Merge tag 'for-linus-4.9-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from David Vrabel:

 - advertise control feature flags in xenstore

 - fix x86 build when XEN_PVHVM is disabled

* tag 'for-linus-4.9-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xenbus: check return value of xenbus_scanf()
  xenbus: prefer list_for_each()
  x86: xen: move cpu_up functions out of ifdef
  xenbus: advertise control feature flags

3 files changed, 34 insertions, 19 deletions

diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index e12bd3635f83..26e5e8507f03 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -168,7 +168,9 @@ out:
 #endif  /* CONFIG_HIBERNATE_CALLBACKS */
 
 struct shutdown_handler {
-        const char *command;
+#define SHUTDOWN_CMD_SIZE 11
+        const char command[SHUTDOWN_CMD_SIZE];
+        bool flag;
         void (*cb)(void);
 };
 
@@ -206,22 +208,22 @@ static void do_reboot(void)
         ctrl_alt_del();
 }
 
+static struct shutdown_handler shutdown_handlers[] = {
+        { "poweroff",   true,   do_poweroff },
+        { "halt",       false,  do_poweroff },
+        { "reboot",     true,   do_reboot   },
+#ifdef CONFIG_HIBERNATE_CALLBACKS
+        { "suspend",    true,   do_suspend  },
+#endif
+};
+
 static void shutdown_handler(struct xenbus_watch *watch,
                              const char **vec, unsigned int len)
 {
         char *str;
         struct xenbus_transaction xbt;
         int err;
-        static struct shutdown_handler handlers[] = {
-                { "poweroff",   do_poweroff },
-                { "halt",       do_poweroff },
-                { "reboot",     do_reboot   },
-#ifdef CONFIG_HIBERNATE_CALLBACKS
-                { "suspend",    do_suspend  },
-#endif
-                {NULL, NULL},
-        };
-        static struct shutdown_handler *handler;
+        int idx;
 
         if (shutting_down != SHUTDOWN_INVALID)
                 return;
@@ -238,13 +240,13 @@ static void shutdown_handler(struct xenbus_watch *watch,
                 return;
         }
 
-        for (handler = &handlers[0]; handler->command; handler++) {
-                if (strcmp(str, handler->command) == 0)
+        for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
+                if (strcmp(str, shutdown_handlers[idx].command) == 0)
                         break;
         }
 
         /* Only acknowledge commands which we are prepared to handle. */
-        if (handler->cb)
+        if (idx < ARRAY_SIZE(shutdown_handlers))
                 xenbus_write(xbt, "control", "shutdown", "");
 
         err = xenbus_transaction_end(xbt, 0);
@@ -253,8 +255,8 @@ static void shutdown_handler(struct xenbus_watch *watch,
                 goto again;
         }
 
-        if (handler->cb) {
-                handler->cb();
+        if (idx < ARRAY_SIZE(shutdown_handlers)) {
+                shutdown_handlers[idx].cb();
         } else {
                 pr_info("Ignoring shutdown request: %s\n", str);
                 shutting_down = SHUTDOWN_INVALID;
@@ -310,6 +312,9 @@ static struct notifier_block xen_reboot_nb = {
 static int setup_shutdown_watcher(void)
 {
         int err;
+        int idx;
+#define FEATURE_PATH_SIZE (SHUTDOWN_CMD_SIZE + sizeof("feature-"))
+        char node[FEATURE_PATH_SIZE];
 
         err = register_xenbus_watch(&shutdown_watch);
         if (err) {
@@ -326,6 +331,14 @@ static int setup_shutdown_watcher(void)
         }
 #endif
 
+        for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
+                if (!shutdown_handlers[idx].flag)
+                        continue;
+                snprintf(node, FEATURE_PATH_SIZE, "feature-%s",
+                         shutdown_handlers[idx].command);
+                xenbus_printf(XBT_NIL, "control", node, "%u", 1);
+        }
+
         return 0;
 }
 
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index c1010f018bd8..1e8be12ebb55 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -364,7 +364,7 @@ out:
 
 static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u)
 {
-        struct watch_adapter *watch, *tmp_watch;
+        struct watch_adapter *watch;
         char *path, *token;
         int err, rc;
         LIST_HEAD(staging_q);
@@ -399,7 +399,7 @@ static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u)
                 }
                 list_add(&watch->list, &u->watches);
         } else {
-                list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) {
+                list_for_each_entry(watch, &u->watches, list) {
                         if (!strcmp(watch->token, token) &&
                             !strcmp(watch->watch.node, path)) {
                                 unregister_xenbus_watch(&watch->watch);
diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index 611a23119675..6d40a972ffb2 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -335,7 +335,9 @@ static int backend_state;
 static void xenbus_reset_backend_state_changed(struct xenbus_watch *w,
                                         const char **v, unsigned int l)
 {
-        xenbus_scanf(XBT_NIL, v[XS_WATCH_PATH], "", "%i", &backend_state);
+        if (xenbus_scanf(XBT_NIL, v[XS_WATCH_PATH], "", "%i",
+                         &backend_state) != 1)
+                backend_state = XenbusStateUnknown;
         printk(KERN_DEBUG "XENBUS: backend %s %s\n",
                         v[XS_WATCH_PATH], xenbus_strstate(backend_state));
         wake_up(&backend_state_wq);