mirror of https://github.com/torvalds/linux.git
tty: use lock guard()s in tty_io
guard()s and scoped_guard()s express more clearly what is protected by locks. And also makes the code cleaner as it can return immediately in case of short returns. Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20250425111315.1036184-3-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby (SUSE)
Greg Kroah-Hartman
parent
3eabc1a34b
commit
f49573f2f5
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@ -276,11 +276,10 @@ static void check_tty_count(struct tty_struct *tty, const char *routine)
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struct list_head *p;
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int count = 0, kopen_count = 0;
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spin_lock(&tty->files_lock);
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list_for_each(p, &tty->tty_files) {
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count++;
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}
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spin_unlock(&tty->files_lock);
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scoped_guard(spinlock, &tty->files_lock)
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list_for_each(p, &tty->tty_files)
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count++;
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if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
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tty->driver->subtype == PTY_TYPE_SLAVE &&
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tty->link && tty->link->count)
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@ -378,7 +377,7 @@ EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
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*/
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struct tty_driver *tty_find_polling_driver(char *name, int *line)
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{
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struct tty_driver *p, *res = NULL;
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struct tty_driver *p;
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int tty_line = 0;
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int len;
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char *str, *stp;
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@ -392,7 +391,8 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line)
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len = str - name;
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tty_line = simple_strtoul(str, &str, 10);
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mutex_lock(&tty_mutex);
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guard(mutex)(&tty_mutex);
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/* Search through the tty devices to look for a match */
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list_for_each_entry(p, &tty_drivers, tty_drivers) {
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if (!len || strncmp(name, p->name, len) != 0)
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@ -405,14 +405,12 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line)
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if (tty_line >= 0 && tty_line < p->num && p->ops &&
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p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
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res = tty_driver_kref_get(p);
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*line = tty_line;
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break;
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return tty_driver_kref_get(p);
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}
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}
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mutex_unlock(&tty_mutex);
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return res;
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return NULL;
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}
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EXPORT_SYMBOL_GPL(tty_find_polling_driver);
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#endif
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@ -531,16 +529,15 @@ EXPORT_SYMBOL_GPL(tty_wakeup);
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*/
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static struct file *tty_release_redirect(struct tty_struct *tty)
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{
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struct file *f = NULL;
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guard(spinlock)(&redirect_lock);
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spin_lock(&redirect_lock);
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if (redirect && file_tty(redirect) == tty) {
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f = redirect;
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struct file *f = redirect;
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redirect = NULL;
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return f;
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}
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spin_unlock(&redirect_lock);
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return f;
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return NULL;
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}
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/**
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@ -765,11 +762,8 @@ void __stop_tty(struct tty_struct *tty)
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*/
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void stop_tty(struct tty_struct *tty)
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{
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unsigned long flags;
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spin_lock_irqsave(&tty->flow.lock, flags);
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guard(spinlock_irqsave)(&tty->flow.lock);
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__stop_tty(tty);
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spin_unlock_irqrestore(&tty->flow.lock, flags);
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}
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EXPORT_SYMBOL(stop_tty);
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@ -796,11 +790,8 @@ void __start_tty(struct tty_struct *tty)
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*/
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void start_tty(struct tty_struct *tty)
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{
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unsigned long flags;
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spin_lock_irqsave(&tty->flow.lock, flags);
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guard(spinlock_irqsave)(&tty->flow.lock);
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__start_tty(tty);
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spin_unlock_irqrestore(&tty->flow.lock, flags);
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}
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EXPORT_SYMBOL(start_tty);
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@ -809,7 +800,8 @@ static void tty_update_time(struct tty_struct *tty, bool mtime)
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time64_t sec = ktime_get_real_seconds();
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struct tty_file_private *priv;
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spin_lock(&tty->files_lock);
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guard(spinlock)(&tty->files_lock);
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list_for_each_entry(priv, &tty->tty_files, list) {
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struct inode *inode = file_inode(priv->file);
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struct timespec64 time = mtime ? inode_get_mtime(inode) : inode_get_atime(inode);
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@ -827,7 +819,6 @@ static void tty_update_time(struct tty_struct *tty, bool mtime)
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inode_set_atime(inode, sec, 0);
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}
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}
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spin_unlock(&tty->files_lock);
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}
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/*
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@ -2314,13 +2305,12 @@ static int tiocsti(struct tty_struct *tty, u8 __user *p)
