[PATCH 08/28] devlink: Refactor strlcat() to seq_buf in __devlink_compat_running_version()

__devlink_compat_running_version() appends running firmware version
strings and spaces to "buf" inside nested netlink attribute loops using
strlcat(), rescanning "buf" on every iteration.

In preparation for removing the deprecated strlcat() API[1], use struct
seq_buf anchored at the current length of "buf" and append each version
entry with seq_buf_printf().

Link: https://github.com/KSPP/linux/issues/370 [1]
Cc: codemender-patching+linux@google.com
Assisted-by: CoPilot:v1 [editor_update_file, shell_command_run]
Signed-off-by: Bill Wendling <morbo@google.com>
---
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---
 net/devlink/dev.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/devlink/dev.c b/net/devlink/dev.c
index 55959b0ff5ab..987b071345c4 100644
--- a/net/devlink/dev.c
+++ b/net/devlink/dev.c

@@ -5,6 +5,7 @@
  */
 
 #include <linux/device.h>
+#include <linux/seq_buf.h>
 #include <net/genetlink.h>
 #include <net/sock.h>
 #include "devl_internal.h"

@@ -1190,6 +1191,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 {
 	struct devlink_info_req req = {};
 	const struct nlattr *nlattr;
+	struct seq_buf s;
 	struct sk_buff *msg;
 	int rem, err;
 

@@ -1202,6 +1204,9 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 	if (err)
 		goto free_msg;
 
+	seq_buf_init(&s, buf, len);
+	s.len = strnlen(buf, len);
+
 	nla_for_each_attr_type(nlattr, DEVLINK_ATTR_INFO_VERSION_RUNNING,
 			       (void *)msg->data, msg->len, rem) {
 		const struct nlattr *kv;

@@ -1209,8 +1214,7 @@ static void __devlink_compat_running_version(struct devlink *devlink,
 
 		nla_for_each_nested_type(kv, DEVLINK_ATTR_INFO_VERSION_VALUE,
 					 nlattr, rem_kv) {
-			strlcat(buf, nla_data(kv), len);
-			strlcat(buf, " ", len);
+			seq_buf_printf(&s, "%s ", (const char *)nla_data(kv));
 		}
 	}
 free_msg:

-- 
2.55.0.1032.g73a4cd73de-goog