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authorPaul Fulghum <paulkf@microgate.com>2006-06-28 04:26:47 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-28 14:59:05 -0700
commit817d6d3bceaf34c99f5343820f9b9e6021f0655c (patch)
tree651104833124262db46c2a372b7adb55289cd8dd /drivers/char/tty_io.c
parente0ac4761fa52acda90f9f53819c81474b511e3af (diff)
[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/tty_io.c')
-rw-r--r--drivers/char/tty_io.c15
1 files changed, 2 insertions, 13 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index bd74e82d8a7..b846d87f2b5 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);
}