[PATCH] doc: clarification about setting SO_ZEROCOPY

[PATCH] doc: clarification about setting SO_ZEROCOPY

[Kornilios Kourtis]

Signed-off-by: Kornilios Kourtis <kou@zurich.ibm.com>
---
 Documentation/networking/msg_zerocopy.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/networking/msg_zerocopy.rst b/Documentation/networking/msg_zerocopy.rst
index 77f6d7e..c3380f4 100644
--- a/Documentation/networking/msg_zerocopy.rst
+++ b/Documentation/networking/msg_zerocopy.rst
@@ -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
 ------------
-- 
2.4.3

Re: [PATCH] doc: clarification about setting SO_ZEROCOPY

[Willem de Bruijn]

On Tue, Jan 9, 2018 at 3:52 AM, Kornilios Kourtis <kou@zurich.ibm.com> wrote:
> Signed-off-by: Kornilios Kourtis <kou@zurich.ibm.com>

Acked-by: Willem de Bruijn <willemb@google.com>

Thanks, Kornilios.

> ---
>  Documentation/networking/msg_zerocopy.rst | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/Documentation/networking/msg_zerocopy.rst b/Documentation/networking/msg_zerocopy.rst
> index 77f6d7e..c3380f4 100644
> --- a/Documentation/networking/msg_zerocopy.rst
> +++ b/Documentation/networking/msg_zerocopy.rst
> @@ -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.

Re: [PATCH] doc: clarification about setting SO_ZEROCOPY

[David Miller]

From: Kornilios Kourtis <kou@zurich.ibm.com>
Date: Tue, 9 Jan 2018 09:52:22 +0100

> Signed-off-by: Kornilios Kourtis <kou@zurich.ibm.com>

Applied, thank you.