From: Eran Ben Elisha <eranbe@mellanox.com>
Date: Sun, 29 Mar 2020 14:05:55 +0300
Subject: devlink: Add auto dump flag to health reporter
Patch-mainline: v5.7-rc1
Git-commit: 48bb52c80be0e462328f58ca3a34ecfef3584320
References: bsc#1176774

On low memory system, run time dumps can consume too much memory. Add
administrator ability to disable auto dumps per reporter as part of the
error flow handle routine.

This attribute is not relevant while executing
DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET.

By default, auto dump is activated for any reporter that has a dump method,
as part of the reporter registration to devlink.

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/uapi/linux/devlink.h |    2 ++
 net/core/devlink.c           |   26 ++++++++++++++++++++++----
 2 files changed, 24 insertions(+), 4 deletions(-)

--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -429,6 +429,8 @@ enum devlink_attr {
 	DEVLINK_ATTR_NETNS_FD,			/* u32 */
 	DEVLINK_ATTR_NETNS_PID,			/* u32 */
 	DEVLINK_ATTR_NETNS_ID,			/* u32 */
+
+	DEVLINK_ATTR_HEALTH_REPORTER_AUTO_DUMP,	/* u8 */
 	/* add new attributes above here, update the policy in devlink.c */
 
 	__DEVLINK_ATTR_MAX,
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -5089,6 +5089,7 @@ struct devlink_health_reporter {
 	struct mutex dump_lock; /* lock parallel read/write from dump buffers */
 	u64 graceful_period;
 	bool auto_recover;
+	bool auto_dump;
 	u8 health_state;
 	u64 dump_ts;
 	u64 dump_real_ts;
@@ -5155,6 +5156,7 @@ devlink_health_reporter_create(struct de
 	reporter->devlink = devlink;
 	reporter->graceful_period = graceful_period;
 	reporter->auto_recover = !!ops->recover;
+	reporter->auto_dump = !!ops->dump;
 	mutex_init(&reporter->dump_lock);
 	refcount_set(&reporter->refcount, 1);
 	list_add_tail(&reporter->list, &devlink->reporter_list);
@@ -5235,6 +5237,10 @@ devlink_nl_health_reporter_fill(struct s
 	    nla_put_u64_64bit(msg, DEVLINK_ATTR_HEALTH_REPORTER_DUMP_TS_NS,
 			      reporter->dump_real_ts, DEVLINK_ATTR_PAD))
 		goto reporter_nest_cancel;
+	if (reporter->ops->dump &&
+	    nla_put_u8(msg, DEVLINK_ATTR_HEALTH_REPORTER_AUTO_DUMP,
+		       reporter->auto_dump))
+		goto reporter_nest_cancel;
 
 	nla_nest_end(msg, reporter_attr);
 	genlmsg_end(msg, hdr);
@@ -5381,10 +5387,12 @@ int devlink_health_report(struct devlink
 
 	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, NULL);
-	mutex_unlock(&reporter->dump_lock);
+	if (reporter->auto_dump) {
+		mutex_lock(&reporter->dump_lock);
+		/* store current dump of current error, for later analysis */
+		devlink_health_do_dump(reporter, priv_ctx, NULL);
+		mutex_unlock(&reporter->dump_lock);
+	}
 
 	if (reporter->auto_recover)
 		return devlink_health_reporter_recover(reporter,
@@ -5558,6 +5566,11 @@ devlink_nl_cmd_health_reporter_set_doit(
 		err = -EOPNOTSUPP;
 		goto out;
 	}
+	if (!reporter->ops->dump &&
+	    info->attrs[DEVLINK_ATTR_HEALTH_REPORTER_AUTO_DUMP]) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
 
 	if (info->attrs[DEVLINK_ATTR_HEALTH_REPORTER_GRACEFUL_PERIOD])
 		reporter->graceful_period =
@@ -5567,6 +5580,10 @@ devlink_nl_cmd_health_reporter_set_doit(
 		reporter->auto_recover =
 			nla_get_u8(info->attrs[DEVLINK_ATTR_HEALTH_REPORTER_AUTO_RECOVER]);
 
+	if (info->attrs[DEVLINK_ATTR_HEALTH_REPORTER_AUTO_DUMP])
+		reporter->auto_dump =
+		nla_get_u8(info->attrs[DEVLINK_ATTR_HEALTH_REPORTER_AUTO_DUMP]);
+
 	devlink_health_reporter_put(reporter);
 	return 0;
 out:
@@ -6313,6 +6330,7 @@ static const struct nla_policy devlink_n
 	[DEVLINK_ATTR_NETNS_PID] = { .type = NLA_U32 },
 	[DEVLINK_ATTR_NETNS_FD] = { .type = NLA_U32 },
 	[DEVLINK_ATTR_NETNS_ID] = { .type = NLA_U32 },
+	[DEVLINK_ATTR_HEALTH_REPORTER_AUTO_DUMP] = { .type = NLA_U8 },
 };
 
 static const struct genl_ops devlink_nl_ops[] = {