| From | Peter Hurley <> | Subject | [PATCH 03/18] tty: Simplify tty buffer/ldisc interface with helper function | Date | Tue, 19 Mar 2013 16:21:38 -0400 |
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Ldisc interface functions must be called with interrupts enabled. Separating the ldisc calls into a helper function simplies the spin lock management.
Update the buffer's read index _after_ the data has been received by the ldisc.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> --- drivers/tty/tty_buffer.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-)
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 6aa40f0..77e8115 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -403,6 +403,19 @@ int tty_prepare_flip_string_flags(struct tty_port *port, EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); +static int receive_buf(struct tty_struct *tty, const unsigned char *char_buf, + char *flag_buf, int count) +{ + struct tty_ldisc *disc = tty->ldisc; + + if (disc->ops->receive_room) + tty->receive_room = disc->ops->receive_room(tty); + if (count > tty->receive_room) + count = tty->receive_room; + if (count) + disc->ops->receive_buf(tty, char_buf, flag_buf, count); + return count; +} /** * flush_to_ldisc @@ -454,19 +467,16 @@ static void flush_to_ldisc(struct work_struct *work) line discipline as we want to empty the queue */ if (test_bit(TTYP_FLUSHPENDING, &port->iflags)) break; - if (disc->ops->receive_room) - tty->receive_room = disc->ops->receive_room(tty); - if (!tty->receive_room) - 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(&buf->lock, flags); - disc->ops->receive_buf(tty, char_buf, - flag_buf, count); + + count = receive_buf(tty, char_buf, flag_buf, count); + spin_lock_irqsave(&buf->lock, flags); + if (!count) + break; + head->read += count; } clear_bit(TTYP_FLUSHING, &port->iflags); } -- 1.8.1.2
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