From mboxrd@z Thu Jan  1 00:00:00 1970
From: Johan Hovold <johan@kernel.org>
Subject: Re: [PATCH v3 2/3] i2c: add support for Diolan DLN-2 USB-I2C adapter
Date: Mon, 8 Sep 2014 18:30:58 +0200
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To: Octavian Purdila <octavian.purdila@intel.com>
Cc: Johan Hovold <johan@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Linus Walleij <linus.walleij@linaro.org>, Alexandre Courbot <gnurou@gmail.com>, wsa@the-dreams.de, Samuel Ortiz <sameo@linux.intel.com>, Lee Jones <lee.jones@linaro.org>, Arnd Bergmann <arnd@arndb.de>, Daniel Baluta <daniel.baluta@intel.com>, Laurentiu Palcu <laurentiu.palcu@intel.com>, linux-usb@vger.kernel.org, lkml <linux-kernel@vger.kernel.org>, linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org
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On Mon, Sep 08, 2014 at 06:57:29PM +0300, Octavian Purdila wrote:
> On Mon, Sep 8, 2014 at 5:44 PM, Johan Hovold <johan@kernel.org> wrote:
> 
> <snip>
> 
> Hi Johan,
> 
> Again, thanks for the detailed review, I am addressing your review
> comments as we speak. Some questions below.
> 
> <snip>
> 
> > > +     int ret, len;
> > > +     struct tx_data {
> > > +             u8 port;
> > > +             u8 addr;
> > > +             u8 mem_addr_len;
> > > +             __le32 mem_addr;
> > > +             __le16 buf_len;
> > > +             u8 buf[DLN2_I2C_MAX_XFER_SIZE];
> > > +     } __packed tx;
> >
> > Allocate these buffers dynamically (possibly at probe).
> >
> 
> I double checked this, and DLN2_I2C_MAX_XFER_SIZE should actually be <
> 64 as the USB endpoint configuration max packet size is 64. In this
> case, can we keep it on the stack?

It's better to lift that restriction and allocate it dynamically. Using
larger buffers (> EP size) is also more efficient.

> <snip>
> 
> > > +     int ret, buf_len, rx_len = sizeof(rx);
> >
> > Again, one declaration per line.
> 
> AFAICS there are many places where declaration on the same line
> (initialization included) are used. When did this became a coding
> style issue?

It's ugly, hurts readability, and can also obfuscate the fact that your
function really needs to be refactored.

And it's in the CodingStyle:

	"To this end, use just one data declaration per line (no commas
	for multiple data declarations)."

Johan