[rds-devel] [PATCH net-next 1/2] rds: Correct endian annotation of port and addr assignments

[Allison Henderson]

On Thu, 2025-06-19 at 14:58 +0100, Simon Horman wrote:
> Correct the endianness annotation of port assignments:
> 
>   A host byte order value (RDS_TCP_PORT) is correctly converted to
>   network byte order (big endian) using htons. But it is then cast back to
>   host byte order before assigning to a variable that expects a big endian
>   value.  Address this by dropping the cast.
> 
>   This is not a bug because, while the endian annotation is changed by
>   this patch, the assigned value is unchanged.
> 
> Also correct the endianness of address assignment.
> 
>   A host byte order value (INADDR_ANY) is incorrectly assigned as-is to
>   a variable that expects a big endian value. Address this by converting
>   the value to network byte order (big endian).
> 
>   This is not a bug because INADDR_ANY is 0, which is isomorphic
>   with regards to endian conversions. IOW, while the endian annotation
>   is changed by this patch, the assigned value is unchanged.
> 
> Incorrect endian annotations appear to date back to IPv4-only code added
> by commit 70041088e3b9 ("RDS: Add TCP transport to RDS").
> 
> Flagged by Sparse.
> 
> Signed-off-by: Simon Horman <horms at kernel.org>

These changes look fine to me.  Thanks for the catch!
Reviewed-by: Allison Henderson <allison.henderson at oracle.com>

> ---
>  net/rds/tcp_listen.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
> index d89bd8d0c354..b5c801c629a4 100644
> --- a/net/rds/tcp_listen.c
> +++ b/net/rds/tcp_listen.c
> @@ -298,15 +298,15 @@ struct socket *rds_tcp_listen_init(struct net *net, bool isv6)
>  		sin6 = (struct sockaddr_in6 *)&ss;
>  		sin6->sin6_family = PF_INET6;
>  		sin6->sin6_addr = in6addr_any;
> -		sin6->sin6_port = (__force u16)htons(RDS_TCP_PORT);
> +		sin6->sin6_port = htons(RDS_TCP_PORT);
>  		sin6->sin6_scope_id = 0;
>  		sin6->sin6_flowinfo = 0;
>  		addr_len = sizeof(*sin6);
>  	} else {
>  		sin = (struct sockaddr_in *)&ss;
>  		sin->sin_family = PF_INET;
> -		sin->sin_addr.s_addr = INADDR_ANY;
> -		sin->sin_port = (__force u16)htons(RDS_TCP_PORT);
> +		sin->sin_addr.s_addr = htonl(INADDR_ANY);
> +		sin->sin_port = htons(RDS_TCP_PORT);
>  		addr_len = sizeof(*sin);
>  	}
>  
>