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path: root/drivers/tty/tty_io.c
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Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r--drivers/tty/tty_io.c47
1 files changed, 39 insertions, 8 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 892c92354745..a7eacef1bd22 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1463,13 +1463,13 @@ static int tty_reopen(struct tty_struct *tty)
{
struct tty_driver *driver = tty->driver;
- if (!tty->count)
- return -EIO;
-
if (driver->type == TTY_DRIVER_TYPE_PTY &&
driver->subtype == PTY_TYPE_MASTER)
return -EIO;
+ if (!tty->count)
+ return -EAGAIN;
+
if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
return -EBUSY;
@@ -2065,9 +2065,13 @@ retry_open:
if (tty) {
mutex_unlock(&tty_mutex);
- tty_lock(tty);
- /* safe to drop the kref from tty_driver_lookup_tty() */
- tty_kref_put(tty);
+ retval = tty_lock_interruptible(tty);
+ tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
+ if (retval) {
+ if (retval == -EINTR)
+ retval = -ERESTARTSYS;
+ goto err_unref;
+ }
retval = tty_reopen(tty);
if (retval < 0) {
tty_unlock(tty);
@@ -2083,7 +2087,11 @@ retry_open:
if (IS_ERR(tty)) {
retval = PTR_ERR(tty);
- goto err_file;
+ if (retval != -EAGAIN || signal_pending(current))
+ goto err_file;
+ tty_free_file(filp);
+ schedule();
+ goto retry_open;
}
tty_add_file(tty, filp);
@@ -2152,6 +2160,7 @@ retry_open:
return 0;
err_unlock:
mutex_unlock(&tty_mutex);
+err_unref:
/* after locks to avoid deadlock */
if (!IS_ERR_OR_NULL(driver))
tty_driver_kref_put(driver);
@@ -2649,6 +2658,28 @@ static int tiocsetd(struct tty_struct *tty, int __user *p)
}
/**
+ * tiocgetd - get line discipline
+ * @tty: tty device
+ * @p: pointer to user data
+ *
+ * Retrieves the line discipline id directly from the ldisc.
+ *
+ * Locking: waits for ldisc reference (in case the line discipline
+ * is changing or the tty is being hungup)
+ */
+
+static int tiocgetd(struct tty_struct *tty, int __user *p)
+{
+ struct tty_ldisc *ld;
+ int ret;
+
+ ld = tty_ldisc_ref_wait(tty);
+ ret = put_user(ld->ops->num, p);
+ tty_ldisc_deref(ld);
+ return ret;
+}
+
+/**
* send_break - performed time break
* @tty: device to break on
* @duration: timeout in mS
@@ -2874,7 +2905,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case TIOCGSID:
return tiocgsid(tty, real_tty, p);
case TIOCGETD:
- return put_user(tty->ldisc->ops->num, (int __user *)p);
+ return tiocgetd(tty, p);
case TIOCSETD:
return tiocsetd(tty, p);
case TIOCVHANGUP: