xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

USB: serial: clean up throttle handling

Browse Source 
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>
This commit is contained in:
Johan Hovold
2019-04-25 18:05:37 +02:00
parent 3f5edd58d0
commit a8d78d9f38
2 changed files with 9 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/usb/serial/generic.c
View File

@@ -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);