[PATCH] VSOCK: do not disconnect socket when peer has shutdown SEND only

[PATCH] VSOCK: do not disconnect socket when peer has shutdown SEND only

[Ian Campbell]

The peer may be expecting a reply having sent a request and then done a
shutdown(SHUT_WR), so tearing down the whole socket at this point seems
wrong and breaks for me with a client which does a SHUT_WR.

Looking at other socket family's stream_recvmsg callbacks doing a shutdown
here does not seem to be the norm and removing it does not seem to have
had any adverse effects that I can see.

I'm using Stefan's RFC virtio transport patches, I'm unsure of the impact
on the vmci transport.

Signed-off-by: Ian Campbell <ian.campbell@docker.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Cc: Andy King <acking@vmware.com>
Cc: Dmitry Torokhov <dtor@vmware.com>
Cc: Jorgen Hansen <jhansen@vmware.com>
Cc: Adit Ranadive <aditr@vmware.com>
Cc: netdev@vger.kernel.org
---
 net/vmw_vsock/af_vsock.c | 21 +--------------------
 1 file changed, 1 insertion(+), 20 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 1e5f5ed..7a25150 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1789,27 +1789,8 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 	else if (sk->sk_shutdown & RCV_SHUTDOWN)
 		err = 0;
 
-	if (copied > 0) {
-		/* We only do these additional bookkeeping/notification steps
-		 * if we actually copied something out of the queue pair
-		 * instead of just peeking ahead.
-		 */
-
-		if (!(flags & MSG_PEEK)) {
-			/* If the other side has shutdown for sending and there
-			 * is nothing more to read, then modify the socket
-			 * state.
-			 */
-			if (vsk->peer_shutdown & SEND_SHUTDOWN) {
-				if (vsock_stream_has_data(vsk) <= 0) {
-					sk->sk_state = SS_UNCONNECTED;
-					sock_set_flag(sk, SOCK_DONE);
-					sk->sk_state_change(sk);
-				}
-			}
-		}
+	if (copied > 0)
 		err = copied;
-	}
 
 out:
 	release_sock(sk);
-- 
2.8.1

Re: [PATCH] VSOCK: do not disconnect socket when peer has shutdown SEND only

[Stefan Hajnoczi]

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On Wed, May 04, 2016 at 02:21:53PM +0100, Ian Campbell wrote:
> The peer may be expecting a reply having sent a request and then done a
> shutdown(SHUT_WR), so tearing down the whole socket at this point seems
> wrong and breaks for me with a client which does a SHUT_WR.
> 
> Looking at other socket family's stream_recvmsg callbacks doing a shutdown
> here does not seem to be the norm and removing it does not seem to have
> had any adverse effects that I can see.

Seems fine to me.

> I'm using Stefan's RFC virtio transport patches, I'm unsure of the impact
> on the vmci transport.
> 
> Signed-off-by: Ian Campbell <ian.campbell@docker.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Stefan Hajnoczi <stefanha@redhat.com>
> Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
> Cc: Andy King <acking@vmware.com>
> Cc: Dmitry Torokhov <dtor@vmware.com>
> Cc: Jorgen Hansen <jhansen@vmware.com>
> Cc: Adit Ranadive <aditr@vmware.com>
> Cc: netdev@vger.kernel.org
> ---
>  net/vmw_vsock/af_vsock.c | 21 +--------------------
>  1 file changed, 1 insertion(+), 20 deletions(-)
> 
> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> index 1e5f5ed..7a25150 100644
> --- a/net/vmw_vsock/af_vsock.c
> +++ b/net/vmw_vsock/af_vsock.c
> @@ -1789,27 +1789,8 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>  	else if (sk->sk_shutdown & RCV_SHUTDOWN)
>  		err = 0;
>  
> -	if (copied > 0) {
> -		/* We only do these additional bookkeeping/notification steps
> -		 * if we actually copied something out of the queue pair
> -		 * instead of just peeking ahead.
> -		 */
> -
> -		if (!(flags & MSG_PEEK)) {
> -			/* If the other side has shutdown for sending and there
> -			 * is nothing more to read, then modify the socket
> -			 * state.
> -			 */
> -			if (vsk->peer_shutdown & SEND_SHUTDOWN) {
> -				if (vsock_stream_has_data(vsk) <= 0) {
> -					sk->sk_state = SS_UNCONNECTED;
> -					sock_set_flag(sk, SOCK_DONE);
> -					sk->sk_state_change(sk);
> -				}
> -			}
> -		}
> +	if (copied > 0)
>  		err = copied;
> -	}
>  
>  out:
>  	release_sock(sk);
> -- 
> 2.8.1
> 

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Re: [PATCH] VSOCK: do not disconnect socket when peer has shutdown SEND only

[David Miller]

From: Ian Campbell <ian.campbell@docker.com>
Date: Wed,  4 May 2016 14:21:53 +0100

> The peer may be expecting a reply having sent a request and then done a
> shutdown(SHUT_WR), so tearing down the whole socket at this point seems
> wrong and breaks for me with a client which does a SHUT_WR.
> 
> Looking at other socket family's stream_recvmsg callbacks doing a shutdown
> here does not seem to be the norm and removing it does not seem to have
> had any adverse effects that I can see.
> 
> I'm using Stefan's RFC virtio transport patches, I'm unsure of the impact
> on the vmci transport.
> 
> Signed-off-by: Ian Campbell <ian.campbell@docker.com>

Applied and queued up for -stable, thanks.