[PATCH net-next V1 03/12] net/mlx5: E-Switch, Replace vport spin lock with synchronize_irq()

[Saeed Mahameed]

From: Mohamad Haj Yahia <moha...@mellanox.com>

Vport spin lock can be replaced with synchronize_irq() in the right
place, this will remove the need of locking inside irq context.
Locking in esw_enable_vport is not required since vport events are yet
to be enabled, and at esw_disable_vport it is sufficient to
synchronize_irq() to guarantee no further vport events handlers will be
scheduled.

Signed-off-by: Mohamad Haj Yahia <moha...@mellanox.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/eswitch.c | 11 ++---------
 drivers/net/ethernet/mellanox/mlx5/core/eswitch.h |  5 -----
 2 files changed, 2 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c 
b/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c
index dd06619..f01903a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch.c
@@ -713,7 +713,6 @@ static void esw_enable_vport(struct mlx5_eswitch *esw, int 
vport_num,
                             int enable_events)
 {
        struct mlx5_vport *vport = &esw->vports[vport_num];
-       unsigned long flags;
 
        WARN_ON(vport->enabled);
 
@@ -727,9 +726,7 @@ static void esw_enable_vport(struct mlx5_eswitch *esw, int 
vport_num,
        vport->enabled_events = enable_events;
        esw_vport_change_handler(&vport->vport_change_handler);
 
-       spin_lock_irqsave(&vport->lock, flags);
        vport->enabled = true;
-       spin_unlock_irqrestore(&vport->lock, flags);
 
        arm_vport_context_events_cmd(esw->dev, vport_num, enable_events);
 
@@ -761,17 +758,16 @@ static void esw_cleanup_vport(struct mlx5_eswitch *esw, 
u16 vport_num)
 static void esw_disable_vport(struct mlx5_eswitch *esw, int vport_num)
 {
        struct mlx5_vport *vport = &esw->vports[vport_num];
-       unsigned long flags;
 
        if (!vport->enabled)
                return;
 
        esw_debug(esw->dev, "Disabling vport(%d)\n", vport_num);
        /* Mark this vport as disabled to discard new events */
-       spin_lock_irqsave(&vport->lock, flags);
        vport->enabled = false;
        vport->enabled_events = 0;
-       spin_unlock_irqrestore(&vport->lock, flags);
+
+       synchronize_irq(mlx5_get_msix_vec(esw->dev, MLX5_EQ_VEC_ASYNC));
 
        mlx5_modify_vport_admin_state(esw->dev,
                                      
MLX5_QUERY_VPORT_STATE_IN_OP_MOD_ESW_VPORT,
@@ -894,7 +890,6 @@ int mlx5_eswitch_init(struct mlx5_core_dev *dev)
                vport->dev = dev;
                INIT_WORK(&vport->vport_change_handler,
                          esw_vport_change_handler);
-               spin_lock_init(&vport->lock);
        }
 
        esw->total_vports = total_vports;
@@ -942,10 +937,8 @@ void mlx5_eswitch_vport_event(struct mlx5_eswitch *esw, 
struct mlx5_eqe *eqe)
        }
 
        vport = &esw->vports[vport_num];
-       spin_lock(&vport->lock);
        if (vport->enabled)
                queue_work(esw->work_queue, &vport->vport_change_handler);
-       spin_unlock(&vport->lock);
 }
 
 /* Vport Administration */
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch.h 
b/drivers/net/ethernet/mellanox/mlx5/core/eswitch.h
index 3416a42..ba43451 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch.h
@@ -95,11 +95,6 @@ struct mlx5_vport {
        struct hlist_head       mc_list[MLX5_L2_ADDR_HASH_SIZE];
        struct work_struct      vport_change_handler;
 
-       /* This spinlock protects access to vport data, between
-        * "esw_vport_disable" and ongoing interrupt "mlx5_eswitch_vport_event"
-        * once vport marked as disabled new interrupts are discarded.
-        */
-       spinlock_t              lock; /* vport events sync */
        bool                    enabled;
        u16                     enabled_events;
 };
-- 
2.8.0