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Date:   Fri, 24 May 2019 12:39:34 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Andrea Parri <andrea.parri@amarulasolutions.com>
Cc:     linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jorgen Hansen <jhansen@vmware.com>,
        Will Deacon <will.deacon@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        "Paul E. McKenney" <paulmck@linux.ibm.com>
Subject: Re: [PATCH 1/2] vmw_vmci: Clean up uses of atomic*_set()
Message-ID: <20190524103934.GO2606@hirez.programming.kicks-ass.net>
References: <1558694136-19226-1-git-send-email-andrea.parri@amarulasolutions.com>
 <1558694136-19226-2-git-send-email-andrea.parri@amarulasolutions.com>
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On Fri, May 24, 2019 at 12:35:35PM +0200, Andrea Parri wrote:
> The primitive vmci_q_set_pointer() relies on atomic*_set() being of
> type 'void', but this is a non-portable implementation detail.
> 
> Reported-by: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Jorgen Hansen <jhansen@vmware.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: "Paul E. McKenney" <paulmck@linux.ibm.com>
> ---
>  include/linux/vmw_vmci_defs.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/vmw_vmci_defs.h b/include/linux/vmw_vmci_defs.h
> index 0c06178e4985b..eb593868e2e9e 100644
> --- a/include/linux/vmw_vmci_defs.h
> +++ b/include/linux/vmw_vmci_defs.h
> @@ -759,9 +759,9 @@ static inline void vmci_q_set_pointer(atomic64_t *var,
>  				      u64 new_val)
>  {
>  #if defined(CONFIG_X86_32)
> -	return atomic_set((atomic_t *)var, (u32)new_val);
> +	atomic_set((atomic_t *)var, (u32)new_val);
>  #else
> -	return atomic64_set(var, new_val);
> +	atomic64_set(var, new_val);
>  #endif
>  }

All that should just die a horrible death. That code is crap.

See:

  lkml.kernel.org/r/20190524103731.GN2606@hirez.programming.kicks-ass.net