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SubjectRe: [PATCH 07/15] usb: serial: f81534: use usb_control_msg_recv() and usb_control_msg_send()
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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