[v2,03/18] xen/pvcalls: initialize the module and register the xenbus backend

Commit Message

Stefano Stabellini May 19, 2017, 11:22 p.m. UTC

Keep a list of connected frontends. Use a semaphore to protect list
accesses.

Signed-off-by: Stefano Stabellini <[e-mail]>
CC: [e-mail]
CC: [e-mail]
---
 drivers/xen/pvcalls-back.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Comments

Boris Ostrovsky May 25, 2017, 10:12 p.m. UTC | #1

On 05/19/2017 07:22 PM, Stefano Stabellini wrote:
> Keep a list of connected frontends. Use a semaphore to protect list
> accesses.
>
> Signed-off-by: Stefano Stabellini <[e-mail]>
> CC: [e-mail]
> CC: [e-mail]

Reviewed-by: Boris Ostrovsky <[e-mail]>

Patch

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index f3d0daa..9044cf2 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -25,6 +25,11 @@ 
 #include <xen/xenbus.h>
 #include <xen/interface/io/pvcalls.h>
 
+struct pvcalls_back_global {
+	struct list_head frontends;
+	struct semaphore frontends_lock;
+} pvcalls_back_global;
+
 static int pvcalls_back_probe(struct xenbus_device *dev,
 			      const struct xenbus_device_id *id)
 {
@@ -59,3 +64,20 @@  static int pvcalls_back_uevent(struct xenbus_device *xdev,
 	.uevent = pvcalls_back_uevent,
 	.otherend_changed = pvcalls_back_changed,
 };
+
+static int __init pvcalls_back_init(void)
+{
+	int ret;
+
+	if (!xen_domain())
+		return -ENODEV;
+
+	ret = xenbus_register_backend(&pvcalls_back_driver);
+	if (ret < 0)
+		return ret;
+
+	sema_init(&pvcalls_back_global.frontends_lock, 1);
+	INIT_LIST_HEAD(&pvcalls_back_global.frontends);
+	return 0;
+}
+module_init(pvcalls_back_init);