linux-kernel - [PATCH 06/18] xen/pvcalls: handle commands from the frontend

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Date:   Mon, 15 May 2017 13:35:58 -0700
From:   Stefano Stabellini <sstabellini@...nel.org>
To:     xen-devel@...ts.xen.org
Cc:     linux-kernel@...r.kernel.org, sstabellini@...nel.org,
        jgross@...e.com, boris.ostrovsky@...cle.com,
        Stefano Stabellini <stefano@...reto.com>
Subject: [PATCH 06/18] xen/pvcalls: handle commands from the frontend

When the other end notifies us that there are commands to be read
(pvcalls_back_event), wake up the backend thread to parse the command.

The command ring works like most other Xen rings, so use the usual
ring macros to read and write to it. The functions implementing the
commands are empty stubs for now.

Signed-off-by: Stefano Stabellini <stefano@...reto.com>
CC: boris.ostrovsky@...cle.com
CC: jgross@...e.com
---
 drivers/xen/pvcalls-back.c | 115 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 876e577..2b2a49a 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -62,12 +62,127 @@ static void pvcalls_back_ioworker(struct work_struct *work)
 {
 }
 
+static int pvcalls_back_socket(struct xenbus_device *dev,
+		struct xen_pvcalls_request *req)
+{
+	return 0;
+}
+
+static int pvcalls_back_connect(struct xenbus_device *dev,
+				struct xen_pvcalls_request *req)
+{
+	return 0;
+}
+
+static int pvcalls_back_release(struct xenbus_device *dev,
+				struct xen_pvcalls_request *req)
+{
+	return 0;
+}
+
+static int pvcalls_back_bind(struct xenbus_device *dev,
+			     struct xen_pvcalls_request *req)
+{
+	return 0;
+}
+
+static int pvcalls_back_listen(struct xenbus_device *dev,
+			       struct xen_pvcalls_request *req)
+{
+	return 0;
+}
+
+static int pvcalls_back_accept(struct xenbus_device *dev,
+			       struct xen_pvcalls_request *req)
+{
+	return 0;
+}
+
+static int pvcalls_back_poll(struct xenbus_device *dev,
+			     struct xen_pvcalls_request *req)
+{
+	return 0;
+}
+
+static int pvcalls_back_handle_cmd(struct xenbus_device *dev,
+				   struct xen_pvcalls_request *req)
+{
+	int ret = 0;
+
+	switch (req->cmd) {
+	case PVCALLS_SOCKET:
+		ret = pvcalls_back_socket(dev, req);
+		break;
+	case PVCALLS_CONNECT:
+		ret = pvcalls_back_connect(dev, req);
+		break;
+	case PVCALLS_RELEASE:
+		ret = pvcalls_back_release(dev, req);
+		break;
+	case PVCALLS_BIND:
+		ret = pvcalls_back_bind(dev, req);
+		break;
+	case PVCALLS_LISTEN:
+		ret = pvcalls_back_listen(dev, req);
+		break;
+	case PVCALLS_ACCEPT:
+		ret = pvcalls_back_accept(dev, req);
+		break;
+	case PVCALLS_POLL:
+		ret = pvcalls_back_poll(dev, req);
+		break;
+	default:
+		ret = -ENOTSUPP;
+		break;
+	}
+	return ret;
+}
+
 static void pvcalls_back_work(struct work_struct *work)
 {
+	struct pvcalls_back_priv *priv = container_of(work,
+		struct pvcalls_back_priv, register_work);
+	int notify, notify_all = 0, more = 1;
+	struct xen_pvcalls_request req;
+	struct xenbus_device *dev = priv->dev;
+
+	atomic_set(&priv->work, 1);
+
+	while (more || !atomic_dec_and_test(&priv->work)) {
+		while (RING_HAS_UNCONSUMED_REQUESTS(&priv->ring)) {
+			RING_COPY_REQUEST(&priv->ring,
+					  priv->ring.req_cons++,
+					  &req);
+
+			if (pvcalls_back_handle_cmd(dev, &req) > 0) {
+				RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(
+					&priv->ring, notify);
+				notify_all += notify;
+			}
+		}
+
+		if (notify_all)
+			notify_remote_via_irq(priv->irq);
+
+		RING_FINAL_CHECK_FOR_REQUESTS(&priv->ring, more);
+	}
 }
 
 static irqreturn_t pvcalls_back_event(int irq, void *dev_id)
 {
+	struct xenbus_device *dev = dev_id;
+	struct pvcalls_back_priv *priv = NULL;
+
+	if (dev == NULL)
+		return IRQ_HANDLED;
+
+	priv = dev_get_drvdata(&dev->dev);
+	if (priv == NULL)
+		return IRQ_HANDLED;
+
+	atomic_inc(&priv->work);
+	queue_work(priv->wq, &priv->register_work);
+
 	return IRQ_HANDLED;
 }
 
-- 
1.9.1