From d623dfd2836114507d647c9793a80d213d8bffe8 Mon Sep 17 00:00:00 2001
From: Artemy Kovalyov <artemyko@mellanox.com>
Date: Tue, 19 Mar 2019 11:24:39 +0200
Subject: [PATCH 1/1] IB/mlx5: Compare only index part of a memory window rkey
Git-commit: d623dfd2836114507d647c9793a80d213d8bffe8
Patch-mainline: v5.10-rc1
References: bsc#1111666

The InfiniBand Architecture Specification section 10.6.7.2.4 TYPE 2 MEMORY
WINDOWS says that if the CI supports the Base Memory Management Extensions
defined in this specification, the R_Key format for a Type 2 Memory Window
must consist of:

* 24 bit index in the most significant bits of the R_Key, which is owned
  by the CI, and
* 8 bit key in the least significant bits of the R_Key, which is owned by
  the Consumer.

This means that the kernel should compare only the index part of a R_Key
to determine equality with another R_Key.

Fixes: db570d7deafb ("IB/mlx5: Add ODP support to MW")
Signed-off-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Nicolas Morey-Chaisemartin <nmoreychaisemartin@suse.com>
---
 drivers/infiniband/hw/mlx5/odp.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index c20bfc41ecf1..2bc4d67b3e42 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -710,6 +710,15 @@ struct pf_frame {
 	int depth;
 };
 
+static bool mkey_is_eq(struct mlx5_core_mkey *mmkey, u32 key)
+{
+	if (!mmkey)
+		return false;
+	if (mmkey->type == MLX5_MKEY_MW)
+		return mlx5_base_mkey(mmkey->key) == mlx5_base_mkey(key);
+	return mmkey->key == key;
+}
+
 /*
  * Handle a single data segment in a page-fault WQE or RDMA region.
  *
@@ -759,7 +768,7 @@ static int pagefault_single_data_segment(struct mlx5_ib_dev *dev,
 
 next_mr:
 	mmkey = __mlx5_mr_lookup(dev->mdev, mlx5_base_mkey(key));
-	if (!mmkey || mmkey->key != key) {
+	if (!mkey_is_eq(mmkey, key)) {
 		mlx5_ib_dbg(dev, "failed to find mkey %x\n", key);
 		ret = -EFAULT;
 		goto srcu_unlock;
-- 
2.29.2