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*/
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static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
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{
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int err;
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guard(mutex)(&tty->winsize_mutex);
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mutex_lock(&tty->winsize_mutex);
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err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
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mutex_unlock(&tty->winsize_mutex);
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if (copy_to_user(arg, &tty->winsize, sizeof(*arg)))
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return -EFAULT;
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return err ? -EFAULT : 0;
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return 0;
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}
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/**
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@ -2335,10 +2325,10 @@ int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
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{
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struct pid *pgrp;
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/* Lock the tty */
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mutex_lock(&tty->winsize_mutex);
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guard(mutex)(&tty->winsize_mutex);
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if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
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goto done;
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return 0;
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/* Signal the foreground process group */
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pgrp = tty_get_pgrp(tty);
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@ -2347,8 +2337,7 @@ int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
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put_pid(pgrp);
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tty->winsize = *ws;
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done:
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mutex_unlock(&tty->winsize_mutex);
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return 0;
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}
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EXPORT_SYMBOL(tty_do_resize);
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@ -2409,13 +2398,14 @@ static int tioccons(struct file *file)
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return -EBADF;
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if (!(file->f_mode & FMODE_CAN_WRITE))
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return -EINVAL;
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spin_lock(&redirect_lock);
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if (redirect) {
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spin_unlock(&redirect_lock);
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guard(spinlock)(&redirect_lock);
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if (redirect)
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return -EBUSY;
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}
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redirect = get_file(file);
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spin_unlock(&redirect_lock);
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return 0;
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}
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@ -3028,11 +3018,9 @@ void __do_SAK(struct tty_struct *tty)
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struct task_struct *g, *p;
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struct pid *session;
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int i;
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unsigned long flags;
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spin_lock_irqsave(&tty->ctrl.lock, flags);
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session = get_pid(tty->ctrl.session);
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spin_unlock_irqrestore(&tty->ctrl.lock, flags);
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scoped_guard(spinlock_irqsave, &tty->ctrl.lock)
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session = get_pid(tty->ctrl.session);
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tty_ldisc_flush(tty);
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@ -3055,7 +3043,7 @@ void __do_SAK(struct tty_struct *tty)
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PIDTYPE_SID);
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continue;
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}
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task_lock(p);
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guard(task_lock)(p);
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i = iterate_fd(p->files, 0, this_tty, tty);
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if (i != 0) {
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tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
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@ -3063,7 +3051,6 @@ void __do_SAK(struct tty_struct *tty)
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group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
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PIDTYPE_SID);
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}
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task_unlock(p);
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}
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read_unlock(&tasklist_lock);
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put_pid(session);
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@ -3465,9 +3452,8 @@ int tty_register_driver(struct tty_driver *driver)
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goto err_unreg_char;
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}
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mutex_lock(&tty_mutex);
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list_add(&driver->tty_drivers, &tty_drivers);
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mutex_unlock(&tty_mutex);
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scoped_guard(mutex, &tty_mutex)
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list_add(&driver->tty_drivers, &tty_drivers);
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if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
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for (i = 0; i < driver->num; i++) {
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@ -3486,9 +3472,8 @@ int tty_register_driver(struct tty_driver *driver)
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for (i--; i >= 0; i--)
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tty_unregister_device(driver, i);
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mutex_lock(&tty_mutex);
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list_del(&driver->tty_drivers);
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mutex_unlock(&tty_mutex);
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scoped_guard(mutex, &tty_mutex)
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list_del(&driver->tty_drivers);
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err_unreg_char:
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unregister_chrdev_region(dev, driver->num);
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@ -3507,9 +3492,8 @@ void tty_unregister_driver(struct tty_driver *driver)
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{
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unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
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driver->num);
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mutex_lock(&tty_mutex);
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list_del(&driver->tty_drivers);
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mutex_unlock(&tty_mutex);
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scoped_guard(mutex, &tty_mutex)
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list_del(&driver->tty_drivers);
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}
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EXPORT_SYMBOL(tty_unregister_driver);
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