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[PATCH v5 05/18] xen/pvcalls: connect to a frontend

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Introduce a per-frontend data structure named pvcalls_fedata. It
contains pointers to the command ring, its event channel, a list of
active sockets and a tree of passive sockets (passing sockets need to be
looked up from the id on listen, accept and poll commands, while active
sockets only on release).

It also has an unbound workqueue to schedule the work of parsing and
executing commands on the command ring. socket_lock protects the two
lists. In pvcalls_back_global, keep a list of connected frontends.

Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
---
 drivers/xen/pvcalls-back.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 7bce750..e4c2e46 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -33,9 +33,101 @@ struct pvcalls_back_global {
 	struct semaphore frontends_lock;
 } pvcalls_back_global;
 
+/*
+ * Per-frontend data structure. It contains pointers to the command
+ * ring, its event channel, a list of active sockets and a tree of
+ * passive sockets.
+ */
+struct pvcalls_fedata {
+	struct list_head list;
+	struct xenbus_device *dev;
+	struct xen_pvcalls_sring *sring;
+	struct xen_pvcalls_back_ring ring;
+	int irq;
+	struct list_head socket_mappings;
+	struct radix_tree_root socketpass_mappings;
+	struct semaphore socket_lock;
+	struct workqueue_struct *wq;
+	struct work_struct register_work;
+};
+
+static void pvcalls_back_work(struct work_struct *work)
+{
+}
+
+static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
+{
+	return IRQ_HANDLED;
+}
+
 static int backend_connect(struct xenbus_device *dev)
 {
+	int err, evtchn;
+	grant_ref_t ring_ref;
+	struct pvcalls_fedata *fedata = NULL;
+
+	fedata = kzalloc(sizeof(struct pvcalls_fedata), GFP_KERNEL);
+	if (!fedata)
+		return -ENOMEM;
+
+	err = xenbus_scanf(XBT_NIL, dev->otherend, "port", "%u",
+			   &evtchn);
+	if (err != 1) {
+		err = -EINVAL;
+		xenbus_dev_fatal(dev, err, "reading %s/event-channel",
+				 dev->otherend);
+		goto error;
+	}
+
+	err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", "%u", &ring_ref);
+	if (err != 1) {
+		err = -EINVAL;
+		xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
+				 dev->otherend);
+		goto error;
+	}
+
+	err = bind_interdomain_evtchn_to_irqhandler(dev->otherend_id, evtchn,
+						    pvcalls_back_event, 0,
+						    "pvcalls-backend", dev);
+	if (err < 0)
+		goto error;
+	fedata->irq = err;
+
+	fedata->wq = alloc_workqueue("pvcalls_back_wq", WQ_UNBOUND, 1);
+	if (!fedata->wq) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	err = xenbus_map_ring_valloc(dev, &ring_ref, 1, (void**)&fedata->sring);
+	if (err < 0)
+		goto error;
+
+	BACK_RING_INIT(&fedata->ring, fedata->sring, XEN_PAGE_SIZE * 1);
+	fedata->dev = dev;
+
+	INIT_WORK(&fedata->register_work, pvcalls_back_work);
+	INIT_LIST_HEAD(&fedata->socket_mappings);
+	INIT_RADIX_TREE(&fedata->socketpass_mappings, GFP_KERNEL);
+	sema_init(&fedata->socket_lock, 1);
+	dev_set_drvdata(&dev->dev, fedata);
+
+	down(&pvcalls_back_global.frontends_lock);
+	list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
+	up(&pvcalls_back_global.frontends_lock);
+	queue_work(fedata->wq, &fedata->register_work);
+
 	return 0;
+
+ error:
+	if (fedata->sring != NULL)
+		xenbus_unmap_ring_vfree(dev, fedata->sring);
+	if (fedata->wq)
+		destroy_workqueue(fedata->wq);
+	unbind_from_irqhandler(fedata->irq, dev);
+	kfree(fedata);
+	return err;
 }
 
 static int backend_disconnect(struct xenbus_device *dev)
-- 
1.9.1

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[PATCH v5 00/18] introduce the Xen PV Calls backend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 17/18] xen/pvcalls: implement write Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 13/18] xen/pvcalls: implement release command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 10/18] xen/pvcalls: implement listen command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 18/18] xen: introduce a Kconfig option to enable the pvcalls backend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 11/18] xen/pvcalls: implement accept command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 16/18] xen/pvcalls: implement read Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 15/18] xen/pvcalls: implement the ioworker functions Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 02/18] xen/pvcalls: introduce the pvcalls xenbus backend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 12/18] xen/pvcalls: implement poll command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 06/18] xen/pvcalls: handle commands from the frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
    Re: [PATCH v5 06/18] xen/pvcalls: handle commands from the frontend Juergen Gross <jgross@suse.com> - 2017-07-03 13:30 +0200
  [PATCH v5 09/18] xen/pvcalls: implement bind command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
  [PATCH v5 01/18] xen: introduce the pvcalls interface header Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
    [PATCH v5 03/18] xen/pvcalls: initialize the module and register the xenbus backend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
    [PATCH v5 07/18] xen/pvcalls: implement socket command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
    [PATCH v5 05/18] xen/pvcalls: connect to a frontend Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
    [PATCH v5 14/18] xen/pvcalls: disconnect and module_exit Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
    [PATCH v5 08/18] xen/pvcalls: implement connect command Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200
    [PATCH v5 04/18] xen/pvcalls: xenbus state handling Stefano Stabellini <sstabellini@kernel.org> - 2017-06-22 21:20 +0200

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