[PATCH net-next 02/15] net/mlx5: LAG, select the MPESW master from the live member snapshot

[Tariq Toukan <tariqt@nvidia.com>]

From: Shay Drory <shayd@nvidia.com>

The LAG master is marked by the devcom PAIR event when all physical
ports have registered (mlx5_lag_num_devs() == ldev->ports). That does
not work for a virtual LAG of VFs/SFs: those functions are unrelated to
the physical port count.

Select the master from the current membership snapshot in
mlx5_lag_enable_mpesw() via mlx5_virt_lag_mark_master(), and clear it in
mlx5_lag_disable_mpesw(). Unlike the regular path, it walks all LAG
members.
mlx5_get_dev_index() is identical for a PF and all its VFs/SFs, so
tie-break by a stable per-member key is used - PCI BDF for VFs, sfnum
for SFs.

This is gated by a new ldev->virt_lag bit identifying this type of LAG.

Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 .../net/ethernet/mellanox/mlx5/core/lag/lag.c | 46 +++++++++++++++++--
 .../net/ethernet/mellanox/mlx5/core/lag/lag.h |  3 ++
 .../ethernet/mellanox/mlx5/core/lag/mpesw.c   | 42 +++++++++++++----
 .../ethernet/mellanox/mlx5/core/sf/dev/dev.h  | 12 +++++
 4 files changed, 90 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c
index 24086267b4a7..46f125d24f15 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c
@@ -39,6 +39,7 @@
 #include "lib/mlx5.h"
 #include "lib/devcom.h"
 #include "mlx5_core.h"
+#include "sf/dev/dev.h"
 #include "eswitch.h"
 #include "esw/acl/ofld.h"
 #include "lag.h"
@@ -598,7 +599,43 @@ static void mlx5_lag_mark_master(struct mlx5_lag *ldev)
 		xa_set_mark(&ldev->pfs, master_xa_idx, MLX5_LAG_XA_MARK_MASTER);
 }
 
-static void mlx5_lag_clear_master(struct mlx5_lag *ldev)
+static u64 mlx5_lag_member_tiebreak(struct mlx5_core_dev *dev)
+{
+	struct pci_dev *pdev = dev->pdev;
+
+	if (mlx5_core_is_sf(dev))
+		return mlx5_sf_coredev_sfnum(dev);
+
+	return ((u64)pci_domain_nr(pdev->bus) << 16) | pci_dev_id(pdev);
+}
+
+void mlx5_virt_lag_mark_master(struct mlx5_lag *ldev)
+{
+	u64 lowest_tiebreak = U64_MAX;
+	int lowest_dev_idx = INT_MAX;
+	int master_xa_idx = -1;
+	struct lag_func *pf;
+	u64 tiebreak;
+	int dev_idx;
+	int i;
+
+	mlx5_lag_for_each(i, 0, ldev, MLX5_LAG_FILTER_ALL) {
+		pf = mlx5_lag_pf(ldev, i);
+		dev_idx = mlx5_get_dev_index(pf->dev);
+		tiebreak = mlx5_lag_member_tiebreak(pf->dev);
+		if (dev_idx < lowest_dev_idx ||
+		    (dev_idx == lowest_dev_idx && tiebreak < lowest_tiebreak)) {
+			lowest_dev_idx = dev_idx;
+			lowest_tiebreak = tiebreak;
+			master_xa_idx = i;
+		}
+	}
+
+	if (master_xa_idx >= 0)
+		xa_set_mark(&ldev->pfs, master_xa_idx, MLX5_LAG_XA_MARK_MASTER);
+}
+
+void mlx5_lag_clear_master(struct mlx5_lag *ldev)
 {
 	unsigned long idx = 0;
 	void *entry;
@@ -618,7 +655,7 @@ static int mlx5_lag_devcom_event(int event, void *my_data, void *event_data)
 	int idx;
 
 	ldev = mlx5_lag_dev(dev);
-	if (!ldev)
+	if (!ldev || ldev->virt_lag)
 		return 0;
 
 	mutex_lock(&ldev->lock);
@@ -1785,10 +1822,13 @@ struct mlx5_devcom_comp_dev *mlx5_lag_get_devcom_comp(struct mlx5_lag *ldev)
 {
 	struct mlx5_devcom_comp_dev *devcom = NULL;
 	struct lag_func *pf;
+	u32 filter;
 	int i;
 
 	mutex_lock(&ldev->lock);
-	i = mlx5_get_next_lag_func(ldev, 0, MLX5_LAG_FILTER_PORTS);
+	filter = ldev->virt_lag ? MLX5_LAG_FILTER_ALL :
+		MLX5_LAG_FILTER_PORTS;
+	i = mlx5_get_next_lag_func(ldev, 0, filter);
 	if (i < MLX5_MAX_PORTS) {
 		pf = mlx5_lag_pf(ldev, i);
 		devcom = pf->dev->priv.hca_devcom_comp;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.h b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.h
index 0ff337983a6d..dff04f40d8f3 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.h
@@ -84,6 +84,7 @@ struct mlx5_lag {
 	unsigned long		  state_flags;
 	u8			  ports;
 	u8			  buckets;
+	bool			  virt_lag;
 	int			  mode_changes_in_progress;
 	u8			  *v2p_map;
 	struct kref               ref;
@@ -225,6 +226,8 @@ static inline bool mlx5_lag_shared_fdb_supported(struct mlx5_lag *ldev)
 }
 #endif
 bool mlx5_lag_check_prereq(struct mlx5_lag *ldev);
+void mlx5_virt_lag_mark_master(struct mlx5_lag *ldev);
+void mlx5_lag_clear_master(struct mlx5_lag *ldev);
 bool mlx5_lag_is_sd(struct mlx5_core_dev *dev);
 int mlx5_lag_demux_init(struct mlx5_core_dev *dev,
 			struct mlx5_flow_table_attr *ft_attr);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lag/mpesw.c b/drivers/net/ethernet/mellanox/mlx5/core/lag/mpesw.c
index abf72026c751..cdaf72cb0595 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lag/mpesw.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lag/mpesw.c
@@ -109,8 +109,8 @@ static bool mlx5_lag_has_sd_group(struct mlx5_lag *ldev)
 
