[RFC PATCH 06/16] devlink: Reshuffle resource registration logic

From: Leon Romanovsky <leon@kernel.org>
To: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: Leon Romanovsky <leonro@nvidia.com>,
	Ido Schimmel <idosch@nvidia.com>, Jiri Pirko <jiri@nvidia.com>,
	netdev <netdev@vger.kernel.org>
Subject: [RFC PATCH 06/16] devlink: Reshuffle resource registration logic
Date: Mon,  8 Nov 2021 19:05:28 +0200	[thread overview]
Message-ID: <f197bf339088377abad6063ce3efd63faa415a5f.1636390483.git.leonro@nvidia.com> (raw)
In-Reply-To: <cover.1636390483.git.leonro@nvidia.com>

From: Leon Romanovsky <leonro@nvidia.com>

The devlink->lock doesn't need to be held during whole execution of
function, but only when recursive path walk and list addition are
performed. So reshuffle the resource registration logic to allocate
resource and configure it without lock.

As part of this change, complain more louder if driver authors used
already existed resource_id. It is performed outside of the locks as
drivers were supposed to provide unique IDs and such error can't happen.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 net/core/devlink.c | 30 ++++++++++++------------------
 1 file changed, 12 insertions(+), 18 deletions(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index d88e882616bc..a2cd27fd767e 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -9850,17 +9850,9 @@ int devlink_resource_register(struct devlink *devlink,
 {
 	struct devlink_resource *resource;
 	struct list_head *resource_list;
-	bool top_hierarchy;
 	int err = 0;
 
-	top_hierarchy = parent_resource_id == DEVLINK_RESOURCE_ID_PARENT_TOP;
-
-	mutex_lock(&devlink->lock);
-	resource = devlink_resource_find(devlink, NULL, resource_id);
-	if (resource) {
-		err = -EINVAL;
-		goto out;
-	}
+	WARN_ON(devlink_resource_find(devlink, NULL, resource_id));
 
 	resource = kzalloc(sizeof(*resource), GFP_KERNEL);
 	if (!resource) {
@@ -9868,7 +9860,17 @@ int devlink_resource_register(struct devlink *devlink,
 		goto out;
 	}
 
-	if (top_hierarchy) {
+	resource->name = resource_name;
+	resource->size = resource_size;
+	resource->size_new = resource_size;
+	resource->id = resource_id;
+	resource->size_valid = true;
+	memcpy(&resource->size_params, size_params,
+	       sizeof(resource->size_params));
+	INIT_LIST_HEAD(&resource->resource_list);
+
+	mutex_lock(&devlink->lock);
+	if (parent_resource_id == DEVLINK_RESOURCE_ID_PARENT_TOP) {
 		resource_list = &devlink->resource_list;
 	} else {
 		struct devlink_resource *parent_resource;
@@ -9885,14 +9887,6 @@ int devlink_resource_register(struct devlink *devlink,
 		}
 	}
 
-	resource->name = resource_name;
-	resource->size = resource_size;
-	resource->size_new = resource_size;
-	resource->id = resource_id;
-	resource->size_valid = true;
-	memcpy(&resource->size_params, size_params,
-	       sizeof(resource->size_params));
-	INIT_LIST_HEAD(&resource->resource_list);
 	list_add_tail(&resource->list, resource_list);
 out:
 	mutex_unlock(&devlink->lock);
-- 
2.33.1

