From 3cf33a587de48740c2da4d2ea5b414d5e493a2eb Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 6 Jul 2017 11:01:07 -0700 Subject: [PATCH] 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: Stefano Stabellini Reviewed-by: Juergen Gross CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-back.c | 75 +++++++++++++++++++++++++++++++++++++- 1 file changed, 74 insertions(+), 1 deletion(-) diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c index 9a4bdc5e5d34..06bd95d4d552 100644 --- a/drivers/xen/pvcalls-back.c +++ b/drivers/xen/pvcalls-back.c @@ -355,11 +355,34 @@ 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, @@ -502,6 +525,56 @@ 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; } -- 2.45.2