@@ -106,12 +106,8 @@ void usb_serial_generic_deregister(void)
int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
{
int result = 0;
- unsigned long flags;
- spin_lock_irqsave(&port->lock, flags);
- port->throttled = 0;
- port->throttle_req = 0;
- spin_unlock_irqrestore(&port->lock, flags);
+ clear_bit(USB_SERIAL_THROTTLED, &port->flags);
if (port->bulk_in_size)
result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
@@ -375,7 +371,6 @@ void usb_serial_generic_read_bulk_callback(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
unsigned char *data = urb->transfer_buffer;
- unsigned long flags;
bool stopped = false;
int status = urb->status;
int i;
@@ -429,15 +424,10 @@ void usb_serial_generic_read_bulk_callback(struct urb *urb)
if (stopped)
return;
- /* Throttle the device if requested by tty */
- spin_lock_irqsave(&port->lock, flags);
- port->throttled = port->throttle_req;
- if (!port->throttled) {
- spin_unlock_irqrestore(&port->lock, flags);
- usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
- } else {
- spin_unlock_irqrestore(&port->lock, flags);
- }
+ if (test_bit(USB_SERIAL_THROTTLED, &port->flags))
+ return;
+
+ usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
@@ -485,23 +475,16 @@ EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
void usb_serial_generic_throttle(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
- unsigned long flags;
- spin_lock_irqsave(&port->lock, flags);
- port->throttle_req = 1;
- spin_unlock_irqrestore(&port->lock, flags);
+ set_bit(USB_SERIAL_THROTTLED, &port->flags);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
void usb_serial_generic_unthrottle(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
- int was_throttled;
- spin_lock_irq(&port->lock);
- was_throttled = port->throttled;
- port->throttled = port->throttle_req = 0;
- spin_unlock_irq(&port->lock);
+ clear_bit(USB_SERIAL_THROTTLED, &port->flags);
/*
* Matches the smp_mb__after_atomic() in
@@ -509,8 +492,7 @@ void usb_serial_generic_unthrottle(struct tty_struct *tty)
*/
smp_mb();
- if (was_throttled)
- usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
+ usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
@@ -28,6 +28,7 @@
/* USB serial flags */
#define USB_SERIAL_WRITE_BUSY 0
+#define USB_SERIAL_THROTTLED 1
/**
* usb_serial_port: structure for the specific ports of a device.
@@ -67,8 +68,6 @@
* @flags: usb serial port flags
* @write_wait: a wait_queue_head_t used by the port.
* @work: work queue entry for the line discipline waking up.
- * @throttled: nonzero if the read urb is inactive to throttle the device
- * @throttle_req: nonzero if the tty wants to throttle us
* @dev: pointer to the serial device
*
* This structure is used by the usb-serial core and drivers for the specific
@@ -115,8 +114,6 @@ struct usb_serial_port {
unsigned long flags;
wait_queue_head_t write_wait;
struct work_struct work;
- char throttled;
- char throttle_req;
unsigned long sysrq; /* sysrq timeout */
struct device dev;
};
Clean up the throttle implementation by dropping the redundant throttle_req flag which was a remnant from back when there was only a single read URB. Also convert the throttled flag to an atomic bit flag. Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/usb/serial/generic.c | 34 ++++++++-------------------------- include/linux/usb/serial.h | 5 +---- 2 files changed, 9 insertions(+), 30 deletions(-)