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authorPaul Fulghum <paulkf@microgate.com>2006-06-28 04:26:49 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-28 14:59:05 -0700
commit33b37a33c242542fac2980b8ccd90977388b7a8d (patch)
treee3a18605e57e1d1268dd04e9a3e5276f7f0488fe /drivers/char/tty_io.c
parent2c3bb20f46709a0adfa7ea408013edbcab945d5a (diff)
downloadop-kernel-dev-33b37a33c242542fac2980b8ccd90977388b7a8d.zip
op-kernel-dev-33b37a33c242542fac2980b8ccd90977388b7a8d.tar.gz
[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/tty_io.c')
-rw-r--r--drivers/char/tty_io.c16
1 files changed, 4 insertions, 12 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 1f03ebf..8d19f72 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)
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