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path: root/drivers/char/n_tty.c
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Diffstat (limited to 'drivers/char/n_tty.c')
-rw-r--r--drivers/char/n_tty.c160
1 files changed, 79 insertions, 81 deletions
diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index 0c09409fa45..19105ec203f 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -147,10 +147,8 @@ static void put_tty_queue(unsigned char c, struct tty_struct *tty)
static void check_unthrottle(struct tty_struct *tty)
{
- if (tty->count &&
- test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
- tty->driver->unthrottle)
- tty->driver->unthrottle(tty);
+ if (tty->count)
+ tty_unthrottle(tty);
}
/**
@@ -183,22 +181,24 @@ static void reset_buffer_flags(struct tty_struct *tty)
* at hangup) or when the N_TTY line discipline internally has to
* clean the pending queue (for example some signals).
*
- * FIXME: tty->ctrl_status is not spinlocked and relies on
- * lock_kernel() still.
+ * Locking: ctrl_lock
*/
static void n_tty_flush_buffer(struct tty_struct *tty)
{
+ unsigned long flags;
/* clear everything and unthrottle the driver */
reset_buffer_flags(tty);
if (!tty->link)
return;
+ spin_lock_irqsave(&tty->ctrl_lock, flags);
if (tty->link->packet) {
tty->ctrl_status |= TIOCPKT_FLUSHREAD;
wake_up_interruptible(&tty->link->read_wait);
}
+ spin_unlock_irqrestore(&tty->ctrl_lock, flags);
}
/**
@@ -264,17 +264,18 @@ static inline int is_continuation(unsigned char c, struct tty_struct *tty)
* relevant in the world today. If you ever need them, add them here.
*
* Called from both the receive and transmit sides and can be called
- * re-entrantly. Relies on lock_kernel() still.
+ * re-entrantly. Relies on lock_kernel() for tty->column state.
*/
static int opost(unsigned char c, struct tty_struct *tty)
{
int space, spaces;
- space = tty->driver->write_room(tty);
+ space = tty_write_room(tty);
if (!space)
return -1;
+ lock_kernel();
if (O_OPOST(tty)) {
switch (c) {
case '\n':
@@ -283,7 +284,7 @@ static int opost(unsigned char c, struct tty_struct *tty)
if (O_ONLCR(tty)) {
if (space < 2)
return -1;
- tty->driver->put_char(tty, '\r');
+ tty_put_char(tty, '\r');
tty->column = 0;
}
tty->canon_column = tty->column;
@@ -305,7 +306,7 @@ static int opost(unsigned char c, struct tty_struct *tty)
if (space < spaces)
return -1;
tty->column += spaces;
- tty->driver->write(tty, " ", spaces);
+ tty->ops->write(tty, " ", spaces);
return 0;
}
tty->column += spaces;
@@ -322,7 +323,8 @@ static int opost(unsigned char c, struct tty_struct *tty)
break;
}
}
- tty->driver->put_char(tty, c);
+ tty_put_char(tty, c);
+ unlock_kernel();
return 0;
}
@@ -337,7 +339,8 @@ static int opost(unsigned char c, struct tty_struct *tty)
* the simple cases normally found and helps to generate blocks of
* symbols for the console driver and thus improve performance.
*
- * Called from write_chan under the tty layer write lock.
+ * Called from write_chan under the tty layer write lock. Relies
+ * on lock_kernel for the tty->column state.
