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authorPeter Hurley <peter@hurleysoftware.com>2013-06-15 15:28:31 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-06-17 23:55:30 +0400
commit7879a9f9fd4ff4a88b3c51f4ab6718dc7f86ed86 (patch)
treee983db0f0fcf544201b3e457f616ac3c909bbac4 /drivers/tty
parentb84830527645dfe7b7a5cc03518e3c791b4ee9e0 (diff)
downloadlinux-7879a9f9fd4ff4a88b3c51f4ab6718dc7f86ed86.tar.xz
n_tty: Buffer work should not reschedule itself
Although the driver-side input path must update the available buffer space, it should not reschedule itself. If space is still available and the flip buffers are not empty, flush_to_ldisc() will loop again. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/n_tty.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 064616542cb5..4bf0fc0843d7 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -118,14 +118,14 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
* n_tty_set_room - receive space
* @tty: terminal
*
- * Sets tty->receive_room to reflect the currently available space
+ * Updates tty->receive_room to reflect the currently available space
* in the input buffer, and re-schedules the flip buffer work if space
* just became available.
*
* Locks: Concurrent update is protected with read_lock
*/
-static void n_tty_set_room(struct tty_struct *tty)
+static int set_room(struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
int left;
@@ -155,8 +155,13 @@ static void n_tty_set_room(struct tty_struct *tty)
raw_spin_unlock_irqrestore(&ldata->read_lock, flags);
+ return left && !old_left;
+}
+
+static void n_tty_set_room(struct tty_struct *tty)
+{
/* Did this open up the receive buffer? We may need to flip */
- if (left && !old_left) {
+ if (set_room(tty)) {
WARN_RATELIMIT(tty->port->itty == NULL,
"scheduling with invalid itty\n");
/* see if ldisc has been killed - if so, this means that
@@ -1459,7 +1464,7 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
tty->ops->flush_chars(tty);
}
- n_tty_set_room(tty);
+ set_room(tty);
if ((!ldata->icanon && (ldata->read_cnt >= ldata->minimum_to_wake)) ||
L_EXTPROC(tty)) {