Re: [PATCH] RDMA/rxe: Reject unimplemented implicit ODP cleanly

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2026/7/12 18:04, weimin xiong 写道:
> From: xiongweimin <xiongweimin@kylinos.cn>
> 
> rxe advertises ODP but not IB_ODP_SUPPORT_IMPLICIT. The reg_user_mr path
> still contained a dead branch that checked the implicit capability and
> could never succeed.
> 
> Return -EOPNOTSUPP for the implicit ODP address range up front so the
> intent is obvious and the unreachable code is gone.
> 
> Signed-off-by: xiongweimin <xiongweimin@kylinos.cn>
> Cc: linux-rdma@vger.kernel.org
> Cc: Jason Gunthorpe <jgg@nvidia.com>
> ---
> 
> --- a/drivers/infiniband/sw/rxe/rxe_odp.c
> +++ b/drivers/infiniband/sw/rxe/rxe_odp.c
> @@ -87,14 +87,9 @@
>   
>   	rxe_mr_init(access_flags, mr);
>   
> -	if (!start && length == U64_MAX) {
> -		if (iova != 0)
> -			return -EINVAL;
> -		if (!(rxe->attr.odp_caps.general_caps & IB_ODP_SUPPORT_IMPLICIT))
> -			return -EINVAL;
> -
> -		/* Never reach here, for implicit ODP is not implemented. */
> -	}

It seems that the above are for implicit ODP. However the implicit ODP 
is not implemented currently. I am fine with removing this.

Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>

Zhu Yanjun


> +	/* Implicit ODP (start=0, length=U64_MAX) is not implemented. */
> +	if (!start && length == U64_MAX)
> +		return -EOPNOTSUPP;
>   
>   	umem_odp = ib_umem_odp_get(&rxe->ib_dev, start, length, access_flags,
>   				   &rxe_mn_ops);
>