diff options
author | Paul Fulghum <paulkf@microgate.com> | 2006-06-28 11:26:47 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-28 21:59:05 (GMT) |
commit | 817d6d3bceaf34c99f5343820f9b9e6021f0655c (patch) | |
tree | 651104833124262db46c2a372b7adb55289cd8dd /drivers/char | |
parent | e0ac4761fa52acda90f9f53819c81474b511e3af (diff) | |
download | linux-fsl-qoriq-817d6d3bceaf34c99f5343820f9b9e6021f0655c.tar.xz |
[PATCH] remove TTY_DONT_FLIP
Remove TTY_DONT_FLIP tty flag. This flag was introduced in 2.1.X kernels
to prevent the N_TTY line discipline functions read_chan() and
n_tty_receive_buf() from running at the same time. 2.2.15 introduced
tty->read_lock to protect access to the N_TTY read buffer, which is the
only state requiring protection between these two functions.
The current TTY_DONT_FLIP implementation is broken for SMP, and is not
universally honored by drivers that send data directly to the line
discipline receive_buf function.
Because TTY_DONT_FLIP is not necessary, is broken in implementation, and is
not universally honored, it is removed.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/char')
-rw-r--r-- | drivers/char/mxser.c | 1 | ||||
-rw-r--r-- | drivers/char/n_tty.c | 6 | ||||
-rw-r--r-- | drivers/char/pty.c | 2 | ||||
-rw-r--r-- | drivers/char/tty_io.c | 15 |
4 files changed, 4 insertions, 20 deletions
diff --git a/drivers/char/mxser.c b/drivers/char/mxser.c index 645d9d7..72cfd09 100644 --- a/drivers/char/mxser.c +++ b/drivers/char/mxser.c @@ -996,7 +996,6 @@ static int mxser_open(struct tty_struct *tty, struct file *filp) info->session = current->signal->session; info->pgrp = process_group(current); - clear_bit(TTY_DONT_FLIP, &tty->flags); /* status = mxser_get_msr(info->base, 0, info->port); diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c index b9371d5..603b9ad 100644 --- a/drivers/char/n_tty.c +++ b/drivers/char/n_tty.c @@ -1132,7 +1132,7 @@ static inline int input_available_p(struct tty_struct *tty, int amt) * buffer, and once to drain the space from the (physical) beginning of * the buffer to head pointer. * - * Called under the tty->atomic_read_lock sem and with TTY_DONT_FLIP set + * Called under the tty->atomic_read_lock sem * */ @@ -1271,7 +1271,6 @@ do_it_again: } add_wait_queue(&tty->read_wait, &wait); - set_bit(TTY_DONT_FLIP, &tty->flags); while (nr) { /* First test for status change. */ if (tty->packet && tty->link->ctrl_status) { @@ -1315,9 +1314,7 @@ do_it_again: break; } n_tty_set_room(tty); - clear_bit(TTY_DONT_FLIP, &tty->flags); timeout = schedule_timeout(timeout); - set_bit(TTY_DONT_FLIP, &tty->flags); continue; } __set_current_state(TASK_RUNNING); @@ -1394,7 +1391,6 @@ do_it_again: if (time) timeout = time; } - clear_bit(TTY_DONT_FLIP, &tty->flags); mutex_unlock(&tty->atomic_read_lock); remove_wait_queue(&tty->read_wait, &wait); diff --git a/drivers/char/pty.c b/drivers/char/pty.c index 9b5a2c0..0c17f61 100644 --- a/drivers/char/pty.c +++ b/drivers/char/pty.c @@ -101,7 +101,7 @@ static void pty_unthrottle(struct tty_struct * tty) * * FIXME: Our pty_write method is called with our ldisc lock held but * not our partners. We can't just take the other one blindly without - * risking deadlocks. There is also the small matter of TTY_DONT_FLIP + * risking deadlocks. */ static int pty_write(struct tty_struct * tty, const unsigned char *buf, int count) { diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index bd74e82..b846d87 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -784,11 +784,8 @@ restart: } clear_bit(TTY_LDISC, &tty->flags); - clear_bit(TTY_DONT_FLIP, &tty->flags); - if (o_tty) { + if (o_tty) clear_bit(TTY_LDISC, &o_tty->flags); - clear_bit(TTY_DONT_FLIP, &o_tty->flags); - } spin_unlock_irqrestore(&tty_ldisc_lock, flags); /* @@ -1955,7 +1952,6 @@ static void release_dev(struct file * filp) * race with the set_ldisc code path. */ clear_bit(TTY_LDISC, &tty->flags); - clear_bit(TTY_DONT_FLIP, &tty->flags); cancel_delayed_work(&tty->buf.work); /* @@ -2784,13 +2780,6 @@ static void flush_to_ldisc(void *private_) if (disc == NULL) /* !TTY_LDISC */ return; - if (test_bit(TTY_DONT_FLIP, &tty->flags)) { - /* - * Do it after the next timer tick: - */ - schedule_delayed_work(&tty->buf.work, 1); - goto out; - } spin_lock_irqsave(&tty->buf.lock, flags); while((tbuf = tty->buf.head) != NULL) { while ((count = tbuf->commit - tbuf->read) != 0) { @@ -2809,7 +2798,7 @@ static void flush_to_ldisc(void *private_) tty_buffer_free(tty, tbuf); } spin_unlock_irqrestore(&tty->buf.lock, flags); -out: + tty_ldisc_deref(disc); } |