doc: clarification about setting SO_ZEROCOPY

Signed-off-by: Kornilios Kourtis <kou@zurich.ibm.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kornilios Kourtis 2018-01-09 09:52:22 +01:00 committed by David S. Miller
parent 11d827a993
commit af60d61fa8

View File

@ -72,6 +72,10 @@ this flag, a process must first signal intent by setting a socket option:
if (setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY, &one, sizeof(one)))
error(1, errno, "setsockopt zerocopy");
Setting the socket option only works when the socket is in its initial
(TCP_CLOSED) state. Trying to set the option for a socket returned by accept(),
for example, will lead to an EBUSY error. In this case, the option should be set
to the listening socket and it will be inherited by the accepted sockets.
Transmission
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