Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964791AbcDFJ1S (ORCPT ); Wed, 6 Apr 2016 05:27:18 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:60815 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754788AbcDFJ1N (ORCPT ); Wed, 6 Apr 2016 05:27:13 -0400 Date: Wed, 6 Apr 2016 11:26:55 +0200 From: Peter Zijlstra To: Michal Hocko Cc: LKML , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , "David S. Miller" , Tony Luck , Andrew Morton , Chris Zankel , Max Filippov , x86@kernel.org, linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org, Michal Hocko , ysato@users.sourceforge.jp, dalias@libc.org Subject: Re: [PATCH 2/2] sh, rwsem: drop superfluous arch specific implementation Message-ID: <20160406092655.GP3448@twins.programming.kicks-ass.net> References: <20160404090335.GB10272@dhcp22.suse.cz> <1459760800-13477-1-git-send-email-mhocko@kernel.org> <1459760800-13477-2-git-send-email-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1459760800-13477-2-git-send-email-mhocko@kernel.org> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4499 Lines: 170 +Cc maintainers, linux-sh list is very high signal-to-noise as its been appropriated for renesas arm parts. On Mon, Apr 04, 2016 at 11:06:40AM +0200, Michal Hocko wrote: > From: Michal Hocko > > since "locking, rwsem: drop explicit memory barriers" the arch specific > code is basically same as the the generic one so we can drop the > superfluous code. > > Suggested-by: Davidlohr Bueso > Signed-off-by: Michal Hocko > --- > arch/sh/include/asm/Kbuild | 1 + > arch/sh/include/asm/rwsem.h | 130 -------------------------------------------- > 2 files changed, 1 insertion(+), 130 deletions(-) > delete mode 100644 arch/sh/include/asm/rwsem.h > > diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild > index aac452b26aa8..6d866c7a9b74 100644 > --- a/arch/sh/include/asm/Kbuild > +++ b/arch/sh/include/asm/Kbuild > @@ -25,6 +25,7 @@ generic-y += percpu.h > generic-y += poll.h > generic-y += preempt.h > generic-y += resource.h > +generic-y += rwsem.h > generic-y += sembuf.h > generic-y += serial.h > generic-y += shmbuf.h > diff --git a/arch/sh/include/asm/rwsem.h b/arch/sh/include/asm/rwsem.h > deleted file mode 100644 > index 8a457b83d2a5..000000000000 > --- a/arch/sh/include/asm/rwsem.h > +++ /dev/null > @@ -1,130 +0,0 @@ > -/* > - * include/asm-sh/rwsem.h: R/W semaphores for SH using the stuff > - * in lib/rwsem.c. > - */ > - > -#ifndef _ASM_SH_RWSEM_H > -#define _ASM_SH_RWSEM_H > - > -#ifndef _LINUX_RWSEM_H > -#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead" > -#endif > - > -#ifdef __KERNEL__ > - > -#define RWSEM_UNLOCKED_VALUE 0x00000000 > -#define RWSEM_ACTIVE_BIAS 0x00000001 > -#define RWSEM_ACTIVE_MASK 0x0000ffff > -#define RWSEM_WAITING_BIAS (-0x00010000) > -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS > -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) > - > -/* > - * lock for reading > - */ > -static inline void __down_read(struct rw_semaphore *sem) > -{ > - if (atomic_inc_return((atomic_t *)(&sem->count)) <= 0) > - rwsem_down_read_failed(sem); > -} > - > -static inline int __down_read_trylock(struct rw_semaphore *sem) > -{ > - int tmp; > - > - while ((tmp = sem->count) >= 0) { > - if (tmp == cmpxchg(&sem->count, tmp, > - tmp + RWSEM_ACTIVE_READ_BIAS)) { > - return 1; > - } > - } > - return 0; > -} > - > -/* > - * lock for writing > - */ > -static inline void __down_write(struct rw_semaphore *sem) > -{ > - int tmp; > - > - tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS, > - (atomic_t *)(&sem->count)); > - if (tmp != RWSEM_ACTIVE_WRITE_BIAS) > - rwsem_down_write_failed(sem); > -} > - > -static inline int __down_write_killable(struct rw_semaphore *sem) > -{ > - int tmp; > - > - tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS, > - (atomic_t *)(&sem->count)); > - if (tmp != RWSEM_ACTIVE_WRITE_BIAS) > - if (IS_ERR(rwsem_down_write_failed_killable(sem))) > - return -EINTR; > - > - return 0; > -} > - > -static inline int __down_write_trylock(struct rw_semaphore *sem) > -{ > - int tmp; > - > - tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE, > - RWSEM_ACTIVE_WRITE_BIAS); > - return tmp == RWSEM_UNLOCKED_VALUE; > -} > - > -/* > - * unlock after reading > - */ > -static inline void __up_read(struct rw_semaphore *sem) > -{ > - int tmp; > - > - tmp = atomic_dec_return((atomic_t *)(&sem->count)); > - if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0) > - rwsem_wake(sem); > -} > - > -/* > - * unlock after writing > - */ > -static inline void __up_write(struct rw_semaphore *sem) > -{ > - if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS, > - (atomic_t *)(&sem->count)) < 0) > - rwsem_wake(sem); > -} > - > -/* > - * implement atomic add functionality > - */ > -static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem) > -{ > - atomic_add(delta, (atomic_t *)(&sem->count)); > -} > - > -/* > - * downgrade write lock to read lock > - */ > -static inline void __downgrade_write(struct rw_semaphore *sem) > -{ > - int tmp; > - > - tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count)); > - if (tmp < 0) > - rwsem_downgrade_wake(sem); > -} > - > -/* > - * implement exchange and add functionality > - */ > -static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem) > -{ > - return atomic_add_return(delta, (atomic_t *)(&sem->count)); > -} > - > -#endif /* __KERNEL__ */ > -#endif /* _ASM_SH_RWSEM_H */ > -- > 2.8.0.rc3 >