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hso: fix deadlock when receiving bursts of data

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When the module sends bursts of data, sometimes a deadlock happens in
the hso driver when the tty buffer doesn't get the chance to be flushed
quickly enough.

Remove the endless while loop in function put_rxbuf_data() which is
called by the urb completion handler.
If there isn't enough room in the tty buffer, discards all the data
received in the URB.

Cc: David Miller <davem@davemloft.net>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Jan Dumon <j.dumon@option.com>
Signed-off-by: Olivier Sobrie <olivier@sobrie.be>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Olivier Sobrie 2014-07-14 12:08:50 +02:00 committed by David S. Miller
parent 5c763edfe4
commit 8f9818af4e
1 changed files with 20 additions and 24 deletions
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44
drivers/net/usb/hso.c
View File

@ -258,7 +258,6 @@ struct hso_serial {
* so as not to drop characters on the floor.
*/
int curr_rx_urb_idx;
u16 curr_rx_urb_offset;
u8 rx_urb_filled[MAX_RX_URBS];
struct tasklet_struct unthrottle_tasklet;
};
@ -2001,8 +2000,7 @@ static void ctrl_callback(struct urb *urb)
static int put_rxbuf_data(struct urb *urb, struct hso_serial *serial)
{
struct tty_struct *tty;
int write_length_remaining = 0;
int curr_write_len;
int count;
/* Sanity check */
if (urb == NULL || serial == NULL) {
@ -2012,29 +2010,28 @@ static int put_rxbuf_data(struct urb *urb, struct hso_serial *serial)
tty = tty_port_tty_get(&serial->port);
/* Push data to tty */
write_length_remaining = urb->actual_length -
serial->curr_rx_urb_offset;
D1("data to push to tty");
while (write_length_remaining) {
if (tty && test_bit(TTY_THROTTLED, &tty->flags)) {
tty_kref_put(tty);
return -1;
}
curr_write_len = tty_insert_flip_string(&serial->port,
urb->transfer_buffer + serial->curr_rx_urb_offset,
write_length_remaining);
serial->curr_rx_urb_offset += curr_write_len;
write_length_remaining -= curr_write_len;
tty_flip_buffer_push(&serial->port);
if (tty && test_bit(TTY_THROTTLED, &tty->flags)) {
tty_kref_put(tty);
return -1;
}
/* Push data to tty */
D1("data to push to tty");
count = tty_buffer_request_room(&serial->port, urb->actual_length);
if (count >= urb->actual_length) {
tty_insert_flip_string(&serial->port, urb->transfer_buffer,
urb->actual_length);
tty_flip_buffer_push(&serial->port);
} else {
dev_warn(&serial->parent->usb->dev,
"dropping data, %d bytes lost\n", urb->actual_length);
}
tty_kref_put(tty);
if (write_length_remaining == 0) {
serial->curr_rx_urb_offset = 0;
serial->rx_urb_filled[hso_urb_to_index(serial, urb)] = 0;
}
return write_length_remaining;
serial->rx_urb_filled[hso_urb_to_index(serial, urb)] = 0;
return 0;
}
@ -2205,7 +2202,6 @@ static int hso_stop_serial_device(struct hso_device *hso_dev)
}
}
serial->curr_rx_urb_idx = 0;
serial->curr_rx_urb_offset = 0;
if (serial->tx_urb)
usb_kill_urb(serial->tx_urb);