3.16.84-rc1 review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan@kernel.org
commit 38c0d5bdf4973f9f5a888166e9d3e9ed0d32057a upstream.
Commit f4a4cbb2047e ("USB: ir-usb: reimplement using generic framework") switched to using the generic write implementation which may combine multiple write requests into larger transfers. This can break the IrLAP protocol where end-of-frame is determined using the USB short packet mechanism, for example, if multiple frames are sent in rapid succession.
Fixes: f4a4cbb2047e ("USB: ir-usb: reimplement using generic framework") Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/usb/serial/ir-usb.c | 113 +++++++++++++++++++++++++++++------- 1 file changed, 91 insertions(+), 22 deletions(-)
--- a/drivers/usb/serial/ir-usb.c +++ b/drivers/usb/serial/ir-usb.c @@ -49,9 +49,10 @@ static int buffer_size; static int xbof = -1;
static int ir_startup (struct usb_serial *serial); -static int ir_open(struct tty_struct *tty, struct usb_serial_port *port); -static int ir_prepare_write_buffer(struct usb_serial_port *port, - void *dest, size_t size); +static int ir_write(struct tty_struct *tty, struct usb_serial_port *port, + const unsigned char *buf, int count); +static int ir_write_room(struct tty_struct *tty); +static void ir_write_bulk_callback(struct urb *urb); static void ir_process_read_urb(struct urb *urb); static void ir_set_termios(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios); @@ -81,8 +82,9 @@ static struct usb_serial_driver ir_devic .num_ports = 1, .set_termios = ir_set_termios, .attach = ir_startup, - .open = ir_open, - .prepare_write_buffer = ir_prepare_write_buffer, + .write = ir_write, + .write_room = ir_write_room, + .write_bulk_callback = ir_write_bulk_callback, .process_read_urb = ir_process_read_urb, };
@@ -258,35 +260,102 @@ static int ir_startup(struct usb_serial return 0; }
-static int ir_open(struct tty_struct *tty, struct usb_serial_port *port) +static int ir_write(struct tty_struct *tty, struct usb_serial_port *port, + const unsigned char *buf, int count) { - int i; + struct urb *urb = NULL; + unsigned long flags; + int ret;
- for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) - port->write_urbs[i]->transfer_flags = URB_ZERO_PACKET; + if (port->bulk_out_size == 0) + return -EINVAL;
- /* Start reading from the device */ - return usb_serial_generic_open(tty, port); -} + if (count == 0) + return 0;
-static int ir_prepare_write_buffer(struct usb_serial_port *port, - void *dest, size_t size) -{ - unsigned char *buf = dest; - int count; + count = min(count, port->bulk_out_size - 1); + + spin_lock_irqsave(&port->lock, flags); + if (__test_and_clear_bit(0, &port->write_urbs_free)) { + urb = port->write_urbs[0]; + port->tx_bytes += count; + } + spin_unlock_irqrestore(&port->lock, flags); + + if (!urb) + return 0;
/* * The first byte of the packet we send to the device contains an - * inbound header which indicates an additional number of BOFs and + * outbound header which indicates an additional number of BOFs and * a baud rate change. * * See section 5.4.2.2 of the USB IrDA spec. */ - *buf = ir_xbof | ir_baud; + *(u8 *)urb->transfer_buffer = ir_xbof | ir_baud; + + memcpy(urb->transfer_buffer + 1, buf, count); + + urb->transfer_buffer_length = count + 1; + urb->transfer_flags = URB_ZERO_PACKET; + + ret = usb_submit_urb(urb, GFP_ATOMIC); + if (ret) { + dev_err(&port->dev, "failed to submit write urb: %d\n", ret); + + spin_lock_irqsave(&port->lock, flags); + __set_bit(0, &port->write_urbs_free); + port->tx_bytes -= count; + spin_unlock_irqrestore(&port->lock, flags); + + return ret; + } + + return count; +} + +static void ir_write_bulk_callback(struct urb *urb) +{ + struct usb_serial_port *port = urb->context; + int status = urb->status; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + __set_bit(0, &port->write_urbs_free); + port->tx_bytes -= urb->transfer_buffer_length - 1; + spin_unlock_irqrestore(&port->lock, flags); + + switch (status) { + case 0: + break; + case -ENOENT: + case -ECONNRESET: + case -ESHUTDOWN: + dev_dbg(&port->dev, "write urb stopped: %d\n", status); + return; + case -EPIPE: + dev_err(&port->dev, "write urb stopped: %d\n", status); + return; + default: + dev_err(&port->dev, "nonzero write-urb status: %d\n", status); + break; + } + + usb_serial_port_softint(port); +} + +static int ir_write_room(struct tty_struct *tty) +{ + struct usb_serial_port *port = tty->driver_data; + int count = 0; + + if (port->bulk_out_size == 0) + return 0; + + if (test_bit(0, &port->write_urbs_free)) + count = port->bulk_out_size - 1;
- count = kfifo_out_locked(&port->write_fifo, buf + 1, size - 1, - &port->lock); - return count + 1; + return count; }
static void ir_process_read_urb(struct urb *urb)