xen: modify xenstore watch event interface

Today a Xenstore watch event is delivered via a callback function
declared as:

void (*callback)(struct xenbus_watch *,
                 const char **vec, unsigned int len);

As all watch events only ever come with two parameters (path and token)
changing the prototype to:

void (*callback)(struct xenbus_watch *,
                 const char *path, const char *token);

is the natural thing to do.

Apply this change and adapt all users.

Cc: konrad.wilk@oracle.com
Cc: roger.pau@citrix.com
Cc: wei.liu2@citrix.com
Cc: paul.durrant@citrix.com
Cc: netdev@vger.kernel.org

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

7 files changed, 42 insertions, 51 deletions

diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h
index a6b007dfdaa8..51995276f549 100644
--- a/drivers/xen/xenbus/xenbus.h
+++ b/drivers/xen/xenbus/xenbus.h
@@ -40,8 +40,8 @@ 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);
-	void (*otherend_changed)(struct xenbus_watch *watch, const char **vec,
-				 unsigned int len);
+	void (*otherend_changed)(struct xenbus_watch *watch, const char *path,
+				 const char *token);
 	struct bus_type bus;
 };
 
@@ -84,7 +84,7 @@ int xenbus_dev_resume(struct device *dev);
 int xenbus_dev_cancel(struct device *dev);
 
 void xenbus_otherend_changed(struct xenbus_watch *watch,
-			     const char **vec, unsigned int len,
+			     const char *path, const char *token,
 			     int ignore_on_shutdown);
 
 int xenbus_read_otherend_details(struct xenbus_device *xendev,
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 29f82338ab75..82a8866758ee 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -115,7 +115,7 @@ EXPORT_SYMBOL_GPL(xenbus_strstate);
 int xenbus_watch_path(struct xenbus_device *dev, const char *path,
 		      struct xenbus_watch *watch,
 		      void (*callback)(struct xenbus_watch *,
-				       const char **, unsigned int))
+				       const char *, const char *))
 {
 	int err;
 
@@ -153,7 +153,7 @@ EXPORT_SYMBOL_GPL(xenbus_watch_path);
 int xenbus_watch_pathfmt(struct xenbus_device *dev,
 			 struct xenbus_watch *watch,
 			 void (*callback)(struct xenbus_watch *,
-					const char **, unsigned int),
+					  const char *, const char *),
 			 const char *pathfmt, ...)
 {
 	int err;
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index e2bc9b301494..e4b984777507 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -258,26 +258,23 @@ out_fail:
 }
 
 static void watch_fired(struct xenbus_watch *watch,
-			const char **vec,
-			unsigned int len)
+			const char *path,
+			const char *token)
 {
 	struct watch_adapter *adap;
 	struct xsd_sockmsg hdr;
-	const char *path, *token;
-	int path_len, tok_len, body_len, data_len = 0;
+	const char *token_caller;
+	int path_len, tok_len, body_len;
 	int ret;
 	LIST_HEAD(staging_q);
 
 	adap = container_of(watch, struct watch_adapter, watch);
 
-	path = vec[XS_WATCH_PATH];
-	token = adap->token;
+	token_caller = adap->token;
 
 	path_len = strlen(path) + 1;
-	tok_len = strlen(token) + 1;
-	if (len > 2)
-		data_len = vec[len] - vec[2] + 1;
-	body_len = path_len + tok_len + data_len;
+	tok_len = strlen(token_caller) + 1;
+	body_len = path_len + tok_len;
 
 	hdr.type = XS_WATCH_EVENT;
 	hdr.len = body_len;
@@ -288,9 +285,7 @@ static void watch_fired(struct xenbus_watch *watch,
 	if (!ret)
 		ret = queue_reply(&staging_q, path, path_len);
 	if (!ret)
-		ret = queue_reply(&staging_q, token, tok_len);
-	if (!ret && len > 2)
-		ret = queue_reply(&staging_q, vec[2], data_len);
+		ret = queue_reply(&staging_q, token_caller, tok_len);
 
 	if (!ret) {
 		/* success: pass reply list onto watcher */
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 6baffbb6acf9..74888cacd0b0 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -169,7 +169,7 @@ int xenbus_read_otherend_details(struct xenbus_device *xendev,
 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
 
 void xenbus_otherend_changed(struct xenbus_watch *watch,
-			     const char **vec, unsigned int len,
+			     const char *path, const char *token,
 			     int ignore_on_shutdown)
 {
 	struct xenbus_device *dev =
@@ -180,18 +180,15 @@ void xenbus_otherend_changed(struct xenbus_watch *watch,
 	/* Protect us against watches firing on old details when the otherend
 	   details change, say immediately after a resume. */
 	if (!dev->otherend ||
-	    strncmp(dev->otherend, vec[XS_WATCH_PATH],
-		    strlen(dev->otherend))) {
-		dev_dbg(&dev->dev, "Ignoring watch at %s\n",
-			vec[XS_WATCH_PATH]);
+	    strncmp(dev->otherend, path, strlen(dev->otherend))) {
+		dev_dbg(&dev->dev, "Ignoring watch at %s\n", path);
 		return;
 	}
 
 	state = xenbus_read_driver_state(dev->otherend);
 
 	dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
-		state, xenbus_strstate(state), dev->otherend_watch.node,
-		vec[XS_WATCH_PATH]);
+		state, xenbus_strstate(state), dev->otherend_watch.node, path);
 
