[PATCH] tty_driver refcounting

drivers/char/epca.c converted to dynamic allocation

drivers/char/epca.c

@@ -97,8 +97,8 @@ static struct board_info boards[MAXBOARDS];
 
 /* ------------- Begin structures used for driver registeration ---------- */
 
-struct tty_driver pc_driver;
-struct tty_driver pc_info;
+static struct tty_driver *pc_driver;
+static struct tty_driver *pc_info;
 
 /* ------------------ Begin Digi specific structures -------------------- */
 
@@ -204,6 +204,8 @@ static void epcaparam(struct tty_struct *, struct channel *);
 static void receive_data(struct channel *);
 static int pc_ioctl(struct tty_struct *, struct file *,
                     unsigned int, unsigned long);
+static int info_ioctl(struct tty_struct *, struct file *,
+                    unsigned int, unsigned long);
 static void pc_set_termios(struct tty_struct *, struct termios *);
 static void do_softint(void *);
 static void pc_stop(struct tty_struct *);
@@ -491,12 +493,6 @@ static void pc_close(struct tty_struct * tty, struct file * filp)
 	struct channel *ch;
 	unsigned long flags;
 
-	if (tty->driver->subtype == SERIAL_TYPE_INFO) 
-	{
-		return;
-	}
-
-
 	/* ---------------------------------------------------------
 		verifyChannel returns the channel from the tty struct
 		if it is valid.  This serves as a sanity check.
@@ -704,13 +700,6 @@ static int pc_write(struct tty_struct * tty, int from_user,
 		brought into the driver.  
 	------------------------------------------------------------------- */
 
-	/* Stop users from hurting themselves on control minor */
-
-	if (tty->driver->subtype == SERIAL_TYPE_INFO) 
-	{
-		return (0) ;
-	}
-
 	/* ---------------------------------------------------------
 		verifyChannel returns the channel from the tty struct
 		if it is valid.  This serves as a sanity check.
@@ -1306,13 +1295,6 @@ static int pc_open(struct tty_struct *tty, struct file * filp)
 	volatile struct board_chan *bc;
 	volatile unsigned int head;
 
-	/* Nothing "real" happens in open of control device */
-
-	if (tty->driver->subtype == SERIAL_TYPE_INFO) 
-	{
-		return (0) ;
-	}
-
 	line = tty->index;
 	if (line < 0 || line >= nbdevs) 
 	{
@@ -1485,13 +1467,15 @@ static void __exit epca_module_exit(void)
 	save_flags(flags);
 	cli();
 
-	if ((tty_unregister_driver(&pc_driver)) ||  
-	    (tty_unregister_driver(&pc_info)))
+	if ((tty_unregister_driver(pc_driver)) ||  
+	    (tty_unregister_driver(pc_info)))
 	{
 		printk(KERN_WARNING "<Error> - DIGI : cleanup_module failed to un-register tty driver\n");
 		restore_flags(flags);
 		return;
 	}
+	put_tty_driver(pc_driver);
+	put_tty_driver(pc_info);
 
 	for (crd = 0; crd < num_cards; crd++) 
 	{ /* Begin for each card */
@@ -1529,6 +1513,34 @@ static void __exit epca_module_exit(void)
 module_exit(epca_module_exit);
 #endif /* MODULE */
 
+static struct tty_operations pc_ops = {
+	.open = pc_open,
+	.close = pc_close,
+	.write = pc_write,
+	.write_room = pc_write_room,
+	.flush_buffer = pc_flush_buffer,
+	.chars_in_buffer = pc_chars_in_buffer,
+	.flush_chars = pc_flush_chars,
+	.put_char = pc_put_char,
+	.ioctl = pc_ioctl,
+	.set_termios = pc_set_termios,
+	.stop = pc_stop,
+	.start = pc_start,
+	.throttle = pc_throttle,
+	.unthrottle = pc_unthrottle,
+	.hangup = pc_hangup,
+};
+
+static int info_open(struct tty_struct *tty, struct file * filp)
+{
+	return 0;
+}
+
+static struct tty_operations info_ops = {
+	.open = info_open,
+	.ioctl = info_ioctl,
+};
+
 /* ------------------ Begin pc_init  ---------------------- */
 
 int __init pc_init(void)
@@ -1554,13 +1566,22 @@ int __init pc_init(void)
 	struct board_info *bd;
 	unsigned char board_id = 0;
 
-
 #ifdef ENABLE_PCI
 	int pci_boards_found, pci_count;
 
 	pci_count = 0;
 #endif /* ENABLE_PCI */
 
+	pc_driver = alloc_tty_driver(MAX_ALLOC);
+	if (!pc_driver)
+		return -ENOMEM;
+
+	pc_info = alloc_tty_driver(MAX_ALLOC);
+	if (!pc_info) {
+		put_tty_driver(pc_driver);
+		return -ENOMEM;
+	}
+
 	/* -----------------------------------------------------------------------
 		If epca_setup has not been ran by LILO set num_cards to defaults; copy
 		board structure defined by digiConfig into drivers board structure.
@@ -1620,53 +1641,33 @@ int __init pc_init(void)
 
