Merge branch 'mlxsw-Add-support-for-buffer-drop-traps'

Ido Schimmel says:

====================
mlxsw: Add support for buffer drop traps

Petr says:

A recent patch set added the ability to mirror buffer related drops
(e.g., early drops) through a netdev. This patch set adds the ability to
trap such packets to the local CPU for analysis.

The trapping towards the CPU is configured by using tc-trap action
instead of tc-mirred as was done when the packets were mirrored through
a netdev. A future patch set will also add the ability to sample the
dropped packets using tc-sample action.

The buffer related drop traps are added to devlink, which means that the
dropped packets can be reported to user space via the kernel's
drop_monitor module.

Patch set overview:

Patch #1 adds the early_drop trap to devlink

Patch #2 adds extack to a few devlink operations to facilitate better
error reporting to user space. This is necessary - among other things -
because the action of buffer drop traps cannot be changed in mlxsw

Patch #3 performs a small refactoring in mlxsw, patch #4 fixes a bug that
this patchset would trigger.

Patches #5-#6 add the infrastructure required to support different traps
/ trap groups in mlxsw per-ASIC. This is required because buffer drop
traps are not supported by Spectrum-1

Patch #7 extends mlxsw to register the early_drop trap

Patch #8 adds the offload logic for the "trap" action at a qevent block.

Patch #9 adds a mlxsw-specific selftest.
====================

Signed-off-by: David S. Miller <[email protected]>

Documentation/networking/devlink/devlink-trap.rst

@@ -405,6 +405,10 @@ be added to the following table:
      - ``control``
      - Traps packets logged during processing of flow action trap (e.g., via
        tc's trap action)
+   * - ``early_drop``
+     - ``drop``
+     - Traps packets dropped due to the RED (Random Early Detection) algorithm
+       (i.e., early drops)
 
 Driver-specific Packet Traps
 ============================

drivers/net/ethernet/mellanox/mlxsw/core.c

@@ -1177,14 +1177,15 @@ static void mlxsw_devlink_trap_fini(struct devlink *devlink,
 
 static int mlxsw_devlink_trap_action_set(struct devlink *devlink,
 					 const struct devlink_trap *trap,
-					 enum devlink_trap_action action)
+					 enum devlink_trap_action action,
+					 struct netlink_ext_ack *extack)
 {
 	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
 	struct mlxsw_driver *mlxsw_driver = mlxsw_core->driver;
 
 	if (!mlxsw_driver->trap_action_set)
 		return -EOPNOTSUPP;
-	return mlxsw_driver->trap_action_set(mlxsw_core, trap, action);
+	return mlxsw_driver->trap_action_set(mlxsw_core, trap, action, extack);
 }
 
 static int
@@ -1202,14 +1203,15 @@ mlxsw_devlink_trap_group_init(struct devlink *devlink,
 static int
 mlxsw_devlink_trap_group_set(struct devlink *devlink,
 			     const struct devlink_trap_group *group,
-			     const struct devlink_trap_policer *policer)
+			     const struct devlink_trap_policer *policer,
+			     struct netlink_ext_ack *extack)
 {
 	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
 	struct mlxsw_driver *mlxsw_driver = mlxsw_core->driver;
 
 	if (!mlxsw_driver->trap_group_set)
 		return -EOPNOTSUPP;
-	return mlxsw_driver->trap_group_set(mlxsw_core, group, policer);
+	return mlxsw_driver->trap_group_set(mlxsw_core, group, policer, extack);
 }
 
 static int

drivers/net/ethernet/mellanox/mlxsw/core.h

@@ -89,13 +89,15 @@ struct mlxsw_listener {
 };
 
