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[85.228.174.190]) by smtp.gmail.com with ESMTPSA id f18sm1474034lfc.198.2020.12.04.01.15.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Dec 2020 01:15:34 -0800 (PST) Received: from johan by xi.terra with local (Exim 4.93.0.4) (envelope-from ) id 1kl7CB-0005KA-Or; Fri, 04 Dec 2020 10:16:07 +0100 Date: Fri, 4 Dec 2020 10:16:07 +0100 From: Johan Hovold To: Himadri Pandya Cc: johan@kernel.org, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [PATCH 01/15] usb: serial: ark3116: use usb_control_msg_recv() and usb_control_msg_send() Message-ID: References: <20201104064703.15123-1-himadrispandya@gmail.com> <20201104064703.15123-2-himadrispandya@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201104064703.15123-2-himadrispandya@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Wed, Nov 04, 2020 at 12:16:49PM +0530, Himadri Pandya wrote: > The new usb_control_msg_recv() and usb_control_msg_send() nicely wraps > usb_control_msg() with proper error check. Hence use the wrappers > instead of calling usb_control_msg() directly. > > Signed-off-by: Himadri Pandya > --- > drivers/usb/serial/ark3116.c | 29 ++++------------------------- > 1 file changed, 4 insertions(+), 25 deletions(-) > > diff --git a/drivers/usb/serial/ark3116.c b/drivers/usb/serial/ark3116.c > index 71a9206ea1e2..51302892c779 100644 > --- a/drivers/usb/serial/ark3116.c > +++ b/drivers/usb/serial/ark3116.c > @@ -77,38 +77,17 @@ struct ark3116_private { > static int ark3116_write_reg(struct usb_serial *serial, > unsigned reg, __u8 val) > { > - int result; > /* 0xfe 0x40 are magic values taken from original driver */ > - result = usb_control_msg(serial->dev, > - usb_sndctrlpipe(serial->dev, 0), > - 0xfe, 0x40, val, reg, > - NULL, 0, ARK_TIMEOUT); > - if (result) > - return result; > - > - return 0; > + return usb_control_msg_send(serial->dev, 0, 0xfe, 0x40, val, reg, NULL, 0, > + ARK_TIMEOUT, GFP_KERNEL); For control transfers without a data stage there's no point in using usb_control_msg_send() as it already returns a negative errno on error or 0 on success. > } > > static int ark3116_read_reg(struct usb_serial *serial, > unsigned reg, unsigned char *buf) > { > - int result; > /* 0xfe 0xc0 are magic values taken from original driver */ > - result = usb_control_msg(serial->dev, > - usb_rcvctrlpipe(serial->dev, 0), > - 0xfe, 0xc0, 0, reg, > - buf, 1, ARK_TIMEOUT); > - if (result < 1) { > - dev_err(&serial->interface->dev, > - "failed to read register %u: %d\n", > - reg, result); > - if (result >= 0) > - result = -EIO; > - > - return result; > - } > - > - return 0; > + return usb_control_msg_recv(serial->dev, 0, 0xfe, 0xc0, 0, reg, buf, 1, > + ARK_TIMEOUT, GFP_KERNEL); This driver already use a DMA-able transfer buffer which is allocated once and then passed to this helper repeatedly. This change would introduce additional redandant memdup + memcpy for every call and for no real gain. You also have an unrelated change here as you simply remove an existing error message. Please drop this patch. Johan