 #endif /* ENABLE_PCI */
 
-	memset(&pc_driver, 0, sizeof(struct tty_driver));
-	memset(&pc_info, 0, sizeof(struct tty_driver));
-
-	pc_driver.magic = TTY_DRIVER_MAGIC;
-	pc_driver.owner = THIS_MODULE;
-	pc_driver.name = "ttyD"; 
-	pc_driver.major = DIGI_MAJOR; 
-	pc_driver.minor_start = 0;
-	pc_driver.num = MAX_ALLOC;
-	pc_driver.type = TTY_DRIVER_TYPE_SERIAL;
-	pc_driver.subtype = SERIAL_TYPE_NORMAL;
-	pc_driver.init_termios = tty_std_termios;
-	pc_driver.init_termios.c_iflag = 0;
-	pc_driver.init_termios.c_oflag = 0;
-
-	pc_driver.init_termios.c_cflag = B9600 | CS8 | CREAD | CLOCAL | HUPCL;
-	pc_driver.init_termios.c_lflag = 0;
-	pc_driver.flags = TTY_DRIVER_REAL_RAW;
-
-	/* ------------------------------------------------------------------
-		Setup entry points for the driver.  These are primarily called by 
-		the kernel in tty_io.c and n_tty.c
-	--------------------------------------------------------------------- */
-
-	pc_driver.open = pc_open;
-	pc_driver.close = pc_close;
-	pc_driver.write = pc_write;
-	pc_driver.write_room = pc_write_room;
-	pc_driver.flush_buffer = pc_flush_buffer;
-	pc_driver.chars_in_buffer = pc_chars_in_buffer;
-	pc_driver.flush_chars = pc_flush_chars;
-	pc_driver.put_char = pc_put_char;
-	pc_driver.ioctl = pc_ioctl;
-	pc_driver.set_termios = pc_set_termios;
-	pc_driver.stop = pc_stop;
-	pc_driver.start = pc_start;
-	pc_driver.throttle = pc_throttle;
-	pc_driver.unthrottle = pc_unthrottle;
-	pc_driver.hangup = pc_hangup;
-
-	pc_info = pc_driver;
-	pc_info.name = "digi_ctl";
-	pc_info.major = DIGIINFOMAJOR;
-	pc_info.minor_start = 0;
-	pc_info.num = 1;
-	pc_info.init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
-	pc_info.subtype = SERIAL_TYPE_INFO;
+	pc_driver->owner = THIS_MODULE;
+	pc_driver->name = "ttyD"; 
+	pc_driver->major = DIGI_MAJOR; 
+	pc_driver->minor_start = 0;
+	pc_driver->type = TTY_DRIVER_TYPE_SERIAL;
+	pc_driver->subtype = SERIAL_TYPE_NORMAL;
+	pc_driver->init_termios = tty_std_termios;
+	pc_driver->init_termios.c_iflag = 0;
+	pc_driver->init_termios.c_oflag = 0;
+	pc_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | CLOCAL | HUPCL;
+	pc_driver->init_termios.c_lflag = 0;
+	pc_driver->flags = TTY_DRIVER_REAL_RAW;
+	tty_set_operations(pc_driver, &pc_ops);
+
+	pc_info->owner = THIS_MODULE;
+	pc_info->name = "digi_ctl";
+	pc_info->major = DIGIINFOMAJOR;
+	pc_info->minor_start = 0;
+	pc_info->type = TTY_DRIVER_TYPE_SERIAL;
+	pc_info->subtype = SERIAL_TYPE_INFO;
+	pc_info->init_termios = tty_std_termios;
+	pc_info->init_termios.c_iflag = 0;
+	pc_info->init_termios.c_oflag = 0;
+	pc_info->init_termios.c_lflag = 0;
+	pc_info->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
+	pc_info->flags = TTY_DRIVER_REAL_RAW;
+	tty_set_operations(pc_info, &info_ops);
 
 
 	save_flags(flags);
@@ -1791,10 +1792,10 @@ int __init pc_init(void)
 
 	} /* End for each card */
 
-	if (tty_register_driver(&pc_driver))
+	if (tty_register_driver(pc_driver))
 		panic("Couldn't register Digi PC/ driver");
 
-	if (tty_register_driver(&pc_info))
+	if (tty_register_driver(pc_info))
 		panic("Couldn't register Digi PC/ info ");
 
 	/* -------------------------------------------------------------------
@@ -2845,23 +2846,10 @@ static void receive_data(struct channel *ch)
 
 } /* End receive_data */
 
-/* --------------------- Begin pc_ioctl  ----------------------- */
-
-static int pc_ioctl(struct tty_struct *tty, struct file * file,
+static int info_ioctl(struct tty_struct *tty, struct file * file,
 		    unsigned int cmd, unsigned long arg)
-{ /* Begin pc_ioctl */
-
-	digiflow_t dflow;
-	int retval, error;
-	unsigned long flags;
-	unsigned int mflag, mstat;
-	unsigned char startc, stopc;
-	volatile struct board_chan *bc;
-	struct channel *ch = (struct channel *) tty->driver_data;
-	
-	/* The control device has it's own set of commands */
-	if (tty->driver->subtype == SERIAL_TYPE_INFO) 
-	{ /* Begin if subtype is the control device */
+{
+	int error;
 	
 	switch (cmd) 
 	{ /* Begin switch cmd */
@@ -2939,8 +2927,20 @@ static int pc_ioctl(struct tty_struct *tty, struct file * file,
 
 	} /* End switch cmd */
 	return (0) ;
+}
+/* --------------------- Begin pc_ioctl  ----------------------- */
+
+static int pc_ioctl(struct tty_struct *tty, struct file * file,
+		    unsigned int cmd, unsigned long arg)
+{ /* Begin pc_ioctl */
 
-	} /* End if subtype is the control device */
+	digiflow_t dflow;
+	int retval, error;
+	unsigned long flags;
+	unsigned int mflag, mstat;
+	unsigned char startc, stopc;
+	volatile struct board_chan *bc;
+	struct channel *ch = (struct channel *) tty->driver_data;
 	
 	if (ch)
 		bc = ch->brdchan;