[PATCH net-next v2 03/11] devlink: Add health report functionality

From: Eran Ben Elisha <hidden>
Date: 2019-01-17 21:59:55
Subsystem: devlink, networking [general], the rest, tracing · Maintainers: Jiri Pirko, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Steven Rostedt, Masami Hiramatsu

Upon error discover, every driver can report it to the devlink health
mechanism via devlink_health_report function, using the appropriate
reporter registered to it. Driver can pass error specific context which
will be delivered to it as part of the dump / recovery callbacks.

Once an error is reported, devlink health will do the following actions:
* A log is being send to the kernel trace events buffer
* Health status and statistics are being updated for the reporter instance
* Object dump is being taken and stored at the reporter instance (as long
  as there is no other dump which is already stored)
* Auto recovery attempt is being done. depends on:
  - Auto Recovery configuration
  - Grace period vs. time since last recover

Signed-off-by: Eran Ben Elisha <redacted>
Reviewed-by: Moshe Shemesh <redacted>
---
 include/net/devlink.h          |  9 ++++
 include/trace/events/devlink.h | 62 +++++++++++++++++++++++
 net/core/devlink.c             | 93 ++++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 7fe30d67678a..a81a1b7a67d7 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h

@@ -641,6 +641,8 @@ devlink_health_reporter_destroy(struct devlink_health_reporter *reporter);
 
 void *
 devlink_health_reporter_priv(struct devlink_health_reporter *reporter);
+int devlink_health_report(struct devlink_health_reporter *reporter,
+			  const char *msg, void *priv_ctx);
 #else
 
 static inline struct devlink *devlink_alloc(const struct devlink_ops *ops,

@@ -979,6 +981,13 @@ devlink_health_reporter_priv(struct devlink_health_reporter *reporter)
 {
 	return NULL;
 }
+
+static inline int
+devlink_health_report(struct devlink_health_reporter *reporter,
+		      const char *msg, void *priv_ctx)
+{
+	return 0;
+}
 #endif
 
 #endif /* _NET_DEVLINK_H_ */

diff --git a/include/trace/events/devlink.h b/include/trace/events/devlink.h
index 44acfbca1266..7e39d2fc7c75 100644
--- a/include/trace/events/devlink.h
+++ b/include/trace/events/devlink.h

@@ -46,6 +46,65 @@ TRACE_EVENT(devlink_hwmsg,
 		  (int) __entry->len, __get_dynamic_array(buf), __entry->len)
 );
 
+TRACE_EVENT(devlink_health_report,
+	TP_PROTO(const struct devlink *devlink, const char *reporter_name,
+		 const char *msg),
+
+	TP_ARGS(devlink, reporter_name, msg),
+
+	TP_STRUCT__entry(
+		__string(bus_name, devlink->dev->bus->name)
+		__string(dev_name, dev_name(devlink->dev))
+		__string(driver_name, devlink->dev->driver->name)
+		__string(reporter_name, msg)
+		__string(msg, msg)
+	),
+
+	TP_fast_assign(
+		__assign_str(bus_name, devlink->dev->bus->name);
+		__assign_str(dev_name, dev_name(devlink->dev));
+		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(reporter_name, reporter_name);
+		__assign_str(msg, msg);
+	),
+
+	TP_printk("bus_name=%s dev_name=%s driver_name=%s reporter_name=%s: %s",
+		  __get_str(bus_name), __get_str(dev_name),
+		  __get_str(driver_name), __get_str(reporter_name),
+		  __get_str(msg))
+);
+
+TRACE_EVENT(devlink_health_recover_aborted,
+	TP_PROTO(const struct devlink *devlink, const char *reporter_name,
+		 bool health_state, u64 time_since_last_recover),
+
+	TP_ARGS(devlink, reporter_name, health_state, time_since_last_recover),
+
+	TP_STRUCT__entry(
+		__string(bus_name, devlink->dev->bus->name)
+		__string(dev_name, dev_name(devlink->dev))
+		__string(driver_name, devlink->dev->driver->name)
+		__string(reporter_name, reporter_name)
+		__field(bool, health_state)
+		__field(u64, time_since_last_recover)
+	),
+
+	TP_fast_assign(
+		__assign_str(bus_name, devlink->dev->bus->name);
+		__assign_str(dev_name, dev_name(devlink->dev));
+		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(reporter_name, reporter_name);
+		__entry->health_state = health_state;
+		__entry->time_since_last_recover = time_since_last_recover;
+	),
+
+	TP_printk("bus_name=%s dev_name=%s driver_name=%s reporter_name=%s: health_state=%d time_since_last_recover = %llu recover aborted",
+		  __get_str(bus_name), __get_str(dev_name),
+		  __get_str(driver_name), __get_str(reporter_name),
+		  __entry->health_state,
+		  __entry->time_since_last_recover)
+);
+
 #endif /* _TRACE_DEVLINK_H */
 
