hso: fix deadlock when receiving bursts of data
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>
diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 9ca2b41..a4272ed 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -258,7 +258,6 @@
* 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 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 @@
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 @@
}
}
serial->curr_rx_urb_idx = 0;
- serial->curr_rx_urb_offset = 0;
if (serial->tx_urb)
usb_kill_urb(serial->tx_urb);
