Re: [PATCH 2/4] tcp_splice: Check return value of setsockopt() for SO_RCVLOWAT

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, Jun 27, 2024 at 01:45:34AM +0200, Stefano Brivio wrote:
> Spotted by Coverity, harmless as we would consider that successful
> and check on the socket later from the timer, but printing a debug
> message in that case is definitely wise, should it ever happen.
> 
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  tcp_splice.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/tcp_splice.c b/tcp_splice.c
> index 5a406c6..f2d4fc6 100644
> --- a/tcp_splice.c
> +++ b/tcp_splice.c
> @@ -598,11 +598,16 @@ eintr:
>  			    readlen > (long)c->tcp.pipe_size / 10) {
>  				int lowat = c->tcp.pipe_size / 4;
>  
> -				setsockopt(conn->s[fromside], SOL_SOCKET,
> -					   SO_RCVLOWAT, &lowat, sizeof(lowat));
> -
> -				conn_flag(c, conn, lowat_set_flag);
> -				conn_flag(c, conn, lowat_act_flag);
> +				if (setsockopt(conn->s[fromside], SOL_SOCKET,
> +					       SO_RCVLOWAT,
> +					       &lowat, sizeof(lowat))) {
> +					flow_trace(conn,
> +						   "Setting SO_RCVLOWAT %i: %s",
> +						   lowat, strerror(errno));
> +				} else {
> +					conn_flag(c, conn, lowat_set_flag);
> +					conn_flag(c, conn, lowat_act_flag);
> +				}
>  			}
>  
>  			break;

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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