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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yuval Avnery <yuvalav@mellanox.com>,
        Saeed Mahameed <saeedm@mellanox.com>
Subject: [PATCH 4.9 59/76] net/mlx5e: Add a lock on tir list
Date:   Mon, 15 Apr 2019 20:44:23 +0200
Message-Id: <20190415183724.736253909@linuxfoundation.org>
In-Reply-To: <20190415183707.712011689@linuxfoundation.org>
References: <20190415183707.712011689@linuxfoundation.org>
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From: Yuval Avnery <yuvalav@mellanox.com>

[ Upstream commit 80a2a9026b24c6bd34b8d58256973e22270bedec ]

Refresh tirs is looping over a global list of tirs while netdevs are
adding and removing tirs from that list. That is why a lock is
required.

Fixes: 724b2aa15126 ("net/mlx5e: TIRs management refactoring")
Signed-off-by: Yuval Avnery <yuvalav@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_common.c |    7 +++++++
 include/linux/mlx5/driver.h                         |    2 ++
 2 files changed, 9 insertions(+)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_common.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_common.c
@@ -45,7 +45,9 @@ int mlx5e_create_tir(struct mlx5_core_de
 	if (err)
 		return err;
 
+	mutex_lock(&mdev->mlx5e_res.td.list_lock);
 	list_add(&tir->list, &mdev->mlx5e_res.td.tirs_list);
+	mutex_unlock(&mdev->mlx5e_res.td.list_lock);
 
 	return 0;
 }
@@ -53,8 +55,10 @@ int mlx5e_create_tir(struct mlx5_core_de
 void mlx5e_destroy_tir(struct mlx5_core_dev *mdev,
 		       struct mlx5e_tir *tir)
 {
+	mutex_lock(&mdev->mlx5e_res.td.list_lock);
 	mlx5_core_destroy_tir(mdev, tir->tirn);
 	list_del(&tir->list);
+	mutex_unlock(&mdev->mlx5e_res.td.list_lock);
 }
 
 static int mlx5e_create_mkey(struct mlx5_core_dev *mdev, u32 pdn,
@@ -114,6 +118,7 @@ int mlx5e_create_mdev_resources(struct m
 	}
 
 	INIT_LIST_HEAD(&mdev->mlx5e_res.td.tirs_list);
+	mutex_init(&mdev->mlx5e_res.td.list_lock);
 
 	return 0;
 
@@ -151,6 +156,7 @@ int mlx5e_refresh_tirs_self_loopback_ena
 
 	MLX5_SET(modify_tir_in, in, bitmask.self_lb_en, 1);
 
+	mutex_lock(&mdev->mlx5e_res.td.list_lock);
 	list_for_each_entry(tir, &mdev->mlx5e_res.td.tirs_list, list) {
 		err = mlx5_core_modify_tir(mdev, tir->tirn, in, inlen);
 		if (err)
@@ -159,6 +165,7 @@ int mlx5e_refresh_tirs_self_loopback_ena
 
 out:
 	kvfree(in);
+	mutex_unlock(&mdev->mlx5e_res.td.list_lock);
 
 	return err;
 }
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -578,6 +578,8 @@ enum mlx5_pci_status {
 };
 
 struct mlx5_td {
+	/* protects tirs list changes while tirs refresh */
+	struct mutex     list_lock;
 	struct list_head tirs_list;
 	u32              tdn;
 };