netdev - Re: [PATCH] bpf: tcp_bpf_recvmsg should return EAGAIN when nonblocking and no data

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Message-ID: <789e7f30-f567-37d3-6cd2-6d9baaa662e8@gmail.com>
Date:   Mon, 29 Oct 2018 13:30:49 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     daniel@...earbox.net, ast@...nel.org
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH] bpf: tcp_bpf_recvmsg should return EAGAIN when
 nonblocking and no data

On 10/29/2018 12:31 PM, John Fastabend wrote:
> We return 0 in the case of a nonblocking socket that has no data
> available. However, this is incorrect and may confuse applications.
> After this patch we do the correct thing and return the error
> EAGAIN.
> 
> Quoting return codes from recvmsg manpage,
> 
> EAGAIN or EWOULDBLOCK
>  The socket is marked nonblocking and the receive operation would
>  block, or a receive timeout had been set and the timeout expired
>  before data was received.
> 
> Signed-off-by: John Fastabend <john.fastabend@...il.com>
> ---

Add fixes tag.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")