This is a note to let you know that I've just added the patch titled
net/mlx5: Fix race for multiple RoCE enable
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-mlx5-fix-race-for-multiple-roce-enable.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Apr 9 13:58:16 CEST 2018
From: Daniel Jurgens <danielj@xxxxxxxxxxxx>
Date: Thu, 4 Jan 2018 17:25:31 +0200
Subject: net/mlx5: Fix race for multiple RoCE enable
From: Daniel Jurgens <danielj@xxxxxxxxxxxx>
[ Upstream commit 734dc065fc41f6143ff88225aa5d335cb1e0f6aa ]
There are two potential problems with the existing implementation.
1. Enable and disable can race after the atomic operations.
2. If a command fails the refcount is left in an inconsistent state.
Introduce a lock and perform error checking.
Fixes: a6f7d2aff623 ("net/mlx5: Add support for multiple RoCE enable")
Signed-off-by: Daniel Jurgens <danielj@xxxxxxxxxxxx>
Reviewed-by: Parav Pandit <parav@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/mellanox/mlx5/core/vport.c | 33 +++++++++++++++++++-----
include/linux/mlx5/driver.h | 2 -
2 files changed, 28 insertions(+), 7 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/vport.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/vport.c
@@ -36,6 +36,9 @@
#include <linux/mlx5/vport.h>
#include "mlx5_core.h"
+/* Mutex to hold while enabling or disabling RoCE */
+static DEFINE_MUTEX(mlx5_roce_en_lock);
+
static int _mlx5_query_vport_state(struct mlx5_core_dev *mdev, u8 opmod,
u16 vport, u32 *out, int outlen)
{
@@ -998,17 +1001,35 @@ static int mlx5_nic_vport_update_roce_st
int mlx5_nic_vport_enable_roce(struct mlx5_core_dev *mdev)
{
- if (atomic_inc_return(&mdev->roce.roce_en) != 1)
- return 0;
- return mlx5_nic_vport_update_roce_state(mdev, MLX5_VPORT_ROCE_ENABLED);
+ int err = 0;
+
+ mutex_lock(&mlx5_roce_en_lock);
+ if (!mdev->roce.roce_en)
+ err = mlx5_nic_vport_update_roce_state(mdev, MLX5_VPORT_ROCE_ENABLED);
+
+ if (!err)
+ mdev->roce.roce_en++;
+ mutex_unlock(&mlx5_roce_en_lock);
+
+ return err;
}
EXPORT_SYMBOL_GPL(mlx5_nic_vport_enable_roce);
int mlx5_nic_vport_disable_roce(struct mlx5_core_dev *mdev)
{
- if (atomic_dec_return(&mdev->roce.roce_en) != 0)
- return 0;
- return mlx5_nic_vport_update_roce_state(mdev, MLX5_VPORT_ROCE_DISABLED);
+ int err = 0;
+
+ mutex_lock(&mlx5_roce_en_lock);
+ if (mdev->roce.roce_en) {
+ mdev->roce.roce_en--;
+ if (mdev->roce.roce_en == 0)
+ err = mlx5_nic_vport_update_roce_state(mdev, MLX5_VPORT_ROCE_DISABLED);
+
+ if (err)
+ mdev->roce.roce_en++;
+ }
+ mutex_unlock(&mlx5_roce_en_lock);
+ return err;
}
EXPORT_SYMBOL_GPL(mlx5_nic_vport_disable_roce);
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -794,7 +794,7 @@ struct mlx5_core_dev {
struct mlx5e_resources mlx5e_res;
struct {
struct mlx5_rsvd_gids reserved_gids;
- atomic_t roce_en;
+ u32 roce_en;
} roce;
#ifdef CONFIG_MLX5_FPGA
struct mlx5_fpga_device *fpga;
Patches currently in stable-queue which might be from danielj@xxxxxxxxxxxx are
queue-4.14/net-mlx5-fix-race-for-multiple-roce-enable.patch