 #define __MLXSW_RXL(_func, _trap_id, _en_action, _is_ctrl, _en_trap_group,	\
-		    _dis_action, _enabled_on_register, _dis_trap_group)		\
+		    _dis_action, _enabled_on_register, _dis_trap_group,		\
+		    _mirror_reason)						\
 	{									\
 		.trap_id = MLXSW_TRAP_ID_##_trap_id,				\
 		.rx_listener =							\
 		{								\
 			.func = _func,						\
 			.local_port = MLXSW_PORT_DONT_CARE,			\
+			.mirror_reason = _mirror_reason,			\
 			.trap_id = MLXSW_TRAP_ID_##_trap_id,			\
 		},								\
 		.en_action = MLXSW_REG_HPKT_ACTION_##_en_action,		\
@@ -109,12 +111,17 @@ struct mlxsw_listener {
 #define MLXSW_RXL(_func, _trap_id, _en_action, _is_ctrl, _trap_group,		\
 		  _dis_action)							\
 	__MLXSW_RXL(_func, _trap_id, _en_action, _is_ctrl, _trap_group,		\
-		    _dis_action, true, _trap_group)
+		    _dis_action, true, _trap_group, 0)
 
 #define MLXSW_RXL_DIS(_func, _trap_id, _en_action, _is_ctrl, _en_trap_group,	\
 		      _dis_action, _dis_trap_group)				\
 	__MLXSW_RXL(_func, _trap_id, _en_action, _is_ctrl, _en_trap_group,	\
-		    _dis_action, false, _dis_trap_group)
+		    _dis_action, false, _dis_trap_group, 0)
+
+#define MLXSW_RXL_MIRROR(_func, _session_id, _trap_group, _mirror_reason)	\
+	__MLXSW_RXL(_func, MIRROR_SESSION##_session_id,	TRAP_TO_CPU, false,	\
+		    _trap_group, TRAP_TO_CPU, true, _trap_group,		\
+		    _mirror_reason)
 
 #define MLXSW_EVENTL(_func, _trap_id, _trap_group)				\
 	{									\
@@ -326,12 +333,14 @@ struct mlxsw_driver {
 			  const struct devlink_trap *trap, void *trap_ctx);
 	int (*trap_action_set)(struct mlxsw_core *mlxsw_core,
 			       const struct devlink_trap *trap,
-			       enum devlink_trap_action action);
+			       enum devlink_trap_action action,
+			       struct netlink_ext_ack *extack);
 	int (*trap_group_init)(struct mlxsw_core *mlxsw_core,
 			       const struct devlink_trap_group *group);
 	int (*trap_group_set)(struct mlxsw_core *mlxsw_core,
 			      const struct devlink_trap_group *group,
-			      const struct devlink_trap_policer *policer);
+			      const struct devlink_trap_policer *policer,
+			      struct netlink_ext_ack *extack);
 	int (*trap_policer_init)(struct mlxsw_core *mlxsw_core,
 				 const struct devlink_trap_policer *policer);
 	void (*trap_policer_fini)(struct mlxsw_core *mlxsw_core,

drivers/net/ethernet/mellanox/mlxsw/reg.h

@@ -5614,6 +5614,7 @@ enum mlxsw_reg_htgt_trap_group {
 	MLXSW_REG_HTGT_TRAP_GROUP_SP_L3_EXCEPTIONS,
 	MLXSW_REG_HTGT_TRAP_GROUP_SP_TUNNEL_DISCARDS,
 	MLXSW_REG_HTGT_TRAP_GROUP_SP_ACL_DISCARDS,
+	MLXSW_REG_HTGT_TRAP_GROUP_SP_BUFFER_DISCARDS,
 
 	__MLXSW_REG_HTGT_TRAP_GROUP_MAX,
 	MLXSW_REG_HTGT_TRAP_GROUP_MAX = __MLXSW_REG_HTGT_TRAP_GROUP_MAX - 1

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -3055,6 +3055,7 @@ static int mlxsw_sp1_init(struct mlxsw_core *mlxsw_core,
 	mlxsw_sp->ptp_ops = &mlxsw_sp1_ptp_ops;
 	mlxsw_sp->span_ops = &mlxsw_sp1_span_ops;
 	mlxsw_sp->policer_core_ops = &mlxsw_sp1_policer_core_ops;
+	mlxsw_sp->trap_ops = &mlxsw_sp1_trap_ops;
 	mlxsw_sp->listeners = mlxsw_sp1_listener;
 	mlxsw_sp->listeners_count = ARRAY_SIZE(mlxsw_sp1_listener);
 	mlxsw_sp->lowest_shaper_bs = MLXSW_REG_QEEC_LOWEST_SHAPER_BS_SP1;
@@ -3084,6 +3085,7 @@ static int mlxsw_sp2_init(struct mlxsw_core *mlxsw_core,
 	mlxsw_sp->ptp_ops = &mlxsw_sp2_ptp_ops;
 	mlxsw_sp->span_ops = &mlxsw_sp2_span_ops;
 	mlxsw_sp->policer_core_ops = &mlxsw_sp2_policer_core_ops;
+	mlxsw_sp->trap_ops = &mlxsw_sp2_trap_ops;
 	mlxsw_sp->lowest_shaper_bs = MLXSW_REG_QEEC_LOWEST_SHAPER_BS_SP2;
 