*/
static ssize_t opost_block(struct tty_struct *tty,
@@ -347,12 +350,13 @@ static ssize_t opost_block(struct tty_struct *tty,
int i;
const unsigned char *cp;
- space = tty->driver->write_room(tty);
+ space = tty_write_room(tty);
if (!space)
return 0;
if (nr > space)
nr = space;
+ lock_kernel();
for (i = 0, cp = buf; i < nr; i++, cp++) {
switch (*cp) {
case '\n':
@@ -384,27 +388,15 @@ static ssize_t opost_block(struct tty_struct *tty,
}
}
break_out:
- if (tty->driver->flush_chars)
- tty->driver->flush_chars(tty);
- i = tty->driver->write(tty, buf, i);
+ if (tty->ops->flush_chars)
+ tty->ops->flush_chars(tty);
+ i = tty->ops->write(tty, buf, i);
+ unlock_kernel();
return i;
}
/**
- * put_char - write character to driver
- * @c: character (or part of unicode symbol)
- * @tty: terminal device
- *
- * Queue a byte to the driver layer for output
- */
-
-static inline void put_char(unsigned char c, struct tty_struct *tty)
-{
- tty->driver->put_char(tty, c);
-}
-
-/**
* echo_char - echo characters
* @c: unicode byte to echo
* @tty: terminal device
@@ -416,8 +408,8 @@ static inline void put_char(unsigned char c, struct tty_struct *tty)
static void echo_char(unsigned char c, struct tty_struct *tty)
{
if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') {
- put_char('^', tty);
- put_char(c ^ 0100, tty);
+ tty_put_char(tty, '^');
+ tty_put_char(tty, c ^ 0100);
tty->column += 2;
} else
opost(c, tty);
@@ -426,7 +418,7 @@ static void echo_char(unsigned char c, struct tty_struct *tty)
static inline void finish_erasing(struct tty_struct *tty)
{
if (tty->erasing) {
- put_char('/', tty);
+ tty_put_char(tty, '/');
tty->column++;
tty->erasing = 0;
}
@@ -510,7 +502,7 @@ static void eraser(unsigned char c, struct tty_struct *tty)
if (L_ECHO(tty)) {
if (L_ECHOPRT(tty)) {
if (!tty->erasing) {
- put_char('\\', tty);
+ tty_put_char(tty, '\\');
tty->column++;
tty->erasing = 1;
}
@@ -518,7 +510,7 @@ static void eraser(unsigned char c, struct tty_struct *tty)
echo_char(c, tty);
while (--cnt > 0) {
head = (head+1) & (N_TTY_BUF_SIZE-1);
- put_char(tty->read_buf[head], tty);
+ tty_put_char(tty, tty->read_buf[head]);
}
} else if (kill_type == ERASE && !L_ECHOE(tty)) {
echo_char(ERASE_CHAR(tty), tty);
@@ -546,22 +538,22 @@ static void eraser(unsigned char c, struct tty_struct *tty)
/* Now backup to that column. */
while (tty->column > col) {
/* Can't use opost here. */
- put_char('\b', tty);
+ tty_put_char(tty, '\b');
if (tty->column > 0)
tty->column--;
}
} else {
if (iscntrl(c) && L_ECHOCTL(tty)) {
- put_char('\b', tty);
- put_char(' ', tty);
- put_char('\b', tty);
+ tty_put_char(tty, '\b');
+ tty_put_char(tty, ' ');
+ tty_put_char(tty, '\b');
if (tty->column > 0)
tty->column--;
}
if (!iscntrl(c) || L_ECHOCTL(tty)) {
- put_char('\b', tty);
- put_char(' ', tty);
- put_char('\b', tty);
+ tty_put_char(tty, '\b');
+ tty_put_char(tty, ' ');
+ tty_put_char(tty, '\b');
if (tty->column > 0)
tty->column--;
}
@@ -592,8 +584,7 @@ static inline void isig(int sig, struct tty_struct *tty, int flush)
kill_pgrp(tty->pgrp, sig, 1);
if (flush || !L_NOFLSH(tty)) {
n_tty_flush_buffer(tty);
- if (tty->driver->flush_buffer)
- tty->driver->flush_buffer(tty);
+ tty_driver_flush_buffer(tty);
}
}
@@ -701,7 +692,7 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
((I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty)) ||
- c == INTR_CHAR(tty) || c == QUIT_CHAR(tty)))
+ c == INTR_CHAR(tty) || c == QUIT_CHAR(tty) || c == SUSP_CHAR(tty)))
start_tty(tty);
if (tty->closing) {
