Re: [PATCH] RDMA/cma: Fix unknown symbol when CONFIG_IPV6 is not enabled

[Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

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On Sun, 2017-01-15 at 20:15 +0200, Leon Romanovsky wrote:
> From: Jack Morgenstein <jackm-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
> 
> If IPV6 has not been enabled in the underlying kernel, we must avoid
> calling IPV6 procedures in rdma_cm.ko.
> 
> This requires using "IS_ENABLED(CONFIG_IPV6)" in "if" statements
> surrounding any code which calls external IPV6 procedures.

This seems strange....

> In the instance fixed here, procedure cma_bind_addr() called
> ipv6_addr_type() -- which resulted in calling external procedure
> __ipv6_addr_type().
> 
> Fixes: 6c26a77124ff ("RDMA/cma: fix IPv6 address resolution")
> Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org> # v4.2+
> Cc: Spencer Baugh <sbaugh-n2IX9UM++eDQT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Jack Morgenstein <jackm-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
> Reviewed-by: Moni Shoua <monis-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Signed-off-by: Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> ---
>  drivers/infiniband/core/cma.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/core/cma.c
> b/drivers/infiniband/core/cma.c
> index bd8d051..e19f19c 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -2822,7 +2822,8 @@ static int cma_bind_addr(struct rdma_cm_id *id,
> struct sockaddr *src_addr,
>  	if (!src_addr || !src_addr->sa_family) {
>  		src_addr = (struct sockaddr *) &id-
> >route.addr.src_addr;
>  		src_addr->sa_family = dst_addr->sa_family;
> -		if (dst_addr->sa_family == AF_INET6) {

Why this construct?  Isn't the norm to simply surround the entire if
statement with
#if IS_ENABLED(CONFIG_IPV6)
...
#endif

> +		if (IS_ENABLED(CONFIG_IPV6) &&
> +		    dst_addr->sa_family == AF_INET6) {
>  			struct sockaddr_in6 *src_addr6 = (struct
> sockaddr_in6 *) src_addr;
>  			struct sockaddr_in6 *dst_addr6 = (struct
> sockaddr_in6 *) dst_addr;
>  			src_addr6->sin6_scope_id = dst_addr6-
> >sin6_scope_id;
> --
> 2.10.2
> 
-- 
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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