Commit 3cf33a58 authored by Stefano Stabellini's avatar Stefano Stabellini Committed by Boris Ostrovsky
Browse files

xen/pvcalls: implement poll command 



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.

[ boris: fixed long lines ]

Signed-off-by: default avatarStefano Stabellini <stefano@aporeto.com>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent 6f474e71

drivers/xen/pvcalls-back.c

+74 −1
Original line number Diff line number Diff line
@@ -355,12 +355,35 @@ out_error: 
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;



	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,

			     struct xen_pvcalls_request *req)
@@ -502,6 +525,56 @@ out_error: 
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;

}

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