[PATCH 7/8] i2c: add 'transferred' field to struct i2c_msg

[Russell King - ARM Linux]

On Sat, Oct 27, 2012 at 04:32:24PM +0200, Jean Delvare wrote:
> On Thu, 25 Oct 2012 15:18:00 +0100, Russell King - ARM Linux wrote:
> > On Thu, Oct 25, 2012 at 03:56:33PM +0200, Jean Delvare wrote:
> > > The original idea of using the hole in the i2c_msg structure is from
> > > David Brownell, who was apparently familiar with such practice, so I
> > > assumed it was OK. Actually I still assume it is, until someone comes
> > > with an supported architecture where it is not.
> > 
> > According to Al Viro, that would be m68k.
> 
> OK... So to make things clear, let me ask Al directly about it. Al, can
> you please tell us if:
> 
> --- a/include/uapi/linux/i2c.h
> +++ b/include/uapi/linux/i2c.h
>  struct i2c_msg {
>  	__u16 addr;		/* slave address			*/
>  	__u16 flags;
>  	__u16 len;		/* msg length				*/
> +	__u16 transferred;	/* actual bytes transferred             */
>  	__u8 *buf;		/* pointer to msg data			*/
>  };
>  
> would break binary compatibility on m68k or any other architecture you
> are familiar with? Note that struct i2c_msg isn't declared with
> attribute packed, so my assumption was that pointer "buf" was align on
> at least 4 bytes, leaving a hole between len and buf. Am I wrong?

So, you're attitude here is "I don't believe you, you are lying".  Well,
if you have that level of distrust of your fellow developers, then you
don't deserve to be a Linux developer at all - and given that why should
I take any notice of you in the future over I2C stuff.

Especially as you've just proven that you don't know how to deal properly
with APIs...

Quite frankly I find your attitude towards me here totally disgusting and
insulting.

Not surprisingly, I didn't lie (I don't lie) and so I didn't "make up"
that M68k is one such architecture, and you've now had the confirmation
from Al.

So, I look forward to your apology for _implying_ that I'm a liar over
this issue, or if not, your resignation as I2C maintainer.

Thanks.