[PATCH v2 3/3] Docs: usb: update writesize, copy_from_user, usb_fill_bulk_urb, usb_submit_urb

From: Philipp Hortmann
Date: Sat Oct 30 2021 - 07:25:19 EST


update code examples writesize, copy_from_user, usb_fill_bulk_urb,
usb_submit_urb in skel_write() according to usb-skeleton.c

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@xxxxxxxxx>
---
.../driver-api/usb/writing_usb_driver.rst | 24 ++++++++++---------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/Documentation/driver-api/usb/writing_usb_driver.rst b/Documentation/driver-api/usb/writing_usb_driver.rst
index 24374cdb677b..9cdd9f923974 100644
--- a/Documentation/driver-api/usb/writing_usb_driver.rst
+++ b/Documentation/driver-api/usb/writing_usb_driver.rst
@@ -185,24 +185,26 @@ space, points the urb to the data and submits the urb to the USB
subsystem. This can be seen in the following code::

/* we can only write as much as 1 urb will hold */
- bytes_written = (count > skel->bulk_out_size) ? skel->bulk_out_size : count;
+ size_t writesize = min_t(size_t, count, MAX_TRANSFER);

/* copy the data from user space into our urb */
- copy_from_user(skel->write_urb->transfer_buffer, buffer, bytes_written);
+ copy_from_user(buf, user_buffer, writesize);

/* set up our urb */
- usb_fill_bulk_urb(skel->write_urb,
- skel->dev,
- usb_sndbulkpipe(skel->dev, skel->bulk_out_endpointAddr),
- skel->write_urb->transfer_buffer,
- bytes_written,
+ usb_fill_bulk_urb(urb,
+ dev->udev,
+ usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
+ buf,
+ writesize,
skel_write_bulk_callback,
- skel);
+ dev);

/* send the data out the bulk port */
- result = usb_submit_urb(skel->write_urb);
- if (result) {
- err("Failed submitting write urb, error %d", result);
+ retval = usb_submit_urb(urb, GFP_KERNEL);
+ if (retval) {
+ dev_err(&dev->interface->dev,
+ "%s - failed submitting write urb, error %d\n",
+ __func__, retval);
}


--
2.25.1