Re: [PATCH] poll(2) timeout values

[Alan Cox]

On Iau, 2005-11-10 at 16:49 -0800, Ulrich Drepper wrote:
> On 11/10/05, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
> > No. The poll POSIX libc call takes an int. What the kernel ones does
> > with the top bits is irrelevant to applications.
> 
> The issue is that if the high bits are not handled special then
> somebody might cause problems.  E.g., overflowing the division or so. 
> Therefore the kernel has to sanitize the argument and then why not use
> the easiest way to do this?

Why does the kernel have to sanitize the input. Last time I checked
undefined inputs gave undefined outputs in the standards. fopen(NULL,
NULL) seems to crash glibc for example.

The kernel has to behave correctly given valid sensible inputs. Masking
the top bits is not behaving correctly

	"sleep ages"
	"no I'll sleep a short time"

Surely it would be far better to do

	if((timeout >> 31) >> 1) 
		return -EINVAL;

for 64bit systems

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/