 	return mlxsw_sp_init(mlxsw_core, mlxsw_bus_info, extack);
@@ -3111,6 +3113,7 @@ static int mlxsw_sp3_init(struct mlxsw_core *mlxsw_core,
 	mlxsw_sp->ptp_ops = &mlxsw_sp2_ptp_ops;
 	mlxsw_sp->span_ops = &mlxsw_sp3_span_ops;
 	mlxsw_sp->policer_core_ops = &mlxsw_sp2_policer_core_ops;
+	mlxsw_sp->trap_ops = &mlxsw_sp2_trap_ops;
 	mlxsw_sp->lowest_shaper_bs = MLXSW_REG_QEEC_LOWEST_SHAPER_BS_SP3;
 
 	return mlxsw_sp_init(mlxsw_core, mlxsw_bus_info, extack);

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -177,6 +177,7 @@ struct mlxsw_sp {
 	const struct mlxsw_sp_ptp_ops *ptp_ops;
 	const struct mlxsw_sp_span_ops *span_ops;
 	const struct mlxsw_sp_policer_core_ops *policer_core_ops;
+	const struct mlxsw_sp_trap_ops *trap_ops;
 	const struct mlxsw_listener *listeners;
 	size_t listeners_count;
 	u32 lowest_shaper_bs;
@@ -983,6 +984,10 @@ struct mlxsw_sp_mall_mirror_entry {
 	int span_id;
 };
 
+struct mlxsw_sp_mall_trap_entry {
+	int span_id;
+};
+
 struct mlxsw_sp_mall_entry {
 	struct list_head list;
 	unsigned long cookie;
@@ -991,6 +996,7 @@ struct mlxsw_sp_mall_entry {
 	bool ingress;
 	union {
 		struct mlxsw_sp_mall_mirror_entry mirror;
+		struct mlxsw_sp_mall_trap_entry trap;
 		struct mlxsw_sp_port_sample sample;
 	};
 	struct rcu_head rcu;
@@ -1177,12 +1183,14 @@ void mlxsw_sp_trap_fini(struct mlxsw_core *mlxsw_core,
 			const struct devlink_trap *trap, void *trap_ctx);
 int mlxsw_sp_trap_action_set(struct mlxsw_core *mlxsw_core,
 			     const struct devlink_trap *trap,
-			     enum devlink_trap_action action);
+			     enum devlink_trap_action action,
+			     struct netlink_ext_ack *extack);
 int mlxsw_sp_trap_group_init(struct mlxsw_core *mlxsw_core,
 			     const struct devlink_trap_group *group);
 int mlxsw_sp_trap_group_set(struct mlxsw_core *mlxsw_core,
 			    const struct devlink_trap_group *group,
-			    const struct devlink_trap_policer *policer);
+			    const struct devlink_trap_policer *policer,
+			    struct netlink_ext_ack *extack);
 int
 mlxsw_sp_trap_policer_init(struct mlxsw_core *mlxsw_core,
 			   const struct devlink_trap_policer *policer);
@@ -1196,6 +1204,8 @@ int
 mlxsw_sp_trap_policer_counter_get(struct mlxsw_core *mlxsw_core,
 				  const struct devlink_trap_policer *policer,
 				  u64 *p_drops);
+int mlxsw_sp_trap_group_policer_hw_id_get(struct mlxsw_sp *mlxsw_sp, u16 id,
+					  bool *p_enabled, u16 *p_hw_id);
 
 static inline struct net *mlxsw_sp_net(struct mlxsw_sp *mlxsw_sp)
 {

drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c

@@ -1289,19 +1289,18 @@ struct mlxsw_sp_qevent_binding {
 
 static LIST_HEAD(mlxsw_sp_qevent_block_cb_list);
 
