netdev - [PATCH net-next 8/9] net/mlx5: Remove devl_unlock from mlx5_devlink_eswitch_mode

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Message-Id: <20220711081408.69452-9-saeed@kernel.org>
Date:   Mon, 11 Jul 2022 01:14:07 -0700
From:   Saeed Mahameed <saeed@...nel.org>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Eric Dumazet <edumazet@...gle.com>
Cc:     Saeed Mahameed <saeedm@...dia.com>, netdev@...r.kernel.org,
        Moshe Shemesh <moshe@...dia.com>,
        Leon Romanovsky <leonro@...dia.com>
Subject: [PATCH net-next 8/9] net/mlx5: Remove devl_unlock from mlx5_devlink_eswitch_mode_set

From: Moshe Shemesh <moshe@...dia.com>

The callback mlx5_devlink_eswitch_mode_set() had unlocked devlink as a
temporary workaround once devlink instance lock was added to devlink
eswitch callbacks. Now that all flows triggered by this function
that took devlink lock are using devl_ API and all parallel paths are
locked we can remove this workaround.

Signed-off-by: Moshe Shemesh <moshe@...dia.com>
Reviewed-by: Leon Romanovsky <leonro@...dia.com>
Signed-off-by: Saeed Mahameed <saeedm@...dia.com>
---
 .../mellanox/mlx5/core/eswitch_offloads.c     | 20 -------------------
 1 file changed, 20 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
index ccda3a0a2594..d3da52e3fc67 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
@@ -2177,10 +2177,8 @@ static int esw_create_restore_table(struct mlx5_eswitch *esw)
 static int esw_offloads_start(struct mlx5_eswitch *esw,
 			      struct netlink_ext_ack *extack)
 {
-	struct devlink *devlink = priv_to_devlink(esw->dev);
 	int err, err1;
 
-	devl_lock(devlink);
 	esw->mode = MLX5_ESWITCH_OFFLOADS;
 	err = mlx5_eswitch_enable_locked(esw, esw->dev->priv.sriov.num_vfs);
 	if (err) {
@@ -2202,7 +2200,6 @@ static int esw_offloads_start(struct mlx5_eswitch *esw,
 					   "Inline mode is different between vports");
 		}
 	}
-	devl_unlock(devlink);
 	return err;
 }
 
@@ -3243,10 +3240,8 @@ int esw_offloads_enable(struct mlx5_eswitch *esw)
 static int esw_offloads_stop(struct mlx5_eswitch *esw,
 			     struct netlink_ext_ack *extack)
 {
-	struct devlink *devlink = priv_to_devlink(esw->dev);
 	int err, err1;
 
-	devl_lock(devlink);
 	esw->mode = MLX5_ESWITCH_LEGACY;
 	err = mlx5_eswitch_enable_locked(esw, MLX5_ESWITCH_IGNORE_NUM_VFS);
 	if (err) {
@@ -3258,7 +3253,6 @@ static int esw_offloads_stop(struct mlx5_eswitch *esw,
 					   "Failed setting eswitch back to offloads");
 		}
 	}
-	devl_unlock(devlink);
 
 	return err;
 }
@@ -3366,15 +3360,6 @@ int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
 	if (esw_mode_from_devlink(mode, &mlx5_mode))
 		return -EINVAL;
 
-	/* FIXME: devl_unlock() followed by devl_lock() inside driver callback
-	 * is never correct and prone to races. It's a transitional workaround,
-	 * never repeat this pattern.
-	 *
-	 * This code MUST be fixed before removing devlink_mutex as it is safe
-	 * to do only because of that mutex.
-	 */
-	devl_unlock(devlink);
-
 	mlx5_lag_disable_change(esw->dev);
 	err = mlx5_esw_try_lock(esw);
 	if (err < 0) {
@@ -3387,9 +3372,7 @@ int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
 	if (cur_mlx5_mode == mlx5_mode)
 		goto unlock;
 
-	devl_lock(devlink);
 	mlx5_eswitch_disable_locked(esw);
-	devl_unlock(devlink);
 	if (mode == DEVLINK_ESWITCH_MODE_SWITCHDEV) {
 		if (mlx5_devlink_trap_get_num_active(esw->dev)) {
 			NL_SET_ERR_MSG_MOD(extack,
@@ -3400,9 +3383,7 @@ int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
 		err = esw_offloads_start(esw, extack);
 	} else if (mode == DEVLINK_ESWITCH_MODE_LEGACY) {
 		err = esw_offloads_stop(esw, extack);
-		devl_lock(devlink);
 		mlx5_rescan_drivers(esw->dev);
-		devl_unlock(devlink);
 	} else {
 		err = -EINVAL;
 	}
@@ -3411,7 +3392,6 @@ int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
 	mlx5_esw_unlock(esw);
 enable_lag:
 	mlx5_lag_enable_change(esw->dev);
-	devl_lock(devlink);
 	return err;
 }
 
-- 
2.36.1