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Subject[PATCH 6/9] USB: serial: fix generic chars_in_buffer
Date
Make sure chars_in_buffer accounts also for data in host stack queues.

This fixes the problem with tty_wait_until_sent returning too soon at
close which could cause the final write urb to be cancelled.

Reported-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
---
drivers/usb/serial/generic.c | 15 +++++++++++----
1 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index ba61c74..8d6d790 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -308,10 +308,14 @@ static int usb_serial_generic_write_start(struct usb_serial_port *port)
/* don't have to grab the lock here, as we will
retry if != 0 */
port->write_urb_busy = 0;
- } else
- result = count;
+ return result;
+ }

- return result;
+ spin_lock_irqsave(&port->lock, flags);
+ port->tx_bytes_flight += count;
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ return count;
}

/**
@@ -399,7 +403,7 @@ int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
if (serial->type->max_in_flight_urbs)
chars = port->tx_bytes_flight;
else
- chars = kfifo_len(&port->write_fifo);
+ chars = kfifo_len(&port->write_fifo) + port->tx_bytes_flight;
spin_unlock_irqrestore(&port->lock, flags);

dbg("%s - returns %d", __func__, chars);
@@ -509,7 +513,10 @@ void usb_serial_generic_write_bulk_callback(struct urb *urb)
port->urbs_in_flight = 0;
spin_unlock_irqrestore(&port->lock, flags);
} else {
+ spin_lock_irqsave(&port->lock, flags);
+ port->tx_bytes_flight -= urb->transfer_buffer_length;
port->write_urb_busy = 0;
+ spin_unlock_irqrestore(&port->lock, flags);

if (status)
kfifo_reset_out(&port->write_fifo);
--
1.7.0.2


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