Commit 44a0c019 authored by Jon Povey's avatar Jon Povey Committed by Greg Kroah-Hartman
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USB: g_serial: don't set low_latency flag

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: default avatarJon Povey <>
Cc: Maulik Mankad <>
Cc: stable <>
Acked-by: default avatarDavid Brownell <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 93416253
......@@ -536,17 +536,11 @@ recycle:
list_move(&req->list, &port->read_pool);
/* Push from tty to ldisc; this is immediate with low_latency, and
* may trigger callbacks to this driver ... so drop the spinlock.
/* Push from tty to ldisc; without low_latency set this is handled by
* a workqueue, so we won't get callbacks and can hold port_lock
if (tty && do_push) {
/* 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->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 (port->port_usb) {
struct gserial *gser = port->port_usb;
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