USB: serial: allow drivers to define bulk buffer sizes

Allow drivers to define custom bulk in/out buffer sizes in struct
usb_serial_driver. If not set, fall back to the default buffer size
which matches the endpoint size.

Three drivers are currently freeing the pre-allocated buffers and
allocating larger ones to achieve this at port probe (ftdi_sio) or even
at port open (ipaq and iuu_phoenix), which needless to say is suboptimal.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index b7682fed1d9c..ab311dab3383 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -179,6 +179,8 @@ static inline void usb_set_serial_data(struct usb_serial *serial, void *data)
  * @id_table: pointer to a list of usb_device_id structures that define all
  *      of the devices this structure can support.
  * @num_ports: the number of different ports this device will have.
+ * @bulk_in_size: bytes to allocate for bulk-in buffer (0 = end-point size)
+ * @bulk_out_size: bytes to allocate for bulk-out buffer (0 = end-point size)
  * @calc_num_ports: pointer to a function to determine how many ports this
  *      device has dynamically.  It will be called after the probe()
  *      callback is called, but before attach()
@@ -223,6 +225,9 @@ struct usb_serial_driver {
         struct usb_dynids       dynids;
         int                     max_in_flight_urbs;
 
+        size_t                  bulk_in_size;
+        size_t                  bulk_out_size;
+
         int (*probe)(struct usb_serial *serial, const struct usb_device_id *id);
         int (*attach)(struct usb_serial *serial);
         int (*calc_num_ports) (struct usb_serial *serial);