netdev - [PATCH net-next v3 06/10] net: netconsole: track explicitly if msgbody was written to buffer

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Message-ID: <20240910100410.2690012-7-leitao@debian.org>
Date: Tue, 10 Sep 2024 03:04:01 -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
Subject: [PATCH net-next v3 06/10] net: netconsole: track explicitly if msgbody was written to buffer

The current check to determine if the message body was fully sent is
difficult to follow. To improve clarity, introduce a variable that
explicitly tracks whether the message body (msgbody) has been completely
sent, indicating when it's time to begin sending userdata.

Additionally, add comments to make the code more understandable for
others who may work with it.

Signed-off-by: Breno Leitao <leitao@...ian.org>
Reviewed-by: Simon Horman <horms@...nel.org>
---
 drivers/net/netconsole.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index ddf38141d30b..1366b948bcbf 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1128,6 +1128,7 @@ static void send_msg_fragmented(struct netconsole_target *nt,
 	 */
 	while (offset < body_len) {
 		int this_header = header_len;
+		bool msgbody_written = false;
 		int this_offset = 0;
 		int this_chunk = 0;
 
@@ -1146,12 +1147,22 @@ static void send_msg_fragmented(struct netconsole_target *nt,
 			this_offset += this_chunk;
 		}
 
+		if (offset + this_offset >= msgbody_len)
+			/* msgbody was finally written, either in the previous
+			 * messages and/or in the current buf. Time to write
+			 * the userdata.
+			 */
+			msgbody_written = true;
+
 		/* Msg body is fully written and there is pending userdata to
 		 * write, append userdata in this chunk
 		 */
-		if (offset + this_offset >= msgbody_len &&
-		    offset + this_offset < body_len) {
+		if (msgbody_written && offset + this_offset < body_len) {
+			/* Track how much user data was already sent. First
+			 * time here, sent_userdata is zero
+			 */
 			int sent_userdata = (offset + this_offset) - msgbody_len;
+			/* offset of bytes used in current buf */
 			int preceding_bytes = this_chunk + this_header;
 
 			if (WARN_ON_ONCE(sent_userdata < 0))
-- 
2.43.5