[PATCH -next 09/27] tty: Remove TTY_CLOSING

Peter Hurley
2014-10-16T20:26:11Z

Now that re-open is not permitted for a legacy BSD pty master,
using TTY_CLOSING to indicate when a tty can be torn-down is
no longer necessary.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
---
drivers/tty/tty_io.c | 14 ++------------
include/linux/tty.h | 1 -
2 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index ded0445..55f9931 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1197,7 +1197,7 @@ void tty_write_message(struct tty_struct *tty, char *msg)
if (tty) {
mutex_lock(&tty->atomic_write_lock);
tty_lock(tty);
- if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
+ if (tty->ops->write && tty->count > 0) {
tty_unlock(tty);
tty->ops->write(tty, msg, strlen(msg));
} else
@@ -1887,16 +1887,6 @@ int tty_release(struct inode *inode, struct file *filp)
/*
* Perform some housekeeping before deciding whether to return.
*
- * Set the TTY_CLOSING flag if this was the last open. In the
- * case of a pty we may have to wait around for the other side
- * to close, and TTY_CLOSING makes sure we can't be reopened.
- */
- if (tty_closing)
- set_bit(TTY_CLOSING, &tty->flags);
- if (o_tty_closing)
- set_bit(TTY_CLOSING, &o_tty->flags);
-
- /*
* If _either_ side is closing, make sure there aren't any
* processes that still think tty or o_tty is their controlling
* tty.
@@ -1911,7 +1901,7 @@ int tty_release(struct inode *inode, struct file *filp)

mutex_unlock(&tty_mutex);
tty_unlock_pair(tty, o_tty);
- /* At this point the TTY_CLOSING flag should ensure a dead tty
+ /* At this point, the tty->count == 0 should ensure a dead tty
cannot be re-opened by a racing opener */

/* check whether both sides are closing ... */
diff --git a/include/linux/tty.h b/include/linux/tty.h
index ff0dd7a..35b29f0 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -316,7 +316,6 @@ struct tty_file_private {
#define TTY_EXCLUSIVE 3 /* Exclusive open mode */
#define TTY_DEBUG 4 /* Debugging */
#define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */
-#define TTY_CLOSING 7 /* ->close() in progress */
#define TTY_LDISC_OPEN 11 /* Line discipline is open */
#define TTY_PTY_LOCK 16 /* pty private */
#define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */
--
2.1.1