[PATCH net-next v3 3/9] devlink: find snapshot in devlink_nl_cmd_region_read_dumpit

[Jacob Keller <jacob.e.keller@intel.com>]

The snapshot pointer is obtained inside of the function
devlink_nl_region_read_snapshot_fill. Simplify this function by locating
the snapshot upfront in devlink_nl_cmd_region_read_dumpit instead. This
aligns with how other netlink attributes are handled, and allows us to
exit slightly earlier if an invalid snapshot ID is provided.

It also allows us to pass the snapshot pointer directly to the
devlink_nl_region_read_snapshot_fill, and remove the now unused attrs
parameter.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
---
Changes since v2:
* Fixed capitalization of NL_SET_ERR_MSG_ATTR

 net/core/devlink.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 8d44ef3c1ea8..b89649919bba 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -6463,24 +6463,16 @@ static int devlink_nl_cmd_region_read_chunk_fill(struct sk_buff *msg,
 
 static int devlink_nl_region_read_snapshot_fill(struct sk_buff *skb,
 						struct devlink *devlink,
-						struct devlink_region *region,
-						struct nlattr **attrs,
+						struct devlink_snapshot *snapshot,
 						u64 start_offset,
 						u64 end_offset,
 						u64 *new_offset)
 {
-	struct devlink_snapshot *snapshot;
 	u64 curr_offset = start_offset;
-	u32 snapshot_id;
 	int err = 0;
 
 	*new_offset = start_offset;
 
-	snapshot_id = nla_get_u32(attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]);
-	snapshot = devlink_region_snapshot_get_by_id(region, snapshot_id);
-	if (!snapshot)
-		return -EINVAL;
-
 	while (curr_offset < end_offset) {
 		u32 data_size;
 		u8 *data;
@@ -6506,14 +6498,16 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 					     struct netlink_callback *cb)
 {
 	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+	struct nlattr *chunks_attr, *region_attr, *snapshot_attr;
 	u64 ret_offset, start_offset, end_offset = U64_MAX;
-	struct nlattr *chunks_attr, *region_attr;
 	struct nlattr **attrs = info->attrs;
 	struct devlink_port *port = NULL;
+	struct devlink_snapshot *snapshot;
 	struct devlink_region *region;
 	const char *region_name;
 	struct devlink *devlink;
 	unsigned int index;
+	u32 snapshot_id;
 	void *hdr;
 	int err;
 
@@ -6561,6 +6555,15 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 		goto out_unlock;
 	}
 
+	snapshot_attr = attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID];
+	snapshot_id = nla_get_u32(snapshot_attr);
+	snapshot = devlink_region_snapshot_get_by_id(region, snapshot_id);
+	if (!snapshot) {
+		NL_SET_ERR_MSG_ATTR(cb->extack, snapshot_attr, "Requested snapshot does not exist");
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
 	if (attrs[DEVLINK_ATTR_REGION_CHUNK_ADDR] &&
 	    attrs[DEVLINK_ATTR_REGION_CHUNK_LEN]) {
 		if (!start_offset)
@@ -6610,7 +6613,7 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 	}
 
 	err = devlink_nl_region_read_snapshot_fill(skb, devlink,
-						   region, attrs,
+						   snapshot,
 						   start_offset,
 						   end_offset, &ret_offset);
 
-- 
2.38.1.420.g319605f8f00e