tty: remove tty_lock_nested
This changes all remaining users of tty_lock_nested
to be non-recursive, which lets us kill this function.
As a consequence, we won't need to keep the lock count
any more, which allows more simplifications later.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index bb22cf4..dcf7d36 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -492,10 +492,8 @@
* tasklist_lock to walk task list for hangup event
* ->siglock to protect ->signal/->sighand
*/
-static void do_tty_hangup(struct work_struct *work)
+void tty_vhangup_locked(struct tty_struct *tty)
{
- struct tty_struct *tty =
- container_of(work, struct tty_struct, hangup_work);
struct file *cons_filp = NULL;
struct file *filp, *f = NULL;
struct task_struct *p;
@@ -517,8 +515,6 @@
/* inuse_filps is protected by the single tty lock,
this really needs to change if we want to flush the
workqueue with the lock held */
- tty_lock_nested(); /* called with BTM held from pty_close and
- others */
check_tty_count(tty, "do_tty_hangup");
file_list_lock();
@@ -598,11 +594,20 @@
*/
set_bit(TTY_HUPPED, &tty->flags);
tty_ldisc_enable(tty);
- tty_unlock();
if (f)
fput(f);
}
+static void do_tty_hangup(struct work_struct *work)
+{
+ struct tty_struct *tty =
+ container_of(work, struct tty_struct, hangup_work);
+
+ tty_lock();
+ tty_vhangup_locked(tty);
+ tty_unlock();
+}
+
/**
* tty_hangup - trigger a hangup event
* @tty: tty to hangup
@@ -638,7 +643,9 @@
printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
#endif
- do_tty_hangup(&tty->hangup_work);
+ tty_lock();
+ tty_vhangup_locked(tty);
+ tty_unlock();
}
EXPORT_SYMBOL(tty_vhangup);
@@ -719,10 +726,12 @@
tty = get_current_tty();
if (tty) {
tty_pgrp = get_pid(tty->pgrp);
- tty_lock_nested(); /* see above */
- if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
- tty_vhangup(tty);
- tty_unlock();
+ if (on_exit) {
+ tty_lock();
+ if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
+ tty_vhangup_locked(tty);
+ tty_unlock();
+ }
tty_kref_put(tty);
} else if (on_exit) {
struct pid *old_pgrp;
@@ -1213,18 +1222,14 @@
int ret;
if (driver->ops->install) {
- tty_lock_nested(); /* already called with BTM held */
ret = driver->ops->install(driver, tty);
- tty_unlock();
return ret;
}
if (tty_init_termios(tty) == 0) {
- tty_lock_nested();
tty_driver_kref_get(driver);
tty->count++;
driver->ttys[idx] = tty;
- tty_unlock();
return 0;
}
return -ENOMEM;
@@ -1317,15 +1322,11 @@
struct tty_struct *tty;
int retval;
- tty_lock_nested(); /* always called with tty lock held already */
-
/* Check if pty master is being opened multiple times */
if (driver->subtype == PTY_TYPE_MASTER &&
(driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
- tty_unlock();
return ERR_PTR(-EIO);
}
- tty_unlock();
/*
* First time open is complex, especially for PTY devices.
@@ -1369,9 +1370,7 @@
if (printk_ratelimit())
printk(KERN_INFO "tty_init_dev: ldisc open failed, "
"clearing slot %d\n", idx);
- tty_lock_nested();
release_tty(tty, idx);
- tty_unlock();
return ERR_PTR(retval);
}