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USB: serial: opticon: add chars_in_buffer() implementation

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Add a chars_in_buffer() implementation so that the tty layer will wait
for outgoing buffered data to be drained when needed (e.g. on final
close()).

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Johan Hovold 2020-01-14 12:01:45 +01:00
parent b3a987b026
commit a00e718230
1 changed files with 28 additions and 17 deletions
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45
drivers/usb/serial/opticon.c
View file

@ -41,6 +41,7 @@ struct opticon_private {
bool rts; bool rts;
bool cts; bool cts;
int outstanding_urbs; int outstanding_urbs;
int outstanding_bytes;
}; };
@ -169,6 +170,7 @@ static void opticon_write_control_callback(struct urb *urb)
spin_lock_irqsave(&priv->lock, flags); spin_lock_irqsave(&priv->lock, flags);
--priv->outstanding_urbs; --priv->outstanding_urbs;
priv->outstanding_bytes -= urb->transfer_buffer_length;
spin_unlock_irqrestore(&priv->lock, flags); spin_unlock_irqrestore(&priv->lock, flags);
usb_serial_port_softint(port); usb_serial_port_softint(port);
@ -182,8 +184,8 @@ static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
struct urb *urb; struct urb *urb;
unsigned char *buffer; unsigned char *buffer;
unsigned long flags; unsigned long flags;
int status;
struct usb_ctrlrequest *dr; struct usb_ctrlrequest *dr;
int ret = -ENOMEM;
spin_lock_irqsave(&priv->lock, flags); spin_lock_irqsave(&priv->lock, flags);
if (priv->outstanding_urbs > URB_UPPER_LIMIT) { if (priv->outstanding_urbs > URB_UPPER_LIMIT) {
@ -192,19 +194,16 @@ static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
return 0; return 0;
} }
priv->outstanding_urbs++; priv->outstanding_urbs++;
priv->outstanding_bytes += count;
spin_unlock_irqrestore(&priv->lock, flags); spin_unlock_irqrestore(&priv->lock, flags);
buffer = kmalloc(count, GFP_ATOMIC); buffer = kmalloc(count, GFP_ATOMIC);
if (!buffer) { if (!buffer)
count = -ENOMEM;
goto error_no_buffer; goto error_no_buffer;
}
urb = usb_alloc_urb(0, GFP_ATOMIC); urb = usb_alloc_urb(0, GFP_ATOMIC);
if (!urb) { if (!urb)
count = -ENOMEM;
goto error_no_urb; goto error_no_urb;
}
memcpy(buffer, buf, count); memcpy(buffer, buf, count);
@ -213,10 +212,8 @@ static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
/* The connected devices do not have a bulk write endpoint, /* The connected devices do not have a bulk write endpoint,
* to transmit data to de barcode device the control endpoint is used */ * to transmit data to de barcode device the control endpoint is used */
dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC); dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
if (!dr) { if (!dr)
count = -ENOMEM;
goto error_no_dr; goto error_no_dr;
}
dr->bRequestType = USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT; dr->bRequestType = USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT;
dr->bRequest = 0x01; dr->bRequest = 0x01;
@ -230,12 +227,9 @@ static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
opticon_write_control_callback, port); opticon_write_control_callback, port);
/* send it down the pipe */ /* send it down the pipe */
status = usb_submit_urb(urb, GFP_ATOMIC); ret = usb_submit_urb(urb, GFP_ATOMIC);
if (status) { if (ret) {
dev_err(&port->dev, dev_err(&port->dev, "failed to submit write urb: %d\n", ret);
"%s - usb_submit_urb(write endpoint) failed status = %d\n",
__func__, status);
count = status;
goto error; goto error;
} }
@ -253,8 +247,10 @@ error_no_urb:
error_no_buffer: error_no_buffer:
spin_lock_irqsave(&priv->lock, flags); spin_lock_irqsave(&priv->lock, flags);
--priv->outstanding_urbs; --priv->outstanding_urbs;
priv->outstanding_bytes -= count;
spin_unlock_irqrestore(&priv->lock, flags); spin_unlock_irqrestore(&priv->lock, flags);
return count;
return ret;
} }
static int opticon_write_room(struct tty_struct *tty) static int opticon_write_room(struct tty_struct *tty)
@ -279,6 +275,20 @@ static int opticon_write_room(struct tty_struct *tty)
return 2048; return 2048;
} }
static int opticon_chars_in_buffer(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
struct opticon_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
int count;
spin_lock_irqsave(&priv->lock, flags);
count = priv->outstanding_bytes;
spin_unlock_irqrestore(&priv->lock, flags);
return count;
}
static int opticon_tiocmget(struct tty_struct *tty) static int opticon_tiocmget(struct tty_struct *tty)
{ {
struct usb_serial_port *port = tty->driver_data; struct usb_serial_port *port = tty->driver_data;
@ -383,6 +393,7 @@ static struct usb_serial_driver opticon_device = {
.open = opticon_open, .open = opticon_open,
.write = opticon_write, .write = opticon_write,
.write_room = opticon_write_room, .write_room = opticon_write_room,
.chars_in_buffer = opticon_chars_in_buffer,
.throttle = usb_serial_generic_throttle, .throttle = usb_serial_generic_throttle,
.unthrottle = usb_serial_generic_unthrottle, .unthrottle = usb_serial_generic_unthrottle,
.get_serial = get_serial_info, .get_serial = get_serial_info,