@@ -725,7 +716,7 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
tty->lnext = 0;
if (L_ECHO(tty)) {
if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
- put_char('\a', tty); /* beep if no space */
+ tty_put_char(tty, '\a'); /* beep if no space */
return;
}
/* Record the column of first canon char. */
@@ -739,13 +730,6 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
return;
}
- if (c == '\r') {
- if (I_IGNCR(tty))
- return;
- if (I_ICRNL(tty))
- c = '\n';
- } else if (c == '\n' && I_INLCR(tty))
- c = '\r';
if (I_IXON(tty)) {
if (c == START_CHAR(tty)) {
start_tty(tty);
@@ -756,6 +740,7 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
return;
}
}
+
if (L_ISIG(tty)) {
int signal;
signal = SIGINT;
@@ -775,8 +760,7 @@ send_signal:
*/
if (!L_NOFLSH(tty)) {
n_tty_flush_buffer(tty);
- if (tty->driver->flush_buffer)
- tty->driver->flush_buffer(tty);
+ tty_driver_flush_buffer(tty);
}
if (L_ECHO(tty))
echo_char(c, tty);
@@ -785,6 +769,15 @@ send_signal:
return;
}
}
+
+ if (c == '\r') {
+ if (I_IGNCR(tty))
+ return;
+ if (I_ICRNL(tty))
+ c = '\n';
+ } else if (c == '\n' && I_INLCR(tty))
+ c = '\r';
+
if (tty->icanon) {
if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
(c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
@@ -796,8 +789,8 @@ send_signal:
if (L_ECHO(tty)) {
finish_erasing(tty);
if (L_ECHOCTL(tty)) {
- put_char('^', tty);
- put_char('\b', tty);
+ tty_put_char(tty, '^');
+ tty_put_char(tty, '\b');
}
}
return;
@@ -818,7 +811,7 @@ send_signal:
if (c == '\n') {
if (L_ECHO(tty) || L_ECHONL(tty)) {
if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
- put_char('\a', tty);
+ tty_put_char(tty, '\a');
opost('\n', tty);
}
goto handle_newline;
@@ -836,7 +829,7 @@ send_signal:
*/
if (L_ECHO(tty)) {
if (tty->read_cnt >= N_TTY_BUF_SIZE-1)
- put_char('\a', tty);
+ tty_put_char(tty, '\a');
/* Record the column of first canon char. */
if (tty->canon_head == tty->read_head)
tty->canon_column = tty->column;
@@ -866,7 +859,7 @@ handle_newline:
finish_erasing(tty);
if (L_ECHO(tty)) {
if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
- put_char('\a', tty); /* beep if no space */
+ tty_put_char(tty, '\a'); /* beep if no space */
return;
}
if (c == '\n')
@@ -970,8 +963,8 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
break;
}
}
- if (tty->driver->flush_chars)
- tty->driver->flush_chars(tty);
+ if (tty->ops->flush_chars)
+ tty->ops->flush_chars(tty);
}
n_tty_set_room(tty);
@@ -987,12 +980,8 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
* mode. We don't want to throttle the driver if we're in
* canonical mode and don't have a newline yet!
*/
- if (tty->receive_room < TTY_THRESHOLD_THROTTLE) {
- /* check TTY_THROTTLED first so it indicates our state */
- if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
- tty->driver->throttle)
- tty->driver->throttle(tty);
- }
+ if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
+ tty_throttle(tty);
}
int is_ignored(int sig)
@@ -1076,6 +1065,9 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
tty->real_raw = 0;
}
n_tty_set_room(tty);
+ /* The termios change make the tty ready for I/O */
+ wake_up_interruptible(&tty->write_wait);
+ wake_up_interruptible(&tty->read_wait);
}
/**
@@ -1194,6 +1186,11 @@ extern ssize_t redirected_tty_write(struct file *, const char __user *,
* Perform job control management checks on this file/tty descriptor
* and if appropriate send any needed signals and return a negative
* error code if action should be taken.