-static int mlxsw_sp_qevent_mirror_configure(struct mlxsw_sp *mlxsw_sp,
-					    struct mlxsw_sp_mall_entry *mall_entry,
-					    struct mlxsw_sp_qevent_binding *qevent_binding)
+static int mlxsw_sp_qevent_span_configure(struct mlxsw_sp *mlxsw_sp,
+					  struct mlxsw_sp_mall_entry *mall_entry,
+					  struct mlxsw_sp_qevent_binding *qevent_binding,
+					  const struct mlxsw_sp_span_agent_parms *agent_parms,
+					  int *p_span_id)
 {
 	struct mlxsw_sp_port *mlxsw_sp_port = qevent_binding->mlxsw_sp_port;
 	struct mlxsw_sp_span_trigger_parms trigger_parms = {};
-	struct mlxsw_sp_span_agent_parms agent_parms = {
-		.to_dev = mall_entry->mirror.to_dev,
-	};
 	int span_id;
 	int err;
 
-	err = mlxsw_sp_span_agent_get(mlxsw_sp, &span_id, &agent_parms);
+	err = mlxsw_sp_span_agent_get(mlxsw_sp, &span_id, agent_parms);
 	if (err)
 		return err;
 
@@ -1320,7 +1319,7 @@ static int mlxsw_sp_qevent_mirror_configure(struct mlxsw_sp *mlxsw_sp,
 	if (err)
 		goto err_trigger_enable;
 
-	mall_entry->mirror.span_id = span_id;
+	*p_span_id = span_id;
 	return 0;
 
 err_trigger_enable:
@@ -1333,21 +1332,65 @@ static int mlxsw_sp_qevent_mirror_configure(struct mlxsw_sp *mlxsw_sp,
 	return err;
 }
 
-static void mlxsw_sp_qevent_mirror_deconfigure(struct mlxsw_sp *mlxsw_sp,
-					       struct mlxsw_sp_mall_entry *mall_entry,
-					       struct mlxsw_sp_qevent_binding *qevent_binding)
+static void mlxsw_sp_qevent_span_deconfigure(struct mlxsw_sp *mlxsw_sp,
+					     struct mlxsw_sp_qevent_binding *qevent_binding,
+					     int span_id)
 {
 	struct mlxsw_sp_port *mlxsw_sp_port = qevent_binding->mlxsw_sp_port;
 	struct mlxsw_sp_span_trigger_parms trigger_parms = {
-		.span_id = mall_entry->mirror.span_id,
+		.span_id = span_id,
 	};
 
