[PATCH] tty_driver refcounting

drivers/char/pty.c converted to dynamic allocation

diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index b1cd8070771e1828b5380b8f3e3e719b20444724..f91f50897543f6fa7804732dd053f0765c42ccbd 100644 (file)
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -31,24 +31,12 @@
 #include <asm/bitops.h>
 #include <linux/devpts_fs.h>
 
-struct pty_struct {
-       int     magic;
-       wait_queue_head_t open_wait;
-};
-
-#define PTY_MAGIC 0x5001
-
-static struct tty_driver pty_driver, pty_slave_driver;
-
-/* Note: one set of tables for BSD and one for Unix98 */
-static struct pty_struct pty_state[NR_PTYS];
+static struct tty_driver *pty_driver, *pty_slave_driver;
 
 #ifdef CONFIG_UNIX98_PTYS
 /* These are global because they are accessed in tty_io.c */
-struct tty_driver ptm_driver;
-struct tty_driver pts_driver;
-
-static struct pty_struct ptm_state[UNIX98_NR_MAJORS*NR_PTYS];
+struct tty_driver *ptm_driver;
+struct tty_driver *pts_driver;
 #endif
 
 static void pty_close(struct tty_struct * tty, struct file * filp)
@@ -74,7 +62,7 @@ static void pty_close(struct tty_struct * tty, struct file * filp)
        if (tty->driver->subtype == PTY_TYPE_MASTER) {
                set_bit(TTY_OTHER_CLOSED, &tty->flags);
 #ifdef CONFIG_UNIX98_PTYS
-               if (tty->driver == &ptm_driver)
+               if (tty->driver == ptm_driver)
                        devpts_pty_kill(tty->index);
 #endif
                tty_vhangup(tty->link);
@@ -287,16 +275,10 @@ static void pty_flush_buffer(struct tty_struct *tty)
 
 static int pty_open(struct tty_struct *tty, struct file * filp)
 {
-       int     retval;
-       int     line;
-       struct  pty_struct *pty;
+       int     retval = -ENODEV;
 
-       retval = -ENODEV;
        if (!tty || !tty->link)
                goto out;
-       line = tty->index;
-       pty = (struct pty_struct *)(tty->driver->driver_state) + line;
-       tty->driver_data = pty;
 
        retval = -EIO;
        if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
@@ -307,7 +289,6 @@ static int pty_open(struct tty_struct *tty, struct file * filp)
                goto out;
 
        clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
-       wake_up_interruptible(&pty->open_wait);
        set_bit(TTY_THROTTLED, &tty->flags);
        set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
        retval = 0;
@@ -321,105 +302,114 @@ static void pty_set_termios(struct tty_struct *tty, struct termios *old_termios)
         tty->termios->c_cflag |= (CS8 | CREAD);
 }
 
+static struct tty_operations pty_ops = {
+       .open = pty_open,
+       .close = pty_close,
+       .write = pty_write,
+       .write_room = pty_write_room,
+       .flush_buffer = pty_flush_buffer,
+       .chars_in_buffer = pty_chars_in_buffer,
+       .unthrottle = pty_unthrottle,
+       .set_termios = pty_set_termios,
+};
+
 int __init pty_init(void)
 {
-       int i;
-
        /* Traditional BSD devices */
 
