On Mon, Oct 29, 2018 at 1:32 PM John Fastabend [off-list ref] wrote:

On 10/29/2018 12:31 PM, John Fastabend wrote:

quoted

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@gmail.com>

Acked-by: Song Liu <redacted>

quoted

---

Add fixes tag.

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