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USB: g_serial: don't set low_latency flag

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No longer set low_latency flag as it causes this warning backtrace:

  WARNING: at kernel/mutex.c:207 __mutex_lock_slowpath+0x6c/0x288()

Fix associated locking and wakeups.

Signed-off-by: Jon Povey <jon.povey@racelogic.co.uk>
Cc: Maulik Mankad <x0082077@ti.com>
Cc: stable <stable@kernel.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jon Povey
2010-06-14 19:41:04 +09:00
committed by Greg Kroah-Hartman
parent 9341625307
commit 44a0c0190b
1 changed files with 2 additions and 13 deletions
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15
drivers/usb/gadget/u_serial.c
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@@ -536,17 +536,11 @@ recycle:
list_move(&req->list, &port->read_pool); list_move(&req->list, &port->read_pool);
} }
/* Push from tty to ldisc; this is immediate with low_latency, and /* Push from tty to ldisc; without low_latency set this is handled by
* may trigger callbacks to this driver ... so drop the spinlock. * a workqueue, so we won't get callbacks and can hold port_lock
*/ */
if (tty && do_push) { if (tty && do_push) {
spin_unlock_irq(&port->port_lock);
tty_flip_buffer_push(tty); tty_flip_buffer_push(tty);
wake_up_interruptible(&tty->read_wait);
spin_lock_irq(&port->port_lock);
/* tty may have been closed */
tty = port->port_tty;
} }
@@ -784,11 +778,6 @@ static int gs_open(struct tty_struct *tty, struct file *file)
port->open_count = 1; port->open_count = 1;
port->openclose = false; port->openclose = false;
/* low_latency means ldiscs work in tasklet context, without
* needing a workqueue schedule ... easier to keep up.
*/
tty->low_latency = 1;
/* if connected, start the I/O stream */ /* if connected, start the I/O stream */
if (port->port_usb) { if (port->port_usb) {
struct gserial *gser = port->port_usb; struct gserial *gser = port->port_usb;