[dpdk-stable] patch 'net/mlx5: fix memory region lookup' has been queued to LTS release 17.11.1

[Yuanhan Liu]

Hi,

FYI, your patch has been queued to LTS release 17.11.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 01/26/18. So please
shout if anyone has objections.

Thanks.

	--yliu

---
>From af08e1a32a95d9076f827f8f37eb35ffe957932f Mon Sep 17 00:00:00 2001
From: Yongseok Koh <yskoh at mellanox.com>
Date: Thu, 18 Jan 2018 23:52:55 -0800
Subject: [PATCH] net/mlx5: fix memory region lookup

[ upstream commit f81ec748434bfef078be57fc880313e832765ad1 ]

This patch reverts:
	commit 3a6f2eb8c5c5 ("net/mlx5: fix Memory Region registration")

Although granularity of chunks in a mempool is a cacheline, addresses are
extended to align to page boundary for performance reason in device when
registering a MR (Memory Region). This could make some regions overlap,
then can cause Tx completion error due to incorrect LKEY search. If the
error occurs, the Tx queue will get stuck. It is because buffer address is
compared against aligned addresses for Memory Region. Saving original
addresses of mempool for comparison doesn't create any overlap.

Fixes: b0b093845793 ("net/mlx5: use buffer address for LKEY search")
Fixes: 3a6f2eb8c5c5 ("net/mlx5: fix Memory Region registration")

Reported-by: Xueming Li <xuemingl at mellanox.com>
Signed-off-by: Xueming Li <xuemingl at mellanox.com>
Signed-off-by: Yongseok Koh <yskoh at mellanox.com>
Acked-by: Nelio Laranjeiro <nelio.laranjeiro at 6wind.com>
---
 drivers/net/mlx5/mlx5_mr.c   | 5 +++--
 drivers/net/mlx5/mlx5_rxtx.h | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c
index 6b29eed..2776dc7 100644
--- a/drivers/net/mlx5/mlx5_mr.c
+++ b/drivers/net/mlx5/mlx5_mr.c
@@ -291,6 +291,9 @@ priv_mr_new(struct priv *priv, struct rte_mempool *mp)
 	DEBUG("mempool %p area start=%p end=%p size=%zu",
 	      (void *)mp, (void *)start, (void *)end,
 	      (size_t)(end - start));
+	/* Save original addresses for exact MR lookup. */
+	mr->start = start;
+	mr->end = end;
 	/* Round start and end to page boundary if found in memory segments. */
 	for (i = 0; (i < RTE_MAX_MEMSEG) && (ms[i].addr != NULL); ++i) {
 		uintptr_t addr = (uintptr_t)ms[i].addr;
@@ -309,8 +312,6 @@ priv_mr_new(struct priv *priv, struct rte_mempool *mp)
 			    IBV_ACCESS_LOCAL_WRITE);
 	mr->mp = mp;
 	mr->lkey = rte_cpu_to_be_32(mr->mr->lkey);
-	mr->start = start;
-	mr->end = (uintptr_t)mr->mr->addr + mr->mr->length;
 	rte_atomic32_inc(&mr->refcnt);
 	DEBUG("%p: new Memory Region %p refcnt: %d", (void *)priv,
 	      (void *)mr, rte_atomic32_read(&mr->refcnt));
diff --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h
index 301cd75..05aec29 100644
--- a/drivers/net/mlx5/mlx5_rxtx.h
+++ b/drivers/net/mlx5/mlx5_rxtx.h
@@ -543,7 +543,7 @@ static __rte_always_inline uint32_t
 mlx5_tx_mb2mr(struct mlx5_txq_data *txq, struct rte_mbuf *mb)
 {
 	uint16_t i = txq->mr_cache_idx;
-	uintptr_t addr = rte_pktmbuf_mtod_offset(mb, uintptr_t, DATA_LEN(mb));
+	uintptr_t addr = rte_pktmbuf_mtod(mb, uintptr_t);
 	struct mlx5_mr *mr;
 
 	assert(i < RTE_DIM(txq->mp2mr));
-- 
2.7.4