 	/*
 	 * Ignore xenbus transitions during shutdown. This prevents us doing
diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
index f46b4dc72c76..b0bed4faf44c 100644
--- a/drivers/xen/xenbus/xenbus_probe_backend.c
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -181,9 +181,9 @@ static int xenbus_probe_backend(struct xen_bus_type *bus, const char *type,
 }
 
 static void frontend_changed(struct xenbus_watch *watch,
-			    const char **vec, unsigned int len)
+			     const char *path, const char *token)
 {
-	xenbus_otherend_changed(watch, vec, len, 0);
+	xenbus_otherend_changed(watch, path, token, 0);
 }
 
 static struct xen_bus_type xenbus_backend = {
@@ -204,11 +204,11 @@ static struct xen_bus_type xenbus_backend = {
 };
 
 static void backend_changed(struct xenbus_watch *watch,
-			    const char **vec, unsigned int len)
+			    const char *path, const char *token)
 {
 	DPRINTK("");
 
-	xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_backend);
+	xenbus_dev_changed(path, &xenbus_backend);
 }
 
 static struct xenbus_watch be_watch = {
diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index d7b77a62e6e7..19e45ce21f89 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -86,9 +86,9 @@ static int xenbus_uevent_frontend(struct device *_dev,
 
 
 static void backend_changed(struct xenbus_watch *watch,
-			    const char **vec, unsigned int len)
+			    const char *path, const char *token)
 {
-	xenbus_otherend_changed(watch, vec, len, 1);
+	xenbus_otherend_changed(watch, path, token, 1);
 }
 
 static void xenbus_frontend_delayed_resume(struct work_struct *w)
@@ -153,11 +153,11 @@ static struct xen_bus_type xenbus_frontend = {
 };
 
 static void frontend_changed(struct xenbus_watch *watch,
-			     const char **vec, unsigned int len)
+			     const char *path, const char *token)
 {
 	DPRINTK("");
 
-	xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend);
+	xenbus_dev_changed(path, &xenbus_frontend);
 }
 
 
@@ -332,13 +332,13 @@ static DECLARE_WAIT_QUEUE_HEAD(backend_state_wq);
 static int backend_state;
 
 static void xenbus_reset_backend_state_changed(struct xenbus_watch *w,
-					const char **v, unsigned int l)
+					const char *path, const char *token)
 {
-	if (xenbus_scanf(XBT_NIL, v[XS_WATCH_PATH], "", "%i",
+	if (xenbus_scanf(XBT_NIL, path, "", "%i",
 			 &backend_state) != 1)
 		backend_state = XenbusStateUnknown;
 	printk(KERN_DEBUG "XENBUS: backend %s %s\n",
-			v[XS_WATCH_PATH], xenbus_strstate(backend_state));
+	       path, xenbus_strstate(backend_state));
 	wake_up(&backend_state_wq);
 }
 
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 4c49d8709765..ebc768f44abe 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -64,8 +64,8 @@ struct xs_stored_msg {
 		/* Queued watch events. */
 		struct {
 			struct xenbus_watch *handle;
-			char **vec;
-			unsigned int vec_size;
+			const char *path;
+			const char *token;
 		} watch;
 	} u;
 };
@@ -765,7 +765,7 @@ void unregister_xenbus_watch(struct xenbus_watch *watch)
 		if (msg->u.watch.handle != watch)
 			continue;
 		list_del(&msg->list);
-		kfree(msg->u.watch.vec);
+		kfree(msg->u.watch.path);
 		kfree(msg);
 	}
 	spin_unlock(&watch_events_lock);
@@ -833,11 +833,10 @@ static int xenwatch_thread(void *unused)
 
 		if (ent != &watch_events) {
 			msg = list_entry(ent, struct xs_stored_msg, list);
-			msg->u.watch.handle->callback(
-				msg->u.watch.handle,
-				(const char **)msg->u.watch.vec,
-				msg->u.watch.vec_size);
-			kfree(msg->u.watch.vec);
+			msg->u.watch.handle->callback(msg->u.watch.handle,
+						      msg->u.watch.path,
+						      msg->u.watch.token);
+			kfree(msg->u.watch.path);
 			kfree(msg);
 		}
 
@@ -903,24 +902,24 @@ static int process_msg(void)
 	body[msg->hdr.len] = '\0';
 
 	if (msg->hdr.type == XS_WATCH_EVENT) {
-		msg->u.watch.vec = split(body, msg->hdr.len,
-					 &msg->u.watch.vec_size);
-		if (IS_ERR(msg->u.watch.vec)) {
-			err = PTR_ERR(msg->u.watch.vec);
+		if (count_strings(body, msg->hdr.len) != 2) {
+			err = -EINVAL;
 			kfree(msg);
+			kfree(body);
 			goto out;
 		}
+		msg->u.watch.path = (const char *)body;
+		msg->u.watch.token = (const char *)strchr(body, '\0') + 1;
 
 		spin_lock(&watches_lock);
-		msg->u.watch.handle = find_watch(
-			msg->u.watch.vec[XS_WATCH_TOKEN]);
+		msg->u.watch.handle = find_watch(msg->u.watch.token);
 		if (msg->u.watch.handle != NULL) {
 			spin_lock(&watch_events_lock);
 			list_add_tail(&msg->list, &watch_events);
 			wake_up(&watch_events_waitq);
 			spin_unlock(&watch_events_lock);
 		} else {
-			kfree(msg->u.watch.vec);
+			kfree(body);
 			kfree(msg);
 		}
 		spin_unlock(&watches_lock);