linux-kernel - Re: [PATCH 2/4] staging/serqt_usb2: refactor qt_read_bulk_callback() in serqt

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Date:	Wed, 14 Nov 2012 15:41:11 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	YAMANE Toshiaki <yamanetoshi@...il.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Devendra Naga <devendra.aaru@...il.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Alan Stern <stern@...land.harvard.edu>,
	Mauro Carvalho Chehab <mchehab@...hat.com>,
	devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] staging/serqt_usb2: refactor qt_read_bulk_callback()
 in serqt_usb2.c

On Sat, Nov 10, 2012 at 06:33:56AM +0900, YAMANE Toshiaki wrote:
> Modified to eliminate the deep nesting and redundant description.
> 
> Signed-off-by: YAMANE Toshiaki <yamanetoshi@...il.com>
> ---
>  drivers/staging/serqt_usb2/serqt_usb2.c |  147 +++++++++++++++++--------------
>  1 file changed, 80 insertions(+), 67 deletions(-)
> 
> diff --git a/drivers/staging/serqt_usb2/serqt_usb2.c b/drivers/staging/serqt_usb2/serqt_usb2.c
> index 9bc8923..0395bdf 100644
> --- a/drivers/staging/serqt_usb2/serqt_usb2.c
> +++ b/drivers/staging/serqt_usb2/serqt_usb2.c
> @@ -291,22 +291,89 @@ static void qt_interrupt_callback(struct urb *urb)
>  	/* FIXME */
>  }
>  
> +static int qt_status_change(unsigned int limit,
> +			    unsigned char *data,
> +			    int i,
> +			    struct quatech_port *qt_port,
> +			    struct usb_serial_port *port)
> +{
> +	void (*fn)(struct quatech_port *, unsigned char);
> +
> +	if (0x00 == data[i + 2]) {
> +		dev_dbg(&port->dev, "Line status status.\n");
> +		fn = ProcessLineStatus;
> +	} else {
> +		dev_dbg(&port->dev, "Modem status status.\n");
> +		fn = ProcessModemStatus;
> +	}
> +
> +	if (i > limit) {

Why can't we test whether i == (RxCount - 3) earlier and handle
the errors there?  That way we wouldn't need to pass the limit
variable.

In fact, this whole function is sort of nasty.  We start by doing
a switch (data[i + 2]) { then we combine the 0x00 and 0x01 and call
this function which separates them out and sets a function pointer
and then calls the function point?  Get rid of this whole function.

You shouldn't need to use function pointers to do this; that's too
many levels of abstraction.

> +		dev_dbg(&port->dev,
> +			"Illegal escape seuences in received data\n");
> +		return 0;
> +	}
> +
> +	(*fn)(qt_port, data[i + 3]);
> +
> +	return 1;
> +}
> +

[snip]

>  	if (urb->status) {
>  		qt_port->ReadBulkStopped = 1;
> -		dev_dbg(&urb->dev->dev, "%s - nonzero write bulk status received: %d\n",
> +		dev_dbg(&urb->dev->dev,
> +			"%s - nonzero write bulk status received: %d\n",
>  			__func__, urb->status);

Don't mix in these unrelated 80 character limit changes.

regards,
dan carpenter

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