[PATCH net-next 04/10] rxrpc: Requeue call for recvmsg if more data

From	David Howells <dhowells@redhat.com>
Newsgroups	linux.kernel
Subject	[PATCH net-next 04/10] rxrpc: Requeue call for recvmsg if more data
Date	2016-09-14 00:30 +0200
Message-ID	<sh4ng-823-29@gated-at.bofh.it> (permalink)
References	<sh4nf-823-3@gated-at.bofh.it>
Organization	Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903

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rxrpc_recvmsg() needs to make sure that the call it has just been
processing gets requeued for further attention if the buffer has been
filled and there's more data to be consumed.  The softirq producer only
queues the call and wakes the socket if it fills the first slot in the
window, so userspace might end up sleeping forever otherwise, despite there
being data available.

This is not a problem provided the userspace buffer is big enough or it
empties the buffer completely before more data comes in.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 net/rxrpc/recvmsg.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index 20d0b5c6f81b..16ff56f69256 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -463,6 +463,10 @@ try_again:
 					 flags, &copied);
 		if (ret == -EAGAIN)
 			ret = 0;
+
+		if (after(call->rx_top, call->rx_hard_ack) &&
+		    call->rxtx_buffer[(call->rx_hard_ack + 1) & RXRPC_RXTX_BUFF_MASK])
+			rxrpc_notify_socket(call);
 		break;
 	default:
 		ret = 0;

Thread

[PATCH net-next 00/10] rxrpc: Miscellaneous fixes David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  [PATCH net-next 05/10] rxrpc: Add missing unlock in  rxrpc_call_accept() David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  [PATCH net-next 01/10] rxrpc: Make sure we initialise the peer hash  key David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  [PATCH net-next 03/10] rxrpc: The IDLE ACK packet should use  rxrpc_idle_ack_delay David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  [PATCH net-next 10/10] rxrpc: Correctly initialise,  limit and transmit call->rx_winsize David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  [PATCH net-next 06/10] rxrpc: Use skb->len not skb->data_len David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  [PATCH net-next 04/10] rxrpc: Requeue call for recvmsg if more data David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  [PATCH net-next 09/10] rxrpc: Fix prealloc refcounting David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  [PATCH net-next 08/10] rxrpc: Adjust the call ref tracepoint to  show kernel API refs David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  [PATCH net-next 07/10] rxrpc: Allow tx_winsize to grow in response  to an ACK David Howells <dhowells@redhat.com> - 2016-09-14 00:30 +0200
  Re: [PATCH net-next 00/10] rxrpc: Miscellaneous fixes David Miller <davem@davemloft.net> - 2016-09-16 08:00 +0200

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