 static int mlx5_lag_enable_mpesw(struct mlx5_lag *ldev)
 {
-	int idx = mlx5_lag_get_dev_index_by_seq(ldev, MLX5_LAG_P1);
 	struct mlx5_core_dev *dev0;
+	int idx;
 	int err;
 
 	if (ldev->mode == MLX5_LAG_MODE_MPESW)
@@ -119,20 +119,32 @@ static int mlx5_lag_enable_mpesw(struct mlx5_lag *ldev)
 	if (ldev->mode != MLX5_LAG_MODE_NONE)
 		return -EINVAL;
 
-	if (idx < 0)
-		return -EINVAL;
+	/* VFs/SFs (nested LAG) are not marked by the LAG devcom PAIR event;
+	 * select the master from the current snapshot before resolving it via
+	 * mlx5_lag_get_dev_index_by_seq().
+	 */
+	if (ldev->virt_lag)
+		mlx5_virt_lag_mark_master(ldev);
+
+	idx = mlx5_lag_get_dev_index_by_seq(ldev, MLX5_LAG_P1);
+	if (idx < 0) {
+		err = -EINVAL;
+		goto err_clear_master;
+	}
 
 	dev0 = mlx5_lag_pf(ldev, idx)->dev;
 	if (mlx5_eswitch_mode(dev0) != MLX5_ESWITCH_OFFLOADS ||
 	    !MLX5_CAP_PORT_SELECTION(dev0, port_select_flow_table) ||
 	    !MLX5_CAP_GEN(dev0, create_lag_when_not_master_up) ||
 	    !mlx5_lag_check_prereq(ldev) ||
-	    !mlx5_lag_shared_fdb_supported_filter(ldev, MLX5_LAG_FILTER_ALL))
-		return -EOPNOTSUPP;
+	    !mlx5_lag_shared_fdb_supported_filter(ldev, MLX5_LAG_FILTER_ALL)) {
+		err = -EOPNOTSUPP;
+		goto err_clear_master;
+	}
 
 	err = mlx5_mpesw_metadata_set(ldev);
 	if (err)
-		return err;
+		goto err_clear_master;
 
 	if (mlx5_lag_has_sd_group(ldev))
 		mlx5_mpesw_teardown_sd_fdb(ldev);
@@ -143,13 +155,19 @@ static int mlx5_lag_enable_mpesw(struct mlx5_lag *ldev)
 		mlx5_core_warn(dev0,
 			       "Failed to create LAG in MPESW mode (%d)\n",
 			       err);
-		if (mlx5_lag_has_sd_group(ldev))
-			mlx5_mpesw_restore_sd_fdb(ldev);
-		mlx5_mpesw_metadata_cleanup(ldev);
-		return err;
+		goto err_restore;
 	}
 
 	return 0;
+
+err_restore:
+	if (mlx5_lag_has_sd_group(ldev))
+		mlx5_mpesw_restore_sd_fdb(ldev);
+	mlx5_mpesw_metadata_cleanup(ldev);
+err_clear_master:
+	if (ldev->virt_lag)
+		mlx5_lag_clear_master(ldev);
+	return err;
 }
 
 void mlx5_lag_disable_mpesw(struct mlx5_lag *ldev)
@@ -161,6 +179,10 @@ void mlx5_lag_disable_mpesw(struct mlx5_lag *ldev)
 	mlx5_lag_shared_fdb_destroy(ldev, MLX5_LAG_FILTER_ALL);
 	if (mlx5_lag_has_sd_group(ldev))
 		mlx5_mpesw_restore_sd_fdb(ldev);
+
+	/* Pair with the master mark taken at MPESW create for VFs. */
+	if (ldev->virt_lag)
+		mlx5_lag_clear_master(ldev);
 }
 
 void mlx5_mpesw_sd_devcoms_lock(struct mlx5_lag *ldev)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/dev.h b/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/dev.h
index 3ab0449c770c..382162baabdb 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/dev.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/dev.h
@@ -19,6 +19,13 @@ struct mlx5_sf_dev {
 	u16 fn_id;
 };
 
+static inline u32 mlx5_sf_coredev_sfnum(struct mlx5_core_dev *mdev)
+{
+	struct auxiliary_device *adev = mlx5_sf_coredev_to_adev(mdev);
+
+	return container_of(adev, struct mlx5_sf_dev, adev)->sfnum;
+}
+
 struct mlx5_sf_peer_devlink_event_ctx {
 	u16 fn_id;
 	struct devlink *devlink;
@@ -68,6 +75,11 @@ static inline bool mlx5_sf_dev_allocated(const struct mlx5_core_dev *dev)
 	return false;
 }
 
+static inline u32 mlx5_sf_coredev_sfnum(struct mlx5_core_dev *mdev)
+{
+	return 0;
+}
+
 #endif
 
 #endif
-- 
2.44.0