[PATCH 4.9 26/32] xen/xenbus/xen_bus_type: Support will_handle watch callback

Greg Kroah-Hartman
2021-01-07T14:20:00Z

From: SeongJae Park <sjpark@amazon.de>

commit be987200fbaceaef340872841d4f7af2c5ee8dc3 upstream.

This commit adds support of the 'will_handle' watch callback for
'xen_bus_type' users.

This is part of XSA-349

Cc: stable@vger.kernel.org
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reported-by: Michael Kurth <mku@amazon.de>
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/xen/xenbus/xenbus_probe.c | 3 ++-
drivers/xen/xenbus/xenbus_probe.h | 2 ++
2 files changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -137,7 +137,8 @@ static int watch_otherend(struct xenbus_
container_of(dev->dev.bus, struct xen_bus_type, bus);

return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
- NULL, bus->otherend_changed,
+ bus->otherend_will_handle,
+ bus->otherend_changed,
"%s/%s", dev->otherend, "state");
}

--- a/drivers/xen/xenbus/xenbus_probe.h
+++ b/drivers/xen/xenbus/xenbus_probe.h
@@ -42,6 +42,8 @@ struct xen_bus_type {
int (*get_bus_id)(char bus_id[XEN_BUS_ID_SIZE], const char *nodename);
int (*probe)(struct xen_bus_type *bus, const char *type,
const char *dir);
+ bool (*otherend_will_handle)(struct xenbus_watch *watch,
+ const char **vec, unsigned int len);
void (*otherend_changed)(struct xenbus_watch *watch, const char **vec,
unsigned int len);
struct bus_type bus;