On 2/22/06, Karsten Keil <[email protected]> wrote:
> On Tue, Feb 21, 2006 at 11:14:15PM +0100, Jesper Juhl wrote:
> > From: Jesper Juhl <[email protected]>
> >
> >
> > Fix compile warning about copy_to_user() unused result in isdn_ppp.c
> > drivers/isdn/i4l/isdn_ppp.c:785: warning: ignoring return value of `copy_to_user', declared with attribute warn_unused_result
> >
> >
> > Signed-off-by: Jesper Juhl <[email protected]>
> >
> > ---
> >
> > drivers/isdn/i4l/isdn_ppp.c | 5 ++++-
> > 1 files changed, 4 insertions(+), 1 deletion(-)
> >
> > --- linux-2.6.16-rc4-mm1-orig/drivers/isdn/i4l/isdn_ppp.c 2006-01-03 04:21:10.000000000 +0100
> > +++ linux-2.6.16-rc4-mm1/drivers/isdn/i4l/isdn_ppp.c 2006-02-21 23:07:57.000000000 +0100
> > @@ -782,7 +782,10 @@ isdn_ppp_read(int min, struct file *file
> > is->first = b;
> >
> > spin_unlock_irqrestore(&is->buflock, flags);
> > - copy_to_user(buf, save_buf, count);
> > + if (copy_to_user(buf, save_buf, count)) {
> > + kfree(save_buf);
> > + return -EFAULT;
> > + }
> > kfree(save_buf);
> >
> > return count;
>
> What about:
>
> --- linux-2.6.16-rc4-mm1-orig/drivers/isdn/i4l/isdn_ppp.c 2006-01-03 04:21:10.000000000 +0100
> +++ linux-2.6.16-rc4-mm1/drivers/isdn/i4l/isdn_ppp.c 2006-02-21 23:07:57.000000000 +0100
> @@ -782,7 +782,8 @@ isdn_ppp_read(int min, struct file *file
> is->first = b;
>
> spin_unlock_irqrestore(&is->buflock, flags);
> - copy_to_user(buf, save_buf, count);
> + if (copy_to_user(buf, save_buf, count))
> + count = -EFAULT;
> kfree(save_buf);
>
> return count;
>
> should result in a conditional move instead of jumps.
>
I actually considered that, but decided against it since I thought it
would be confusing use / misuse of 'count'.
Either version is fine by me. It's not likely to get hit in any case
due to the verify_area() call further up in the code.
> But I'm OK with the original patch as well, for both version you can add
>
> Signed-off-by: Karsten Keil <[email protected]>
>
Thanks.
Andrew: could you please apply either my or Karsten's version to -mm ?
--
Jesper Juhl <[email protected]>
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