1 files changed, 59 insertions, 74 deletions

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 407b0d87b7c1..e2d92cf70eb7 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -276,11 +276,10 @@ static void check_tty_count(struct tty_struct *tty, const char *routine)
 	struct list_head *p;
 	int count = 0, kopen_count = 0;
 
-	spin_lock(&tty->files_lock);
-	list_for_each(p, &tty->tty_files) {
-		count++;
-	}
-	spin_unlock(&tty->files_lock);
+	scoped_guard(spinlock, &tty->files_lock)
+		list_for_each(p, &tty->tty_files)
+			count++;
+
 	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
 	    tty->driver->subtype == PTY_TYPE_SLAVE &&
 	    tty->link && tty->link->count)
@@ -350,22 +349,19 @@ int tty_dev_name_to_number(const char *name, dev_t *number)
 		return ret;
 
 	prefix_length = str - name;
-	mutex_lock(&tty_mutex);
+
+	guard(mutex)(&tty_mutex);
 
 	list_for_each_entry(p, &tty_drivers, tty_drivers)
 		if (prefix_length == strlen(p->name) && strncmp(name,
 					p->name, prefix_length) == 0) {
 			if (index < p->num) {
 				*number = MKDEV(p->major, p->minor_start + index);
-				goto out;
+				return 0;
 			}
 		}
 
-	/* if here then driver wasn't found */
-	ret = -ENODEV;
-out:
-	mutex_unlock(&tty_mutex);
-	return ret;
+	return -ENODEV;
 }
 EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
 
@@ -381,7 +377,7 @@ EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
  */
 struct tty_driver *tty_find_polling_driver(char *name, int *line)
 {
-	struct tty_driver *p, *res = NULL;
+	struct tty_driver *p;
 	int tty_line = 0;
 	int len;
 	char *str, *stp;
@@ -395,7 +391,8 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line)
 	len = str - name;
 	tty_line = simple_strtoul(str, &str, 10);
 
-	mutex_lock(&tty_mutex);
+	guard(mutex)(&tty_mutex);
+
 	/* Search through the tty devices to look for a match */
 	list_for_each_entry(p, &tty_drivers, tty_drivers) {
 		if (!len || strncmp(name, p->name, len) != 0)
@@ -408,14 +405,12 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line)
 
 		if (tty_line >= 0 && tty_line < p->num && p->ops &&
 		    p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
-			res = tty_driver_kref_get(p);
 			*line = tty_line;
-			break;
+			return tty_driver_kref_get(p);
 		}
 	}
-	mutex_unlock(&tty_mutex);
 
-	return res;
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
 #endif
@@ -462,7 +457,6 @@ static void tty_show_fdinfo(struct seq_file *m, struct file *file)
 }
 
 static const struct file_operations tty_fops = {
-	.llseek		= no_llseek,
 	.read_iter	= tty_read,
 	.write_iter	= tty_write,
 	.splice_read	= copy_splice_read,
@@ -477,7 +471,6 @@ static const struct file_operations tty_fops = {
 };
 
 static const struct file_operations console_fops = {
-	.llseek		= no_llseek,
 	.read_iter	= tty_read,
 	.write_iter	= redirected_tty_write,
 	.splice_read	= copy_splice_read,
@@ -491,7 +484,6 @@ static const struct file_operations console_fops = {
 };
 
 static const struct file_operations hung_up_tty_fops = {
-	.llseek		= no_llseek,
 	.read_iter	= hung_up_tty_read,
 	.write_iter	= hung_up_tty_write,
 	.poll		= hung_up_tty_poll,
@@ -537,16 +529,15 @@ EXPORT_SYMBOL_GPL(tty_wakeup);
  */
 static struct file *tty_release_redirect(struct tty_struct *tty)
 {
-	struct file *f = NULL;
+	guard(spinlock)(&redirect_lock);
 
-	spin_lock(&redirect_lock);
 	if (redirect && file_tty(redirect) == tty) {
-		f = redirect;
+		struct file *f = redirect;
 		redirect = NULL;
+		return f;
 	}
-	spin_unlock(&redirect_lock);
 
