linux-kernel - [PATCH net] devlink: Hold devlink lock on health reporter dump get

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Message-ID: <1696173580-222744-1-git-send-email-moshe@nvidia.com>
Date:   Sun, 1 Oct 2023 18:19:40 +0300
From:   Moshe Shemesh <moshe@...dia.com>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, <netdev@...r.kernel.org>
CC:     Jiri Pirko <jiri@...dia.com>, <linux-kernel@...r.kernel.org>,
        "Moshe Shemesh" <moshe@...dia.com>
Subject: [PATCH net] devlink: Hold devlink lock on health reporter dump get

Devlink health dump get callback should take devlink lock as any other
devlink callback. Add devlink lock to the callback and to any call for
devlink_health_do_dump().

As devlink lock is added to any callback of dump, the reporter dump_lock
is now redundant and can be removed.

Fixes: d3efc2a6a6d8 ("net: devlink: remove devlink_mutex")
Signed-off-by: Moshe Shemesh <moshe@...dia.com>
Reviewed-by: Jiri Pirko <jiri@...dia.com>
---
 net/devlink/health.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/net/devlink/health.c b/net/devlink/health.c
index 638cad8d5c65..51e6e81e31bb 100644
--- a/net/devlink/health.c
+++ b/net/devlink/health.c
@@ -58,7 +58,6 @@ struct devlink_health_reporter {
 	struct devlink *devlink;
 	struct devlink_port *devlink_port;
 	struct devlink_fmsg *dump_fmsg;
-	struct mutex dump_lock; /* lock parallel read/write from dump buffers */
 	u64 graceful_period;
 	bool auto_recover;
 	bool auto_dump;
@@ -125,7 +124,6 @@ __devlink_health_reporter_create(struct devlink *devlink,
 	reporter->graceful_period = graceful_period;
 	reporter->auto_recover = !!ops->recover;
 	reporter->auto_dump = !!ops->dump;
-	mutex_init(&reporter->dump_lock);
 	return reporter;
 }
 
@@ -226,7 +224,6 @@ EXPORT_SYMBOL_GPL(devlink_health_reporter_create);
 static void
 devlink_health_reporter_free(struct devlink_health_reporter *reporter)
 {
-	mutex_destroy(&reporter->dump_lock);
 	if (reporter->dump_fmsg)
 		devlink_fmsg_free(reporter->dump_fmsg);
 	kfree(reporter);
@@ -625,10 +622,10 @@ int devlink_health_report(struct devlink_health_reporter *reporter,
 	}
 
 	if (reporter->auto_dump) {
-		mutex_lock(&reporter->dump_lock);
+		devl_lock(devlink);
 		/* store current dump of current error, for later analysis */
 		devlink_health_do_dump(reporter, priv_ctx, NULL);
-		mutex_unlock(&reporter->dump_lock);
+		devl_unlock(devlink);
 	}
 
 	if (!reporter->auto_recover)
@@ -1262,7 +1259,7 @@ int devlink_nl_cmd_health_reporter_diagnose_doit(struct sk_buff *skb,
 }
 
 static struct devlink_health_reporter *
-devlink_health_reporter_get_from_cb(struct netlink_callback *cb)
+devlink_health_reporter_get_from_cb_lock(struct netlink_callback *cb)
 {
 	const struct genl_info *info = genl_info_dump(cb);
 	struct devlink_health_reporter *reporter;
@@ -1272,10 +1269,12 @@ devlink_health_reporter_get_from_cb(struct netlink_callback *cb)
 	devlink = devlink_get_from_attrs_lock(sock_net(cb->skb->sk), attrs);
 	if (IS_ERR(devlink))
 		return NULL;
-	devl_unlock(devlink);
 
 	reporter = devlink_health_reporter_get_from_attrs(devlink, attrs);
-	devlink_put(devlink);
+	if (!reporter) {
+		devl_unlock(devlink);
+		devlink_put(devlink);
+	}
 	return reporter;
 }
 
@@ -1284,16 +1283,20 @@ int devlink_nl_cmd_health_reporter_dump_get_dumpit(struct sk_buff *skb,
 {
 	struct devlink_nl_dump_state *state = devlink_dump_state(cb);
 	struct devlink_health_reporter *reporter;
+	struct devlink *devlink;
 	int err;
 
-	reporter = devlink_health_reporter_get_from_cb(cb);
+	reporter = devlink_health_reporter_get_from_cb_lock(cb);
 	if (!reporter)
 		return -EINVAL;
 
-	if (!reporter->ops->dump)
+	devlink = reporter->devlink;
+	if (!reporter->ops->dump) {
+		devl_unlock(devlink);
+		devlink_put(devlink);
 		return -EOPNOTSUPP;
+	}
 
-	mutex_lock(&reporter->dump_lock);
 	if (!state->idx) {
 		err = devlink_health_do_dump(reporter, NULL, cb->extack);
 		if (err)
@@ -1309,7 +1312,8 @@ int devlink_nl_cmd_health_reporter_dump_get_dumpit(struct sk_buff *skb,
 	err = devlink_fmsg_dumpit(reporter->dump_fmsg, skb, cb,
 				  DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET);
 unlock:
-	mutex_unlock(&reporter->dump_lock);
+	devl_unlock(devlink);
+	devlink_put(devlink);
 	return err;
 }
 
@@ -1326,9 +1330,7 @@ int devlink_nl_cmd_health_reporter_dump_clear_doit(struct sk_buff *skb,
 	if (!reporter->ops->dump)
 		return -EOPNOTSUPP;
 
-	mutex_lock(&reporter->dump_lock);
 	devlink_health_dump_clear(reporter);
-	mutex_unlock(&reporter->dump_lock);
 	return 0;
 }
 
-- 
2.27.0