xen/xenbus: Add 'will_handle' callback support in xenbus_watch_path()

Some code does not directly make 'xenbus_watch' object and call
'register_xenbus_watch()' but use 'xenbus_watch_path()' instead.  This
commit adds support of 'will_handle' callback in the
'xenbus_watch_path()' and it's wrapper, 'xenbus_watch_pathfmt()'.

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>

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 76912c5..1d8b8d2 100644 (file)
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -675,7 +675,8 @@ static int xen_blkbk_probe(struct xenbus_device *dev,
        /* setup back pointer */
        be->blkif->be = be;
 
-       err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed,
+       err = xenbus_watch_pathfmt(dev, &be->backend_watch, NULL,
+                                  backend_changed,
                                   "%s/%s", dev->nodename, "physical-device");
        if (err)
                goto fail;

diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 00f6f8d..6f10e09 100644 (file)
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -824,7 +824,7 @@ static void connect(struct backend_info *be)
        xenvif_carrier_on(be->vif);
 
        unregister_hotplug_status_watch(be);
-       err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
+       err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, NULL,
                                   hotplug_status_changed,
                                   "%s/%s", dev->nodename, "hotplug-status");
        if (!err)

diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index 4b99ec3..e7c692c 100644 (file)
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -689,7 +689,7 @@ static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
 
        /* watch the backend node for backend configuration information */
        err = xenbus_watch_path(dev, dev->nodename, &pdev->be_watch,
-                               xen_pcibk_be_watch);
+                               NULL, xen_pcibk_be_watch);
        if (err)
                goto out;
 

diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 0a21a12..0cd7289 100644 (file)
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -127,19 +127,22 @@ EXPORT_SYMBOL_GPL(xenbus_strstate);
  */
 int xenbus_watch_path(struct xenbus_device *dev, const char *path,
                      struct xenbus_watch *watch,
+                     bool (*will_handle)(struct xenbus_watch *,
+                                         const char *, const char *),
                      void (*callback)(struct xenbus_watch *,
                                       const char *, const char *))
 {
        int err;
 
        watch->node = path;
-       watch->will_handle = NULL;
+       watch->will_handle = will_handle;
        watch->callback = callback;
 
        err = register_xenbus_watch(watch);
 
        if (err) {
                watch->node = NULL;
+               watch->will_handle = NULL;
                watch->callback = NULL;
                xenbus_dev_fatal(dev, err, "adding watch on %s", path);
        }
@@ -166,6 +169,8 @@ EXPORT_SYMBOL_GPL(xenbus_watch_path);
  */
 int xenbus_watch_pathfmt(struct xenbus_device *dev,
                         struct xenbus_watch *watch,
+                        bool (*will_handle)(struct xenbus_watch *,
+                                       const char *, const char *),
                         void (*callback)(struct xenbus_watch *,
                                          const char *, const char *),
                         const char *pathfmt, ...)
@@ -182,7 +187,7 @@ int xenbus_watch_pathfmt(struct xenbus_device *dev,
                xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
                return -ENOMEM;
        }
-       err = xenbus_watch_path(dev, path, watch, callback);
+       err = xenbus_watch_path(dev, path, watch, will_handle, callback);
 
        if (err)
                kfree(path);

diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 38725d9..4c3d1b8 100644 (file)
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -136,7 +136,7 @@ static int watch_otherend(struct xenbus_device *dev)
                container_of(dev->dev.bus, struct xen_bus_type, bus);
 
        return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
-                                   bus->otherend_changed,
+                                   NULL, bus->otherend_changed,
                                    "%s/%s", dev->otherend, "state");
 }
 

diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index baa88bf..c8574d1 100644 (file)
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -204,10 +204,14 @@ void xenbus_probe(struct work_struct *);
 
 int xenbus_watch_path(struct xenbus_device *dev, const char *path,
                      struct xenbus_watch *watch,
+                     bool (*will_handle)(struct xenbus_watch *,
+                                         const char *, const char *),
                      void (*callback)(struct xenbus_watch *,
                                       const char *, const char *));
-__printf(4, 5)
+__printf(5, 6)
 int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
+                        bool (*will_handle)(struct xenbus_watch *,
+                                            const char *, const char *),
                         void (*callback)(struct xenbus_watch *,
                                          const char *, const char *),
                         const char *pathfmt, ...);