linux-kernel - Re: [PATCH RFC net-next 1/2] netconsole: extract message fragmentation into write_msg

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Message-ID: <aSRY1AI7zDF-h-A9@pathway.suse.cz>
Date: Mon, 24 Nov 2025 14:08:36 +0100
From: Petr Mladek <pmladek@...e.com>
To: Breno Leitao <leitao@...ian.org>
Cc: Jakub Kicinski <kuba@...nel.org>, horms@...nel.org, efault@....de,
	john.ogness@...utronix.de, Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	calvin@...nvd.org, asml.silence@...il.com, kernel-team@...a.com,
	gustavold@...il.com, asantostc@...il.com
Subject: Re: [PATCH RFC net-next 1/2] netconsole: extract message
 fragmentation into write_msg_target()

On Fri 2025-11-21 03:26:07, Breno Leitao wrote:
> Refactor the message fragmentation logic in write_msg() by extracting it
> into a separate write_msg_target() helper function. This makes the code
> more maintainable and prepares for future reuse in nbcon support for
> non-extended consoles.
> 
> The helper function takes a target, message, and length, then handles
> splitting the message into MAX_PRINT_CHUNK-sized fragments for sending
> via send_udp().
> 
> No functional change intended.

> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -1559,6 +1559,20 @@ static void append_release(char *buf)
>  	scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release);
>  }
>  
> +static void write_msg_target(struct netconsole_target *nt, const char *msg,
> +			     unsigned int len)
> +{
> +	const char *tmp = msg;
> +	int frag, left = len;
> +
> +	while (left > 0) {
> +		frag = min(left, MAX_PRINT_CHUNK);
> +		send_udp(nt, tmp, frag);
> +		tmp += frag;
> +		left -= frag;
> +	}
> +}
> +
>  static void send_fragmented_body(struct netconsole_target *nt,
>  				 const char *msgbody, int header_len,
>  				 int msgbody_len, int extradata_len)
> @@ -1748,13 +1760,7 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
>  			 * at least one target if we die inside here, instead
>  			 * of unnecessarily keeping all targets in lock-step.
>  			 */
> -			tmp = msg;
> -			for (left = len; left;) {
> -				frag = min(left, MAX_PRINT_CHUNK);
> -				send_udp(nt, tmp, frag);
> -				tmp += frag;
> -				left -= frag;
> -			}
> +			write_msg_target(nt, msg, len);

I would call the new function send_msg_udp() to make it symetric with:

static void write_ext_msg(struct console *con, const char *msg,
			  unsigned int len)
{
[...]
			send_ext_msg_udp(nt, msg, len);
[...]
}

By other words, use "write_*()" when struct console * is passed
and send_*_udp() when struct netconsole_target * is passed.

The inconsistence confused me... ;-)

Note that write_msg()/write_ext_msg() are cut&pasted.
The only difference would be send_msg_udp()/send_ext_msg_udp().

>  		}
>  	}
>  	spin_unlock_irqrestore(&target_list_lock, flags);

Otherwise, I confirm that it is just a refactoring with no
functional change.

Feel free to use, ideally after the renaming function:

Reviewed-by: Petr Mladek <pmladek@...e.com>

Best Regards,
Petr