Message-ID: <1415967071.15154.9.camel@localhost>
Subject: Re: [PATCH v2 net-next 1/7] bpf: add 'flags' attribute to
 BPF_MAP_UPDATE_ELEM command
From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Alexei Starovoitov <ast@plumgrid.com>
Cc: "David S. Miller" <davem@davemloft.net>, Ingo Molnar <mingo@kernel.org>,
        Andy Lutomirski <luto@amacapital.net>,
        Daniel Borkmann <dborkman@redhat.com>,
        Eric Dumazet <edumazet@google.com>, linux-api@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Date: Fri, 14 Nov 2014 13:11:11 +0100
In-Reply-To: <1415929010-9361-2-git-send-email-ast@plumgrid.com>
References: <1415929010-9361-1-git-send-email-ast@plumgrid.com>
	 <1415929010-9361-2-git-send-email-ast@plumgrid.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org

On Do, 2014-11-13 at 17:36 -0800, Alexei Starovoitov wrote:
> the current meaning of BPF_MAP_UPDATE_ELEM syscall command is:
> either update existing map element or create a new one.
> Initially the plan was to add a new command to handle the case of
> 'create new element if it didn't exist', but 'flags' style looks
> cleaner and overall diff is much smaller (more code reused), so add 'flags'
> attribute to BPF_MAP_UPDATE_ELEM command with the following meaning:
>  #define BPF_ANY	0 /* create new element or update existing */
>  #define BPF_NOEXIST	1 /* create new element if it didn't exist */
>  #define BPF_EXIST	2 /* update existing element */

Would a cmpxchg-alike function be handy here?

Bye,
Hannes


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/