-       memset(&pty_state, 0, sizeof(pty_state));
-       for (i = 0; i < NR_PTYS; i++)
-               init_waitqueue_head(&pty_state[i].open_wait);
-       memset(&pty_driver, 0, sizeof(struct tty_driver));
-       pty_driver.magic = TTY_DRIVER_MAGIC;
-       pty_driver.owner = THIS_MODULE;
-       pty_driver.driver_name = "pty_master";
-       pty_driver.name = "pty";
-       pty_driver.devfs_name = "pty/m";
-       pty_driver.major = PTY_MASTER_MAJOR;
-       pty_driver.minor_start = 0;
-       pty_driver.num = NR_PTYS;
-       pty_driver.type = TTY_DRIVER_TYPE_PTY;
-       pty_driver.subtype = PTY_TYPE_MASTER;
-       pty_driver.init_termios = tty_std_termios;
-       pty_driver.init_termios.c_iflag = 0;
-       pty_driver.init_termios.c_oflag = 0;
-       pty_driver.init_termios.c_cflag = B38400 | CS8 | CREAD;
-       pty_driver.init_termios.c_lflag = 0;
-       pty_driver.flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
-       pty_driver.driver_state = pty_state;
-       pty_driver.other = &pty_slave_driver;
-
-       pty_driver.open = pty_open;
-       pty_driver.close = pty_close;
-       pty_driver.write = pty_write;
-       pty_driver.write_room = pty_write_room;
-       pty_driver.flush_buffer = pty_flush_buffer;
-       pty_driver.chars_in_buffer = pty_chars_in_buffer;
-       pty_driver.unthrottle = pty_unthrottle;
-       pty_driver.set_termios = pty_set_termios;
-
-       pty_slave_driver = pty_driver;
-       pty_slave_driver.driver_name = "pty_slave";
-       pty_slave_driver.proc_entry = 0;
-       pty_slave_driver.name = "ttyp";
-       pty_slave_driver.devfs_name = "pty/s";
-       pty_slave_driver.subtype = PTY_TYPE_SLAVE;
-       pty_slave_driver.major = PTY_SLAVE_MAJOR;
-       pty_slave_driver.minor_start = 0;
-       pty_slave_driver.init_termios = tty_std_termios;
-       pty_slave_driver.init_termios.c_cflag = B38400 | CS8 | CREAD;
-       /* Slave ptys are registered when their corresponding master pty
-        * is opened, and unregistered when the pair is closed.
-        */
-       pty_slave_driver.flags |= TTY_DRIVER_NO_DEVFS;
-       pty_slave_driver.driver_state = pty_state;
-       pty_slave_driver.other = &pty_driver;
-
-       if (tty_register_driver(&pty_driver))
+       pty_driver = alloc_tty_driver(NR_PTYS);
+       if (!pty_driver)
+               panic("Couldn't allocate pty driver");
+
+       pty_slave_driver = alloc_tty_driver(NR_PTYS);
+       if (!pty_slave_driver)
+               panic("Couldn't allocate pty slave driver");
+
+       pty_driver->owner = THIS_MODULE;
+       pty_driver->driver_name = "pty_master";
+       pty_driver->name = "pty";
+       pty_driver->devfs_name = "pty/m";
+       pty_driver->major = PTY_MASTER_MAJOR;
+       pty_driver->minor_start = 0;
+       pty_driver->type = TTY_DRIVER_TYPE_PTY;
+       pty_driver->subtype = PTY_TYPE_MASTER;
+       pty_driver->init_termios = tty_std_termios;
+       pty_driver->init_termios.c_iflag = 0;
+       pty_driver->init_termios.c_oflag = 0;
+       pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
+       pty_driver->init_termios.c_lflag = 0;
+       pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
+       pty_driver->other = pty_slave_driver;
+       tty_set_operations(pty_driver, &pty_ops);
+       pty_driver->ioctl = pty_bsd_ioctl;
+
+       pty_slave_driver->owner = THIS_MODULE;
+       pty_slave_driver->driver_name = "pty_slave";
+       pty_slave_driver->name = "ttyp";
+       pty_slave_driver->devfs_name = "pty/s";
+       pty_slave_driver->major = PTY_SLAVE_MAJOR;
+       pty_slave_driver->minor_start = 0;
+       pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
+       pty_slave_driver->subtype = PTY_TYPE_SLAVE;
+       pty_slave_driver->init_termios = tty_std_termios;
+       pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
+       pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
+                       TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
+       pty_slave_driver->other = pty_driver;
+       tty_set_operations(pty_slave_driver, &pty_ops);
+
+       if (tty_register_driver(pty_driver))
                panic("Couldn't register pty driver");
-       if (tty_register_driver(&pty_slave_driver))
+       if (tty_register_driver(pty_slave_driver))
                panic("Couldn't register pty slave driver");
 
-       /* 
-        * only the master pty gets this ioctl (which is why we
-        * assign it here, instead of up with the rest of the
-        * pty_driver initialization. <cananian@alumni.princeton.edu>
-        */
-       pty_driver.ioctl = pty_bsd_ioctl;
 
