Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753152AbdFMH2F (ORCPT ); Tue, 13 Jun 2017 03:28:05 -0400 Received: from mx2.suse.de ([195.135.220.15]:41705 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752622AbdFMH2E (ORCPT ); Tue, 13 Jun 2017 03:28:04 -0400 Subject: Re: [PATCH v3 12/18] xen/pvcalls: implement poll command To: Stefano Stabellini , xen-devel@lists.xen.org Cc: linux-kernel@vger.kernel.org, boris.ostrovsky@oracle.com, Stefano Stabellini References: <1496431915-20774-1-git-send-email-sstabellini@kernel.org> <1496431915-20774-12-git-send-email-sstabellini@kernel.org> From: Juergen Gross Message-ID: Date: Tue, 13 Jun 2017 09:28:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <1496431915-20774-12-git-send-email-sstabellini@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3777 Lines: 122 On 02/06/17 21:31, Stefano Stabellini wrote: > Implement poll on passive sockets by requesting a delayed response with > mappass->reqcopy, and reply back when there is data on the passive > socket. > > Poll on active socket is unimplemented as by the spec, as the frontend > should just wait for events and check the indexes on the indexes page. > > Only support one outstanding poll (or accept) request for every passive > socket at any given time. > > Signed-off-by: Stefano Stabellini > CC: boris.ostrovsky@oracle.com > CC: jgross@suse.com > --- > drivers/xen/pvcalls-back.c | 75 ++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 73 insertions(+), 2 deletions(-) > > diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c > index f1173f4..82f350d 100644 > --- a/drivers/xen/pvcalls-back.c > +++ b/drivers/xen/pvcalls-back.c > @@ -344,11 +344,33 @@ static void __pvcalls_back_accept(struct work_struct *work) > static void pvcalls_pass_sk_data_ready(struct sock *sock) > { > struct sockpass_mapping *mappass = sock->sk_user_data; > + struct pvcalls_fedata *priv; > + struct xen_pvcalls_response *rsp; > + unsigned long flags; > + int notify; > > if (mappass == NULL) > return; > > - queue_work(mappass->wq, &mappass->register_work); > + priv = mappass->priv; > + spin_lock_irqsave(&mappass->copy_lock, flags); > + if (mappass->reqcopy.cmd == PVCALLS_POLL) { > + rsp = RING_GET_RESPONSE(&priv->ring, priv->ring.rsp_prod_pvt++); > + rsp->req_id = mappass->reqcopy.req_id; > + rsp->u.poll.id = mappass->reqcopy.u.poll.id; > + rsp->cmd = mappass->reqcopy.cmd; > + rsp->ret = 0; > + > + mappass->reqcopy.cmd = 0; > + spin_unlock_irqrestore(&mappass->copy_lock, flags); > + > + RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&priv->ring, notify); > + if (notify) > + notify_remote_via_irq(mappass->priv->irq); > + } else { > + spin_unlock_irqrestore(&mappass->copy_lock, flags); > + queue_work(mappass->wq, &mappass->register_work); > + } > } > > static int pvcalls_back_bind(struct xenbus_device *dev, > @@ -493,7 +515,56 @@ static int pvcalls_back_accept(struct xenbus_device *dev, > static int pvcalls_back_poll(struct xenbus_device *dev, > struct xen_pvcalls_request *req) > { > - return 0; > + struct pvcalls_fedata *priv; > + struct sockpass_mapping *mappass; > + struct xen_pvcalls_response *rsp; > + struct inet_connection_sock *icsk; > + struct request_sock_queue *queue; > + unsigned long flags; > + int ret; > + bool data; > + > + priv = dev_get_drvdata(&dev->dev); > + > + mappass = radix_tree_lookup(&priv->socketpass_mappings, req->u.poll.id); > + if (mappass == NULL) > + return -EINVAL; > + > + /* > + * Limitation of the current implementation: only support one > + * concurrent accept or poll call on one socket. > + */ > + spin_lock_irqsave(&mappass->copy_lock, flags); > + if (mappass->reqcopy.cmd != 0) { > + ret = -EINTR; > + goto out; > + } > + > + mappass->reqcopy = *req; > + icsk = inet_csk(mappass->sock->sk); > + queue = &icsk->icsk_accept_queue; > + spin_lock(&queue->rskq_lock); > + data = queue->rskq_accept_head != NULL; > + spin_unlock(&queue->rskq_lock); > + if (data) { > + mappass->reqcopy.cmd = 0; > + ret = 0; > + goto out; > + } > + spin_unlock_irqrestore(&mappass->copy_lock, flags); > + > + /* Tell the caller we don't need to send back a notification yet */ > + return -1; > + > +out: > + spin_unlock_irqrestore(&mappass->copy_lock, flags); > + > + rsp = RING_GET_RESPONSE(&priv->ring, priv->ring.rsp_prod_pvt++); > + rsp->req_id = req->req_id; > + rsp->cmd = req->cmd; > + rsp->u.poll.id = req->u.poll.id; > + rsp->ret = ret; > + return ret; return 0; Juergen > } > > static int pvcalls_back_handle_cmd(struct xenbus_device *dev, >