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tty: make receive_buf() return the amout of bytes received

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it makes it simpler to keep track of the amount of
bytes received and simplifies how flush_to_ldisc counts
the remaining bytes. It also fixes a bug of lost bytes
on n_tty when flushing too many bytes via the USB
serial gadget driver.

Tested-by: Stefan Bigler <stefan.bigler@keymile.com>
Tested-by: Toby Gray <toby.gray@realvnc.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Felipe Balbi
2011-03-21 12:25:08 +02:00
committed by Greg Kroah-Hartman
parent e9a470f445
commit b1c43f82c5
20 changed files with 125 additions and 113 deletions
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15
drivers/tty/tty_buffer.c
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@ -416,6 +416,7 @@ static void flush_to_ldisc(struct work_struct *work)
struct tty_buffer *head, *tail = tty->buf.tail;
int seen_tail = 0;
while ((head = tty->buf.head) != NULL) {
int copied;
int count;
char *char_buf;
unsigned char *flag_buf;
@ -442,17 +443,19 @@ static void flush_to_ldisc(struct work_struct *work)
line discipline as we want to empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags))
break;
if (!tty->receive_room || seen_tail)
break;
if (count > tty->receive_room)
count = tty->receive_room;
char_buf = head->char_buf_ptr + head->read;
flag_buf = head->flag_buf_ptr + head->read;
head->read += count;
spin_unlock_irqrestore(&tty->buf.lock, flags);
disc->ops->receive_buf(tty, char_buf,
copied = disc->ops->receive_buf(tty, char_buf,
flag_buf, count);
spin_lock_irqsave(&tty->buf.lock, flags);
head->read += copied;
if (copied == 0 || seen_tail) {
schedule_work(&tty->buf.work);
break;
}
}
clear_bit(TTY_FLUSHING, &tty->flags);
}