Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groec...

[pandora-kernel.git] / drivers / tty / n_tty.c

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 95d0a9c..c3954fb 100644 (file)
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -81,6 +81,38 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
        return put_user(x, ptr);
 }
 
+/**
+ *     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".
+ */
+
+static void n_tty_set_room(struct tty_struct *tty)
+{
+       /* tty->read_cnt is not read locked ? */
+       int     left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
+       int old_left;
+
+       /*
+        * If we are doing input canonicalization, and there are no
+        * pending newlines, let characters through without limit, so
+        * that erase characters will be handled.  Other excess
+        * characters will be beeped.
+        */
+       if (left <= 0)
+               left = tty->icanon && !tty->canon_data;
+       old_left = tty->receive_room;
+       tty->receive_room = left;
+
+       /* Did this open up the receive buffer? We may need to flip */
+       if (left && !old_left)
+               schedule_work(&tty->buf.work);
+}
+
 static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
 {
        if (tty->read_cnt < N_TTY_BUF_SIZE) {
@@ -152,6 +184,7 @@ static void reset_buffer_flags(struct tty_struct *tty)
 
        tty->canon_head = tty->canon_data = tty->erasing = 0;
        memset(&tty->read_flags, 0, sizeof tty->read_flags);
+       n_tty_set_room(tty);
        check_unthrottle(tty);
 }
 
@@ -1327,19 +1360,17 @@ static void n_tty_write_wakeup(struct tty_struct *tty)
  *     calls one at a time and in order (or using flush_to_ldisc)
  */
 
-static unsigned int n_tty_receive_buf(struct tty_struct *tty,
-               const unsigned char *cp, char *fp, int count)
+static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
+                             char *fp, int count)
 {
        const unsigned char *p;
        char *f, flags = TTY_NORMAL;
        int     i;
        char    buf[64];
        unsigned long cpuflags;
-       int left;
-       int ret = 0;
 
        if (!tty->read_buf)
-               return 0;
+               return;
 
        if (tty->real_raw) {
                spin_lock_irqsave(&tty->read_lock, cpuflags);
@@ -1349,7 +1380,6 @@ static unsigned int n_tty_receive_buf(struct tty_struct *tty,
                memcpy(tty->read_buf + tty->read_head, cp, i);
                tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
                tty->read_cnt += i;
-               ret += i;
                cp += i;
                count -= i;
 
@@ -1359,10 +1389,8 @@ static unsigned int n_tty_receive_buf(struct tty_struct *tty,
                memcpy(tty->read_buf + tty->read_head, cp, i);
                tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
                tty->read_cnt += i;
-               ret += i;
                spin_unlock_irqrestore(&tty->read_lock, cpuflags);
        } else {
-               ret = count;
                for (i = count, p = cp, f = fp; i; i--, p++) {
                        if (f)
                                flags = *f++;
@@ -1390,6 +1418,8 @@ static unsigned int n_tty_receive_buf(struct tty_struct *tty,
                        tty->ops->flush_chars(tty);
        }
 
+       n_tty_set_room(tty);
+
        if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) ||
                L_EXTPROC(tty)) {
                kill_fasync(&tty->fasync, SIGIO, POLL_IN);
@@ -1402,12 +1432,8 @@ static unsigned int n_tty_receive_buf(struct tty_struct *tty,
         * mode.  We don't want to throttle the driver if we're in
         * canonical mode and don't have a newline yet!
         */
-       left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
-
-       if (left < TTY_THRESHOLD_THROTTLE)
+       if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
                tty_throttle(tty);
-
-       return ret;
 }
 
 int is_ignored(int sig)
@@ -1451,6 +1477,7 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
        if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
                tty->raw = 1;
                tty->real_raw = 1;
+               n_tty_set_room(tty);
                return;
        }
        if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
@@ -1503,6 +1530,7 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
                else
                        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);
@@ -1784,7 +1812,10 @@ do_it_again:
                                retval = -ERESTARTSYS;
                                break;
                        }
+                       /* FIXME: does n_tty_set_room need locking ? */
+                       n_tty_set_room(tty);
                        timeout = schedule_timeout(timeout);
+                       BUG_ON(!tty->read_buf);
                        continue;
                }
                __set_current_state(TASK_RUNNING);
@@ -1855,8 +1886,10 @@ do_it_again:
                 * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
                 * we won't get any more characters.
                 */
-               if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE)
+               if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) {
+                       n_tty_set_room(tty);
                        check_unthrottle(tty);
+               }
 
                if (b - buf >= minimum)
                        break;
@@ -1878,6 +1911,7 @@ do_it_again:
        } else if (test_and_clear_bit(TTY_PUSH, &tty->flags))
                 goto do_it_again;
 
+       n_tty_set_room(tty);
        return retval;
 }