 /* This part must be outside protection */

@@ -64,6 +123,9 @@ static inline void trace_devlink_hwmsg(const struct devlink *devlink,
 {
 }
 
+static inline void trace_devlink_health(const char *msg)
+{
+}
 #endif /* _TRACE_DEVLINK_H */
 
 #endif

diff --git a/net/core/devlink.c b/net/core/devlink.c
index fec169a28dba..943d3e7dea6a 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c

@@ -4110,6 +4110,16 @@ struct devlink_health_reporter {
 	u64 graceful_period;
 	bool auto_recover;
 	u8 health_state;
+	u8 dump_avail;
+	u64 dump_ts;
+	u64 error_count;
+	u64 recovery_count;
+	u64 last_recovery_ts;
+};
+
+enum devlink_health_reporter_state {
+	DEVLINK_HEALTH_REPORTER_STATE_HEALTHY,
+	DEVLINK_HEALTH_REPORTER_STATE_ERROR,
 };
 
 void *

@@ -4224,6 +4234,89 @@ devlink_health_reporter_destroy(struct devlink_health_reporter *reporter)
 }
 EXPORT_SYMBOL_GPL(devlink_health_reporter_destroy);
 
+static int
+devlink_health_reporter_recover(struct devlink_health_reporter *reporter,
+				void *priv_ctx)
+{
+	int err;
+
+	if (!reporter->ops->recover)
+		return -EOPNOTSUPP;
+
+	err = reporter->ops->recover(reporter, priv_ctx);
+	if (err)
+		return err;
+
+	reporter->recovery_count++;
+	reporter->health_state = DEVLINK_HEALTH_REPORTER_STATE_HEALTHY;
+	reporter->last_recovery_ts = jiffies;
+
+	return 0;
+}
+
+static int devlink_health_do_dump(struct devlink_health_reporter *reporter,
+				  void *priv_ctx)
+{
+	int err;
+
+	if (!reporter->ops->dump)
+		return 0;
+
+	if (reporter->dump_avail)
+		return 0;
+
+	devlink_health_buffers_reset(reporter->dump_buffers_array,
+				     DEVLINK_HEALTH_SIZE_TO_BUFFERS(reporter->ops->dump_size));
+	err = reporter->ops->dump(reporter, reporter->dump_buffers_array,
+				     DEVLINK_HEALTH_BUFFER_SIZE,
+				     DEVLINK_HEALTH_SIZE_TO_BUFFERS(reporter->ops->dump_size),
+				     priv_ctx);
+	if (!err) {
+		reporter->dump_avail = true;
+		reporter->dump_ts = jiffies;
+	}
+
+	return err;
+}
+
+int devlink_health_report(struct devlink_health_reporter *reporter,
+			  const char *msg, void *priv_ctx)
+{
+	struct devlink *devlink = reporter->devlink;
+	int err = 0;
+
+	/* write a log message of the current error */
+	WARN_ON(!msg);
+	trace_devlink_health_report(devlink, reporter->ops->name, msg);
+	reporter->error_count++;
+
+	/* abort if the previous error wasn't recovered */
+	if (reporter->auto_recover &&
+	    (reporter->health_state != DEVLINK_HEALTH_REPORTER_STATE_HEALTHY ||
+	     jiffies - reporter->last_recovery_ts <
+	     msecs_to_jiffies(reporter->graceful_period))) {
+		trace_devlink_health_recover_aborted(devlink,
+						     reporter->ops->name,
+						     reporter->health_state,
+						     jiffies -
+						     reporter->last_recovery_ts);
+		return -ECANCELED;
+	}
+
+	reporter->health_state = DEVLINK_HEALTH_REPORTER_STATE_ERROR;
+
+	mutex_lock(&reporter->dump_lock);
+	/* store current dump of current error, for later analysis */
+	devlink_health_do_dump(reporter, priv_ctx);
+	mutex_unlock(&reporter->dump_lock);
+
+	if (reporter->auto_recover)
+		err = devlink_health_reporter_recover(reporter, priv_ctx);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(devlink_health_report);
+
 static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING },
 	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING },

-- 
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