-	return f;
+	return NULL;
 }
 
 /**
@@ -771,11 +762,8 @@ void __stop_tty(struct tty_struct *tty)
  */
 void stop_tty(struct tty_struct *tty)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&tty->flow.lock, flags);
+	guard(spinlock_irqsave)(&tty->flow.lock);
 	__stop_tty(tty);
-	spin_unlock_irqrestore(&tty->flow.lock, flags);
 }
 EXPORT_SYMBOL(stop_tty);
 
@@ -802,11 +790,8 @@ void __start_tty(struct tty_struct *tty)
  */
 void start_tty(struct tty_struct *tty)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&tty->flow.lock, flags);
+	guard(spinlock_irqsave)(&tty->flow.lock);
 	__start_tty(tty);
-	spin_unlock_irqrestore(&tty->flow.lock, flags);
 }
 EXPORT_SYMBOL(start_tty);
 
@@ -815,7 +800,8 @@ static void tty_update_time(struct tty_struct *tty, bool mtime)
 	time64_t sec = ktime_get_real_seconds();
 	struct tty_file_private *priv;
 
-	spin_lock(&tty->files_lock);
+	guard(spinlock)(&tty->files_lock);
+
 	list_for_each_entry(priv, &tty->tty_files, list) {
 		struct inode *inode = file_inode(priv->file);
 		struct timespec64 time = mtime ? inode_get_mtime(inode) : inode_get_atime(inode);
@@ -833,7 +819,6 @@ static void tty_update_time(struct tty_struct *tty, bool mtime)
 				inode_set_atime(inode, sec, 0);
 		}
 	}
-	spin_unlock(&tty->files_lock);
 }
 
 /*
@@ -2225,6 +2210,12 @@ static int __tty_fasync(int fd, struct file *filp, int on)
 	if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
 		goto out;
 
+	if (on) {
+		retval = file_f_owner_allocate(filp);
+		if (retval)
+			goto out;
+	}
+
 	retval = fasync_helper(fd, filp, on, &tty->fasync);
 	if (retval <= 0)
 		goto out;
@@ -2314,13 +2305,12 @@ static int tiocsti(struct tty_struct *tty, u8 __user *p)
  */
 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
 {
-	int err;
+	guard(mutex)(&tty->winsize_mutex);
 
-	mutex_lock(&tty->winsize_mutex);
-	err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
-	mutex_unlock(&tty->winsize_mutex);
+	if (copy_to_user(arg, &tty->winsize, sizeof(*arg)))
+		return -EFAULT;
 
-	return err ? -EFAULT : 0;
+	return 0;
 }
 
 /**
@@ -2335,10 +2325,10 @@ int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
 {
 	struct pid *pgrp;
 
-	/* Lock the tty */
-	mutex_lock(&tty->winsize_mutex);
+	guard(mutex)(&tty->winsize_mutex);
+
 	if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
-		goto done;
+		return 0;
 
 	/* Signal the foreground process group */
 	pgrp = tty_get_pgrp(tty);
@@ -2347,8 +2337,7 @@ int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
 	put_pid(pgrp);
 
 	tty->winsize = *ws;
-done:
-	mutex_unlock(&tty->winsize_mutex);
+
 	return 0;
 }
 EXPORT_SYMBOL(tty_do_resize);
@@ -2409,13 +2398,14 @@ static int tioccons(struct file *file)
 		return -EBADF;
 	if (!(file->f_mode & FMODE_CAN_WRITE))
 		return -EINVAL;
-	spin_lock(&redirect_lock);
-	if (redirect) {
-		spin_unlock(&redirect_lock);
+
+	guard(spinlock)(&redirect_lock);
+
+	if (redirect)
 		return -EBUSY;
-	}
+
 	redirect = get_file(file);
-	spin_unlock(&redirect_lock);
+
 	return 0;
 }
 
@@ -2622,14 +2612,13 @@ static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
 
 static int tty_set_serial(struct tty_struct *tty, struct serial_struct *ss)
 {
-	char comm[TASK_COMM_LEN];
 	int flags;
 
 	flags = ss->flags & ASYNC_DEPRECATED;
 
 	if (flags)
 		pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
-				__func__, get_task_comm(comm, current), flags);
+				__func__, current->comm, flags);
 
 	if (!tty->ops->set_serial)
 		return -ENOTTY;
@@ -3029,11 +3018,9 @@ void __do_SAK(struct tty_struct *tty)
 	struct task_struct *g, *p;
 	struct pid *session;
 	int i;
-	unsigned long flags;
 
