Re: [RFC 01/32] fs: introduce new 'struct inode_time'

Andreas Schwab
2014-05-31T08:39:12Z

Geert Uytterhoeven <geert@linux-m68k.org> writes:

> Hi Arnd,
>
> On Fri, May 30, 2014 at 10:01 PM, Arnd Bergmann <arnd@arndb.de> wrote:
>> + * The variant using bit fields is less efficient to access, but
>> + * small and has a wider range as the 32-bit one, plus it keeps
>> + * the signedness of the original timespec.
>> + */
>> +struct inode_time {
>> + long long tv_sec : 34;
>> + int tv_nsec : 30;
>> +};
>
> Don't you need 31 bits for tv_nsec, to accommodate for the sign bit?
> I know you won't really store negative numbers there, but storing a large
> positive number will become negative on read out, won't it?

Only if the int bitfield is signed. Bitfields are weird, aren't they? :-)

Andreas.

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Andreas Schwab, schwab@linux-m68k.org
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