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Commit 734dc065 authored by Daniel Jurgens's avatar Daniel Jurgens Committed by Jason Gunthorpe
Browse files

net/mlx5: Fix race for multiple RoCE enable 



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: a6f7d2af ("net/mlx5: Add support for multiple RoCE enable")
Signed-off-by: default avatarDaniel Jurgens <danielj@mellanox.com>
Reviewed-by: default avatarParav Pandit <parav@mellanox.com>
Signed-off-by: default avatarLeon Romanovsky <leon@kernel.org>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent 776a3906

drivers/net/ethernet/mellanox/mlx5/core/vport.c

+27 −6
Original line number Diff line number Diff line
@@ -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)

{
@@ -988,17 +991,35 @@ static int mlx5_nic_vport_update_roce_state(struct mlx5_core_dev *mdev, 


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);

include/linux/mlx5/driver.h

+1 −1
Original line number Diff line number Diff line
@@ -835,7 +835,7 @@ 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;