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 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: net-mlx5-fix-race-for-multiple-roce-enable.patch and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon Apr 9 10:16:32 CEST 2018
From: Daniel Jurgens danielj@mellanox.com Date: Thu, 4 Jan 2018 17:25:31 +0200 Subject: net/mlx5: Fix race for multiple RoCE enable
From: Daniel Jurgens danielj@mellanox.com
[ 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@mellanox.com Reviewed-by: Parav Pandit parav@mellanox.com Signed-off-by: Leon Romanovsky leon@kernel.org Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -826,7 +826,7 @@ 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@mellanox.com are
queue-4.15/net-mlx5-fix-race-for-multiple-roce-enable.patch