+ *
+ * FIXME:
+ * Locking: None - redirected write test is safe, testing
+ * current->signal should possibly lock current->sighand
+ * pgrp locking ?
*/
static int job_control(struct tty_struct *tty, struct file *file)
@@ -1246,6 +1243,7 @@ static ssize_t read_chan(struct tty_struct *tty, struct file *file,
ssize_t size;
long timeout;
unsigned long flags;
+ int packet;
do_it_again:
@@ -1289,16 +1287,19 @@ do_it_again:
if (mutex_lock_interruptible(&tty->atomic_read_lock))
return -ERESTARTSYS;
}
+ packet = tty->packet;
add_wait_queue(&tty->read_wait, &wait);
while (nr) {
/* First test for status change. */
- if (tty->packet && tty->link->ctrl_status) {
+ if (packet && tty->link->ctrl_status) {
unsigned char cs;
if (b != buf)
break;
+ spin_lock_irqsave(&tty->link->ctrl_lock, flags);
cs = tty->link->ctrl_status;
tty->link->ctrl_status = 0;
+ spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
if (tty_put_user(tty, cs, b++)) {
retval = -EFAULT;
b--;
@@ -1333,6 +1334,7 @@ do_it_again:
retval = -ERESTARTSYS;
break;
}
+ /* FIXME: does n_tty_set_room need locking ? */
n_tty_set_room(tty);
timeout = schedule_timeout(timeout);
continue;
@@ -1340,7 +1342,7 @@ do_it_again:
__set_current_state(TASK_RUNNING);
/* Deal with packet mode. */
- if (tty->packet && b == buf) {
+ if (packet && b == buf) {
if (tty_put_user(tty, TIOCPKT_DATA, b++)) {
retval = -EFAULT;
b--;
@@ -1388,6 +1390,8 @@ do_it_again:
break;
} else {
int uncopied;
+ /* The copy function takes the read lock and handles
+ locking internally for this case */
uncopied = copy_from_read_buf(tty, &b, &nr);
uncopied += copy_from_read_buf(tty, &b, &nr);
if (uncopied) {
@@ -1429,7 +1433,6 @@ do_it_again:
goto do_it_again;
n_tty_set_room(tty);
-
return retval;
}
@@ -1492,11 +1495,11 @@ static ssize_t write_chan(struct tty_struct *tty, struct file *file,
break;
b++; nr--;
}
- if (tty->driver->flush_chars)
- tty->driver->flush_chars(tty);
+ if (tty->ops->flush_chars)
+ tty->ops->flush_chars(tty);
} else {
while (nr > 0) {
- c = tty->driver->write(tty, b, nr);
+ c = tty->ops->write(tty, b, nr);
if (c < 0) {
retval = c;
goto break_out;
@@ -1533,11 +1536,6 @@ break_out:
*
* This code must be sure never to sleep through a hangup.
* Called without the kernel lock held - fine
- *
- * FIXME: if someone changes the VMIN or discipline settings for the
- * terminal while another process is in poll() the poll does not
- * recompute the new limits. Possibly set_termios should issue
- * a read wakeup to fix this bug.
*/
static unsigned int normal_poll(struct tty_struct *tty, struct file *file,
@@ -1561,9 +1559,9 @@ static unsigned int normal_poll(struct tty_struct *tty, struct file *file,
else
tty->minimum_to_wake = 1;
}
- if (!tty_is_writelocked(tty) &&
- tty->driver->chars_in_buffer(tty) < WAKEUP_CHARS &&
- tty->driver->write_room(tty) > 0)
+ if (tty->ops->write && !tty_is_writelocked(tty) &&
+ tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
+ tty_write_room(tty) > 0)
mask |= POLLOUT | POLLWRNORM;
return mask;
}