Revert "TTY: call tty_driver_lookup_tty unconditionally"
This reverts commit 631180aca723cb92e128fdac5fd144e913ca84e5.
It caused problems when /dev/tty is a pty:
https://lkml.org/lkml/2011/10/12/401
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 0425170..767ecbb 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1821,7 +1821,7 @@
static int tty_open(struct inode *inode, struct file *filp)
{
- struct tty_struct *tty;
+ struct tty_struct *tty = NULL;
int noctty, retval;
struct tty_driver *driver;
int index;
@@ -1892,14 +1892,17 @@
return -ENODEV;
}
got_driver:
- /* check whether we're reopening an existing tty */
- tty = tty_driver_lookup_tty(driver, inode, index);
- if (IS_ERR(tty)) {
- tty_unlock();
- mutex_unlock(&tty_mutex);
- tty_driver_kref_put(driver);
- tty_free_file(filp);
- return PTR_ERR(tty);
+ if (!tty) {
+ /* check whether we're reopening an existing tty */
+ tty = tty_driver_lookup_tty(driver, inode, index);
+
+ if (IS_ERR(tty)) {
+ tty_unlock();
+ mutex_unlock(&tty_mutex);
+ tty_driver_kref_put(driver);
+ tty_free_file(filp);
+ return PTR_ERR(tty);
+ }
}
if (tty) {