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Subject[PATCH v2 5/6] TTY: remove tty_locked
Date
We used it really only serial and ami_serial. The rest of the
callsites were BUG/WARN_ONs to check if BTM is held. Now that we
pruned tty_locked from both of the real users, we can get rid of
tty_lock along with __big_tty_mutex_owner.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alan Cox <alan@linux.intel.com>
---
drivers/tty/serial/serial_core.c | 4 ----
drivers/tty/tty_ldisc.c | 1 -
drivers/tty/tty_mutex.c | 12 ------------
drivers/tty/vt/selection.c | 4 ++--
include/linux/tty.h | 2 --
5 files changed, 2 insertions(+), 21 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 4786232..44c2963 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1245,8 +1245,6 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
struct uart_port *uport;
unsigned long flags;

- BUG_ON(!tty_locked());
-
if (!state)
return;

@@ -1411,7 +1409,6 @@ static void uart_hangup(struct tty_struct *tty)
struct tty_port *port = &state->port;
unsigned long flags;

- BUG_ON(!tty_locked());
pr_debug("uart_hangup(%d)\n", state->uart_port->line);

mutex_lock(&port->mutex);
@@ -1498,7 +1495,6 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
struct tty_port *port;
int retval, line = tty->index;

- BUG_ON(!tty_locked());
pr_debug("uart_open(%d) called\n", line);

/*
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index ef925d5..512c49f 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -450,7 +450,6 @@ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
if (ld->ops->open) {
int ret;
/* BTM here locks versus a hangup event */
- WARN_ON(!tty_locked());
ret = ld->ops->open(tty);
if (ret)
clear_bit(TTY_LDISC_OPEN, &tty->flags);
diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c
index 3b2bb77..9ff986c 100644
--- a/drivers/tty/tty_mutex.c
+++ b/drivers/tty/tty_mutex.c
@@ -15,30 +15,18 @@
* Don't use in new code.
*/
static DEFINE_MUTEX(big_tty_mutex);
-struct task_struct *__big_tty_mutex_owner;
-EXPORT_SYMBOL_GPL(__big_tty_mutex_owner);

/*
* Getting the big tty mutex.
*/
void __lockfunc tty_lock(void)
{
- struct task_struct *task = current;
-
- WARN_ON(__big_tty_mutex_owner == task);
-
mutex_lock(&big_tty_mutex);
- __big_tty_mutex_owner = task;
}
EXPORT_SYMBOL(tty_lock);

void __lockfunc tty_unlock(void)
{
- struct task_struct *task = current;
-
- WARN_ON(__big_tty_mutex_owner != task);
- __big_tty_mutex_owner = NULL;
-
mutex_unlock(&big_tty_mutex);
}
EXPORT_SYMBOL(tty_unlock);
diff --git a/drivers/tty/vt/selection.c b/drivers/tty/vt/selection.c
index fb864e7..7a0a12a 100644
--- a/drivers/tty/vt/selection.c
+++ b/drivers/tty/vt/selection.c
@@ -301,6 +301,8 @@ int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *t
/* Insert the contents of the selection buffer into the
* queue of the tty associated with the current console.
* Invoked by ioctl().
+ *
+ * Locking: always called with BTM from vt_ioctl
*/
int paste_selection(struct tty_struct *tty)
{
@@ -310,8 +312,6 @@ int paste_selection(struct tty_struct *tty)
struct tty_ldisc *ld;
DECLARE_WAITQUEUE(wait, current);

- /* always called with BTM from vt_ioctl */
- WARN_ON(!tty_locked());

console_lock();
poke_blanked_console();
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 44bc0c5..6d5eceb 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -600,8 +600,6 @@ extern long vt_compat_ioctl(struct tty_struct *tty,
/* functions for preparation of BKL removal */
extern void __lockfunc tty_lock(void) __acquires(tty_lock);
extern void __lockfunc tty_unlock(void) __releases(tty_lock);
-extern struct task_struct *__big_tty_mutex_owner;
-#define tty_locked() (current == __big_tty_mutex_owner)

/*
* wait_event_interruptible_tty -- wait for a condition with the tty lock held
--
1.7.6



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