Re: [RFC][PATCH 5/5] arch: Sanitize atomic_t bitwise ops

[Linus Torvalds]

On Thu, Feb 6, 2014 at 5:48 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> Many archs have atomic_{set,clear}_mask() but not all. Remove these
> and provide a comprehensive set of bitops:
>
>   atomic{,64}_{and,or,xor}{,_return}()

Who uses these, and why?

The "_return()" versions of atomic ops are noticeably slower and more
complex on common architectures (ie x86), and apparently there is no
use of them since they didn't exist.

So why add them? Just to encourage people to do bad things?

                  Linus
--
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/