From f34d7a5b7010b82fe97da95496b9971435530062 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Wed, 30 Apr 2008 00:54:13 -0700 Subject: tty: The big operations rework - Operations are now a shared const function block as with most other Linux objects - Introduce wrappers for some optional functions to get consistent behaviour - Wrap put_char which used to be patched by the tty layer - Document which functions are needed/optional - Make put_char report success/fail - Cache the driver->ops pointer in the tty as tty->ops - Remove various surplus lock calls we no longer need - Remove proc_write method as noted by Alexey Dobriyan - Introduce some missing sanity checks where certain driver/ldisc combinations would oops as they didn't check needed methods were present [akpm@linux-foundation.org: fix fs/compat_ioctl.c build] [akpm@linux-foundation.org: fix isicom] [akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build] [akpm@linux-foundation.org: fix kgdb] Signed-off-by: Alan Cox Acked-by: Greg Kroah-Hartman Cc: Jason Wessel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/tty_io.c | 174 +++++++++++++++++++++----------------------------- 1 file changed, 72 insertions(+), 102 deletions(-) (limited to 'drivers/char/tty_io.c') diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index b1692afd797e..f69fb8d7a680 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1108,8 +1108,8 @@ restart: a reference to the old ldisc. If we ended up flipping back to the existing ldisc we have two references to it */ - if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) - tty->driver->set_ldisc(tty); + if (tty->ldisc.num != o_ldisc.num && tty->ops->set_ldisc) + tty->ops->set_ldisc(tty); tty_ldisc_put(o_ldisc.num); @@ -1181,9 +1181,8 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line) if (*str == '\0') str = NULL; - if (tty_line >= 0 && tty_line <= p->num && p->poll_init && - !p->poll_init(p, tty_line, str)) { - + if (tty_line >= 0 && tty_line <= p->num && p->ops && + p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) { res = p; *line = tty_line; break; @@ -1452,8 +1451,7 @@ static void do_tty_hangup(struct work_struct *work) /* We may have no line discipline at this point */ if (ld->flush_buffer) ld->flush_buffer(tty); - if (tty->driver->flush_buffer) - tty->driver->flush_buffer(tty); + tty_driver_flush_buffer(tty); if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && ld->write_wakeup) ld->write_wakeup(tty); @@ -1516,11 +1514,11 @@ static void do_tty_hangup(struct work_struct *work) * So we just call close() the right number of times. */ if (cons_filp) { - if (tty->driver->close) + if (tty->ops->close) for (n = 0; n < closecount; n++) - tty->driver->close(tty, cons_filp); - } else if (tty->driver->hangup) - (tty->driver->hangup)(tty); + tty->ops->close(tty, cons_filp); + } else if (tty->ops->hangup) + (tty->ops->hangup)(tty); /* * We don't want to have driver/ldisc interactions beyond * the ones we did here. The driver layer expects no @@ -1752,8 +1750,8 @@ void stop_tty(struct tty_struct *tty) wake_up_interruptible(&tty->link->read_wait); } spin_unlock_irqrestore(&tty->ctrl_lock, flags); - if (tty->driver->stop) - (tty->driver->stop)(tty); + if (tty->ops->stop) + (tty->ops->stop)(tty); } EXPORT_SYMBOL(stop_tty); @@ -1786,8 +1784,8 @@ void start_tty(struct tty_struct *tty) wake_up_interruptible(&tty->link->read_wait); } spin_unlock_irqrestore(&tty->ctrl_lock, flags); - if (tty->driver->start) - (tty->driver->start)(tty); + if (tty->ops->start) + (tty->ops->start)(tty); /* If we have a running line discipline it may need kicking */ tty_wakeup(tty); } @@ -1972,10 +1970,13 @@ static ssize_t tty_write(struct file *file, const char __user *buf, tty = (struct tty_struct *)file->private_data; if (tty_paranoia_check(tty, inode, "tty_write")) return -EIO; - if (!tty || !tty->driver->write || + if (!tty || !tty->ops->write || (test_bit(TTY_IO_ERROR, &tty->flags))) return -EIO; - + /* Short term debug to catch buggy drivers */ + if (tty->ops->write_room == NULL) + printk(KERN_ERR "tty driver %s lacks a write_room method.