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, 6 insertions, 2 deletions

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index f3f65171de3..538924627eb 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -901,7 +901,9 @@ int usb_serial_probe(struct usb_interface *interface,
                         dev_err(&interface->dev, "No free urbs available\n");
                         goto probe_error;
                 }
-                buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
+                buffer_size = serial->type->bulk_in_size;
+                if (!buffer_size)
+                        buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
                 port->bulk_in_size = buffer_size;
                 port->bulk_in_endpointAddress = endpoint->bEndpointAddress;
                 port->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
@@ -927,7 +929,9 @@ int usb_serial_probe(struct usb_interface *interface,
                 }
                 if (kfifo_alloc(&port->write_fifo, PAGE_SIZE, GFP_KERNEL))
                         goto probe_error;
-                buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
+                buffer_size = serial->type->bulk_out_size;
+                if (!buffer_size)
+                        buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
                 port->bulk_out_size = buffer_size;
                 port->bulk_out_endpointAddress = endpoint->bEndpointAddress;
                 port->bulk_out_buffer = kmalloc(buffer_size, GFP_KERNEL);