Date: Mon, 12 Dec 2005 10:50:56 +0530 From: rashmi ns <nsrashmi@gmail.com> To: freebsd-hackers@freebsd.org, freebsd-drivers@freebsd.org Subject: Re: Help Reqd: "uiomove" transferring zero bytes from user-kernel space Message-ID: <9f9993160512112120g42121d74pb9339971f0b89a61@mail.gmail.com> In-Reply-To: <9f9993160512112003i56f25cd6t78533717fec580d1@mail.gmail.com> References: <9f9993160512112003i56f25cd6t78533717fec580d1@mail.gmail.com>
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Sorry ,
uiomove does not written no of bytes copied from user_space
to kernel space or from kernel space to userspace .My understanding
was wrong .
uiomove returns 0 on success .
Regards,
Rashmi
On 12/12/05, rashmi ns <nsrashmi@gmail.com> wrote:
> Hello Team,
> when i use "uiomove" in the character device
> interface the no of bytes transfrerred between kernel and userspace is
> zero .but the actual data transferred when trraced through
> "uio->resid" is correct .can any one explain why this is happening ?
>
> /*Character Device Interfaces*/
> static struct cdevsw hdlc_cdevsw =3D {
>
> .d_maj =3D CDEV_MAJOR,
> .d_open =3D hdlc_open,
> .d_read =3D hdlc_read,
> .d_write =3D hdlc_write,
> .d_ioctl =3D hdlc_ioctl,
> .d_close =3D hdlc_close,
> .d_version =3D D_VERSION,
> };
> static int hdlc_write(dev_t dev, struct uio *uio, int ioflag)
> {
> int towrite,written; /*char device inf*/
> written=3Duiomove((void *)write_tx_buffer,towrite,uio);
> uprintf("uio->resid=3D%d",uio->uio_resid);
> uprintf("No of bytes written =3D%d",written);
>
>
>
>
> }
>
> Thanks and Regards,
> Rashmi.N.S
>
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