[PATCH v2 1/4] xenbus: move xenbus_dev_shutdown() into frontend code...

Paul Durrant
2019-12-10T11:34:15Z

...and make it static

xenbus_dev_shutdown() is seemingly intended to cause clean shutdown of PV
frontends when a guest is rebooted. Indeed the function waits for a
conpletion which is only set by a call to xenbus_frontend_closed().

This patch removes the shutdown() method from backends and moves
xenbus_dev_shutdown() from xenbus_probe.c into xenbus_probe_frontend.c,
renaming it appropriately and making it static.

NOTE: In the case where the backend is running in a driver domain, the
toolstack should have already terminated any frontends that may be
using it (since Xen does not support re-startable PV driver domains)
so xenbus_dev_shutdown() should never be called.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
---
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
---
drivers/xen/xenbus/xenbus.h | 2 --
drivers/xen/xenbus/xenbus_probe.c | 23 ---------------------
drivers/xen/xenbus/xenbus_probe_backend.c | 1 -
drivers/xen/xenbus/xenbus_probe_frontend.c | 24 +++++++++++++++++++++-
4 files changed, 23 insertions(+), 27 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h
index d75a2385b37c..5f5b8a7d5b80 100644
--- a/drivers/xen/xenbus/xenbus.h
+++ b/drivers/xen/xenbus/xenbus.h
@@ -116,8 +116,6 @@ int xenbus_probe_devices(struct xen_bus_type *bus);

void xenbus_dev_changed(const char *node, struct xen_bus_type *bus);

-void xenbus_dev_shutdown(struct device *_dev);
-
int xenbus_dev_suspend(struct device *dev);
int xenbus_dev_resume(struct device *dev);
int xenbus_dev_cancel(struct device *dev);
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 4461f4583476..a10311c348b9 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -281,29 +281,6 @@ int xenbus_dev_remove(struct device *_dev)
}
EXPORT_SYMBOL_GPL(xenbus_dev_remove);

-void xenbus_dev_shutdown(struct device *_dev)
-{
- struct xenbus_device *dev = to_xenbus_device(_dev);
- unsigned long timeout = 5*HZ;
-
- DPRINTK("%s", dev->nodename);
-
- get_device(&dev->dev);
- if (dev->state != XenbusStateConnected) {
- pr_info("%s: %s: %s != Connected, skipping\n",
- __func__, dev->nodename, xenbus_strstate(dev->state));
- goto out;
- }
- xenbus_switch_state(dev, XenbusStateClosing);
- timeout = wait_for_completion_timeout(&dev->down, timeout);
- if (!timeout)
- pr_info("%s: %s timeout closing device\n",
- __func__, dev->nodename);
- out:
- put_device(&dev->dev);
-}
-EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
-
int xenbus_register_driver_common(struct xenbus_driver *drv,
struct xen_bus_type *bus,
struct module *owner, const char *mod_name)
diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
index b0bed4faf44c..14876faff3b0 100644
--- a/drivers/xen/xenbus/xenbus_probe_backend.c
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -198,7 +198,6 @@ static struct xen_bus_type xenbus_backend = {
.uevent = xenbus_uevent_backend,
.probe = xenbus_dev_probe,
.remove = xenbus_dev_remove,
- .shutdown = xenbus_dev_shutdown,
.dev_groups = xenbus_dev_groups,
},
};
diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index a7d90a719cea..8a1650bbe18f 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -126,6 +126,28 @@ static int xenbus_frontend_dev_probe(struct device *dev)
return xenbus_dev_probe(dev);
}

+static void xenbus_frontend_dev_shutdown(struct device *_dev)
+{
+ struct xenbus_device *dev = to_xenbus_device(_dev);
+ unsigned long timeout = 5*HZ;
+
+ DPRINTK("%s", dev->nodename);
+
+ get_device(&dev->dev);
+ if (dev->state != XenbusStateConnected) {
+ pr_info("%s: %s: %s != Connected, skipping\n",
+ __func__, dev->nodename, xenbus_strstate(dev->state));
+ goto out;
+ }
+ xenbus_switch_state(dev, XenbusStateClosing);
+ timeout = wait_for_completion_timeout(&dev->down, timeout);
+ if (!timeout)
+ pr_info("%s: %s timeout closing device\n",
+ __func__, dev->nodename);
+ out:
+ put_device(&dev->dev);
+}
+
static const struct dev_pm_ops xenbus_pm_ops = {
.suspend = xenbus_dev_suspend,
.resume = xenbus_frontend_dev_resume,
@@ -146,7 +168,7 @@ static struct xen_bus_type xenbus_frontend = {
.uevent = xenbus_uevent_frontend,
.probe = xenbus_frontend_dev_probe,
.remove = xenbus_dev_remove,
- .shutdown = xenbus_dev_shutdown,
+ .shutdown = xenbus_frontend_dev_shutdown,
.dev_groups = xenbus_dev_groups,

.pm = &xenbus_pm_ops,
--
2.20.1