static void tty_buffer_init(struct tty_struct *tty)
{
+ spin_lock_init(&tty->buf.lock);
tty->buf.head = NULL;
tty->buf.tail = NULL;
tty->buf.free = NULL;
p->used = 0;
p->size = size;
p->next = NULL;
+ p->active = 0;
p->char_buf_ptr = (char *)(p->data);
p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
/* printk("Flip create %p\n", p); */
int tty_buffer_request_room(struct tty_struct *tty, size_t size)
{
- struct tty_buffer *b = tty->buf.tail, *n;
- int left = 0;
+ struct tty_buffer *b, *n;
+ int left;
+ unsigned long flags;
+
+ spin_lock_irqsave(&tty->buf.lock, flags);
/* 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 != NULL)
+ if ((b = tty->buf.tail) != NULL) {
left = b->size - b->used;
- if(left >= size)
- return size;
- /* This is the slow path - looking for new buffers to use */
- n = tty_buffer_find(tty, size);
- if(n == NULL)
- return left;
- if(b != NULL)
- b->next = n;
- else
- tty->buf.head = n;
- tty->buf.tail = n;
+ b->active = 1;
+ } else
+ left = 0;
+
+ if (left < size) {
+ /* This is the slow path - looking for new buffers to use */
+ if ((n = tty_buffer_find(tty, size)) != NULL) {
+ if (b != NULL) {
+ b->next = n;
+ b->active = 0;
+ } else
+ tty->buf.head = n;
+ tty->buf.tail = n;
+ n->active = 1;
+ } else
+ size = left;
+ }
+
+ spin_unlock_irqrestore(&tty->buf.lock, flags);
return size;
}
int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size)
{
int space = tty_buffer_request_room(tty, size);
- struct tty_buffer *tb = tty->buf.tail;
- *chars = tb->char_buf_ptr + tb->used;
- memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
- tb->used += space;
+ if (likely(space)) {
+ struct tty_buffer *tb = tty->buf.tail;
+ *chars = tb->char_buf_ptr + tb->used;
+ memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
+ tb->used += space;
+ }
return space;
}
int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size)
{
int space = tty_buffer_request_room(tty, size);
- struct tty_buffer *tb = tty->buf.tail;
- *chars = tb->char_buf_ptr + tb->used;
- *flags = tb->flag_buf_ptr + tb->used;
- tb->used += space;
+ if (likely(space)) {
+ struct tty_buffer *tb = tty->buf.tail;
+ *chars = tb->char_buf_ptr + tb->used;
+ *flags = tb->flag_buf_ptr + tb->used;
+ tb->used += space;
+ }
return space;
}
schedule_delayed_work(&tty->buf.work, 1);
goto out;
}
- spin_lock_irqsave(&tty->read_lock, flags);
- while((tbuf = tty->buf.head) != NULL) {
+ spin_lock_irqsave(&tty->buf.lock, flags);
+ while((tbuf = tty->buf.head) != NULL && !tbuf->active) {
tty->buf.head = tbuf->next;
if (tty->buf.head == NULL)
tty->buf.tail = NULL;
- spin_unlock_irqrestore(&tty->read_lock, flags);
+ spin_unlock_irqrestore(&tty->buf.lock, flags);
/* printk("Process buffer %p for %d\n", tbuf, tbuf->used); */
disc->receive_buf(tty, tbuf->char_buf_ptr,
tbuf->flag_buf_ptr,
tbuf->used);
- spin_lock_irqsave(&tty->read_lock, flags);
+ spin_lock_irqsave(&tty->buf.lock, flags);
tty_buffer_free(tty, tbuf);
}
- spin_unlock_irqrestore(&tty->read_lock, flags);
+ spin_unlock_irqrestore(&tty->buf.lock, flags);
out:
tty_ldisc_deref(disc);
}
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;
+ spin_unlock_irqrestore(&tty->buf.lock, flags);
+
if (tty->low_latency)
flush_to_ldisc((void *) tty);
else