Subject: [net-next 14/14] net/mlx5: Devcom, extend mlx5_devcom_send_event to work with more than two devices

From: Saeed Mahameed <[email-masked]>
Date: Wed, 31 May 2023 23:01:18 -0700

From: Shay Drory <[email-masked]>

mlx5_devcom_send_event is used to send event from one eswitch to the
other. In other words, only one event is sent, which means, no error
mechanism is needed.
However, In case devcom have more than two eswitches, a proper error
mechanism is needed. Hence, in case of error, devcom will perform the
error unwind, since devcom knows how many events were successful.

Signed-off-by: Shay Drory <[email-masked]>
Reviewed-by: Mark Bloch <[email-masked]>
Reviewed-by: Roi Dayan <[email-masked]>
Signed-off-by: Saeed Mahameed <[email-masked]>
---
 .../mellanox/mlx5/core/eswitch_offloads.c       |  4 +++-
 .../ethernet/mellanox/mlx5/core/lib/devcom.c    | 17 +++++++++++++++--
 .../ethernet/mellanox/mlx5/core/lib/devcom.h    |  2 +-
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
index 09367a320741..29de4e759f4f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
@@ -2892,7 +2892,8 @@ void mlx5_esw_offloads_devcom_init(struct mlx5_eswitch *esw)
 	esw->num_peers = 0;
 	mlx5_devcom_send_event(devcom,
 			       MLX5_DEVCOM_ESW_OFFLOADS,
-			       ESW_OFFLOADS_DEVCOM_PAIR, esw);
+			       ESW_OFFLOADS_DEVCOM_PAIR,
+			       ESW_OFFLOADS_DEVCOM_UNPAIR, esw);
 }
 
 void mlx5_esw_offloads_devcom_cleanup(struct mlx5_eswitch *esw)
@@ -2906,6 +2907,7 @@ void mlx5_esw_offloads_devcom_cleanup(struct mlx5_eswitch *esw)
 		return;
 
 	mlx5_devcom_send_event(devcom, MLX5_DEVCOM_ESW_OFFLOADS,
+			       ESW_OFFLOADS_DEVCOM_UNPAIR,
 			       ESW_OFFLOADS_DEVCOM_UNPAIR, esw);
 
 	mlx5_devcom_unregister_component(devcom, MLX5_DEVCOM_ESW_OFFLOADS);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c
index 96a3b7b9a5cd..8472bbb3cd58 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c
@@ -193,7 +193,7 @@ void mlx5_devcom_unregister_component(struct mlx5_devcom *devcom,
 
 int mlx5_devcom_send_event(struct mlx5_devcom *devcom,
 			   enum mlx5_devcom_components id,
-			   int event,
+			   int event, int rollback_event,
 			   void *event_data)
 {
 	struct mlx5_devcom_component *comp;
@@ -210,10 +210,23 @@ int mlx5_devcom_send_event(struct mlx5_devcom *devcom,
 
 		if (i != devcom->idx && data) {
 			err = comp->handler(event, data, event_data);
-			break;
+			if (err)
+				goto rollback;
 		}
 	}
 
+	up_write(&comp->sem);
+	return 0;
+
+rollback:
+	while (i--) {
+		void *data = rcu_dereference_protected(comp->device[i].data,
+						       lockdep_is_held(&comp->sem));
+
+		if (i != devcom->idx && data)
+			comp->handler(rollback_event, data, event_data);
+	}
+
 	up_write(&comp->sem);
 	return err;
 }
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.h b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.h
index b7f72f1a5367..bb1970ba8730 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.h
@@ -30,7 +30,7 @@ void mlx5_devcom_unregister_component(struct mlx5_devcom *devcom,
 
 int mlx5_devcom_send_event(struct mlx5_devcom *devcom,
 			   enum mlx5_devcom_components id,
-			   int event,
+			   int event, int rollback_event,
 			   void *event_data);
 
 void mlx5_devcom_comp_set_ready(struct mlx5_devcom *devcom,
-- 
2.40.1