From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265477AbUHYJw5 (ORCPT ); Wed, 25 Aug 2004 05:52:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265196AbUHYJw5 (ORCPT ); Wed, 25 Aug 2004 05:52:57 -0400 Received: from TYO206.gate.nec.co.jp ([202.32.8.206]:27366 "EHLO tyo206.gate.nec.co.jp") by vger.kernel.org with ESMTP id S265477AbUHYJv7 (ORCPT ); Wed, 25 Aug 2004 05:51:59 -0400 Message-ID: <025001c48a89$2bbd37b0$f97d220a@linux.bs1.fc.nec.co.jp> From: "Kaigai Kohei" To: "James Morris" Cc: "Stephen Smalley" , "SELinux-ML(Eng)" , "Linux Kernel ML(Eng)" References: Subject: [PATCH]atomic_inc_return() for i386/x86_64 (Re: RCU issue with SELinux) Date: Wed, 25 Aug 2004 18:52:02 +0900 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_NextPart_000_024D_01C48AD4.9B98AAB0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. ------=_NextPart_000_024D_01C48AD4.9B98AAB0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit Hi James, thanks for your comment. > > In IA-32 or x86_64, can anybady implement atomic_inc_return()? > > If it can not, I'll try to make alternative macros or inline functions. > > If you can get this done, it will be very useful, as I could allso run > some benchmarks on my test systems. atomic_inc_return() is not defined for arm,arm26,i386,x86_64 and um archtectures. This attached patch adds atomic_inc_return() and atomic_dec_return() to arm,i386 and x86_64. It is implemented by 'xaddl' operation with LOCK prefix for i386 and x86_64. But this operation is permitted after i486 processor only. Another implementation may be necessary for i386SX/DX processor. But 'xaddl' operation is used in 'include/asm-i386/rwsem.h' unconditionally. I think it has agreed on using 'xaddl' operation in past days. Is it acceptable? Any comment please. (*) The implementation for ARM is simple wrapper to atomic_add_return(). -------- Kai Gai ------=_NextPart_000_024D_01C48AD4.9B98AAB0 Content-Type: application/octet-stream; name="atomic_inc_return-2.6.8.1.patch" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="atomic_inc_return-2.6.8.1.patch" --- linux-2.6.8.1/include/asm-arm/atomic.h 2004-08-14 19:54:50.000000000 = +0900=0A= +++ linux-2.6.8.1.rcu/include/asm-arm/atomic.h 2004-08-24 = 19:31:56.000000000 +0900=0A= @@ -194,8 +194,10 @@=0A= #define atomic_dec(v) atomic_sub(1, v)=0A= =0A= #define atomic_inc_and_test(v) (atomic_add_return(1, v) =3D=3D 0)=0A= #define atomic_dec_and_test(v) (atomic_sub_return(1, v) =3D=3D 0)=0A= +#define atomic_inc_return(v) (atomic_add_return(1, v))=0A= +#define atomic_dec_return(v) (atomic_sub_return(1, v))=0A= =0A= #define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0)=0A= =0A= /* Atomic operations are already serializing on ARM */=0A= --- linux-2.6.8.1/include/asm-i386/atomic.h 2004-08-14 = 19:55:09.000000000 +0900=0A= +++ linux-2.6.8.1.rcu/include/asm-i386/atomic.h 2004-08-25 = 11:57:08.000000000 +0900=0A= @@ -175,8 +175,34 @@=0A= :"ir" (i), "m" (v->counter) : "memory");=0A= return c;=0A= }=0A= =0A= +/**=0A= + * atomic_add_return - add and return=0A= + * @v: pointer of type atomic_t=0A= + * @i: integer value to add=0A= + *=0A= + * Atomically adds @i to @v and returns @i + @v=0A= + */=0A= +static __inline__ int atomic_add_return(int i, atomic_t *v)=0A= +{=0A= + /* NOTICE: This function can be used on i486+ */=0A= + int __i =3D i;=0A= + __asm__ __volatile__(=0A= + LOCK "xaddl %0, %1;"=0A= + :"=3Dr"(i)=0A= + :"m"(v->counter), "0"(i));=0A= + return i + __i;=0A= +}=0A= +=0A= +static __inline__ int atomic_sub_return(int i, atomic_t *v)=0A= +{=0A= + return atomic_add_return(-i,v);=0A= +}=0A= +=0A= +#define atomic_inc_return(v) (atomic_add_return(1,v))=0A= +#define atomic_dec_return(v) (atomic_sub_return(1,v))=0A= +=0A= /* These are x86-specific, used by some header files */=0A= #define atomic_clear_mask(mask, addr) \=0A= __asm__ __volatile__(LOCK "andl %0,%1" \=0A= : : "r" (~(mask)),"m" (*addr) : "memory")=0A= --- linux-2.6.8.1/include/asm-x86_64/atomic.h 2004-08-14 = 19:56:23.000000000 +0900=0A= +++ linux-2.6.8.1.rcu/include/asm-x86_64/atomic.h 2004-08-25 = 11:57:36.000000000 +0900=0A= @@ -177,8 +177,33 @@=0A= :"ir" (i), "m" (v->counter) : "memory");=0A= return c;=0A= }=0A= =0A= +/**=0A= + * atomic_add_return - add and return=0A= + * @v: pointer of type atomic_t=0A= + * @i: integer value to add=0A= + *=0A= + * Atomically adds @i to @v and returns @i + @v=0A= + */=0A= +static __inline__ int atomic_add_return(int i, atomic_t *v)=0A= +{=0A= + int __i =3D i;=0A= + __asm__ __volatile__(=0A= + LOCK "xaddl %0, %1;"=0A= + :"=3Dr"(i)=0A= + :"m"(v->counter), "0"(i));=0A= + return i + __i;=0A= +}=0A= +=0A= +static __inline__ int atomic_sub_return(int i, atomic_t *v)=0A= +{=0A= + return atomic_add_return(-i,v);=0A= +}=0A= +=0A= +#define atomic_inc_return(v) (atomic_add_return(1,v))=0A= +#define atomic_dec_return(v) (atomic_sub_return(1,v))=0A= +=0A= /* These are x86-specific, used by some header files */=0A= #define atomic_clear_mask(mask, addr) \=0A= __asm__ __volatile__(LOCK "andl %0,%1" \=0A= : : "r" (~(mask)),"m" (*addr) : "memory")=0A= ------=_NextPart_000_024D_01C48AD4.9B98AAB0--