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| author | Paul Fulghum <paulkf@microgate.com> | 2006-06-28 04:26:49 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-28 14:59:05 -0700 |
| commit | 33b37a33c242542fac2980b8ccd90977388b7a8d (patch) | |
| tree | e3a18605e57e1d1268dd04e9a3e5276f7f0488fe /drivers/char | |
| parent | 2c3bb20f46709a0adfa7ea408013edbcab945d5a (diff) | |
| download | linux-33b37a33c242542fac2980b8ccd90977388b7a8d.tar.gz linux-33b37a33c242542fac2980b8ccd90977388b7a8d.tar.bz2 linux-33b37a33c242542fac2980b8ccd90977388b7a8d.zip | |
[PATCH] remove active field from tty buffer structure
Remove 'active' field from tty buffer structure. This was added in 2.6.16
as part of a patch to make the new tty buffering SMP safe. This field is
unnecessary with the more intelligently written flush_to_ldisc that adds
receive_room handling.
Removing this field reverts to simpler logic where the tail buffer is
always the 'active' buffer, which should not be freed by flush_to_ldisc.
(active == buffer being filled with new data)
The result is simpler, smaller, and faster tty buffer code.
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/tty_io.c | 16 |
1 files changed, 4 insertions, 12 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 1f03ebf165d9..8d19f7281f0b 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -267,7 +267,6 @@ static struct tty_buffer *tty_buffer_alloc(size_t size) p->used = 0; p->size = size; p->next = NULL; - p->active = 0; p->commit = 0; p->read = 0; p->char_buf_ptr = (char *)(p->data); @@ -327,10 +326,9 @@ int tty_buffer_request_room(struct tty_struct *tty, size_t size) /* OPTIMISATION: We could keep a per tty "zero" sized buffer to remove this conditional if its worth it. This would be invisible to the callers */ - if ((b = tty->buf.tail) != NULL) { + if ((b = tty->buf.tail) != NULL) left = b->size - b->used; - b->active = 1; - } else + else left = 0; if (left < size) { @@ -338,12 +336,10 @@ int tty_buffer_request_room(struct tty_struct *tty, size_t size) if ((n = tty_buffer_find(tty, size)) != NULL) { if (b != NULL) { b->next = n; - b->active = 0; b->commit = b->used; } else tty->buf.head = n; tty->buf.tail = n; - n->active = 1; } else size = left; } @@ -404,10 +400,8 @@ void tty_schedule_flip(struct tty_struct *tty) { unsigned long flags; spin_lock_irqsave(&tty->buf.lock, flags); - if (tty->buf.tail != NULL) { - tty->buf.tail->active = 0; + if (tty->buf.tail != NULL) tty->buf.tail->commit = tty->buf.tail->used; - } spin_unlock_irqrestore(&tty->buf.lock, flags); schedule_delayed_work(&tty->buf.work, 1); } @@ -2902,10 +2896,8 @@ void tty_flip_buffer_push(struct tty_struct *tty) { unsigned long flags; spin_lock_irqsave(&tty->buf.lock, flags); - if (tty->buf.tail != NULL) { - tty->buf.tail->active = 0; + if (tty->buf.tail != NULL) tty->buf.tail->commit = tty->buf.tail->used; - } spin_unlock_irqrestore(&tty->buf.lock, flags); if (tty->low_latency) |