1 files changed, 23 insertions, 14 deletions

diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index 1a8d6591c20..015209a9881 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -485,6 +485,7 @@ static int setup_one_line(struct line *lines, int n, char *init,
                           const struct chan_opts *opts, char **error_out)
 {
         struct line *line = &lines[n];
+        struct tty_driver *driver = line->driver->driver;
         int err = -EINVAL;
 
         mutex_lock(&line->count_lock);
@@ -498,6 +499,7 @@ static int setup_one_line(struct line *lines, int n, char *init,
                 if (line->valid) {
                         line->valid = 0;
                         kfree(line->init_str);
+                        tty_unregister_device(driver, n);
                         parse_chan_pair(NULL, line, n, opts, error_out);
                         err = 0;
                 }
@@ -507,9 +509,19 @@ static int setup_one_line(struct line *lines, int n, char *init,
                         *error_out = "Failed to allocate memory";
                         return -ENOMEM;
                 }
+                if (line->valid)
+                        tty_unregister_device(driver, n);
                 line->init_str = new;
                 line->valid = 1;
                 err = parse_chan_pair(new, line, n, opts, error_out);
+                if (!err) {
+                        struct device *d = tty_register_device(driver, n, NULL);
+                        if (IS_ERR(d)) {
+                                *error_out = "Failed to register device";
+                                err = PTR_ERR(d);
+                                parse_chan_pair(NULL, line, n, opts, error_out);
+                        }
+                }
                 if (err) {
                         line->init_str = NULL;
                         line->valid = 0;
@@ -640,15 +652,15 @@ int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
         return setup_one_line(lines, n, "none", NULL, error_out);
 }
 
-struct tty_driver *register_lines(struct line_driver *line_driver,
-                                  const struct tty_operations *ops,
-                                  struct line *lines, int nlines)
+int register_lines(struct line_driver *line_driver,
+                   const struct tty_operations *ops,
+                   struct line *lines, int nlines)
 {
-        int i;
         struct tty_driver *driver = alloc_tty_driver(nlines);
+        int err;
 
         if (!driver)
-                return NULL;
+                return -ENOMEM;
 
         driver->driver_name = line_driver->name;
         driver->name = line_driver->device_name;
@@ -656,24 +668,21 @@ struct tty_driver *register_lines(struct line_driver *line_driver,
         driver->minor_start = line_driver->minor_start;
         driver->type = line_driver->type;
         driver->subtype = line_driver->subtype;
-        driver->flags = TTY_DRIVER_REAL_RAW;
+        driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
         driver->init_termios = tty_std_termios;
         tty_set_operations(driver, ops);
 
-        if (tty_register_driver(driver)) {
+        err = tty_register_driver(driver);
+        if (err) {
                 printk(KERN_ERR "register_lines : can't register %s driver\n",
                        line_driver->name);
                 put_tty_driver(driver);
-                return NULL;
-        }
-
-        for(i = 0; i < nlines; i++) {
-                if (!lines[i].valid)
-                        tty_unregister_device(driver, i);
+                return err;
         }
 
+        line_driver->driver = driver;
         mconsole_register_dev(&line_driver->mc);
-        return driver;
+        return 0;
 }
 
 static DEFINE_SPINLOCK(winch_handler_lock);