[dpdk-stable] patch 'net/ena: fix Rx descriptors allocation' has been queued to stable release 17.02.1

[Yuanhan Liu]

Hi,

FYI, your patch has been queued to stable release 17.02.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/28/17. So please
shout if anyone has objections.

Thanks.

	--yliu

---
>From d88124bb6df1836e78e4234d247cc5574b40d330 Mon Sep 17 00:00:00 2001
From: Michal Krawczyk <mk at semihalf.com>
Date: Mon, 10 Apr 2017 16:28:08 +0200
Subject: [PATCH] net/ena: fix Rx descriptors allocation

[ upstream commit a467e8f37a3eec98210c0c3ec04bf6e9506ddd81 ]

When application tried to allocate 1024 descriptors, device was not
initializing properly.

This patch solves it by avoiding allocation of all descriptors in the
ring in one attempt. At least one descriptor must remain unused in the
HW ring.

Fixes: 1173fca25af9 ("ena: add polling-mode driver")

Signed-off-by: Michal Krawczyk <mk at semihalf.com>
Reviewed-by: Jakub Palider <jpalider at gmail.com>
Acked-by: Jan Medala <jan.medala at outlook.com>
---
 drivers/net/ena/ena_ethdev.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
index b5e6db6..90cf2ad 100644
--- a/drivers/net/ena/ena_ethdev.c
+++ b/drivers/net/ena/ena_ethdev.c
@@ -919,7 +919,7 @@ static int ena_start(struct rte_eth_dev *dev)
 
 static int ena_queue_restart(struct ena_ring *ring)
 {
-	int rc;
+	int rc, bufs_num;
 
 	ena_assert_msg(ring->configured == 1,
 		       "Trying to restart unconfigured queue\n");
@@ -930,8 +930,9 @@ static int ena_queue_restart(struct ena_ring *ring)
 	if (ring->type == ENA_RING_TYPE_TX)
 		return 0;
 
-	rc = ena_populate_rx_queue(ring, ring->ring_size);
-	if ((unsigned int)rc != ring->ring_size) {
+	bufs_num = ring->ring_size - 1;
+	rc = ena_populate_rx_queue(ring, bufs_num);
+	if (rc != bufs_num) {
 		PMD_INIT_LOG(ERR, "Failed to populate rx ring !");
 		return (-1);
 	}
@@ -1143,7 +1144,7 @@ static int ena_populate_rx_queue(struct ena_ring *rxq, unsigned int count)
 		return 0;
 
 	in_use = rxq->next_to_use - rxq->next_to_clean;
-	ena_assert_msg(((in_use + count) <= ring_size), "bad ring state");
+	ena_assert_msg(((in_use + count) < ring_size), "bad ring state");
 
 	count = RTE_MIN(count,
 			(uint16_t)(ring_size - (next_to_use & ring_mask)));
@@ -1574,6 +1575,7 @@ static uint16_t eth_ena_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
 		recv_idx++;
 	}
 
+	desc_in_use += 1;
 	/* Burst refill to save doorbells, memory barriers, const interval */
 	if (ring_size - desc_in_use > ENA_RING_DESCS_RATIO(ring_size))
 		ena_populate_rx_queue(rx_ring, ring_size - desc_in_use);
-- 
1.9.0