\n", + tty->driver->name); ld = tty_ldisc_ref_wait(tty); if (!ld->write) ret = -EIO; @@ -2122,6 +2123,7 @@ static int init_dev(struct tty_driver *driver, int idx, goto fail_no_mem; initialize_tty_struct(tty); tty->driver = driver; + tty->ops = driver->ops; tty->index = idx; tty_line_name(driver, idx, tty->name); @@ -2152,6 +2154,7 @@ static int init_dev(struct tty_driver *driver, int idx, goto free_mem_out; initialize_tty_struct(o_tty); o_tty->driver = driver->other; + o_tty->ops = driver->ops; o_tty->index = idx; tty_line_name(driver->other, idx, o_tty->name); @@ -2456,8 +2459,8 @@ static void release_dev(struct file *filp) } } #endif - if (tty->driver->close) - tty->driver->close(tty, filp); + if (tty->ops->close) + tty->ops->close(tty, filp); /* * Sanity check: if tty->count is going to zero, there shouldn't be @@ -2740,8 +2743,8 @@ got_driver: printk(KERN_DEBUG "opening %s...", tty->name); #endif if (!retval) { - if (tty->driver->open) - retval = tty->driver->open(tty, filp); + if (tty->ops->open) + retval = tty->ops->open(tty, filp); else retval = -ENODEV; } @@ -2840,7 +2843,7 @@ static int ptmx_open(struct inode *inode, struct file *filp) goto out1; check_tty_count(tty, "tty_open"); - retval = ptm_driver->open(tty, filp); + retval = ptm_driver->ops->open(tty, filp); if (!retval) return 0; out1: @@ -3336,25 +3339,20 @@ static int tiocsetd(struct tty_struct *tty, int __user *p) static int send_break(struct tty_struct *tty, unsigned int duration) { - int retval = -EINTR; - - lock_kernel(); if (tty_write_lock(tty, 0) < 0) - goto out; - tty->driver->break_ctl(tty, -1); + return -EINTR; + tty->ops->break_ctl(tty, -1); if (!signal_pending(current)) msleep_interruptible(duration); - tty->driver->break_ctl(tty, 0); + tty->ops->break_ctl(tty, 0); tty_write_unlock(tty); if (!signal_pending(current)) - retval = 0; -out: - unlock_kernel(); - return retval; + return -EINTR; + return 0; } /** - * tiocmget - get modem status + * tty_tiocmget - get modem status * @tty: tty device * @file: user file pointer * @p: pointer to result @@ -3369,10 +3367,8 @@ static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p { int retval = -EINVAL; - if (tty->driver->tiocmget) { - lock_kernel(); - retval = tty->driver->tiocmget(tty, file); - unlock_kernel(); + if (tty->ops->tiocmget) { + retval = tty->ops->tiocmget(tty, file); if (retval >= 0) retval = put_user(retval, p); @@ -3381,7 +3377,7 @@ static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p } /** - * tiocmset - set modem status + * tty_tiocmset - set modem status * @tty: tty device * @file: user file pointer * @cmd: command - clear bits, set bits or set all @@ -3398,7 +3394,7 @@ static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int { int retval = -EINVAL; - if (tty->driver->tiocmset) { + if (tty->ops->tiocmset) { unsigned int set, clear, val; retval = get_user(val, p); @@ -3422,9 +3418,7 @@ static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; - lock_kernel(); - retval = tty->driver->tiocmset(tty, file, set, clear); - unlock_kernel(); + retval = tty->ops->tiocmset(tty, file, set, clear); } return retval; } @@ -3455,23 +3449,25 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) retval = -EINVAL; - if (!tty->driver->break_ctl) { + if (!tty->ops->break_ctl) { switch (cmd) { case TIOCSBRK: case TIOCCBRK: - if (tty->driver->ioctl) - retval = tty->driver->ioctl(tty, file, cmd, arg); + if (tty->ops->ioctl) + retval = tty->ops->ioctl(tty, file, cmd, arg); + if (retval != -EINVAL && retval != -ENOIOCTLCMD) + printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name); return retval; /* These two ioctl's always return success; even if */ /* the driver doesn't support them. */ case TCSBRK: case TCSBRKP: - if (!tty->driver->ioctl) + if (!tty->ops->ioctl) return 0; - lock_kernel(); - retval = tty->driver->ioctl(tty, file, cmd, arg); - unlock_kernel(); + retval = tty->ops->ioctl(tty, file, cmd, arg); + if (retval != -EINVAL && retval != -ENOIOCTLCMD) + printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name); if (retval == -ENOIOCTLCMD) retval = 0; return retval; @@ -3491,9 +3487,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if (retval) return retval; if (cmd != TIOCCBRK) { - lock_kernel(); tty_wait_until_sent(tty, 0); - unlock_kernel(); if (signal_pending(current)) return -EINTR; } @@ -3531,7 +3525,6 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case TIOCGSID: return tiocgsid(tty, real_tty, p); case TIOCGETD: - /* FIXME: check this is ok */ return put_user(tty->ldisc.num, (int __user *)p); case TIOCSETD: return tiocsetd(tty, p); @@ -3543,15 +3536,13 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) * Break handling */ case TIOCSBRK: /* Turn break on, unconditionally */ - lock_kernel(); - tty->driver->break_ctl(tty, -1); - unlock_kernel(); + if (tty->ops->break_ctl) + tty->ops->break_ctl(tty, -1); return 0; case TIOCCBRK: /* Turn break off, unconditionally */ - lock_kernel(); - tty->driver->break_ctl(tty, 0); - unlock_kernel(); + if (tty->ops->break_ctl) + tty->ops->break_ctl(tty, 0); return 0; case TCSBRK: /* SVID version: non-zero arg --> no break */ /* non-zero arg means wait for all output data @@ -3580,8 +3571,8 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) } break; } - if (tty->driver->ioctl) { - retval = (tty->driver->ioctl)(tty, file, cmd, arg); + if (tty->ops->ioctl) { + retval = (tty->ops->ioctl)(tty, file, cmd, arg); if (retval != -ENOIOCTLCMD) return retval; } @@ -3608,8 +3599,8 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd, if (tty_paranoia_check(tty, inode, "tty_ioctl")) return -EINVAL; - if (tty->driver->compat_ioctl) { - retval = (tty->driver->compat_ioctl)(tty, file, cmd, arg); + if (tty->ops->compat_ioctl) { + retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg); if (retval != -ENOIOCTLCMD) return retval; } @@ -3659,8 +3650,7 @@ void __do_SAK(struct tty_struct *tty) tty_ldisc_flush(tty); - if (tty->driver->flush_buffer) - tty->driver->flush_buffer(tty); + tty_driver_flush_buffer(tty); read_lock(&tasklist_lock); /* Kill the entire session */ @@ -3871,15 +3861,27 @@ static void initialize_tty_struct(struct tty_struct *tty) INIT_WORK(&tty->SAK_work, do_SAK_work); } -/* - * The default put_char routine if the driver did not define one. +/** + * tty_put_char - write one character to a tty + * @tty: tty + * @ch: character + * + * Write one byte to the tty using the provided put_char method + * if present. Returns the number of characters successfully output. + * + * Note: the specific put_char operation in the driver layer may go + * away soon. Don't call it directly, use this method */ -static void tty_default_put_char(struct tty_struct *tty, unsigned char ch) +int tty_put_char(struct tty_struct *tty, unsigned char ch) { - tty->driver->write(tty, &ch, 1); + if (tty->ops->put_char) + return tty->ops->put_char(tty, ch); + return tty->ops->write(tty, &ch, 1); } +EXPORT_SYMBOL_GPL(tty_put_char); + static struct class *tty_class; /** @@ -3962,37 +3964,8 @@ void put_tty_driver(struct tty_driver *driver) void tty_set_operations(struct tty_driver *driver, const struct tty_operations *op) { - driver->open = op->open; - driver->close = op->close; - driver->write = op->write; - driver->put_char = op->put_char; - driver->flush_chars = op->flush_chars; - driver->write_room = op->write_room; - driver->chars_in_buffer = op->chars_in_buffer; - driver->ioctl = op->ioctl; - driver->compat_ioctl = op->compat_ioctl; - driver->set_termios = op->set_termios; - driver->throttle = op->throttle; - driver->unthrottle = op->unthrottle; - driver->stop = op->stop; - driver->start = op->start; - driver->hangup = op->hangup; - driver->break_ctl = op->break_ctl; - driver->flush_buffer = op->flush_buffer; - driver->set_ldisc = op->set_ldisc; - driver->wait_until_sent = op->wait_until_sent; - driver->send_xchar = op->send_xchar; - driver->read_proc = op->read_proc; - driver->write_proc = op->write_proc; - driver->tiocmget = op->tiocmget; - driver->tiocmset = op->tiocmset; -#ifdef CONFIG_CONSOLE_POLL - driver->poll_init = op->poll_init; - driver->poll_get_char = op->poll_get_char; - driver->poll_put_char = op->poll_put_char; -#endif -} - + driver->ops = op; +}; EXPORT_SYMBOL(alloc_tty_driver); EXPORT_SYMBOL(put_tty_driver); @@ -4055,9 +4028,6 @@ int tty_register_driver(struct tty_driver *driver) return error; } - if (!driver->put_char) - driver->put_char = tty_default_put_char; - mutex_lock(&tty_mutex); list_add(&driver->tty_drivers, &tty_drivers); mutex_unlock(&tty_mutex); -- cgit v1.2.2