[PATCH] epca: prevent panic on tty_register_driver() failure

Make epca fail on initialization failure instead of panic.

Cc: "Digi International, Inc" <Eng.Linux@digi.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Scott Kilau <scottk@digi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/char/epca.c

@@ -1157,6 +1157,7 @@ static int __init pc_init(void)
 	int crd;
 	struct board_info *bd;
 	unsigned char board_id = 0;
+	int err = -ENOMEM;
 
 	int pci_boards_found, pci_count;
 
@@ -1164,13 +1165,11 @@ static int __init pc_init(void)
 
 	pc_driver = alloc_tty_driver(MAX_ALLOC);
 	if (!pc_driver)
-		return -ENOMEM;
+		goto out1;
 
 	pc_info = alloc_tty_driver(MAX_ALLOC);
-	if (!pc_info) {
-		put_tty_driver(pc_driver);
-		return -ENOMEM;
-	}
+	if (!pc_info)
+		goto out2;
 
 	/* -----------------------------------------------------------------------
 		If epca_setup has not been ran by LILO set num_cards to defaults; copy
@@ -1370,11 +1369,17 @@ static int __init pc_init(void)
 
 	} /* End for each card */
 
-	if (tty_register_driver(pc_driver))
-		panic("Couldn't register Digi PC/ driver");
+	err = tty_register_driver(pc_driver);
+	if (err) {
+		printk(KERN_ERR "Couldn't register Digi PC/ driver");
+		goto out3;
+	}
 
-	if (tty_register_driver(pc_info))
-		panic("Couldn't register Digi PC/ info ");
+	err = tty_register_driver(pc_info);
+	if (err) {
+		printk(KERN_ERR "Couldn't register Digi PC/ info ");
+		goto out4;
+	}
 
 	/* -------------------------------------------------------------------
 	   Start up the poller to check for events on all enabled boards
@@ -1385,6 +1390,15 @@ static int __init pc_init(void)
 	mod_timer(&epca_timer, jiffies + HZ/25);
 	return 0;
 
+out4:
+	tty_unregister_driver(pc_driver);
+out3:
+	put_tty_driver(pc_info);
+out2:
+	put_tty_driver(pc_driver);
+out1:
+	return err;
+
 } /* End pc_init */
 
 /* ------------------ Begin post_fep_init  ---------------------- */