Re: [PATCH] kexec jump: fix compiling warning on xchg(&kexec_lock, 0) in kernel_kexec()

Linus Torvalds
2008-08-13T17:02:51Z

On Wed, 13 Aug 2008, Andrew Morton wrote:
>
> We don't need to create that local. I queued this:

No, please don't.

Just don't take this whole patch-series until it's cleaned up. There is
absolutely no excuse for using xchg as a locking primitive. Nothing like
this should be queued anywhere, it should be burned and the ashes should
be scattered over the atlantic so that nobody will ever see them again.

F*ck me with a spoon, if you have to use xchg() to do a trylock, why the
hell isn't the unlock sequence then

smp_mb();
var = 0;

instead? Not that that's really right either, but at least it avoids the
_ridiculous_ crap. The real solution is probably to use a spinlock and
trylock/unlock.

Linus