Re: [PATCH -next] RDMA/hns: Fix return in hns_roce_rereg_user_mr()

From: Leon Romanovsky <leon@kernel.org>
To: YueHaibing <yuehaibing@huawei.com>
Cc: liangwenpeng@huawei.com, liweihang@huawei.com,
	dledford@redhat.com, jgg@ziepe.ca, chenglang@huawei.com,
	linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH -next] RDMA/hns: Fix return in hns_roce_rereg_user_mr()
Date: Wed, 4 Aug 2021 16:53:21 +0300	[thread overview]
Message-ID: <YQqb0U43eQUGK641@unreal> (raw)
In-Reply-To: <20210804125939.20516-1-yuehaibing@huawei.com>

On Wed, Aug 04, 2021 at 08:59:39PM +0800, YueHaibing wrote:
> If re-registering an MR in hns_roce_rereg_user_mr(), we should
> return NULL instead of pass 0 to ERR_PTR.
> 
> Fixes: 4e9fc1dae2a9 ("RDMA/hns: Optimize the MR registration process")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> ---
>  drivers/infiniband/hw/hns/hns_roce_mr.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/hw/hns/hns_roce_mr.c b/drivers/infiniband/hw/hns/hns_roce_mr.c
> index 006c84bb3f9f..7089ac780291 100644
> --- a/drivers/infiniband/hw/hns/hns_roce_mr.c
> +++ b/drivers/infiniband/hw/hns/hns_roce_mr.c
> @@ -352,7 +352,9 @@ struct ib_mr *hns_roce_rereg_user_mr(struct ib_mr *ibmr, int flags, u64 start,
>  free_cmd_mbox:
>  	hns_roce_free_cmd_mailbox(hr_dev, mailbox);
>  
> -	return ERR_PTR(ret);
> +	if (ret)
> +		return ERR_PTR(ret);
> +	return NULL;
>  }

I don't understand this function, it returns or ERR_PTR() or NULL, but
should return &mr->ibmr in success path. How does it work?

Thanks

>  
>  int hns_roce_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
> -- 
> 2.17.1
> 