From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-next] rds: do not call ->conn_alloc with GFP_KERNEL
Date: Tue, 13 Feb 2018 12:04:21 -0500 (EST)
Message-ID: <20180213.120421.840213231623736121.davem@davemloft.net>
References: <1518478238-164533-1-git-send-email-sowmini.varadhan@oracle.com>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Cc: netdev@vger.kernel.org, santosh.shilimkar@oracle.com,
        rds-devel@oss.oracle.com
To: sowmini.varadhan@oracle.com
Return-path: <netdev-owner@vger.kernel.org>
Received: from shards.monkeyblade.net ([184.105.139.130]:41988 "EHLO
        shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S964869AbeBMREY (ORCPT
        <rfc822;netdev@vger.kernel.org>); Tue, 13 Feb 2018 12:04:24 -0500
In-Reply-To: <1518478238-164533-1-git-send-email-sowmini.varadhan@oracle.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Date: Mon, 12 Feb 2018 15:30:38 -0800

> diff --git a/net/rds/connection.c b/net/rds/connection.c
> index 94e190f..d0f5889 100644
> --- a/net/rds/connection.c
> +++ b/net/rds/connection.c
> @@ -221,6 +221,8 @@ static void __rds_conn_path_init(struct rds_connection *conn,
>  		conn->c_path[i].cp_index = i;
>  	}
>  	rcu_read_lock();
> +	gfp &= ~GFP_KERNEL;
> +	gfp |= GFP_ATOMIC;
>  	if (rds_destroy_pending(conn))
>  		ret = -ENETDOWN;
>  	else

I'd never seen this kind of gfp masking before, so I did a grep around
and the only cases I saw of this kind of usage were for things like
GFP_DMA and such.

I could not find one case that did it to convert a sleeping into a non-
sleeping GFP mask.

Let's not over-engineer this.  For one thing, whatever allocation bits
came down from the callers, we are going to lose here.

So just pass straight GFP_ATOMIC into the routines below here instead
of the 'gfp' variable.

Thanks.