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Groups > linux.kernel > #1680586

[PATCH v6 12/18] xen/pvcalls: implement poll command

From Stefano Stabellini <sstabellini@kernel.org>
Newsgroups linux.kernel
Subject [PATCH v6 12/18] xen/pvcalls: implement poll command
Date 2017-07-03 23:20 +0200
Message-ID <tZgVc-7a5-33@gated-at.bofh.it> (permalink)
References <tZgLv-75o-7@gated-at.bofh.it> <tZgLv-75o-9@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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 <stefano@aporeto.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
---
 drivers/xen/pvcalls-back.c | 73 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 72 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 75b7b9a9..dba7bbf 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -350,11 +350,33 @@ 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 *fedata;
+	struct xen_pvcalls_response *rsp;
+	unsigned long flags;
+	int notify;
 
 	if (mappass == NULL)
 		return;
 
-	queue_work(mappass->wq, &mappass->register_work);
+	fedata = mappass->fedata;
+	spin_lock_irqsave(&mappass->copy_lock, flags);
+	if (mappass->reqcopy.cmd == PVCALLS_POLL) {
+		rsp = RING_GET_RESPONSE(&fedata->ring, fedata->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(&fedata->ring, notify);
+		if (notify)
+			notify_remote_via_irq(mappass->fedata->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,
@@ -505,6 +527,55 @@ static int pvcalls_back_accept(struct xenbus_device *dev,
 static int pvcalls_back_poll(struct xenbus_device *dev,
 			     struct xen_pvcalls_request *req)
 {
+	struct pvcalls_fedata *fedata;
+	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;
+
+	fedata = dev_get_drvdata(&dev->dev);
+
+	down(&fedata->socket_lock);
+	mappass = radix_tree_lookup(&fedata->socketpass_mappings, req->u.poll.id);
+	up(&fedata->socket_lock);
+	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;
+	data = queue->rskq_accept_head != NULL;
+	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(&fedata->ring, fedata->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 0;
 }
 
-- 
1.9.1

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Thread

[PATCH v6 00/18] introduce the Xen PV Calls backend Stefano Stabellini <stefano@aporeto.com> - 2017-07-03 23:10 +0200
  [PATCH v6 02/18] xen/pvcalls: introduce the pvcalls xenbus backend Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:10 +0200
  [PATCH v6 16/18] xen/pvcalls: implement read Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:10 +0200
    Re: [PATCH v6 16/18] xen/pvcalls: implement read Juergen Gross <jgross@suse.com> - 2017-07-04 09:40 +0200
  [PATCH v6 08/18] xen/pvcalls: implement connect command Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:10 +0200
    Re: [PATCH v6 08/18] xen/pvcalls: implement connect command Juergen Gross <jgross@suse.com> - 2017-07-04 09:20 +0200
      Re: [PATCH v6 08/18] xen/pvcalls: implement connect command Stefano Stabellini <sstabellini@kernel.org> - 2017-07-05 23:20 +0200
  [PATCH v6 07/18] xen/pvcalls: implement socket command Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:10 +0200
  [PATCH v6 05/18] xen/pvcalls: connect to a frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:10 +0200
    Re: [PATCH v6 05/18] xen/pvcalls: connect to a frontend Juergen Gross <jgross@suse.com> - 2017-07-04 09:00 +0200
      Re: [PATCH v6 05/18] xen/pvcalls: connect to a frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-07-05 22:40 +0200
  [PATCH v6 13/18] xen/pvcalls: implement release command Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:10 +0200
    Re: [PATCH v6 13/18] xen/pvcalls: implement release command Juergen Gross <jgross@suse.com> - 2017-07-04 09:40 +0200
  [PATCH v6 06/18] xen/pvcalls: handle commands from the frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
    Re: [PATCH v6 06/18] xen/pvcalls: handle commands from the frontend Juergen Gross <jgross@suse.com> - 2017-07-04 09:00 +0200
      Re: [PATCH v6 06/18] xen/pvcalls: handle commands from the  frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-07-05 22:50 +0200
  [PATCH v6 01/18] xen: introduce the pvcalls interface header Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
    [PATCH v6 11/18] xen/pvcalls: implement accept command Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
      Re: [PATCH v6 11/18] xen/pvcalls: implement accept command Juergen Gross <jgross@suse.com> - 2017-07-04 09:30 +0200
    [PATCH v6 09/18] xen/pvcalls: implement bind command Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
      Re: [PATCH v6 09/18] xen/pvcalls: implement bind command Juergen Gross <jgross@suse.com> - 2017-07-04 09:30 +0200
        Re: [PATCH v6 09/18] xen/pvcalls: implement bind command Stefano Stabellini <sstabellini@kernel.org> - 2017-07-05 23:20 +0200
    [PATCH v6 14/18] xen/pvcalls: disconnect and module_exit Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
      Re: [PATCH v6 14/18] xen/pvcalls: disconnect and module_exit Juergen Gross <jgross@suse.com> - 2017-07-04 09:40 +0200
        Re: [PATCH v6 14/18] xen/pvcalls: disconnect and module_exit Stefano Stabellini <sstabellini@kernel.org> - 2017-07-05 23:30 +0200
    [PATCH v6 03/18] xen/pvcalls: initialize the module and register the xenbus backend Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
    [PATCH v6 12/18] xen/pvcalls: implement poll command Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
      Re: [PATCH v6 12/18] xen/pvcalls: implement poll command Juergen Gross <jgross@suse.com> - 2017-07-04 09:30 +0200
    [PATCH v6 10/18] xen/pvcalls: implement listen command Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
    [PATCH v6 04/18] xen/pvcalls: xenbus state handling Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
      Re: [PATCH v6 04/18] xen/pvcalls: xenbus state handling Juergen Gross <jgross@suse.com> - 2017-07-04 10:10 +0200
        Re: [PATCH v6 04/18] xen/pvcalls: xenbus state handling Stefano Stabellini <sstabellini@kernel.org> - 2017-07-05 22:30 +0200
    [PATCH v6 15/18] xen/pvcalls: implement the ioworker functions Stefano Stabellini <sstabellini@kernel.org> - 2017-07-03 23:20 +0200
      Re: [PATCH v6 15/18] xen/pvcalls: implement the ioworker functions Juergen Gross <jgross@suse.com> - 2017-07-04 09:50 +0200
        Re: [PATCH v6 15/18] xen/pvcalls: implement the ioworker functions Stefano Stabellini <sstabellini@kernel.org> - 2017-07-05 23:30 +0200

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