[PATCH 2/3] nptl: Move cancel state out of cancelhandling

[Florian Weimer]

* Adhemerval Zanella via Libc-alpha:

> diff --git a/nptl/pthread_setcancelstate.c b/nptl/pthread_setcancelstate.c
> index 4d7f413e19..aa1c8073a8 100644
> --- a/nptl/pthread_setcancelstate.c
> +++ b/nptl/pthread_setcancelstate.c
> @@ -31,39 +31,9 @@ __pthread_setcancelstate (int state, int *oldstate)
>  
>    self = THREAD_SELF;
>  
> -  int oldval = THREAD_GETMEM (self, cancelhandling);
> -  while (1)
> -    {
> -      int newval = (state == PTHREAD_CANCEL_DISABLE
> -		    ? oldval | CANCELSTATE_BITMASK
> -		    : oldval & ~CANCELSTATE_BITMASK);
> -
> -      /* Store the old value.  */
> -      if (oldstate != NULL)
> -	*oldstate = ((oldval & CANCELSTATE_BITMASK)
> -		     ? PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
> -
> -      /* Avoid doing unnecessary work.  The atomic operation can
> -	 potentially be expensive if the memory has to be locked and
> -	 remote cache lines have to be invalidated.  */
> -      if (oldval == newval)
> -	break;
> -
> -      /* Update the cancel handling word.  This has to be done
> -	 atomically since other bits could be modified as well.  */
> -      int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
> -					      oldval);
> -      if (__glibc_likely (curval == oldval))
> -	{
> -	  if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
> -	    __do_cancel ();
> -
> -	  break;
> -	}
> -
> -      /* Prepare for the next round.  */
> -      oldval = curval;
> -    }
> +  if (oldstate != NULL)
> +    *oldstate = self->cancelstate;
> +  self->cancelstate = state;
>  
>    return 0;
>  }

Why isn't this needed anymore?  I think this should be mentioned
explicitly in the commit message.