From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933711AbdC3KlX (ORCPT ); Thu, 30 Mar 2017 06:41:23 -0400 Received: from foss.arm.com ([217.140.101.70]:44852 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933644AbdC3KlU (ORCPT ); Thu, 30 Mar 2017 06:41:20 -0400 Date: Thu, 30 Mar 2017 11:40:59 +0100 From: Mark Rutland To: Ingo Molnar Cc: Dmitry Vyukov , peterz@infradead.org, mingo@redhat.com, akpm@linux-foundation.org, will.deacon@arm.com, aryabinin@virtuozzo.com, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 4/8] asm-generic: add atomic-instrumented.h Message-ID: <20170330104058.GB16211@leverpostej> References: <20170329171526.GB26135@leverpostej> <20170330064339.GA20935@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170330064339.GA20935@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 30, 2017 at 08:43:39AM +0200, Ingo Molnar wrote: > > * Mark Rutland wrote: > > > With some minimal CPP, it can be a lot more manageable: > > > > ---- > > #define INSTR_ATOMIC_XCHG(order) \ > > static __always_inline int atomic_xchg##order(atomic_t *v, int i) \ > > { \ > > kasan_check_write(v, sizeof(*v)); \ > > arch_atomic_xchg##order(v, i); \ > > } > > > > #define INSTR_ATOMIC_XCHG() > > > > #ifdef arch_atomic_xchg_relaxed > > INSTR_ATOMIC_XCHG(_relaxed) > > #define atomic_xchg_relaxed atomic_xchg_relaxed > > #endif > > > > #ifdef arch_atomic_xchg_acquire > > INSTR_ATOMIC_XCHG(_acquire) > > #define atomic_xchg_acquire atomic_xchg_acquire > > #endif > > > > #ifdef arch_atomic_xchg_relaxed > > INSTR_ATOMIC_XCHG(_relaxed) > > #define atomic_xchg_relaxed atomic_xchg_relaxed > > #endif > > Yeah, small detail: the third one wants to be _release, right? Yes; my bad. > > Is there any objection to some light CPP usage as above for adding the > > {relaxed,acquire,release} variants? > > No objection from me to that way of writing it, this still looks very readable, > and probably more readable than the verbose variants. It's similar in style to > linux/atomic.h which has a good balance of C versus CPP. Great. I'll follow the above pattern when adding the ordering variants. > What I objected to was the deep nested code generation approach in the original > patch. > > CPP is fine in many circumstances, but there's a level of (ab-)use where it > becomes counterproductive. Sure, that makes sense to me. Thanks, Mark.