linux-kernel - [PATCH net-next v5 2/9] net: netconsole: split send_ext_msg

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Message-ID: <20241017095028.3131508-3-leitao@debian.org>
Date: Thu, 17 Oct 2024 02:50:17 -0700
From: Breno Leitao <leitao@...ian.org>
To: kuba@...nel.org,
	davem@...emloft.net,
	edumazet@...gle.com,
	pabeni@...hat.com
Cc: thepacketgeek@...il.com,
	horms@...nel.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	davej@...emonkey.org.uk,
	vlad.wing@...il.com,
	max@...sevol.com,
	kernel-team@...a.com
Subject: [PATCH net-next v5 2/9] net: netconsole: split send_ext_msg_udp() function

The send_ext_msg_udp() function has become quite large, currently
spanning 102 lines. Its complexity, along with extensive pointer and
offset manipulation, makes it difficult to read and error-prone.

The function has evolved over time, and it’s now due for a refactor.

To improve readability and maintainability, isolate the case where no
message fragmentation occurs into a separate function, into a new
send_msg_no_fragmentation() function. This scenario covers about 95% of
the messages.

Signed-off-by: Breno Leitao <leitao@...ian.org>
Reviewed-by: Simon Horman <horms@...nel.org>
---
 drivers/net/netconsole.c | 46 +++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 17 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index a006507c92c6..23fe9edff26e 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1058,6 +1058,32 @@ static struct notifier_block netconsole_netdev_notifier = {
 	.notifier_call  = netconsole_netdev_event,
 };
 
+static void send_msg_no_fragmentation(struct netconsole_target *nt,
+				      const char *msg,
+				      const char *userdata,
+				      int msg_len,
+				      int release_len)
+{
+	static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
+	const char *release;
+
+	if (release_len) {
+		release = init_utsname()->release;
+
+		scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg);
+		msg_len += release_len;
+	} else {
+		memcpy(buf, msg, msg_len);
+	}
+
+	if (userdata)
+		msg_len += scnprintf(&buf[msg_len],
+				     MAX_PRINT_CHUNK - msg_len,
+				     "%s", userdata);
+
+	netpoll_send_udp(&nt->np, buf, msg_len);
+}
+
 /**
  * send_ext_msg_udp - send extended log message to target
  * @nt: target to send message to
@@ -1090,23 +1116,9 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
 		release_len = strlen(release) + 1;
 	}
 
-	if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK) {
-		/* No fragmentation needed */
-		if (nt->release) {
-			scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg);
-			msg_len += release_len;
-		} else {
-			memcpy(buf, msg, msg_len);
-		}
-
-		if (userdata)
-			msg_len += scnprintf(&buf[msg_len],
-					     MAX_PRINT_CHUNK - msg_len,
-					     "%s", userdata);
-
-		netpoll_send_udp(&nt->np, buf, msg_len);
-		return;
-	}
+	if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK)
+		return send_msg_no_fragmentation(nt, msg, userdata, msg_len,
+						 release_len);
 
 	/* need to insert extra header fields, detect header and body */
 	header = msg;
-- 
2.43.5