Pete,
Many thanks for your comment/concern. I borrowed an TIOCGICOUNT implementation from usb/serial/io_ti.c:
case TIOCGICOUNT:
dbg("%s - (%d) TIOCGICOUNT RX=%d, TX=%d", __func__,
port->number, edge_port->icount.rx, edge_port->icount.tx);
if (copy_to_user((void __user *)arg, &edge_port->icount,
sizeof(edge_port->icount)))
return -EFAULT;
return 0;
}
There are 2 similar TIOCGICOUNT implementations listed in
ark3116.c
io_edgeport.c
io_ti.c
mos7720.c
mos7840.c
ti_usb_3410_5052.c
files under usb/serial/ directory. One based on io_ti.c and another based on io_edgeport.c. I borrowed one from io_ti.c, since it looked more effecient to me. I searched for any mention of get_icount function under linux-2.6.35 and didn't find any file which declared or called this function:
[vtsozik@SR71 linux-2.6.35]$ find . -type f -name '*.[c,h]' | xargs grep get_icount
[vtsozik@SR71 linux-2.6.35]$
I'm wondering if you could give me a bit more information on this. Otherwise I would really prefer to proceed with something that already exists and tested. If by some reason you believe that alternative implementation from io_edgeport.c (please see code snippet below) should be used please let me know. Again I didn't see any reason for extra copy.
case TIOCGICOUNT:
cnow = edge_port->icount;
memset(&icount, 0, sizeof(icount));
icount.cts = cnow.cts;
icount.dsr = cnow.dsr;
icount.rng = cnow.rng;
icount.dcd = cnow.dcd;
icount.rx = cnow.rx;
icount.tx = cnow.tx;
icount.frame = cnow.frame;
icount.overrun = cnow.overrun;
icount.parity = cnow.parity;
icount.brk = cnow.brk;
icount.buf_overrun = cnow.buf_overrun;
dbg("%s (%d) TIOCGICOUNT RX=%d, TX=%d",
__func__, port->number, icount.rx, icount.tx);
if (copy_to_user((void __user *)arg, &icount, sizeof(icount)))
return -EFAULT;
return 0;
}
Thank you in advance,
Vadim.
--- On Sun, 12/26/10, Pete Zaitcev <zaitcev@xxxxxxxxxx> wrote:
> From: Pete Zaitcev <zaitcev@xxxxxxxxxx>
> Subject: Re: [PATCH 1/1] mct_u232: IOCTL implementation
> To: "Tsozik" <tsozik@xxxxxxxxx>
> Cc: "Greg Kroah-Hartman" <gregkh@xxxxxxx>, linux-usb@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx
> Date: Sunday, December 26, 2010, 12:49 PM
> On Sat, 25 Dec 2010 21:39:39 -0800
> (PST)
> Tsozik <tsozik@xxxxxxxxx>
> wrote:
>
> > +++ mct_u232.c 2010-12-25 21:44:57.714640343
> -0500
> > +static int mct_u232_ioctl(struct tty_struct
> *tty, struct file *file,
> > +
> unsigned int cmd,
> unsigned long arg)
> > +{
> > + case TIOCGICOUNT:
> > +
> dbg("%s - (%d) TIOCGICOUNT RX=%d, TX=%d", __func__,
> > +
> port->number,
> mct_u232_port->icount.rx, mct_u232_port->icount.tx);
> > +
> if (copy_to_user((void __user *)arg,
> &mct_u232_port->icount,
> > +
> sizeof(mct_u232_port->icount)))
> > +
> return -EFAULT;
>
> This looks suspicious. Didn't we relocate the machinery for
> TIOCGICOUNT
> into a generic place? Please examine how ->get_icount
> works before
> hand-rolling the ioctl.
>
> -- Pete
>
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