Re: [PATCHv5 for-next 1/1] RDMA/rxe: Disable ipv6 features when ipv6.disable in cmdline

[Kamal Heib <kheib@redhat.com>]

On 4/14/21 2:42 AM, Zhu Yanjun wrote:
> From: Zhu Yanjun <zyjzyj2000@gmail.com>
> 
> When ipv6.disable=1 is set in cmdline, ipv6 is actually disabled
> in the stack. As such, the operations of ipv6 in RXE will fail.
> So ipv6 features in RXE should also be disabled in RXE.
> 
> Link: https://lore.kernel.org/linux-rdma/880d7b59-4b17-a44f-1a91-88257bfc3aaa@redhat.com/T/#t
> Fixes: 8700e3e7c4857 ("Soft RoCE driver")
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Signed-off-by: Zhu Yanjun <zyjzyj2000@gmail.com>
> ---
> V4->V5: Clean up signature block and remove error message
> V3->V4: Check the returned value instead of ipv6 module
> V2->V3: Remove print message
> V1->V2: Modify the pr_info messages
> ---
>  drivers/infiniband/sw/rxe/rxe_net.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
> index 01662727dca0..984c3ac449bd 100644
> --- a/drivers/infiniband/sw/rxe/rxe_net.c
> +++ b/drivers/infiniband/sw/rxe/rxe_net.c
> @@ -208,7 +208,13 @@ static struct socket *rxe_setup_udp_tunnel(struct net *net, __be16 port,
>  	/* Create UDP socket */
>  	err = udp_sock_create(net, &udp_cfg, &sock);
>  	if (err < 0) {
> -		pr_err("failed to create udp socket. err = %d\n", err);
> +		/* If UDP tunnel over ipv6 fails with -EAFNOSUPPORT, the tunnel
> +		 * over ipv4 still works. This error message will not pop out.
> +		 * If UDP tunnle over ipv4 fails or other errors with ipv6
> +		 * tunnel, this error should pop out.
> +		 */
> +		if (!((err == -EAFNOSUPPORT) && (ipv6)))
> +			pr_err("failed to create udp socket. err = %d\n", err);
>  		return ERR_PTR(err);
>  	}
>  
> @@ -620,6 +626,11 @@ static int rxe_net_ipv6_init(void)
>  	recv_sockets.sk6 = rxe_setup_udp_tunnel(&init_net,
>  						htons(ROCE_V2_UDP_DPORT), true);
>  	if (IS_ERR(recv_sockets.sk6)) {
> +		/* Though IPv6 is not supported, IPv4 still needs to continue
> +		 */
> +		if (PTR_ERR(recv_sockets.sk6) == -EAFNOSUPPORT)
> +			return 0;
> +
>  		recv_sockets.sk6 = NULL;
>  		pr_err("Failed to create IPv6 UDP tunnel\n");
>  		return -1;
> 

I think the following change is much simpler than changing the udp_sock_create()
helper function?


diff --git a/drivers/infiniband/sw/rxe/rxe_net.c
b/drivers/infiniband/sw/rxe/rxe_net.c
index 01662727dca0..b56d6f76ab31 100644
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -621,6 +621,11 @@ static int rxe_net_ipv6_init(void)
                                                htons(ROCE_V2_UDP_DPORT), true);
        if (IS_ERR(recv_sockets.sk6)) {
                recv_sockets.sk6 = NULL;
+               if (PTR_ERR(recv_sockets.sk6) == -EAFNOSUPPORT) {
+                       pr_warn("Create IPv6 UDP tunnel is not supported\n");
+                       return 0;
+               }
+
                pr_err("Failed to create IPv6 UDP tunnel\n");
                return -1;
        }
-- 
2.26.3


Thanks,
Kamal