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Date:   Fri, 29 Oct 2021 21:40:04 +0200
From:   Philipp Hortmann <philipp.g.hortmann@gmail.com>
To:     corbet@lwn.net, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     linux-usb@vger.kernel.org
Subject: [PATCH 3/3] Docs: usb: update writesize, copy_from_user,
 usb_fill_bulk_urb, usb_submit_urb
Message-ID: <939d9e91d1ac12003a08d7694b6d6bd29ba2a57d.1635533924.git.philipp.g.hortmann@gmail.com>
References: <cover.1635533924.git.philipp.g.hortmann@gmail.com>
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Precedence: bulk

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@gmail.com>
---
 .../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 14eda0342649..02c28ee10b91 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