lkml.org 
[lkml]   [2018]   [Oct]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/2] sysctl: add overflow detection to proc_get_long()
On Sun, Oct 14, 2018 at 08:53:46PM +0200, Christian Brauner wrote:

> > Yecchh... First of all, the cast back to unsigned long long is completely
> > pointless. What's more,
>
> Sorry, seriously asking: why? This was meant to handle the case where
> sizeof(unsigned long long) != sizeof(unsigned long) and I just looked at
> _kstrtoul() which does the same:
>
> int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
> {
> unsigned long long tmp;
> int rv;
>
> rv = kstrtoull(s, base, &tmp);
> if (rv < 0)
> return rv;
> if (tmp != (unsigned long long)(unsigned long)tmp)
> return -ERANGE;
> *res = tmp;
> return 0;
> }
>
> Sorry, if I'm being dense here.

C quiz:
given that type of e1 is unsigned long long and type of e2 -
unsigned long, what conversions are going to happen in e1 == e2?

[relevant part of C standard: 6.5.9 (Equality operators),
6.3.1.8 (Usual arithmetic conversions)]

\
 
 \ /
  Last update: 2018-10-15 02:04    [W:0.058 / U:3.804 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site