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path: root/drivers/tty/n_tty.c
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Diffstat (limited to 'drivers/tty/n_tty.c')
-rw-r--r--drivers/tty/n_tty.c88
1 files changed, 51 insertions, 37 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 6c7fe90ad72..4bf0fc0843d 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -89,6 +89,7 @@ struct n_tty_data {
int read_head;
int read_tail;
int read_cnt;
+ int minimum_to_wake;
unsigned char *echo_buf;
unsigned int echo_pos;
@@ -114,22 +115,25 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
}
/**
- * n_tty_set__room - receive space
+ * n_tty_set_room - receive space
* @tty: terminal
*
- * Called by the driver to find out how much data it is
- * permitted to feed to the line discipline without any being lost
- * and thus to manage flow control. Not serialized. Answers for the
- * "instant".
+ * 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;
int old_left;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&ldata->read_lock, flags);
- /* ldata->read_cnt is not read locked ? */
if (I_PARMRK(tty)) {
/* Multiply read_cnt by 3, since each byte might take up to
* three times as many spaces when PARMRK is set (depending on
@@ -149,8 +153,15 @@ static void n_tty_set_room(struct tty_struct *tty)
old_left = tty->receive_room;
tty->receive_room = left;
+ 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
@@ -647,8 +658,7 @@ static void process_echoes(struct tty_struct *tty)
if (no_space_left)
break;
} else {
- if (O_OPOST(tty) &&
- !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
+ if (O_OPOST(tty)) {
int retval = do_output_char(c, tty, space);
if (retval < 0)
break;
@@ -1454,9 +1464,9 @@ 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 >= tty->minimum_to_wake)) ||
+ if ((!ldata->icanon && (ldata->read_cnt >= ldata->minimum_to_wake)) ||
L_EXTPROC(tty)) {
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
if (waitqueue_active(&tty->read_wait))
@@ -1516,12 +1526,7 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
wake_up_interruptible(&tty->read_wait);
ldata->icanon = (L_ICANON(tty) != 0);
- if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
- ldata->raw = 1;
- ldata->real_raw = 1;
- n_tty_set_room(tty);
- return;
- }
+
if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
@@ -1642,7 +1647,7 @@ static int n_tty_open(struct tty_struct *tty)
tty->disc_data = ldata;
reset_buffer_flags(tty->disc_data);
ldata->column = 0;
- tty->minimum_to_wake = 1;
+ ldata->minimum_to_wake = 1;
tty->closing = 0;
/* indicate buffer work may resume */
clear_bit(TTY_LDISC_HALTED, &tty->flags);
@@ -1806,21 +1811,17 @@ do_it_again:
minimum = time = 0;
timeout = MAX_SCHEDULE_TIMEOUT;
if (!ldata->icanon) {
- time = (HZ / 10) * TIME_CHAR(tty);
minimum = MIN_CHAR(tty);
if (minimum) {
+ time = (HZ / 10) * TIME_CHAR(tty);
if (time)
- tty->minimum_to_wake = 1;
+ ldata->minimum_to_wake = 1;
else if (!waitqueue_active(&tty->read_wait) ||
- (tty->minimum_to_wake > minimum))
- tty->minimum_to_wake = minimum;
+ (ldata->minimum_to_wake > minimum))
+ ldata->minimum_to_wake = minimum;
} else {
- timeout = 0;
- if (time) {
- timeout = time;
- time = 0;
- }
- tty->minimum_to_wake = minimum = 1;
+ timeout = (HZ / 10) * TIME_CHAR(tty);
+ ldata->minimum_to_wake = minimum = 1;
}
}
@@ -1860,9 +1861,9 @@ do_it_again:
TASK_RUNNING. */
set_current_state(TASK_INTERRUPTIBLE);
- if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
+ if (((minimum - (b - buf)) < ldata->minimum_to_wake) &&
((minimum - (b - buf)) >= 1))
- tty->minimum_to_wake = (minimum - (b - buf));
+ ldata->minimum_to_wake = (minimum - (b - buf));
if (!input_available_p(tty, 0)) {
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
@@ -1881,7 +1882,6 @@ do_it_again:
retval = -ERESTARTSYS;
break;
}
- /* FIXME: does n_tty_set_room need locking ? */
n_tty_set_room(tty);
timeout = schedule_timeout(timeout);
continue;
@@ -1979,7 +1979,7 @@ do_it_again:
remove_wait_queue(&tty->read_wait, &wait);
if (!waitqueue_active(&tty->read_wait))
- tty->minimum_to_wake = minimum;
+ ldata->minimum_to_wake = minimum;
__set_current_state(TASK_RUNNING);
size = b - buf;
@@ -2045,7 +2045,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
retval = -EIO;
break;
}
- if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
+ if (O_OPOST(tty)) {
while (nr > 0) {
ssize_t num = process_output_block(tty, b, nr);
if (num < 0) {
@@ -2111,6 +2111,7 @@ break_out:
static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
poll_table *wait)
{
+ struct n_tty_data *ldata = tty->disc_data;
unsigned int mask = 0;
poll_wait(file, &tty->read_wait, wait);
@@ -2125,9 +2126,9 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
mask |= POLLHUP;
if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
if (MIN_CHAR(tty) && !TIME_CHAR(tty))
- tty->minimum_to_wake = MIN_CHAR(tty);
+ ldata->minimum_to_wake = MIN_CHAR(tty);
else
- tty->minimum_to_wake = 1;
+ ldata->minimum_to_wake = 1;
}
if (tty->ops->write && !tty_is_writelocked(tty) &&
tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
@@ -2175,6 +2176,18 @@ static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
}
}
+static void n_tty_fasync(struct tty_struct *tty, int on)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+
+ if (!waitqueue_active(&tty->read_wait)) {
+ if (on)
+ ldata->minimum_to_wake = 1;
+ else if (!tty->fasync)
+ ldata->minimum_to_wake = N_TTY_BUF_SIZE;
+ }
+}
+
struct tty_ldisc_ops tty_ldisc_N_TTY = {
.magic = TTY_LDISC_MAGIC,
.name = "n_tty",
@@ -2188,7 +2201,8 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = {
.set_termios = n_tty_set_termios,
.poll = n_tty_poll,
.receive_buf = n_tty_receive_buf,
- .write_wakeup = n_tty_write_wakeup
+ .write_wakeup = n_tty_write_wakeup,
+ .fasync = n_tty_fasync,
};
/**
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-15 22:49:55 +0000