Re: [PATCH] Printer Gadget Driver v0.2.0 (kernel 2.6.21.3)

On Saturday 10 November 2007, Craig W. Nadler wrote:
> +       /* we've already been disconnected ... no i/o is active */
> +       /* Free all memory for this driver. */
> +       if (likely(!list_empty(&dev->tx_reqs_active)))
> +               ERROR(dev, "Driver still has active transfer left.\n");
> +

That would be "if (unlikely(...))" ... although branch hinting
in cold paths is probably best avoided.

I'll repost a slightly tweaked version of this patch; those would
be best as WARN_ON() calls.


> I changed the IOCTL code to 'G', the same as the gadgetfs, and offset

Actually gadgetfs uses 'g' (lowercase).  Mr. Grep tells me that
uppercase G is used by include/asm-parisc/grfioctl.h ...


> the ioctl call number by 0x10.
>
> #define GADGET_GET_PRINTER_STATUS      _IOR('G', 0x10, unsigned char)
> #define GADGET_SET_PRINTER_STATUS      _IOWR('G', 0x11, unsigned char)
>
> Is that an acceptable approach?

I don't think I'll object too much.  But I will make sure
the gadgetfs header has a corresponding note, and enlarge
that offset to avoid future problems.  (All that's really
important is that the ioctl codes be unique.)

A minor warning:  ENOIOCTLCMD is not the right code to
use for "wrong device type".  That's ENOTTY ... stupid,
but the standard for like ever.

- Dave


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