        /* Unix98 devices */
 #ifdef CONFIG_UNIX98_PTYS
        devfs_mk_dir("pts");
        printk("pty: %d Unix98 ptys configured\n", UNIX98_NR_MAJORS*NR_PTYS);
-       ptm_driver = pty_driver;
-       ptm_driver.name = "ptm";
-       ptm_driver.proc_entry = 0;
-       ptm_driver.major = UNIX98_PTY_MASTER_MAJOR;
-       ptm_driver.minor_start = 0;
-       ptm_driver.num = UNIX98_NR_MAJORS * NR_PTYS;
-       ptm_driver.other = &pts_driver;
-       ptm_driver.flags |= TTY_DRIVER_NO_DEVFS;
-       ptm_driver.driver_state = ptm_state;
-
-       for (i = 0; i < UNIX98_NR_MAJORS*NR_PTYS; i++)
-               init_waitqueue_head(&ptm_state[i].open_wait);
-       
-       pts_driver = pty_slave_driver;
-       pts_driver.name = "pts";
-       pts_driver.proc_entry = 0;
-       pts_driver.major = UNIX98_PTY_SLAVE_MAJOR;
-       pts_driver.minor_start = 0;
-       pts_driver.num = UNIX98_NR_MAJORS * NR_PTYS;
-       pts_driver.other = &ptm_driver;
-       pts_driver.flags |= TTY_DRIVER_NO_DEVFS;
-       pts_driver.driver_state = ptm_state;
-       
-       ptm_driver.ioctl = pty_unix98_ioctl;
+       ptm_driver = alloc_tty_driver(UNIX98_NR_MAJORS * NR_PTYS);
+       if (!ptm_driver)
+               panic("Couldn't allocate Unix98 ptm driver");
+       pts_driver = alloc_tty_driver(UNIX98_NR_MAJORS * NR_PTYS);
+       if (!pts_driver)
+               panic("Couldn't allocate Unix98 pts driver");
+
+       ptm_driver->owner = THIS_MODULE;
+       ptm_driver->driver_name = "pty_master";
+       ptm_driver->name = "ptm";
+       ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
+       ptm_driver->minor_start = 0;
+       ptm_driver->type = TTY_DRIVER_TYPE_PTY;
+       ptm_driver->subtype = PTY_TYPE_MASTER;
+       ptm_driver->init_termios = tty_std_termios;
+       ptm_driver->init_termios.c_iflag = 0;
+       ptm_driver->init_termios.c_oflag = 0;
+       ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
+       ptm_driver->init_termios.c_lflag = 0;
+       ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
+                               TTY_DRIVER_NO_DEVFS;
+       ptm_driver->other = pts_driver;
+       tty_set_operations(ptm_driver, &pty_ops);
+       ptm_driver->ioctl = pty_unix98_ioctl;
+
+       pts_driver->owner = THIS_MODULE;
+       pts_driver->driver_name = "pty_slave";
+       pts_driver->name = "pts";
+       pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
+       pts_driver->minor_start = 0;
+       pts_driver->type = TTY_DRIVER_TYPE_PTY;
+       pts_driver->subtype = PTY_TYPE_SLAVE;
+       pts_driver->init_termios = tty_std_termios;
+       pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
+       pts_driver->flags = TTY_DRIVER_RESET_TERMIOS |
+                       TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
+       pts_driver->other = ptm_driver;
+       tty_set_operations(pts_driver, &pty_ops);
        
-       if (tty_register_driver(&ptm_driver))
+       if (tty_register_driver(ptm_driver))
                panic("Couldn't register Unix98 ptm driver");
-       if (tty_register_driver(&pts_driver))
+       if (tty_register_driver(pts_driver))
                panic("Couldn't register Unix98 pts driver");
 #endif
        return 0;

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 75acb3a8716739683ed01be1108f5ac75573112e..9ba999eb7454ae4061873343c6b69f4df0c48863 100644 (file)
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -126,8 +126,8 @@ LIST_HEAD(tty_drivers);                     /* linked list of tty drivers */
 struct tty_ldisc ldiscs[NR_LDISCS];    /* line disc dispatch table     */
 
 #ifdef CONFIG_UNIX98_PTYS
-extern struct tty_driver ptm_driver;   /* Unix98 pty masters; for /dev/ptmx */
-extern struct tty_driver pts_driver;   /* Unix98 pty slaves;  for /dev/ptmx */
+extern struct tty_driver *ptm_driver;  /* Unix98 pty masters; for /dev/ptmx */
+extern struct tty_driver *pts_driver;  /* Unix98 pty slaves;  for /dev/ptmx */
 #endif
 
 extern void disable_early_printk(void);
@@ -1349,14 +1349,14 @@ retry_open:
 #ifdef CONFIG_UNIX98_PTYS
                /* find a device that is not in use. */
                retval = -1;
-               driver = &ptm_driver;
+               driver = ptm_driver;
                for (index = 0; index < driver->num ; index++)
                        if (!init_dev(driver, index, &tty))
                                goto ptmx_found; /* ok! */
                return -EIO; /* no free ptys */
        ptmx_found:
                set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
-               devpts_pty_new(index, MKDEV(pts_driver.major, pts_driver.minor_start) + index);
+               devpts_pty_new(index, MKDEV(pts_driver->major, pts_driver->minor_start) + index);
                noctty = 1;
 #else
                return -ENODEV;