linux-kernel - [PATCH net-next v5 3/9] net: netconsole: separate fragmented message handling in send_ext

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Message-ID: <20241017095028.3131508-4-leitao@debian.org>
Date: Thu, 17 Oct 2024 02:50:18 -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 3/9] net: netconsole: separate fragmented message handling in send_ext_msg

Following the previous change, where the non-fragmented case was moved
to its own function, this update introduces a new function called
send_msg_fragmented to specifically manage scenarios where message
fragmentation is required.

Signed-off-by: Breno Leitao <leitao@...ian.org>
Reviewed-by: Simon Horman <horms@...nel.org>
---
 drivers/net/netconsole.c | 76 +++++++++++++++++++++++++---------------
 1 file changed, 48 insertions(+), 28 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 23fe9edff26e..6e916131c061 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1084,42 +1084,23 @@ static void send_msg_no_fragmentation(struct netconsole_target *nt,
 	netpoll_send_udp(&nt->np, buf, msg_len);
 }
 
-/**
- * send_ext_msg_udp - send extended log message to target
- * @nt: target to send message to
- * @msg: extended log message to send
- * @msg_len: length of message
- *
- * Transfer extended log @msg to @nt.  If @msg is longer than
- * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
- * ncfrag header field added to identify them.
- */
-static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
-			     int msg_len)
+static void send_msg_fragmented(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 */
+	int offset = 0, userdata_len = 0;
 	const char *header, *body;
-	int offset = 0;
 	int header_len, body_len;
 	const char *release;
-	int release_len = 0;
-	int userdata_len = 0;
-	char *userdata = NULL;
 
 #ifdef CONFIG_NETCONSOLE_DYNAMIC
-	userdata = nt->userdata_complete;
-	userdata_len = nt->userdata_length;
+	if (userdata)
+		userdata_len = nt->userdata_length;
 #endif
 
-	if (nt->release) {
-		release = init_utsname()->release;
-		release_len = strlen(release) + 1;
-	}
-
-	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;
 	body = memchr(msg, ';', msg_len);
@@ -1134,11 +1115,18 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
 	 * Transfer multiple chunks with the following extra header.
 	 * "ncfrag=<byte-offset>/<total-bytes>"
 	 */
-	if (nt->release)
+	if (release_len) {
+		release = init_utsname()->release;
 		scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release);
+	}
+
+	/* Copy the header into the buffer */
 	memcpy(buf + release_len, header, header_len);
 	header_len += release_len;
 
+	/* for now on, the header will be persisted, and the body
+	 * will be replaced
+	 */
 	while (offset < body_len + userdata_len) {
 		int this_header = header_len;
 		int this_offset = 0;
@@ -1190,6 +1178,38 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
 	}
 }
 
+/**
+ * send_ext_msg_udp - send extended log message to target
+ * @nt: target to send message to
+ * @msg: extended log message to send
+ * @msg_len: length of message
+ *
+ * Transfer extended log @msg to @nt.  If @msg is longer than
+ * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with
+ * ncfrag header field added to identify them.
+ */
+static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
+			     int msg_len)
+{
+	char *userdata = NULL;
+	int userdata_len = 0;
+	int release_len = 0;
+
+#ifdef CONFIG_NETCONSOLE_DYNAMIC
+	userdata = nt->userdata_complete;
+	userdata_len = nt->userdata_length;
+#endif
+
+	if (nt->release)
+		release_len = strlen(init_utsname()->release) + 1;
+
+	if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK)
+		return send_msg_no_fragmentation(nt, msg, userdata, msg_len,
+						 release_len);
+
+	return send_msg_fragmented(nt, msg, userdata, msg_len, release_len);
+}
+
 static void write_ext_msg(struct console *con, const char *msg,
 			  unsigned int len)
 {
-- 
2.43.5