 	mlxsw_sp_span_trigger_disable(mlxsw_sp_port, qevent_binding->span_trigger,
 				      qevent_binding->tclass_num);
 	mlxsw_sp_span_agent_unbind(mlxsw_sp, qevent_binding->span_trigger, mlxsw_sp_port,
 				   &trigger_parms);
 	mlxsw_sp_span_analyzed_port_put(mlxsw_sp_port, true);
-	mlxsw_sp_span_agent_put(mlxsw_sp, mall_entry->mirror.span_id);
+	mlxsw_sp_span_agent_put(mlxsw_sp, span_id);
+}
+
+static int mlxsw_sp_qevent_mirror_configure(struct mlxsw_sp *mlxsw_sp,
+					    struct mlxsw_sp_mall_entry *mall_entry,
+					    struct mlxsw_sp_qevent_binding *qevent_binding)
+{
+	struct mlxsw_sp_span_agent_parms agent_parms = {
+		.to_dev = mall_entry->mirror.to_dev,
+	};
+
+	return mlxsw_sp_qevent_span_configure(mlxsw_sp, mall_entry, qevent_binding,
+					      &agent_parms, &mall_entry->mirror.span_id);
+}
+
+static void mlxsw_sp_qevent_mirror_deconfigure(struct mlxsw_sp *mlxsw_sp,
+					       struct mlxsw_sp_mall_entry *mall_entry,
+					       struct mlxsw_sp_qevent_binding *qevent_binding)
+{
+	mlxsw_sp_qevent_span_deconfigure(mlxsw_sp, qevent_binding, mall_entry->mirror.span_id);
+}
+
+static int mlxsw_sp_qevent_trap_configure(struct mlxsw_sp *mlxsw_sp,
+					  struct mlxsw_sp_mall_entry *mall_entry,
+					  struct mlxsw_sp_qevent_binding *qevent_binding)
+{
+	struct mlxsw_sp_span_agent_parms agent_parms = {};
+	int err;
+
+	err = mlxsw_sp_trap_group_policer_hw_id_get(mlxsw_sp,
+						    DEVLINK_TRAP_GROUP_GENERIC_ID_BUFFER_DROPS,
+						    &agent_parms.policer_enable,
+						    &agent_parms.policer_id);
+	if (err)
+		return err;
+
+	return mlxsw_sp_qevent_span_configure(mlxsw_sp, mall_entry, qevent_binding,
+					      &agent_parms, &mall_entry->trap.span_id);
+}
+
+static void mlxsw_sp_qevent_trap_deconfigure(struct mlxsw_sp *mlxsw_sp,
+					     struct mlxsw_sp_mall_entry *mall_entry,
+					     struct mlxsw_sp_qevent_binding *qevent_binding)
+{
+	mlxsw_sp_qevent_span_deconfigure(mlxsw_sp, qevent_binding, mall_entry->trap.span_id);
 }
 
 static int mlxsw_sp_qevent_entry_configure(struct mlxsw_sp *mlxsw_sp,
@@ -1357,6 +1400,8 @@ static int mlxsw_sp_qevent_entry_configure(struct mlxsw_sp *mlxsw_sp,
 	switch (mall_entry->type) {
 	case MLXSW_SP_MALL_ACTION_TYPE_MIRROR:
 		return mlxsw_sp_qevent_mirror_configure(mlxsw_sp, mall_entry, qevent_binding);
+	case MLXSW_SP_MALL_ACTION_TYPE_TRAP:
+		return mlxsw_sp_qevent_trap_configure(mlxsw_sp, mall_entry, qevent_binding);
 	default:
 		/* This should have been validated away. */
 		WARN_ON(1);
@@ -1371,6 +1416,8 @@ static void mlxsw_sp_qevent_entry_deconfigure(struct mlxsw_sp *mlxsw_sp,
 	switch (mall_entry->type) {
 	case MLXSW_SP_MALL_ACTION_TYPE_MIRROR:
 		return mlxsw_sp_qevent_mirror_deconfigure(mlxsw_sp, mall_entry, qevent_binding);
+	case MLXSW_SP_MALL_ACTION_TYPE_TRAP:
+		return mlxsw_sp_qevent_trap_deconfigure(mlxsw_sp, mall_entry, qevent_binding);
 	default:
 		WARN_ON(1);
 		return;
@@ -1490,6 +1537,8 @@ static int mlxsw_sp_qevent_mall_replace(struct mlxsw_sp *mlxsw_sp,
 	if (act->id == FLOW_ACTION_MIRRED) {
 		mall_entry->type = MLXSW_SP_MALL_ACTION_TYPE_MIRROR;
 		mall_entry->mirror.to_dev = act->dev;
+	} else if (act->id == FLOW_ACTION_TRAP) {
+		mall_entry->type = MLXSW_SP_MALL_ACTION_TYPE_TRAP;
 	} else {
 		NL_SET_ERR_MSG(f->common.extack, "Unsupported action");
 		err = -EOPNOTSUPP;

drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c

@@ -837,7 +837,8 @@ static int mlxsw_sp_span_policer_id_base_set(struct mlxsw_sp_span *span,
 
 static void mlxsw_sp_span_policer_id_base_unset(struct mlxsw_sp_span *span)
 {
-	refcount_dec(&span->policer_id_base_ref_count);
+	if (refcount_dec_and_test(&span->policer_id_base_ref_count))
+		span->policer_id_base = 0;
 }
 
 static struct mlxsw_sp_span_entry *