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From: Greg Kroah-Hartman on 5 Aug 2010 18:50
From: Arnd Bergmann <arnd(a)arndb.de>

The wait_event_interruptible_timeout in acm_port_down is
never reached. Remove it to avoid possible deadlocks
with the big tty mutex if someone were to start using
the blocking version of acm_port_down.

Signed-off-by: Arnd Bergmann <arnd(a)arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>
---
drivers/usb/class/cdc-acm.c | 12 +++---------
1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 89d260d..1833b3a 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -636,19 +636,13 @@ static void acm_tty_unregister(struct acm *acm)

static int acm_tty_chars_in_buffer(struct tty_struct *tty);

-static void acm_port_down(struct acm *acm, int drain)
+static void acm_port_down(struct acm *acm)
{
int i, nr = acm->rx_buflimit;
mutex_lock(&open_mutex);
if (acm->dev) {
usb_autopm_get_interface(acm->control);
acm_set_control(acm, acm->ctrlout = 0);
- /* try letting the last writes drain naturally */
- if (drain) {
- wait_event_interruptible_timeout(acm->drain_wait,
- (ACM_NW == acm_wb_is_avail(acm)) || !acm->dev,
- ACM_CLOSE_TIMEOUT * HZ);
- }
usb_kill_urb(acm->ctrlurb);
for (i = 0; i < ACM_NW; i++)
usb_kill_urb(acm->wb[i].urb);
@@ -664,7 +658,7 @@ static void acm_tty_hangup(struct tty_struct *tty)
{
struct acm *acm = tty->driver_data;
tty_port_hangup(&acm->port);
- acm_port_down(acm, 0);
+ acm_port_down(acm);
}

static void acm_tty_close(struct tty_struct *tty, struct file *filp)
@@ -685,7 +679,7 @@ static void acm_tty_close(struct tty_struct *tty, struct file *filp)
mutex_unlock(&open_mutex);
return;
}
- acm_port_down(acm, 0);
+ acm_port_down(acm);
tty_port_close_end(&acm->port, tty);
tty_port_tty_set(&acm->port, NULL);
}
--
1.7.2

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Prev: [PATCH 30/67] serial: Change the wait for carrier locking
Next: [PATCH 04/67] serial: add UART_CAP_EFR and UART_CAP_SLEEP flags to 16C950 UARTs definition