mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-03 08:50:17 -04:00
46f0b1ad5b
Create and call new usb_write() instead of usbctrl_vendorreq() from
inside rtw_write{8,16,32,N}().
In old code, rtw_write{8,16,32,N}() called usbctrl_vendorreq() which in
turn uses usb_control_msg() from within a "while" loop to build a control
URB, send it off and wait for completion. usbctrl_vendorreq() was used
for both receiving and sending messages, depending on the "requesttype"
argument which is passed by callers.
Compared to usbctrl_vendorreq(), which manages both reads and writes
from and to the USB endpoint, the new usb_write() manages only writes.
For this purpose it uses the newer USB Core usb_control_msg_send() API.
The latter is preferred according both to suggestions by Greg Kroah-Hartman
and also to its actual design.
A noteworthy feature of usb_control_msg_send() is that the data pointer
can be made to a reference on the stack because it does not have the
restriction that usb_control_msg() has where the data pointer must be to
dynamically allocated memory.
usbctrl_vendorreq() used a "while" loop that we considered unnecessary
so that it is not in the new usb_write(). Furthermore, the latter has no
redundant checking, less obvious comments, no debug prints, and it manages
errors before success case. All in all, usb_write() is simpler than
usbctrl_vendorreq() and uses less lines of code.
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20210924122705.3781-15-fmdefrancesco@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.