From: Johan Hovold <johan@kernel.org>
To: Himadri Pandya <himadrispandya@gmail.com>
Cc: linux-usb@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org, johan@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [Linux-kernel-mentees] [PATCH 07/15] usb: serial: f81534: use usb_control_msg_recv() and usb_control_msg_send()
Date: Fri, 4 Dec 2020 10:55:56 +0100 [thread overview]
Message-ID: <X8oHrKbjAg3nnJ1n@localhost> (raw)
In-Reply-To: <20201104064703.15123-8-himadrispandya@gmail.com>
On Wed, Nov 04, 2020 at 12:16:55PM +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 <himadrispandya@gmail.com>
> ---
> drivers/usb/serial/f81534.c | 63 +++++++++++--------------------------
> 1 file changed, 18 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
> index 5661fd03e545..23eb17a2c052 100644
> --- a/drivers/usb/serial/f81534.c
> +++ b/drivers/usb/serial/f81534.c
> @@ -217,38 +217,26 @@ static int f81534_set_register(struct usb_serial *serial, u16 reg, u8 data)
> struct usb_device *dev = serial->dev;
> size_t count = F81534_USB_MAX_RETRY;
> int status;
> - u8 *tmp;
> -
> - tmp = kmalloc(sizeof(u8), GFP_KERNEL);
> - if (!tmp)
> - return -ENOMEM;
> -
> - *tmp = data;
>
> /*
> * Our device maybe not reply when heavily loading, We'll retry for
> * F81534_USB_MAX_RETRY times.
> */
> while (count--) {
> - status = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
> - F81534_SET_GET_REGISTER,
> - USB_TYPE_VENDOR | USB_DIR_OUT,
> - reg, 0, tmp, sizeof(u8),
> - F81534_USB_TIMEOUT);
> - if (status > 0) {
> - status = 0;
> - break;
> - } else if (status == 0) {
> - status = -EIO;
> + status = usb_control_msg_send(dev, 0, F81534_SET_GET_REGISTER,
> + USB_TYPE_VENDOR | USB_DIR_OUT,
> + reg, 0, &data, sizeof(u8),
> + F81534_USB_TIMEOUT, GFP_KERNEL);
> + if (status) {
> + /* Try again */
> + continue;
> }
> }
Here too this change breaks the logic and the control transfer is now
repeated also after successful transfer (ten times!).
This change would also introduce an additional malloc + memcpy for every
retry.
As this is a function that is used often and the comment suggest that
having to retry isn't that rare, I suggest dropping this patch as well.
Johan
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next prev parent reply other threads:[~2020-12-04 9:55 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-04 6:46 [Linux-kernel-mentees] [PATCH 00/15] usb: serial: avoid using usb_control_msg() directly Himadri Pandya
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 01/15] usb: serial: ark3116: use usb_control_msg_recv() and usb_control_msg_send() Himadri Pandya
2020-12-04 9:16 ` Johan Hovold
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 02/15] usb: serial: belkin_sa: use usb_control_msg_send() Himadri Pandya
2020-12-04 9:17 ` Johan Hovold
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 03/15] usb: serial: ch314: use usb_control_msg_recv() and usb_control_msg_send() Himadri Pandya
2020-12-04 9:24 ` Johan Hovold
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 04/15] usb: serial: cp210x: " Himadri Pandya
2020-12-04 9:34 ` Johan Hovold
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 05/15] usb: serial: cypress_m8: " Himadri Pandya
2020-12-04 9:37 ` Johan Hovold
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 06/15] usb: serial: f81232: " Himadri Pandya
2020-12-04 9:49 ` Johan Hovold
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 07/15] usb: serial: f81534: " Himadri Pandya
2020-12-04 9:55 ` Johan Hovold [this message]
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 08/15] usb: serial: ftdi_sio: " Himadri Pandya
2020-12-04 10:03 ` Johan Hovold
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 09/15] usb: serial: io_edgeport: " Himadri Pandya
2020-12-04 10:10 ` Johan Hovold
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 10/15] usb: serial: io_ti: " Himadri Pandya
2020-12-04 10:12 ` Johan Hovold
2020-11-04 6:46 ` [Linux-kernel-mentees] [PATCH 11/15] usb: serial: ipaq: use usb_control_msg_send() Himadri Pandya
2020-12-04 10:21 ` Johan Hovold
2020-11-04 6:47 ` [Linux-kernel-mentees] [PATCH 12/15] usb: serial: ipw: " Himadri Pandya
2020-12-04 10:27 ` Johan Hovold
2020-11-04 6:47 ` [Linux-kernel-mentees] [PATCH 13/15] usb: serial: iuu_phoenix: " Himadri Pandya
2020-12-04 10:28 ` Johan Hovold
2020-11-04 6:47 ` [Linux-kernel-mentees] [PATCH 14/15] usb: serial: keyspan_pda: use usb_control_msg_recv() and usb_control_msg_send() Himadri Pandya
2020-12-04 10:31 ` Johan Hovold
2020-11-04 6:47 ` [Linux-kernel-mentees] [PATCH 15/15] usb: serial: kl5kusb105: " Himadri Pandya
2020-12-04 10:37 ` Johan Hovold
2020-11-06 10:43 ` [Linux-kernel-mentees] [PATCH 00/15] usb: serial: avoid using usb_control_msg() directly Greg KH
2020-12-04 9:09 ` Johan Hovold
2020-12-24 10:01 ` Himadri Pandya
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