Refactor the send_msg_fragmented() function by extracting the logic for
sending the message body into a new function called
send_fragmented_body().

Now, send_msg_fragmented() handles appending the release and header, and
then delegates the task of sending the body to send_fragmented_body().

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 85 +++++++++++++++++++++++-----------------
 1 file changed, 48 insertions(+), 37 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index be23def330e9..81d7d2b09988 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1066,45 +1066,21 @@ static void append_release(char *buf)
 	scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release);
 }
 
-static void send_msg_fragmented(struct netconsole_target *nt,
-				const char *msg,
-				const char *userdata,
-				int msg_len,
-				int release_len)
+static void send_fragmented_body(struct netconsole_target *nt, char *buf,
+				 const char *msgbody, int header_len,
+				 int msgbody_len)
 {
-	int header_len, msgbody_len, body_len;
-	static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
-	int offset = 0, userdata_len = 0;
-	const char *header, *msgbody;
-
-	if (userdata)
-		userdata_len = nt->userdata_length;
-
-	/* need to insert extra header fields, detect header and msgbody */
-	header = msg;
-	msgbody = memchr(msg, ';', msg_len);
-	if (WARN_ON_ONCE(!msgbody))
-		return;
-
-	header_len = msgbody - header;
-	msgbody_len = msg_len - header_len - 1;
-	msgbody++;
-
-	/*
-	 * Transfer multiple chunks with the following extra header.
-	 * "ncfrag=<byte-offset>/<total-bytes>"
-	 */
-	if (release_len)
-		append_release(buf);
+	int body_len, offset = 0;
+	const char *userdata = NULL;
+	int userdata_len = 0;
 
-	/* Copy the header into the buffer */
-	memcpy(buf + release_len, header, header_len);
-	header_len += release_len;
+#ifdef CONFIG_NETCONSOLE_DYNAMIC
+	userdata = nt->userdata_complete;
+	userdata_len = nt->userdata_length;
+#endif
 
 	body_len = msgbody_len + userdata_len;
-	/* for now on, the header will be persisted, and the msgbody
-	 * will be replaced
-	 */
+
 	while (offset < body_len) {
 		int this_header = header_len;
 		bool msgbody_written = false;
@@ -1112,7 +1088,7 @@ static void send_msg_fragmented(struct netconsole_target *nt,
 		int this_chunk = 0;
 
 		this_header += scnprintf(buf + this_header,
-					 sizeof(buf) - this_header,
+					 MAX_PRINT_CHUNK - this_header,
 					 ",ncfrag=%d/%d;", offset,
 					 body_len);
 
@@ -1161,6 +1137,41 @@ static void send_msg_fragmented(struct netconsole_target *nt,
 	}
 }
 
+static void send_msg_fragmented(struct netconsole_target *nt,
+				const char *msg,
+				int msg_len,
+				int release_len)
+{
+	static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
+	int header_len, msgbody_len;
+	const char *msgbody;
+
+	/* need to insert extra header fields, detect header and msgbody */
+	msgbody = memchr(msg, ';', msg_len);
+	if (WARN_ON_ONCE(!msgbody))
+		return;
+
+	header_len = msgbody - msg;
+	msgbody_len = msg_len - header_len - 1;
+	msgbody++;
+
+	/*
+	 * Transfer multiple chunks with the following extra header.
+	 * "ncfrag=<byte-offset>/<total-bytes>"
+	 */
+	if (release_len)
+		append_release(buf);
+
+	/* Copy the header into the buffer */
+	memcpy(buf + release_len, msg, header_len);
+	header_len += release_len;
+
+	/* for now on, the header will be persisted, and the msgbody
+	 * will be replaced
+	 */
+	send_fragmented_body(nt, buf, msgbody, header_len, msgbody_len);
+}
+
 static void send_msg_no_fragmentation(struct netconsole_target *nt,
 				      const char *msg,
 				      const char *userdata,
@@ -1216,7 +1227,7 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
 		return send_msg_no_fragmentation(nt, msg, userdata, msg_len,
 						 release_len);
 
-	return send_msg_fragmented(nt, msg, userdata, msg_len, release_len);
+	return send_msg_fragmented(nt, msg, msg_len, release_len);
 }
 
 static void write_ext_msg(struct console *con, const char *msg,
-- 
2.43.5

On Tue, Sep 03, 2024 at 07:07:51AM -0700, Breno Leitao wrote:
> Refactor the send_msg_fragmented() function by extracting the logic for
> sending the message body into a new function called
> send_fragmented_body().
> 
> Now, send_msg_fragmented() handles appending the release and header, and
> then delegates the task of sending the body to send_fragmented_body().

I think it would be good to expand a bit on why here.

> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
>  drivers/net/netconsole.c | 85 +++++++++++++++++++++++-----------------
>  1 file changed, 48 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index be23def330e9..81d7d2b09988 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -1066,45 +1066,21 @@ static void append_release(char *buf)
>  	scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release);
>  }
>  
> -static void send_msg_fragmented(struct netconsole_target *nt,
> -				const char *msg,
> -				const char *userdata,
> -				int msg_len,
> -				int release_len)
> +static void send_fragmented_body(struct netconsole_target *nt, char *buf,
> +				 const char *msgbody, int header_len,
> +				 int msgbody_len)
>  {
> -	int header_len, msgbody_len, body_len;
> -	static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
> -	int offset = 0, userdata_len = 0;
> -	const char *header, *msgbody;
> -
> -	if (userdata)
> -		userdata_len = nt->userdata_length;
> -
> -	/* need to insert extra header fields, detect header and msgbody */
> -	header = msg;
> -	msgbody = memchr(msg, ';', msg_len);
> -	if (WARN_ON_ONCE(!msgbody))
> -		return;
> -
> -	header_len = msgbody - header;
> -	msgbody_len = msg_len - header_len - 1;
> -	msgbody++;
> -
> -	/*
> -	 * Transfer multiple chunks with the following extra header.
> -	 * "ncfrag=<byte-offset>/<total-bytes>"
> -	 */
> -	if (release_len)
> -		append_release(buf);
> +	int body_len, offset = 0;
> +	const char *userdata = NULL;
> +	int userdata_len = 0;
>  
> -	/* Copy the header into the buffer */
> -	memcpy(buf + release_len, header, header_len);
> -	header_len += release_len;
> +#ifdef CONFIG_NETCONSOLE_DYNAMIC
> +	userdata = nt->userdata_complete;
> +	userdata_len = nt->userdata_length;
> +#endif

I think that dropping the userdata parameter of send_msg_fragmented() ought
to part of an earlier patch or separate patch. It doesn't seem strictly
related to this patch.

>  
>  	body_len = msgbody_len + userdata_len;
> -	/* for now on, the header will be persisted, and the msgbody
> -	 * will be replaced
> -	 */
> +
>  	while (offset < body_len) {
>  		int this_header = header_len;
>  		bool msgbody_written = false;

...

> @@ -1161,6 +1137,41 @@ static void send_msg_fragmented(struct netconsole_target *nt,
>  	}
>  }
>  
> +static void send_msg_fragmented(struct netconsole_target *nt,
> +				const char *msg,
> +				int msg_len,
> +				int release_len)

...

On Wed, Sep 04, 2024 at 12:16:36PM +0100, Simon Horman wrote:
> On Tue, Sep 03, 2024 at 07:07:51AM -0700, Breno Leitao wrote:
> > Refactor the send_msg_fragmented() function by extracting the logic for
> > sending the message body into a new function called
> > send_fragmented_body().
> > 
> > Now, send_msg_fragmented() handles appending the release and header, and
> > then delegates the task of sending the body to send_fragmented_body().
> 
> I think it would be good to expand a bit on why here.
> 
> > Signed-off-by: Breno Leitao <leitao@debian.org>
> > ---
> >  drivers/net/netconsole.c | 85 +++++++++++++++++++++++-----------------
> >  1 file changed, 48 insertions(+), 37 deletions(-)
> > 
> > diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> > index be23def330e9..81d7d2b09988 100644
> > --- a/drivers/net/netconsole.c
> > +++ b/drivers/net/netconsole.c
> > @@ -1066,45 +1066,21 @@ static void append_release(char *buf)
> >  	scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release);
> >  }
> >  
> > -static void send_msg_fragmented(struct netconsole_target *nt,
> > -				const char *msg,
> > -				const char *userdata,
> > -				int msg_len,
> > -				int release_len)
> > +static void send_fragmented_body(struct netconsole_target *nt, char *buf,
> > +				 const char *msgbody, int header_len,
> > +				 int msgbody_len)
> >  {
> > -	int header_len, msgbody_len, body_len;
> > -	static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */
> > -	int offset = 0, userdata_len = 0;
> > -	const char *header, *msgbody;
> > -
> > -	if (userdata)
> > -		userdata_len = nt->userdata_length;
> > -
> > -	/* need to insert extra header fields, detect header and msgbody */
> > -	header = msg;
> > -	msgbody = memchr(msg, ';', msg_len);
> > -	if (WARN_ON_ONCE(!msgbody))
> > -		return;
> > -
> > -	header_len = msgbody - header;
> > -	msgbody_len = msg_len - header_len - 1;
> > -	msgbody++;
> > -
> > -	/*
> > -	 * Transfer multiple chunks with the following extra header.
> > -	 * "ncfrag=<byte-offset>/<total-bytes>"
> > -	 */
> > -	if (release_len)
> > -		append_release(buf);
> > +	int body_len, offset = 0;
> > +	const char *userdata = NULL;
> > +	int userdata_len = 0;
> >  
> > -	/* Copy the header into the buffer */
> > -	memcpy(buf + release_len, header, header_len);
> > -	header_len += release_len;
> > +#ifdef CONFIG_NETCONSOLE_DYNAMIC
> > +	userdata = nt->userdata_complete;
> > +	userdata_len = nt->userdata_length;
> > +#endif
> 
> I think that dropping the userdata parameter of send_msg_fragmented() ought
> to part of an earlier patch or separate patch. It doesn't seem strictly
> related to this patch.

I agree with you. Let me separate it in a different patch, then.

Thanks for the review,
--breno