-	spin_lock_irqsave(&tty->ctrl.lock, flags);
-	session = get_pid(tty->ctrl.session);
-	spin_unlock_irqrestore(&tty->ctrl.lock, flags);
+	scoped_guard(spinlock_irqsave, &tty->ctrl.lock)
+		session = get_pid(tty->ctrl.session);
 
 	tty_ldisc_flush(tty);
 
@@ -3056,7 +3043,7 @@ void __do_SAK(struct tty_struct *tty)
 					PIDTYPE_SID);
 			continue;
 		}
-		task_lock(p);
+		guard(task_lock)(p);
 		i = iterate_fd(p->files, 0, this_tty, tty);
 		if (i != 0) {
 			tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
@@ -3064,7 +3051,6 @@ void __do_SAK(struct tty_struct *tty)
 			group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
 					PIDTYPE_SID);
 		}
-		task_unlock(p);
 	}
 	read_unlock(&tasklist_lock);
 	put_pid(session);
@@ -3330,10 +3316,12 @@ EXPORT_SYMBOL(tty_unregister_device);
  * __tty_alloc_driver - allocate tty driver
  * @lines: count of lines this driver can handle at most
  * @owner: module which is responsible for this driver
- * @flags: some of %TTY_DRIVER_ flags, will be set in driver->flags
+ * @flags: some of enum tty_driver_flag, will be set in driver->flags
+ *
+ * This should not be called directly, tty_alloc_driver() should be used
+ * instead.
  *
- * This should not be called directly, some of the provided macros should be
- * used instead. Use IS_ERR() and friends on @retval.
+ * Returns: struct tty_driver or a PTR-encoded error (use IS_ERR() and friends).
  */
 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
 		unsigned long flags)
@@ -3464,9 +3452,8 @@ int tty_register_driver(struct tty_driver *driver)
 			goto err_unreg_char;
 	}
 
-	mutex_lock(&tty_mutex);
-	list_add(&driver->tty_drivers, &tty_drivers);
-	mutex_unlock(&tty_mutex);
+	scoped_guard(mutex, &tty_mutex)
+		list_add(&driver->tty_drivers, &tty_drivers);
 
 	if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
 		for (i = 0; i < driver->num; i++) {
@@ -3485,9 +3472,8 @@ err_unreg_devs:
 	for (i--; i >= 0; i--)
 		tty_unregister_device(driver, i);
 
-	mutex_lock(&tty_mutex);
-	list_del(&driver->tty_drivers);
-	mutex_unlock(&tty_mutex);
+	scoped_guard(mutex, &tty_mutex)
+		list_del(&driver->tty_drivers);
 
 err_unreg_char:
 	unregister_chrdev_region(dev, driver->num);
@@ -3506,9 +3492,8 @@ void tty_unregister_driver(struct tty_driver *driver)
 {
 	unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
 				driver->num);
-	mutex_lock(&tty_mutex);
-	list_del(&driver->tty_drivers);
-	mutex_unlock(&tty_mutex);
+	scoped_guard(mutex, &tty_mutex)
+		list_del(&driver->tty_drivers);
 }
 EXPORT_SYMBOL(tty_unregister_driver);
 
@@ -3567,7 +3552,7 @@ static ssize_t show_cons_active(struct device *dev,
 	for_each_console(c) {
 		if (!c->device)
 			continue;
-		if (!c->write)
+		if (!(c->flags & CON_NBCON) && !c->write)
 			continue;
 		if ((c->flags & CON_ENABLED) == 0)
 			continue;
@@ -3618,7 +3603,7 @@ void console_sysfs_notify(void)
 		sysfs_notify(&consdev->kobj, NULL, "active");
 }
 
-static struct ctl_table tty_table[] = {
+static const struct ctl_table tty_table[] = {
 	{
 		.procname	= "legacy_tiocsti",
 		.data		= &tty_legacy_tiocsti,
@@ -3631,7 +3616,7 @@ static struct ctl_table tty_table[] = {
 		.data		= &tty_ldisc_autoload,
 		.maxlen		= sizeof(tty_ldisc_autoload),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
+		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},