Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752571AbYKSHmZ (ORCPT ); Wed, 19 Nov 2008 02:42:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751863AbYKSHmQ (ORCPT ); Wed, 19 Nov 2008 02:42:16 -0500 Received: from an-out-0708.google.com ([209.85.132.246]:43345 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751751AbYKSHmP (ORCPT ); Wed, 19 Nov 2008 02:42:15 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references:x-google-sender-auth; b=rFNjjzwedDfn64IC/rhoOW9MZQjTzw2vbuqkrVbie7EzfhlF00lg70biEiW9WXQOja kCnQjJbA6o1DQ/9bLgpcY+xIc11JLp/KkLpL+vj+vlI/9PcUtpcKU0k+pdHw1qb6s65I JNWvVM2u1aK4yIcIRTQjVmCTdqalu7C//3+9E= Message-ID: <386072610811182342i701497bcne37e6ab0dbefbc5f@mail.gmail.com> Date: Wed, 19 Nov 2008 15:42:14 +0800 From: "Bryan Wu" To: "Andrew Morton" Subject: Re: [PATCH 2/5] Blackfin arch: SMP supporting patchset: Blackfin header files and machine common code Cc: torvalds@linux-foundation.org, mingo@elte.hu, linux-kernel@vger.kernel.org, "Graf Yang" In-Reply-To: <20081118225629.eddd23ae.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1226999108-13839-1-git-send-email-cooloney@kernel.org> <1226999108-13839-3-git-send-email-cooloney@kernel.org> <20081118225629.eddd23ae.akpm@linux-foundation.org> X-Google-Sender-Auth: 33691dd427306bff Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3122 Lines: 109 On Wed, Nov 19, 2008 at 2:56 PM, Andrew Morton wrote: > On Tue, 18 Nov 2008 17:05:05 +0800 Bryan Wu wrote: > >> From: Graf Yang >> >> Blackfin dual core BF561 processor can support SMP like features. >> https://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:smp-like >> >> In this patch, we provide SMP extend to Blackfin header files >> and machine common code >> >> >> ... >> >> +#define atomic_add_unless(v, a, u) \ >> +({ \ >> + int c, old; \ >> + c = atomic_read(v); \ >> + while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \ >> + c = old; \ >> + c != (u); \ >> +}) > > The macro references its args multiple times and will do weird or > inefficient things when called with expressions which have > side-effects, or which do slow things. > Right, I think we can replace them to inline functions >> >> ... >> >> +#include /* save_flags */ >> + >> +static inline void set_bit(int nr, volatile unsigned long *addr) >> { >> int *a = (int *)addr; >> int mask; >> @@ -57,21 +91,23 @@ static __inline__ void clear_bit(int nr, volatile unsigned long *addr) >> a += nr >> 5; >> mask = 1 << (nr & 0x1f); >> local_irq_save(flags); >> - *a &= ~mask; >> + *a |= mask; > > I think you just broke clear_bit(). Maybe I'm misreading the diff. > >> local_irq_restore(flags); >> } >> >> >> ... >> >> +#define smp_mb__before_clear_bit() barrier() >> +#define smp_mb__after_clear_bit() barrier() >> + >> +static inline void __set_bit(int nr, volatile unsigned long *addr) >> +{ >> + int *a = (int *)addr; >> + int mask; >> + >> + a += nr >> 5; >> + mask = 1 << (nr & 0x1f); >> + *a |= mask; >> +} >> + >> +static inline void __clear_bit(int nr, volatile unsigned long *addr) >> +{ >> + int *a = (int *)addr; >> + int mask; >> + >> + a += nr >> 5; >> + mask = 1 << (nr & 0x1f); >> + *a &= ~mask; >> +} >> + >> +static inline void __change_bit(int nr, volatile unsigned long *addr) >> +{ >> + int mask; >> + unsigned long *ADDR = (unsigned long *)addr; >> + >> + ADDR += nr >> 5; >> + mask = 1 << (nr & 31); >> + *ADDR ^= mask; >> +} > > I'm surprised there isn't any generic code which can be used for the above. > As Nick said, include/asm-generic/bitops/non-atomic.h is the generic code. We will try it. >> >> ... >> > > Gad what a lot of code. I don't think I have time to read it all, sorry. > Thanks a lot for the review, I will forward this patchset to linux-arch. -Bryan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/