in the Mempool for Multi-Packet RQ.
-		 * - There is no space for a headroom and scatter is disabled.
+		 * - The packet's stride overlaps a headroom and scatter is off.
 		 */
 		if (len <= rxq->mprq_max_memcpy_len ||
 		    rxq->mprq_repl == NULL ||
 		    (hdrm_overlap > 0 && !rxq->strd_scatter_en)) {
-			/*
-			 * When memcpy'ing packet due to out-of-buffer, the
-			 * packet must be smaller than the target mbuf.
-			 */
-			if (unlikely(rte_pktmbuf_tailroom(pkt) < len)) {
+			if (likely(rte_pktmbuf_tailroom(pkt) >= len)) {
+				rte_memcpy(rte_pktmbuf_mtod(pkt, void *),
+					   addr, len);
+				DATA_LEN(pkt) = len;
+			} else if (rxq->strd_scatter_en) {
+				struct rte_mbuf *prev = pkt;
+				uint32_t seg_len =
+					RTE_MIN(rte_pktmbuf_tailroom(pkt), len);
+				uint32_t rem_len = len - seg_len;
+
+				rte_memcpy(rte_pktmbuf_mtod(pkt, void *),
+					   addr, seg_len);
+				DATA_LEN(pkt) = seg_len;
+				while (rem_len) {
+					struct rte_mbuf *next =
+						rte_pktmbuf_alloc(rxq->mp);
+
+					if (unlikely(next == NULL)) {
+						rte_pktmbuf_free(pkt);
+						++rxq->stats.rx_nombuf;
+						goto out;
+					}
+					NEXT(prev) = next;
+					SET_DATA_OFF(next, 0);
+					addr = RTE_PTR_ADD(addr, seg_len);
+					seg_len = RTE_MIN
+						(rte_pktmbuf_tailroom(next),
+						 rem_len);
+					rte_memcpy
+						(rte_pktmbuf_mtod(next, void *),
+						 addr, seg_len);
+					DATA_LEN(next) = seg_len;
+					rem_len -= seg_len;
+					prev = next;
+					++NB_SEGS(pkt);
+				}
+			} else {
 				rte_pktmbuf_free_seg(pkt);
 				++rxq->stats.idropped;
 				continue;
 			}
-			rte_memcpy(rte_pktmbuf_mtod(pkt, void *), addr, len);
-			DATA_LEN(pkt) = len;
 		} else {
 			rte_iova_t buf_iova;
 			struct rte_mbuf_ext_shared_info *shinfo;
@@ -1737,6 +1767,7 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
 		*(pkts++) = pkt;
 		++i;
 	}
+out:
 	/* Update the consumer indexes. */
 	rxq->consumed_strd = consumed_strd;
 	rte_cio_wmb();
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2020-05-19 14:04:48.003190361 +0100
+++ 0087-net-mlx5-add-multi-segment-packets-in-MPRQ-mode.patch	2020-05-19 14:04:44.272649387 +0100
@@ -1,8 +1,10 @@
-From 775fc97b0125c29f4bd36490f46f5f1e11dc048f Mon Sep 17 00:00:00 2001
+From afca8bc661463f5f6c09ec6ecbcecd88f8f3a7ea Mon Sep 17 00:00:00 2001
 From: Alexander Kozyrev <akozyrev at mellanox.com>
 Date: Thu, 9 Apr 2020 22:23:53 +0000
 Subject: [PATCH] net/mlx5: add multi-segment packets in MPRQ mode
 
+[ upstream commit 775fc97b0125c29f4bd36490f46f5f1e11dc048f ]
+
 The multi-stride operations now allow to reduce a stride size
 while supporting Jumbo frames. That means that it is possible
 to have mbufs configured with a size smaller than the whole
@@ -13,8 +15,6 @@
 mbufs are available. Assemble a multi-segment packet to overcome
 this issue in case scatter mode is enabled, drop a packet if not.
 
-Cc: stable at dpdk.org
-
 Signed-off-by: Alexander Kozyrev <akozyrev at mellanox.com>
 Acked-by: Viacheslav Ovsiienko <viacheslavo at mellanox.com>
 Acked-by: Matan Azrad <matan at mellanox.com>
@@ -23,10 +23,10 @@
  1 file changed, 39 insertions(+), 8 deletions(-)
 
 diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
-index 4c279520d1..7ce3732fd3 100644
+index c2007282f6..ae89406d65 100644
 --- a/drivers/net/mlx5/mlx5_rxtx.c
 +++ b/drivers/net/mlx5/mlx5_rxtx.c
-@@ -1734,22 +1734,52 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
+@@ -1645,22 +1645,52 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
  		 * Memcpy packets to the target mbuf if:
  		 * - The size of packet is smaller than mprq_max_memcpy_len.
  		 * - Out of buffer in the Mempool for Multi-Packet RQ.
@@ -87,7 +87,7 @@
  		} else {
  			rte_iova_t buf_iova;
  			struct rte_mbuf_ext_shared_info *shinfo;
-@@ -1826,6 +1856,7 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
+@@ -1737,6 +1767,7 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
  		*(pkts++) = pkt;
  		++i;
  	}