linux-kernel - Re: [PATCH net-next 6/9] net: netconsole: track explicitly if msgbody was written to buffer

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Message-ID: <20240904110726.GT4792@kernel.org>
Date: Wed, 4 Sep 2024 12:07:26 +0100
From: Simon Horman <horms@...nel.org>
To: Breno Leitao <leitao@...ian.org>
Cc: kuba@...nel.org, davem@...emloft.net, edumazet@...gle.com,
	pabeni@...hat.com, thepacketgeek@...il.com, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, davej@...emonkey.org.uk,
	thevlad@...a.com, max@...sevol.com
Subject: Re: [PATCH net-next 6/9] net: netconsole: track explicitly if
 msgbody was written to buffer

On Tue, Sep 03, 2024 at 07:07:49AM -0700, Breno Leitao wrote:
> 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>

Thanks,

The nit below notwithstanding this looks good to me.

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 22ccd9aa016a..c8a23a7684e5 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -1102,6 +1102,7 @@ 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;
>  
> @@ -1119,12 +1120,22 @@ static void send_msg_fragmented(struct netconsole_target *nt,
>  			memcpy(buf + this_header, msgbody + offset, this_chunk);
>  			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.
> +			 */

Please consider keeping comments <= 80 columns wide.
Likewise in other patches of this series.

checkpatch can be run with an option to check for this.

> +			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
>